Commercial_Poultry_Nutrition

94 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION levels of NSP’s commonly found in cereals enzymes, while those designed to improve and soybean meal. Oligosaccharides as found wheat digestibility should contain cellulase in soybean meal are perhaps the most complex and arabinoxylanase enzymes. structures within the NSP’s and to date have proven difficult to digest with exogenous enzymes. There is potential for adding lipase enzymes Depending upon variety, growing conditions to feeds or fats, to improve digestibility. and oil extraction procedures, soybeans will Improvement in digestion of saturated fats for young contain 4 – 7% of oligosaccharides mainly as birds seems to have the greatest potential. raffinose and stachyose. Because of the absence Although there are no lipase enzymes currently of -galactosidase in chickens, these oligosac- designed for use in animal feeds, preliminary charides remain undigested, and again contribute studies with enzymes obtained from other to increased digesta viscosity, especially in young industries suggest that a 7 – 10% improvement birds. Soybean oligosaccharides can be is possible, with a corresponding increase in diet extracted using ethanol. Such treatment of soy- AME. Since the young chick does not efficiently beans is not commercially viable at this time, re-cycle its bile salts, there have also been although the residual meal has an AMEn value indications that fat digestion can be improved approaching 3,000 kcal/kg, and the meal seems by adding synthetic bile salts to the feed. Again, an interesting ingredient for very young birds. Since these are not commercially available, but it the oligosaccharides are removed by ethanol, then does suggest some potential for the development there is a corresponding loss of dry matter in the of emulsifying agents or detergents. residual soybean meal. The most widely used feed enzyme is phy- Addition of feed enzymes could therefore tase. Phytase cleaves the phytic acid in soybean improve NSP availability, and just as important, meal and cereals, to release phosphorus and reduce the negative impact that these undi- calcium. Phytic acid is a complex structure gested residues have on digesta viscosity. Normal that tightly binds phosphorus, and is the main digestion requires unimpeded movement of storage source of phosphorus in plant material enzyme, substrate and digestion products (Fig. 2.1). Few animals possess the phytase throughout the digesta and especially close to enzyme necessary to cleave the molecule and the absorptive gut wall. As the viscosity of the so phytic acid is largely undigested. Interest in digesta increases, the rate of diffusion decreas- the phytase enzyme arose because phosphorus es, and this causes reduced digestibility of all has become an expensive nutrient, as well as the substrates. The undigested viscous digesta fact that undigested phytic acid adds greatly to subsequently translates to very sticky excreta which manure loading of phosphorus. Phytate also binds causes problems of litter management. Reduction other trace minerals and may conjugate with in digesta viscosity is therefore highly correlated proteins and carbohydrates. Digestion of the with efficacy of enzymes that can digest substrates molecule therefore can potentially release trace such as ß-glucans. In oats and barley the bulk minerals, amino acids and energy, as well as of the NSP’s are ß-glucans, whereas in wheat and calcium and phosphorus. rye, arabinoxylans predominate. Enzymes tailored for barley therefore contain ß-glucanase Phytase enzymes are commonly found in plant materials, and especially for wheat and wheat SECTION 2.3 Feed additives

CHAPTER 2 95 INGREDIENT EVALUATION AND DIET FORMULATION Figure 2.1 Phytic acid by-products the values are quite high. Corn, for phosphorus and calcium. Each 500 units of example, contains just 15 FTU/kg while wheat phytase activity are equivalent to about 1 g of shorts can contain as much as 10,000 FTU/kg. phosphorus as provided by sources such as However, such endogenous phytase may have di-calcium phosphate. Using 500 FTU of only limited usefulness in the digestive tract, since phytase/kg feed therefore provides the equiva- most plant phytases are effective only at around lent of 0.1% P. pH 5, whereas exogenous phytases, usually of microbial origin, seem efficacious from pH 3 to Phytase also liberates some trace minerals and 7. There are variable results reported for efficacy so theoretically, supplemental levels can be of phytase in commercial diets. It has been reduced. As described previously for calcium, suggested that diet calcium level is perhaps the there is an indication that phytase is more effec- major factor in such variance, since high levels tive when moderate, rather than high, levels of of calcium seem to reduce the effectiveness of supplemental zinc are used. The release of phytase enzyme. However, if this concept is true, energy and amino acids by phytase is a more then one wonders why phytase enzymes seem contentious issue. Some research suggests up to so efficacious in layer diets that contain from 4 2% improvement in AMEn and digestible amino – 4.5% calcium. If phytase is used in formulation, acids, although more conservative estimates there are a number of different approaches to are for 15 kcal ME/kg release of energy, with no account for increased phytate availability. Where increase in amino acid availability. Some few ingredients are used, the available phosphorus commercial sources of phytase are sensitive to level of these ingredients can be increased heat, and pelleting at 85 – 90ºC can cause accordingly. Alternatively, the specification for significant loss in phytase. In pelleted feeds, these available phosphorus in the diet can be reduced sources of phytase are most appropriately used or phytase enzyme can be included as an as post-pelleting additives. Other sources of ingredient with specifications for available phytase seem more heat stable, and can be added to the mix prior to pelleting. SECTION 2.3 Feed additives

96 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION h. Pigments also apply to preservation of pigments. Coccidiosis, malabsorption and certain mycotoxins will all The yellow to orange color in avian fatty reduce pigment absorption. Pigmentation in the tissue is caused by various carotenoid pigments. young meat bird is directly proportional to These pigments control the color of the egg pigments fed throughout growth. For the laying yolk, as well as the shanks and beaks of layers, hen however, yolk color is a consequence of and also the skin color that may be important in pigments consumed in the layer feed, and also meat birds. The xanthophylls are the most the transfer of pigments accumulated in the important carotenoids in poultry nutrition, and skin and shanks when the bird was immature. natural ingredients rich in these compounds This transfer of pigments to the ovary occurs are alfalfa meal, corn gluten meal and marigold regardless of diet pigments, and is responsible petal (Table 2.23). for the ‘bleaching’ effect of the shanks and beak of yellow-skinned birds over time. Table 2.23 Xanthophyll content of selected ingredients (mg/kg) Because many of the naturally carotenoid- rich ingredients are low in energy, it is difficult Ingredient Xanthophyll to achieve high levels of pigmentation of meat Corn 20 birds without using various synthetic sources. Wheat 4 Canthaxanthin, astaxanthin and ß-apo-8- Milo 1 carotenoic acid (where allowable in poultry Alfalfa meal 175 diets) can be used to impart the spectrum from Corn gluten meal 275 yellow to orange/red coloration in either skin or Marigold petal egg yolk. As described more fully in Chapter 4, 7,000 there is now interest in enriching eggs with lutein, since this carotenoid is known to be Corn contains much more xanthophylls than important in maintenance of eye health in do other cereals, although high levels of pig- humans. Future designer eggs may well contain mentation can only be achieved from natural concentrated levels of lutein. ingredients by including other products such as alfalfa and corn gluten meal. i. Flavoring agents The various xanthophylls differ in their effect The chicken is not usually considered to on skin and yolk pigmentation. ß-carotene has have the ability to select feed based on flavor, or little pigmenting value, although pigments such organoleptics per se. The chicken has only as zeaxanthin as found in corn, is more easily about 24 taste buds in comparison to 9,000 in deposited, while there is a very high incorporation humans and 25,000 in cattle. Relatively few rate of synthetic products such as ß-apo-8- studies have been conducted with flavoring carotenoic ethyl ester. The zeaxanthin in corn agents for poultry, and for this reason, care tends to impart the darker orange-red colors, where- must be taken in extrapolating data from other as the luteins, as found in alfalfa, cause a more species. For example, sucrose octa-acetate yellow color. Pigments are destroyed by oxidation, solution is reported to be readily accepted by birds, and so addition of antioxidants to feed, and but universally rejected by humans. There general feed management applied to fat protection seems little scope for use of flavoring agents with broiler chickens and turkeys that already seem SECTION 2.3 Feed additives

CHAPTER 2 97 INGREDIENT EVALUATION AND DIET FORMULATION to be eating at near physical capacity. However, j. Worming compounds there may be some potential with breeders for identification of agents that are distasteful to birds, Most floor grown birds are exposed to infec- as an aid in limiting their feed intake. tion from various species of worms. In many instances such challenge can be prevented or We have studied the effect of feeding minimized with the use of antihelmintic agents. cinnamamide to young broilers, as a means of Products based on piperazine and hygromycin regulating feed intake. Cinnamamide is related have been used most commonly over the last 15 to the spice known as cinnamon and is a – 20 years. Piperazine used in diets for laying naturally occurring product in some weed seeds birds has been shown to result in discoloration that is thought to impart bird resistance of the yolk. When administered at 28 d intervals, characteristics as do tannins. Table 2.24 shows one report indicated about 4% incidence of the effect of feeding cinnamamide on growth and discolored yolks which appeared as irregular areas feed intake of young broilers. At the highest of olive to brownish discoloration. Such yolk inclusion level, cinnamamide reduced voluntary discoloration is most pronounced in summer feed intake by around 50%. months especially after prolonged storage at regular egg cooler temperatures. The mottling Table 2.24 Effect of cinnamamide of yolks seen with another commercial product on feed intake and body weight of has been compared to the mottling seen with young broilers calcium-deficient birds, suggesting a similar mode of action. However, we are unaware of any pub- Body Weight Feed Intake lished reports relating worming compounds to (gms) 4-12 day calcium deficiency and problems with shell (gms/bird) quality. Day 4 Day 12 266.4 257.3 k. Ammonia control Control 82.2 170.8 159.2 Various extracts of the yucca plant are Cinnamamide 81.4 claimed to reduce ammonia levels in poultry houses. A soluble component of the yucca (0.2%) plant seems able to bind ammonia, preventing its release from manure, which is especially Cinnamamide 82.8 122.7 104.4 important in confinement housing systems. Most poultry will react adversely to 50 ppm (0.42%) ammonia, and this is in contrast to the level of 20 – 30 ppm which is the usual detection range Flavor agents may be beneficial in masking for humans. Products such as Deodorase® added any unpalatable ingredients, and for maintaining to feed at 100 – 150 g/tonne have been shown a constant feed flavor during formulation changes. to reduce environmental ammonia levels by Flavors may also be useful tools in masking 20 – 30%, and this has been associated with any undesirable changes in drinking water dur- improved growth rate and reduced mortality. ing medication. It is conceivable that use of a sin- gle flavor agent in both feed and medicated water may prevent some of the refusals seen with medicated water, especially for turkey poults. SECTION 2.3 Feed additives

98 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION 2.4 FEED TOXINS and CONTAMINANTS P roducing poultry feed that is free of pockets of moisture can cause microclimates toxins and contaminants is obviously ideal for mold growth. The following is a review the goal of all feed mills. However, this of the major mycotoxins affecting meat birds and is difficult to achieve because many natural feed egg layers. ingredients will contain toxins that are inherent in the feedstuff or have ‘naturally’ contaminated Aflatoxin - Produced by the Aspergillus flavus mold, the feedstuff prior to feed preparation. Mycotoxins aflatoxin is one of the most potent carcinogens are perhaps the best example of such ‘natural’ known. Usually present in cereals in ppb lev- toxins, and together with many plant lectins can els, acute toxicity will occur at 1.2 ppm. Aflatoxin cause poor bird growth and reduced egg production. B1 is the most common form of the toxin, the B In addition to these biological contaminants, designation relating to the fact that the toxin flu- there is also concern about accidental inclusion oresces a blue color when exposed to ultravio- of such products as polychlorinated biphenyls, let light, and so this can be used in the screen- pesticides, fungicides etc. ing of ingredients. Blue fluorescence occurs with other components, and so this simple test screens a. Mycotoxins out negative samples, but needs subsequent chemical analysis for confirmation. Aflatoxin is Mycotoxins are now virtually ubiquitous in found in most cereals, although corn and milo poultry diets, and with ever increasing sophis- are the most common hosts. As with any mold, tication of testing sensitivity, they are routinely Aspergillus growth is greatly reduced when isolated as contaminants of most grains and corn or milo moisture levels are less than 15%. some vegetable protein ingredients. We still do not know the cause of high levels of mold Aflatoxin is a potent hepatotoxin, and so growth occurring in pre-harvest grains. Certainly varying degrees of liver breakdown occur. As such aerobic molds are more prevalent in hot toxicity develops, normal liver function declines, humid conditions, and insect damage to the and reduced growth rate is quickly followed by standing crop seems to provide a route of entry death. Toxicity is enhanced by the presence of for the mold. Unfortunately, visual inspection other toxins such as ochratoxin and T2 toxin. The of harvested grains can be misleading in regard effects of aflatoxin are also much worse if birds to mycotoxin content. Likewise, merely because are infected with aspergillosis. There also seems grains appear moldy, does not mean to say that to be a nutrient interaction, because toxicity is they are contaminated with harmful toxins. In more severe when diets are low in either crude storage, the major factors affecting mold growth protein or methionine or when the diet contains are again temperature and humidity. The higher marginal levels of riboflavin, folic acid or the temperature, the greater the chance of mold vitamin D3. There is no treatment for acute growth. However such mold growth rarely aflatoxicosis, although because of the liver occurs in grains containing less than 14 – 15% disruption, giving higher levels of antioxidants moisture. Unfortunately, many grain silos are not and/or selenium seems to slow the onset of waterproof, or grains are not aerated, and so symptoms and speed up recovery if aflatoxin is removed from the diet. SECTION 2.4 Feed toxins and contaminants

CHAPTER 2 99 INGREDIENT EVALUATION AND DIET FORMULATION There are a number of effective preventative toxin A (OA) is by far the most significant for poul- measures, although not all of these are try. OA is produced by a number of molds, economical. Treating infected grains with with Aspergillus and Penicillium species being most ammonia, hexane or hydrogen peroxide have all commonly involved. OA is toxic at 2 ppm and been shown to reduce aflatoxin levels. Under as with tricothecenes, it has an adverse effect on commercial conditions adding binding agents to protein synthesis. However, OA also affects the feed seems to reduce the adverse effects of kidney function and so the classical signs are aflatoxin. To date, aluminosilicates, bentonite swollen kidneys and associated increased water clays and yeast cell walls have proven effective. intake with wet excreta. Secondary visceral For example adding 10 – 15 kg/tonne of hydrat- gout, which appears as urate deposits over the vis- ed sodium-calcium aluminosilicate has been cera, is common with OA toxicity, due shown to drastically reduce mortality in broilers essentially to failure of uric acid clearance by the and turkeys fed diets containing 0.5 – 1.0 ppm kidney tubules. OA toxicity is compounded by aflatoxin. Such aluminosilicates have limited effects the presence of aflatoxin, DON and T2 toxicosis, on other mycotoxins. and also made worse by feeding diets high in vanadium (usually as a contaminant of phosphates Tricothecenes - Three mycotoxins, namely T2, DAS or limestone). There are no effective preventa- (diacetoxyscirpenol) and DON (Deoxynivalenol tive measures, although birds sometimes respond or vomitoxin) are included in this group. All of to diet manipulation in the form of increasing crude these mycotoxins are produced by Fusarium protein levels. There are also reports of benefi- species molds such as Fusarium graminearum and cial response to increasing diet vitamin C levels, Fusarium roseum. The tricothecenes affect especially in egg layers. protein metabolism and have the characteristic feature of causing mouth lesions in most animals. Other mycotoxins - There are a diverse group of However DON does not seem to be particularly other mycotoxins that periodically cause problems harmful to poultry. Unlike the situation in pigs for poultry. Their occurrence is less and other mammals, birds can tolerate up to 20 frequent than the major mycotoxins already dis- ppm of this mycotoxin. T2 and DAS however are cussed, and in some instances exact toxicity lev- more toxic, causing problems at 2 – 4 ppm. els have not been clearly established.Table 2.25 The adverse effect of tricothecenes is made even summarizes these mycotoxins in terms of effect on worse by the presence of aflatoxin or ochratoxin, poultry and their probable threshold for toxicity. and seems to be worse in young broilers fed ionophore vs non-ionophore anticoccidials. b. Plant toxins There are no really effective treatments, and while the addition of relatively high levels of A number of cereals and vegetable protein antioxidants may slow the disruption of protein crops contain natural toxins that can affect bird synthesis, they are not effective long-term. performance. Adsorbents and binding agents are being devel- oped that specifically bind these toxins. Cyanides - While there are a number of poten- tial feed ingredients that contain natural cyanides, Ochratoxin - As with other mycotoxins, there are cassava (manioc), is probably the most common a number of forms of ochratoxin, although ochra- and contains relatively high levels of this toxin. SECTION 2.4 Feed toxins and contaminants

100 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION Table 2.25 Effect of minor mycotoxins on poultry Mycotoxin Effect Toxicity Comments Fumonisin > 80 ppm Degeneration of nerve Diet thiamin levels Cyclopiazonic acid cell lipids 50 – 100 ppm important Mucosal inflammation Often present along with aflatoxin Oosporin Kidney damage, gout > 200 ppm Most commonly found Citrinin Kidney damage > 150 ppm in corn Ergot Tissue necrosis > 0.5% Commonly associated Fusarochromanone > 50 ppm with ochratoxin Tibial Moniliformin dyschondroplasia > 20 ppm Wheat and rye Zearalenone > 200 ppm Acute death Fusarium species Reproduction, vitamin Mechanism unknown D3 metabolism Can affect shell quality Cassava meal is derived from the tuberous root ment for this amino acid. Thiocyanate is respon- of the cassava plant. Ingestion of this material sible for the goitrogenic effect of cassava, due to by animals can result in enlarged thyroids, due its effect on iodine uptake and metabolism in the to the presence in the meal of cyanogenic glu- thyroid, resulting in reduced output of thyroxine, cosides, the main one being linamarin. These which regulates tissue oxidative functions. glucosides are concentrated in the peel of the root. Cyanate is known to alleviate the toxicity of an On hydrolysis by the enzyme linamarase, the glu- excess of dietary selenium by complexing with cosides produce hydrocyanic acid (HCN), which selenium, thus making it less available to the bird. is highly toxic. In addition to the enzyme in the Linseed meal, which has been known for some root, glucosidic intestinal enzymes and HCl time to alleviate selenium toxicity in animals, has can also hydrolyze the glucosides. been shown to contain two cyanogenic gluco- sides, namely linustatin and neolinustatin. These Hydrocyanic acid inhibits animal tissue res- compounds are closely related in structure to piration by blocking the enzyme cytochrome-oxi- linamarin and thus on hydrolysis yield HCN. dase. HCN is detoxified to produce thiocyanate in the liver which is then excreted via the urine. The cyanide content of cassava varies with This detoxification system utilizes sulfur from variety and can range from 75 to 1000 mg/kg of methionine in the conversion of cyanate to root. Crushing the root releases the enzyme thiocyanate, thus increasing the bird’s require- linamarase which acts on the glucosides to SECTION 2.4 Feed toxins and contaminants

CHAPTER 2 101 INGREDIENT EVALUATION AND DIET FORMULATION produce volatile HCN which is then eliminated antifungal and antibacterial properties, and during drying. Rate of drying in commercial forced have a very pungent taste (mustard, horseradish, air driers is important as it has been reported that etc.). A second, but much smaller group, form at 80 to 100ºC, only 10 to 15% of cyanide is potent anti-thyroid compounds on hydrolysis with removed compared to 80 to 100% detoxifica- 5-vinyloxazolidine-2-thione being the most tion occurring at 47 to 60ºC but with a longer common. If present in large amounts these time. Steam pelleting can also assist in the compounds can impart an intense bitterness. volatization of free HCN. Glucosinolates in the third group all contain an indole side chain, and on hydrolysis yield While there are differing reports as to how much thiocyanate ions which are anti-thyroid or cassava meal can be incorporated into poultry diets goitrogenic. The glucosinolate contents of the without reducing performance, this will obviously various rapeseed cultivars ranges from a high of depend on the concentration of cyanide in the 100 to 200 µM/g to less than 30 µM/g, while new meal. Cassava meals containing up to 50 mg total varieties are claimed to be glucosinolate-free. cyanide/kg have been fed successfully up to 50% inclusion in broiler diets. A significant research program was initiated in Canada in the early 60’s to develop rapeseed Glucosinolates – These belong to a group of anti- varieties low in glucosinolates and erucic acid, nutritive compounds of which over 100 differ- a fatty acid known to result in detrimental meta- ent types are known to occur in members of the bolic problems with certain animals. In 1968, Cruciferae family. The genus Brassica is a mem- the first low erucic acid variety was licensed and ber of this family which includes many impor- shortly thereafter a low glucosinolate variety tant feeds and foods such as, rapeseed, appeared. In 1974, the first double low variety, mustard, kale, radish, cabbage, cauliflower, very low in erucic acid and glucosinolates was etc. In individual species, usually around 12 to licensed. A number of improved varieties were 20 glucosinolates are found, although most of developed and in 1979 the name canola was these are present in small amounts. Hydrolysis adopted in Canada to apply to all double low of these glucosinolates is brought about by the rapeseed cultivars. For reasons not yet completely enzyme myrosinase, which is usually present in understood, reduction of total glucosinolate most glucogenic plants. In the intact plant, the had little effect on the content of the indole group. enzyme and its substrate are separated, but Thus, when expressed as a percent of total with cellular rupture (grinding, insect damage, glucosinolates, this group increases from around etc.) these components are combined and 5 to 40% in the low glucosinolate varieties. hydrolysis can occur. While the feeding value of canola meal has For many plants including rapeseed, been markedly increased for poultry, as compared glucosinolates can be readily divided into three to the older rapeseed varieties, there are still some main groups, based on physiological effects problems encountered. The occurrence of liver and hydrolysis products. By far the largest of these hemorrhages with the feeding of rapeseed meal groups are glucosinolates that yield isothio- is well documented. Unlike the fatty liver hem- cyanates on hydrolysis. These compounds are orrhagic syndrome, these hemorrhages are not volatile and possess a range of antimicrobial, associated with increased liver or abdominal fat SECTION 2.4 Feed toxins and contaminants

102 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION contents. Certain strains of laying hens were more Nitrates – The nitrate content of cereals and plant susceptible than others, however, with most proteins can vary from 1-20 ppm. While having strains it was not uncommon to see signs of the little affect on the bird per se, reduction to condition. While liver hemorrhages have been nitrite, usually by intestinal microbes, can lead significantly reduced in laying hens with intro- to toxicity. Nitrite is readily absorbed from the duction of canola meal, isolated cases are seen gut and diffuses into red blood cells where it oxi- when feeding 10% or more of this product. dizes the ferrous iron of oxyhemoglobin to the Research to date suggests that this is the result ferric state, forming methemoglobin, which is of intact glucosinolates, rather than any of their unable to transport oxygen. Because there has products of hydrolysis. However, it is still been an interest in the role of dietary nitrite in unclear how glucosinolates function in the the incidence of pulmonary hypertension and spon- etiology of hemorrhagic liver. taneous turkey cardiomyopathy. Feeding broil- ers nitrite up to 1600 ppm had no effect on pul- An increase in weight of the thyroid still monary hypertension. However, turkey poults fed occurs following feeding of canola meal, although 1200 ppm nitrite had a numerically higher inci- severity is much reduced from that seen with the dence of STC than did controls (20 vs. 5%). older rapeseed varieties. Thiocyanate is respon- Interestingly, both chicks and poults developed sible for the goitrogenic effect noted with these anemia; poults appeared to be more sensitive to products due to their effect on iodine uptake and the adverse effects of nitrite on hemoglobin metabolism, and so increase in thyroid size is seen. content since the minimum dietary level-caus- Because thiocyanate is the end product of indole ing anemia was 800 ppm in poults and 1200 ppm glucosinolate hydrolysis and levels of this in chicks. Decreased perormance was observed compound are still high in canola, then this with the highest dietary concentration. The product probably accounts for the enlarged results of this study indicate that the dietary thyroids still seen with low glucosinolate meals. levels causing methemoglobinemia, anemia, and decreased body weight are not likely to be Another major problem with the feeding of encountered in cereal grains and legume seeds. rapeseed or canola meal is egg taint which is However, nitrate and nitrite may also be present experienced in certain flocks of layers, and at significant levels in water sources. especially brown egg layers containing Rhode Island Red ancestory. This is the result of a single Tannins – These are water soluble polyphenolic major autosomal semi-dominant gene being plant metabolites that are known to reduce the present which is responsible for the bird lacking performance of poultry when fed at moderate lev- the ability to oxidize trimethylamine (TMA) to TMA els in a diet. Grain sorghum is probably the most oxide which is the odorless excretory product of common feedstuff which contains relatively TMA. While the double low varieties of canola high levels of tannin. However, faba beans, rape- contain very low levels of glucosinolates, there seed and canola meal all contain sufficient tan- is still sufficient present, along with the soluble tan- nins to affect poultry performance. nins, to impair TMA oxidation and thus tainted eggs can result. Because brown-egg layers are quite The growth depressing effect of tannins is common in many parts of the world, canola meal, undoubtedly due to their ability to bind proteins. in such regions is used sparingly for layers. Tannic acid is hydrolyzed by the chick to gallic SECTION 2.4 Feed toxins and contaminants

CHAPTER 2 103 INGREDIENT EVALUATION AND DIET FORMULATION acid, its major hydrolytic product, and to a the cereal. Besides the addition of the methyl lesser extent to the somewhat toxic compounds, donors which have been reported to improve the pyroacetol and pyrogallol. A large portion of the feeding value of high tannin sorghum, products gallic acid is methylated and excreted in the urine such as polyvinylpyrrolidone, and calcium as methyl gallic acid. This pathway offers a hydroxide, or a slurry of sodium carbonate have possible explanation as to why additions of also been reported to give positive responses. methionine, choline and other methyl donors have However, several crude enzyme preparations that been reported to be beneficial when included have been tried were not effective in enhancing in diets containing tannic acid. the feeding value of high tannin sorghum. Much of the work on toxicity of tannins has Tannins have also been implicated in egg yolk involved purified tannic acid. Legume and mottling. Yolk mottling is a condition which cereal tannins are of a condensed type while periodically appears in a flock and without a direct tannic acid is of a hydrolyzable type. Since there involvement of nicarbazin, gossypol or certain are conflicting reports on the degree of growth worming compounds, there is usually no ready depression and the role of methionine in alleviating explanation for its appearance. While several tannin toxicity, it follows that the predominant reports have suggested tannic acid and its detoxification process may differ between these derivatives as possible causes, other than the two compounds. More recent work suggests that addition of commercial tannic acid at levels while gallic acid is the breakdown product of both above 1%, there appears to be no mottling seen condensed tannins and tannic acid, and can be with diets containing up to 2.5% tannins. detoxified by methyl groups, the stability of condensed tannins is such that this route of There are reports suggesting that tannins detoxification may be of little importance. are bound tightly to a fraction of the nitrogen in sorghum and that this reduces protein digestibil- i) Sorghum tannins - The nutritive value of ity. However, because the tannins are relatively sorghum is usually considered to be 90 to 95% insoluble they appear to have little influence in that of corn, due in large part, to its tannin content. complexing with protein. In a recent study There are a number of varieties of sorghum on the with turkeys, a high tannin sorghum variety market which are usually classified as bird resist- when used at 40% in the diet, resulted in ant or non-bird resistant varieties. These have either depressed performance to 8 weeks of age. a low (less than 0.5%) or high (1.5% or higher) However, the feeding of a similar level to turkeys level of tannins. A number of toxic effects have beyond 8 weeks of age had no detrimental been reported with the feeding of high tannin effects. The authors suggest that a more fully sorghum. These include depressed growth and developed digestive system of the older birds may feed utilization, reduced protein digestibility, be able to overcome the anti-nutritional effects lower egg production and leg abnormalities of the tannins. with broilers. While dark colored varieties of sorghum A number of procedures have been tried in seed usually contain higher levels of tannin an attempt to reduce the toxicity of the tannins than do lighter colored varieties, seed color, in in sorghum. These include soaking in water or general, is a poor indicator of the tannin content alkali solution, which are reported to deactivate of sorghum. tannins and thus improve the nutritive value of SECTION 2.4 Feed toxins and contaminants

104 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION ii) Faba Bean Tannins - Raw faba beans are reported values of around 3%. With tannins known to result in depressed performance of concentrated in the hull of both rapeseed and poultry while autoclaving results in a significant canola, the amount of extractable tannins has been improvement in bird performance. Dehulling also investigated and appears to range from 0.02 to results in improved energy value with this effect 2%. The ability of these tannins to inhibit being greater than can be accounted for by amylase in-vitro was not detected. Hence, it has reduction in fiber content. The growth depressing been assumed that the tannins in rapeseed and properties of faba beans are due to two water- canola are bound in such a manner that their acetone soluble fractions, one containing low weight influence on digestibility of other ingredients is polyphenolic compounds, the other containing negligible. condensed tannins, the latter being the major growth inhibiting substance. These condensed tannins Lathyrism - As with many species of animals, poul- are similar to those found in sorghum and are try are susceptible to lathyrism, a metabolic concentrated in the hull fraction. condition caused by the consumption of legume seeds of the genus Lathyrus, of which sweet While proper heat treatment of faba beans peas are a member. The seeds are rich in can markedly increase their nutritive value, protein (25 to 27%) and their availability and there appears to be some detrimental effect on relatively low cost in many Asian and mid- intestinal villi structure regardless of the degree Eastern countries often results in their use in of heat treatment or the fraction of seed consumed. poultry feeds. The causative agents for lathyrism This has led to reports that factors other than those are the lathyrogens, of which lathyrogen usually considered, such as protease inhibitors, beta-aminopropionitrile (BAPN) is the principle phytates and lectins, may be contributing to toxin found. However, there are some synthetic the low nutritional value of faba beans. Tannin- lathyrogens available that have been used in free varieties of faba beans are available that studying the condition. contain less than 0.1% condensed tannins in their hulls compared to over 4% in the high tannin Lathyrism manifests itself in two distinctive varieties. These lighter colored seeds are of forms. Firstly, there is a disorder of the nervous improved nutritive value. Regardless of tannin system leading to a crippling condition and content, appropriate heat treatment improves the referred to as neurolathyrism, and secondly a nutritive value of faba beans. disorder of the collagen and elastin component of connective tissue resulting in a skeletal and/or iii) Rapeseed and Canola Tannins - Rapeseed and vascular disease and referred to as osteolathyrism. canola meal have been reported to contain 2 to Typical symptoms seen with poultry consuming 3% tannin, which is concentrated in the hull. These significant quantities of toxins are depressed tannins have been shown to contribute to the egg performance, ruffled feathers, enlarged hocks, taint problem of these meals, when fed to curled toes, ataxia, leg paralysis and eventually brown-egg layers, due to their inhibitory effect mortality. on trimethylamine oxidase. The original method for assaying tannin also included Most of the poultry research involves specific sinapine. Because the sinapine content of synthesized lathyrogens rather than natural seeds. canola is around 1.5%, a value of 1.5% for BAPN has been shown to inhibit cross-linking total tannins is more realistic than earlier SECTION 2.4 Feed toxins and contaminants

CHAPTER 2 105 INGREDIENT EVALUATION AND DIET FORMULATION compounds in elastin and collagen by inhibiting disorder became known as pink egg white; and the enzyme lysyl oxidase, an important component secondly there was brown or olive pigment in in the synthesis of these compounds. It has also the yolks. This later defect was the result of gossy- been reported to reduce growth rate of chicks, poults pol from the cottonseed pigment glands interacting and ducklings and to reduce egg production of with iron in the egg yolk. adults of these species. BAPN can result in defective shell membranes, so ultimately affecting Although pink albumen discoloration is shell calcification, leading to malformed and known to occur spontaneously, it is usually seen soft-shelled eggs. This effect is similar to that seen with ingestion of products from plants of the with copper deficiency since the enzyme lysyl botanical order, Malvales. Two naturally occurring oxidase is a metalloenzyme that requires copper. cyclic fatty acids have been isolated from plants Consequently, there are reports of copper known to cause the unusual color. These com- alleviating the symptoms of BAPN toxicity. pounds were called malvalic and sterculic acids. A color test developed many years ago by While recommended maximum levels of Halpen, can be used to identify cottonseed oil in inclusion of the various lathyrus seeds, to avoid vegetable oil mixtures. The test has been shown metabolic problems, varies with the type of to be very specific to cyclopropenoid compounds, seed and the lathyrogen content of the seed, a especially malvalic and sterculic fatty acids. general recommendation would be to keep the The pink-white albumen condition noted in dietary level of BAPN below 50 mg/kg of diet. stored eggs, which is common with the ingestion While the addition of lathyrogens to a laying diet of either malvalic or sterculic fatty acids, results results in a decrease in production after 4 to 5 from a combination of conalbumen and egg days, hens seem to return to normal production white protein mixing with iron that diffuses from in 10 to 14 days after receiving a normal diet. the yolk. This is due, in part, to changes in Interestingly there has been some research membrane permeability and an increase in yolk interest on the ability of BAPN to tenderize pH. The amount of these compounds fed, meat from spent hens. This is obviously related storage conditions and breed of hen, have all been to its effect in altering collagen cross-linking by shown to influence the degree and incidence of inhibiting the enzyme lysyl oxidase. the condition. Gossypol - The use of cottonseed products in diets Yolk discoloration is also caused by the for laying hens has long been a problem for nutri- ingestion of gossypol and/or malvalic or sterculic tionists as well as producers. As early as 1891 acid. However, there is a difference in incidence there were reports of mottled egg yolks result- and degree of discoloration and mottling depend- ing from the feeding of cottonseed meal to lay- ing on whether intact gossypol or the fatty acids ers. In the early 1930’s gossypol was identified as are involved. Changes in membrane permeability the compound involved in discoloration of egg and a shift in yolk and albumen pH result in water yolks when hens were fed cotton seed meal. It and albumen protein migrating to the yolks. soon became evident that there were two The severity of the condition will depend on the problems that could occur with the feeding of amount of gossypol ingested and can lead to pasty cottonseed meal to layers: the albumen of custard-like or viscous yolks being observed. These stored eggs developed a pink color and thus the can be seen at ovulation but the condition can SECTION 2.4 Feed toxins and contaminants

106 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION be accentuated with storage. There are reports One of the most common sources of alkaloids of increased embryo mortality during the first week finding its way into animal feeds is grain con- of incubation when breeders are fed high levels taminated with ergot. Samples of ergot can of malvalic or sterculic acid, however, the run as high as 0.4% total alkaloids. Chickens levels fed must be much higher than those receiving 1 to 2% of ergot in their diet can normally present in laying hen diets. show symptoms ranging from depressed growth to necrosis of the extremities, staggers, ataxia, Although varieties of cottonseed have been tremors and convulsions. developed that are gossypol free, their low yield has meant that they are not widely used in c. Autointoxication commercial production. Consequently, much of the cottonseed grown world-wide still contains Autointoxication could be defined as self- appreciable quantities of gossypol. Processing poisoning as it is endogenous in origin and method can markedly reduce the gossypol results from the absorption of waste products of content of the meal to levels less than 0.04% free metabolism or from products of decomposition gossypol. In addition, soluble iron salts can be in the intestine. High fiber diets fed to young chicks added to diets containing cottonseed meal. The can cause obstruction of the digestive tract with iron will complex with gossypol reducing its toxic subsequent absorption of products of decomposition effects. In a recent report, broilers fed a diet with or metabolic wastes. Litter consumed by chicks up to 30% cottonseed meal, with soluble iron or over-consumption of green grass or plants added (to provide a 2:1 ratio of iron to free can also lead to gut impaction problems. gossypol) resulted in no detrimental effect on weight gain or liveability. The chilling or overheating of chicks can lead to vent pasting and occlusion resulting in stasis Alkaloids - Alkaloids are found in a number of of the intestine contents with autointoxication feedstuffs but by far the most important are the being the end result. Birds suffering from autoin- lupine legumes. Seeds of the plant Crotalaria retusa toxication are anorexic, and show increased L., contain up to 4.5% of the pyrolizidine alkaloid water consumption, followed by weakness and monocrotaline and these can be a problem in prostration. A generalized toxaemia may result cereal contamination in some areas of Asia and leading to nervous symptoms prior to death. Australia. The older varieties of lupines were often referred to as bitter lupines, due to the presence d. Bacterial toxins of significant quantities of quinolizidine alkaloids, mainly lupanine. These alkaloids affect the Although losses in birds due to bacterial central nervous system causing depressed toxins are not of great economic importance, they laboured breathing, convulsions and death from do occasionally result in heavy losses in a par- respiratory failure. Newer varieties of lupines now ticular flock. The main organism affecting poul- being grown are very low in alkaloids (less than try is Clostridium botulinum. No significant 0.02%) and have been shown to be well toler- lesions are found in botulism poisoning and a ated by poultry. positive diagnosis is usually based on identification of the organism and its toxin. SECTION 2.4 Feed toxins and contaminants

CHAPTER 2 107 INGREDIENT EVALUATION AND DIET FORMULATION Botulism is caused by the toxin produced from e. Chemotherapeutic drugs the C. botulinum organism under anaerobic conditions. C. botulinum is a saprophyte found While the use of various pharmaceutical in soil and dirt and can also be found in intestinal compounds has contributed significantly to the contents and feces. The mere presence of the development of the modern poultry industry, their organism is sufficient to cause disease or to be misuse can result in toxicity. Some of the more of diagnostic significance. Growth of the organ- common drugs that can result in problems if used ism, in anaerobic conditions, results in the at toxic levels are: production of toxins. Botulism can result from birds eating carcasses of birds which have died i. Sulfonamides – Toxicity is manifested by signs from the disease and also fly larvae from such of ruffled feathers, paleness, poor growth and carcasses. The toxins present in the meat are increased blood clotting time. Hemorrhages in ingested by larva rendering them extremely skin and muscle may be noted and necrosis of the poisonous. Symptoms may appear within a liver, spleen, lungs and kidney are often seen. few hours to a day or two after contaminated feed is eaten. The common symptom noted is paral- ii. Nitrofurans – Toxicity results in depressed ysis, with the leg and wing muscles first affected. growth and hyperexcitability, where chicks If the neck muscles are affected the head hangs cheep and dash about. Enteritis and congestion limp, hence the name ‘limberneck’ which has of the kidneys and lungs, along with body been used to refer to the disease. In mild cases, edema and cardiac degeneration may be noted. leg weakness, ruffled feathers and soft pasty feces may be noted. The severity of the disease iii. Nicarbazin – Toxicity in chicks results in depends on the amount of toxin consumed. birds being listless and showing signs of ataxia, However, death usually occurs as this toxin is very with incoordination and a stilted gait especial- potent. Losses in birds are most commonly due ly in hot weather. Fatty degeneration of the liver to type A and C toxins. Type A, is common in the may be noted. The most common problem mountainous regions of North and South American, with nicarbazin is its effect on laying hens. while type C is world-wide in distribution. Brown eggs will be depigmented and yolk mot- tling may be noted with white and brown eggs. For many years, a disease of wild ducks and other aquatic birds was common in the western f. Toxic seeds part of North America. It is now known that this is due to botulism poisoning. Insect larvae in an Phytotoxins can be considered as any toxic aquatic environment may die as the result of substance derived from plants including roots, anaerobic conditions caused by decaying vegetation. stems, leaves, flower and seeds. Some plants are When these larvae are eaten by birds, botulism organ- toxic throughout the whole growing season isms invade tissues and produce toxins. Prevention while others are only toxic during certain stages relates to proper management procedures that elim- of development. The majority of toxic plants are inate dead and decomposed carcasses around a relatively unpalatable and are usually avoided poultry house. A good rodent and fly control pro- by birds. However, with the absence of succulent gram is also essential as is screening of the build- feed, range birds will consume sufficient foliage ing to eliminate entry of wild birds. or seeds to result in poisoning. Some of the more common poisonous plants are as follows: SECTION 2.4 Feed toxins and contaminants

108 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION i) Black locust (Robinia pseudoacacia) – The toxin coffee seeds become ataxic or partially paralysed is the glycoside robitin-alectin (hemagglutinin). before death. Muscle lesions are similar to It has been reported that the leaves of black locust those seen with vitamin E deficiency. Death often are toxic during early July and August in the N. occurs due to a hyperkalemic heart failure. Hemisphere and cause mortality with chick- Production will return to normal with the removal ens if consumed at this period. Symptoms of the contaminated feed. noted are listlessness, diarrhea, anorexia and paral- ysis with death occurring within several days. iv) Corn cockle (Argostemma githago) – Corn Hemorrhagic enteritis may also be seen. cockle is often harvested with wheat and so can become incorporated into poultry feeds. The ii) Castor bean (Ricinus communis) – Many diet must contain 5% or more of corn cockle to legume seeds contain a protein fraction which show toxic symptoms, which are caused by is capable of agglutinating red blood cells. githagenin, a plant saponin. General weakness, These compounds are referred to as lectins and with decreased respiration and heart rate may be they vary widely in their degree of specificity to noted often associated with diarrhea. types of red blood cells and also their degree of Hydropericardium and edema of the intestine can toxicity. Such legumes must be degraded by heat be seen along with petechial hemorrhages in the treatment in order to detoxify them and so myocardium and congestion and degeneration enhance their nutritive value. Castor bean was of the liver. one of the first such legumes to be investigated and a lectin called ricin was isolated which is v) Coyotillo (Karwinskia humboldtiana) – This extremely poisonous. However, the steaming of plant is indigenous to southwest Texas and castor meal for 1 hour will reduce the toxicity Mexico. The fruit and seed are toxic to poultry of the meal to 1/2000 of its original level. and 3 to 4 days after ingestion generalized tox- Toxicity is seen as progressive paralysis starting aemia signs can be noted, followed by paraly- with the legs and progressing to complete sis and death. prostration. With the exception of blood-stained mucus in the droppings, clinical signs are indis- vi) Cacao (Theobroma cacao) – High levels of cacao tinguishable from those of botulism. A pale bean wastes (in excess of 7% of the diet) are swollen mottled liver is often seen with petechial required to show toxic symptoms caused by the toxin hemorrhages present on the heart and visceral fat. theobromine. Such symptoms include nervous and excitable birds. Birds die in convulsions and iii) Coffee bean seed (Cassia occidentalis; C. obtusi- usually are on their back with legs drawn tightly folia) – Mechanical harvesting methods have against their body. The comb is often cyanotic. increased the danger of contamination of corn and soybeans with coffee bean plants which are vii) Crotalaria seed – A few species are toxic to frequently found in relatively large numbers in poultry the most problematic being C. spectabilis the southern USA. At all levels of incorporation and C. giant (striata). The toxin is a pyrolizidine of the anthraquinone lectins from coffee seeds, alkaloid, designated, monocrotaline. Crotalaria egg production and weight gain are reduced. is a small black or brownish seed and is a con- Platinum colored yolks and profuse diarrhea are taminant in corn and soybeans in the southeast also noted with layers. Birds fed 2 to 4% of the USA. One percent in a chick diet can result in death by 4 weeks of age. Birds become huddled SECTION 2.4 Feed toxins and contaminants

CHAPTER 2 109 INGREDIENT EVALUATION AND DIET FORMULATION having a pale comb and diarrhea and may mon in the northwest USA and produces a exhibit a duck-like walk. With young birds cyanogenic glucoside called viciana, which is abdominal fluid and edema, similar to that seen converted by the enzyme vicianase into hydro- with ascites may be noted. With mature birds, there cyanic acid. Problems comparable to lathyrism is a reduced egg production and massive liver hem- are observed, including excitability, incoordination, orrhages may be noted. The lesions are similar respiratory problems and convulsions. to those reported for toxic fat and salt poisoning. xii) Milkweed – Two common species are viii) Daubentonia seed (Daubentonia longifolia) – Asclepias tuberosa and A. incarnata. They con- This seed can be a problem in the southern tain the bitter glucoside, asclepdin, which is toxic USA. As little as 9 seeds can cause death in 24 to birds. Symptoms vary widely depending on – 72 hours. The comb can be cyanotic, with the the quantity of material consumed. The first sign head hanging to one side. Emaciation and is usually lameness, developing quickly into diarrhea may also be noted. Severe gastroenteritis, complete loss of muscle control. The neck ulceration of the proventriculus and degenera- becomes twisted with the head drawn back. In tion of the liver are not uncommon. some cases symptoms gradually subside. In fatal cases, symptoms become more progressive ix) Glottidium seed (Glottidium vesicarium) – This and prostration, coma and death result. No char- seed is often found in the southeastern USA. acteristic lesions are seen on necropsy. Clinical symptoms are a cyanotic comb and wattles, ruffled feathers, emaciation and xiii) Algae – Certain types of algae, including yellow diarrhea. Necrotic enteritis as well as liver Microcystis aeruginosa, which readily grows in and kidney degeneration are also common many lakes, can become concentrated by wind observations. and deposited on shore or in shallow water. Degradation of this material produces toxins which x) Death camas (Zygadenus) – This is a green range have been responsible for losses in wild and plant with an alkaloid toxin called nuttallii. domestic birds. The condition is usually noted Consumption of 5 to 10 g by a chicken can result in summer months. Toxicity is proportional to in clinical symptoms in 12 hours that include the amount of toxin consumed. Death can incoordination, diarrhea and prostration fol- result in 10 to 45 minutes for mature ducks lowed by death. and chickens. Clinical symptoms include rest- lessness, twitching, muscle spasms, convul- xi) Vetch (Vicia sativa) - Vetch belongs to the sions and death. These symptoms are Leguminosae family which is related to the similar to those seen with strychnine poisoning. legumes Lathyrus, Pisum and Ervum. It is com- SECTION 2.4 Feed toxins and contaminants

110 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION 2.5 FEED MANUFACTURE When vitamin-mineral premixes are pre- pared in quantity ahead of time, they should be I n the early days of poultry nutrition feeds con- clearly labeled and stored in a cool dry place for tained relatively few synthetic ingredients and future use. With the addition of an antioxidant and the smallest amount of any addition amount- the margins of safety provided in most ed to 0.5% or more. Some natural ingredients, how- premixes, they can be held for two to three ever, have been gradually replaced and supplemented months under ideal conditions. Rather than sug- by extremely small quantities of synthetic and puri- gesting the use of products with specific poten- fied ingredients, especially the vitamins, trace cies to supply the vitamins and other nutrients (Table minerals, pigments and various pharmacological 2.26) the units or weights of the compounds compounds. Consequently, the proper mixing of have been indicated and the decision as to prod- feed requires ever increasing technical knowledge. uct use is left to the individual. Some feed man- Improper mixing can result in variation in the ufacturers are capable of making premixes from quality of feed and vitamin or mineral deficiencies more concentrated vitamin and mineral preparations, resulting in lack of protection against disease or chem- since this usually results in a cost saving com- ical or drug toxicity. pared with the use of more dilute preparations. The choice of potency of products for use in the a. Vitamin-Mineral Premixes premixes should be governed, to a large extent, by personnel and the facilities available. Because Micro-ingredients should be properly premixed vitamin and mineral supplements represent a rel- before being added to a feed. It is desirable to atively small part of the total cost of a diet, have similar physical characteristics among margins of safety are being added in most cases. ingredients to be premixed. The diluent suggested Lower levels can be used with satisfactory results for use in the vitamin-mineral premixes is ground under ideal conditions. yellow corn or wheat middlings, both being of medium grind for best results. If the The direct addition of vitamin premixes or other carrier is too coarse, it is not possible to obtain supplements to the feed, at a usage rate less than good distribution of the supplements, while too 1 kg/tonne, is not usually recommended. These fine a carrier leads to dustiness and caking. micro-ingredients should be suitably premixed For mineral mixes, limestone or kaolin (china clay) first, so that at least 1 kg/tonne is added. It is gen- make satisfactory carriers. Where premixes are erally recommended that vitamin-mineral pre- being stored for relatively short periods of time, mixes be added to the mixer after about one-half the vitamin and mineral premix can be combined. of the other ingredients have been included. The However, where mixes are to be stored for time required for a satisfactory mix is very important more than 6 weeks in a warm moist environment, and varies considerably depending upon the it may be advisable to make separate vitamin and equipment used. Usually 2 – 3 minutes is the opti- mineral mixes. Also, if premixes are to be mum for horizontal mixers and up to 5 minutes for shipped long distances and thus subjected to a vertical machines although mixing times are being great deal of handling, and perhaps high tem- continually reduced with newer equipment. This can perature, it is advisable to make separate vitamin vary with the type of mixer and manufacturer’s and mineral mixes. This helps to reduce the specifications should always be followed. physical separation of nutrients and leads to less vitamin deterioration. SECTION 2.5 Feed manufacture

Table 2.26 Vitamin-mineral premixes (without choline) – all premixes should be made up to 1 – 5 kg by the addition of a carrier such as wheat middlings. The amounts shown below are the levels of nutrients to be added per tonne of finished feed. CHICKEN TURKEY WATERFOWL VITAMINS Starter Grower Laying Breeder Starter Grower Breeder Starter Grower Breeder CHAPTER 2 Vitamin A (M.IU) 10.0 8.0 7.5 11.0 10.0 8.0 11.0 10.0 8.0 10.0 INGREDIENT EVALUATION AND DIET FORMULATION Vitamin D3 (M.IU) 3.5 3.3 3.3 3.3 3.5 3.3 3.3 2.5 2.5 3.0 Vitamin E (T.IU) 30.0 20.0 50.0 70.0 40.0 30.0 100.0 20.0 15.0 40.0 Riboflavin (g) 6.0 5.0 5.0 8.0 6.0 5.0 8.0 5.0 4.0 5.5 Thiamin (g) 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Pyridoxine (g) 3.3 3.3 3.3 5.0 3.3 3.3 5.0 3.3 3.3 3.3 Pantothenic acid (g) 15.0 10.0 10.0 15.0 15.0 12.0 15.0 12.0 10.0 10.0 Vitamin B12 (g) .015 .012 .015 .015 .015 .012 .015 .015 .010 .015 Niacin (g) 50.0 30.0 40.0 50.0 50.0 40.0 50.0 50.0 40.0 50.0 Vitamin K (g) 2.0 2.0 2.0 3.0 2.0 2.0 3.0 1.5 1.5 1.5 Folic acid (g) 1.0 1.0 1.0 1.0 1.0 0.5 1.0 1.0 0.5 0.5 Biotin1 (g) 0.15 0.10 0.10 0.15 0.2 0.15 0.2 0.1 0.1 0.1 SECTION 2.5 MINERALS 70.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 70.0 Feed manufacture 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 Manganese (g) 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 Zinc (g) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Copper (g) 50 40 30 40 50 40 40 40 30 30 Selenium (g) Iron (g) All vitamin premixes should contain Ethoxyquin to provide 125g/tonne feed. 1 Increase if diet contains > 10% wheat. 111

112 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION The segregation of ingredients in a mixed feed Recent work has shown that thiamin, folic acid, can occur due to improper handling after mixing. pyridoxine and some vitamin K supplements can This can be a problem when mash feeds containing be relatively unstable in the presence of trace no added fat are blown into bulk bins. However, mineral supplements. This is especially true care in unloading and a cyclone on top of the where the minerals are supplied as sulphate bulk tank will help overcome the problem. This salts, hence special consideration must be given is usually not a great problem when the feed is to the above mentioned vitamins when pelleted or crumbled. premixes contain both vitamins and minerals, and storage is for 4 – 6 weeks. b. Vitamin Stability Most of the other vitamins are fairly stable. Naturally occurring vitamin E is quite unstable, However, care should be taken in storing vita- particularly in the presence of fat and trace mins to ensure their potency. Always store in a minerals, however, vitamin E added as a sup- cool, dry, lightproof space or container. While plement usually is in a highly stable form (e.g. vitamin supplements are an extremely important gelatin coated beadlet containing an antioxidant). part of a well balanced diet, animals usually have sufficient body stores to meet their require- Vitamin A in fish oil and pro-vitamin A ments for several days. Modern poultry farms compounds in yellow corn are easily destroyed receive feed deliveries on a weekly or even in the typical mixed ration. Most dehydrated green more frequent basis. Failure to incorporate the feeds are now treated with an antioxidant that vitamin premix in a delivery of feed will likely helps prevent the destruction of the pro-vitamin have little or no effect on the performance of most A compounds during storage. Today, most classes of poultry, assuming the ‘next delivery’ poultry feeds contain supplementary gelatin- contains the vitamin supplement. For breeding or starch-coated synthetic vitamin A which is quite birds, this may not be true, especially for stable. The inclusion of antioxidants in the feed riboflavin, which could well affect hatchability helps to retain the potency of vitamins A and E if hens are fed a deficient diet for 5 to 7 days. in mixed feed. c. Pelleting Vitamin D3 is the only form of the product to be used in poultry diets, since birds cannot The pelleting process usually involves treat- metabolize vitamin D2. Vitamin D3 supple- ing ground feed with steam and then passing the ments are available in a dry, stabilized form. These hot, moist mash through a die under pressure. The products are reported to be stable when mixed with pellets are then cooled quickly and dried by minerals. Hy-D®, a commercial form of 24(OH)D3 means of forced air. Sufficient water should be is also very stable within premixes and mixed feed. applied so that all feed is moistened. Pelleting at too low a temperature, or with too little steam, results Calcium pantothenate may be destroyed in in a ‘shiny pellet’, due to increased friction on the the presence of supplements containing acid pellet going through the die. Often such pellets ingredients such as niacin, arsenilic acid and 3-nitro. are only the original mash enclosed in a hard cap- The calcium chloride complex of calcium sule and have not benefited from the ‘cooking’ pantothenate is more stable than is conventional process brought about by moisture and heat. calcium pantothenate under acid conditions. SECTION 2.5 Feed manufacture

CHAPTER 2 113 INGREDIENT EVALUATION AND DIET FORMULATION Optimum moisture content of a feed required a significant part of the enhanced efficiency is for good pelleting will vary with the composi- due to birds spending less time when eating tion of the feed, however, a range of 15 to 18% pellets resulting in a reduction in maintenance moisture is usually desirable. Feeds containing energy requirements by the bird. This situation liberal quantities of high fiber ingredients will was demonstrated in the classical study by require a higher level of moisture while feeds low Jensen et al. (Table 2.27). in fiber will require less moisture. A good pellet, when hot, can be reduced to two-thirds of its length Table 2.27 Time spent eating mash without crumbling. Such feed has been ‘steam- and pelleted diets cooked’ and holds together well. Rations can be pelleted at any temperature up to 88ºC that Av. time spent Av. feed will allow for maximum production per hour AGE eating consumed without any major fear of vitamin destruction. (min/12 hr day) (g/bird/12 hr) Mash Pellets Feed mills sometimes experience difficulty in Mash Pellets obtaining good pellets when manufacturing 62 57 corn-soybean diets containing added fat. Products Turkeys such as lignosol or bentonite are reasonably 38 37 effective as binding agents, however, they a (38-45 d) 136 16 have little nutritive value, and so one should con- Jensen et al. (1962) sider whether the advantage of introducing such Chickens material into pelleted or crumbled diets warrants the cost. The inclusion of 10 to 15% of wheat, (21-28 d) 103 34 wheat middlings or to a lesser extent barley will often give a pellet of satisfactory hardness. When The need for good quality pellets is often these ingredients are too expensive, the addition questioned by feed manufacturers since of about 2% of extra water to the mash will aid regrinding of pellets or crumbles and feeding these in producing a better pellet. If this procedure is to birds has little apparent effect on performance. followed, however, extra drying of the pellets is required so that mold growth does not occur dur- There seems little doubt that good quality ing storage. Work in our laboratory has indicated crumbles and pellets can be advantageous for that molasses may be used as a pellet binder. In improving the growth rate of turkeys. However, addition to aiding in pelleting, molasses unlike pellet quality seems of less importance with other binders, also contributes energy to the broiler chickens, especially where high-energy diet and so inclusion levels of 1 to 2% in certain diets are considered. More important in the diets may be beneficial. pelleting process is the treatment of feed with steam and pressure, although it is realized that in certain In addition to the advantages of less feed markets it is difficult to sell feed that is not of ‘ideal’ wastage and ease of handling, pelleted diets are pellet quality. more efficiently utilized by poultry. While some of this improvement is due to chemical changes d. Expanding, extrusion and brought about by heat, moisture and pressure, thermal cooking Extrusion has been used for a number of years to produce dry cereal snack foods and more recent- ly, various pet foods. Extrusion usually involves higher temperatures and pressure than does conventional steam pelleting, and so there is greater SECTION 2.5 Feed manufacture

114 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION potential for starch gelatinization and theoreti- nutrients such as some vitamins and amino cally higher digestibility. Extrusion is however acids. In this context synthetic amino acids much slower than conventional pelleting, and may be more susceptible to heat processing initial capital cost is very high. than those naturally present in other ingredi- ents. One recent study suggested some 6% loss Thermal cooking offers the most extreme of total methionine in an extruded broiler starter processing conditions, where high temperatures that contained 0.18% supplemental methionine. can be maintained for very long periods of For most vitamins, other than vitamin C and time, relative to pelleting, extrusion or expansion. MSBC, normal pelleting conditions are expect- Thermal cooking will result in the best possible ed to result in 8 – 10% loss of potency. Extrusion starch gelatinization etc. and will also give the however, which usually employs much higher best control over microbial content. temperatures, can lead to 10 – 15% loss of most vitamins. Under any heat treatment conditions While all heat processing conditions are there will always be significant loss ( 50%) of going to reduce microbial counts in feed there regular forms of vitamin C, and up to 30 – 50% will be a concomitant loss of heat-sensitive loss of MSBC (Table 2.28). Table 2.28 Effect of steam pelleting, extrusion and expansion on loss of vitamin potency Loss of Vitamin Potency (%) Pelleting Expander Extrusion (82ºC, 30 sec) VITAMIN (117ºC, 20 sec) (120ºC, 60 sec) Vitamin A (beadlet) 7 Vitamin D3 (beadlet) 5 4 12 Vitamin E 5 MSBC 18 28 Thiamin 11 Folic acid 7 39 Vitamin C 45 Choline chloride 2 30 50 9 21 6 14 40 63 13 Adapted for Coehlo, (1994) SECTION 2.5 Feed manufacture

CHAPTER 2 115 INGREDIENT EVALUATION AND DIET FORMULATION 2.6 WATER production, health and feed composition. As a generalization, for any bird up to 8 weeks of W ater, is the most critical nutrient that age, an approximation of water needs can be we consciously supply to birds, yet calculated by multiplying age in days x 6 (e.g. in most instances, it is taken completely 42 d = 252 ml/d). for granted and often receives attention only when mechanical problems occur. Water is by far the In calculating the water needs of egg producing largest single constituent of the body, and rep- stock, it should be realized that water intake is resents about 70% of total body weight. Of this not constant throughout the day, rather it varies body water, about 70% is inside the cells of the depending upon the stage of egg formation (Fig body and 30% is in the fluid surrounding the cells 2.2). These data clearly show a peak in water con- and in the blood. The water content of the body sumption immediately following egg laying, is associated with muscle and other proteins. and again, at the time just prior to the end of a This means that as a bird ages, and its body fat con- normal light cycle. This means that water needs tent increases, then its body water content must be accommodated during these peak times expressed as a percent of body weight will (around 10 – 11 a.m. and 6 – 8 p.m.) within a decrease. The bird obtains its water by drinking, 6 a.m. – 8 p.m. light cycle, because most birds from the feed and by catabolism of body tissues will be in the same stage of egg formation as direct- which is a normal part of growth and development. ed by the light program. a. Water intake Fig. 2.2 Water consumption of laying hens in relation to time of oviposition. Water intake of a bird increases with age, (from Mongin and Sauveur, 1974) although it decreases per unit of body weight. Drinking behaviour is closely associated with feed SECTION 2.6 intake, and so most factors affecting feed intake Water will indirectly influence water intake. At moderate temperatures, birds will consume almost twice as much water by weight as they eat as feed. Any nutrients that increase mineral excretion by the kidney will influence water intake. For example, salt, or an ingredient high in sodium, will increase water intake. Similarly, feeding an ingredient high in potassium such as molasses or soybean meal, or calcium/phosphorus sources contaminated with magnesium, will result in increased water intake. Such increases in water intake are of no major concern to the bird itself, but obviously result in increased water excretion and so wetter manure. Table 2.29 indicates average water consumption of various poultry species maintained at 20 or 32ºC. These figures indicate approximate water usage values and will vary with the stage of

116 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION Table 2.29 Daily ad-lib water consumption of poultry (litres per 1,000 birds) Leghorn pullet 4 wk 20ºC 32ºC 12 wk Laying hen 18 wk 50 75 Non-laying hen 50% prod. Broiler breeder pullet 90% prod. 115 180 Broiler breeder hen 4 wk 140 200 Broiler chicken 12 wk 18 wk 150 250 Turkey 50% prod 80% prod 180 300 Turkey breeder hen 1 wk Turkey breeder tom 3 wk 120 200 Duck 6 wk 9 wk 75 120 Duck breeder 1 wk Goose 4 wk 140 220 12 wk Goose breeder 18 wk 180 300 1 wk 180 300 4 wk 8 wk 210 360 1 wk 24 40 4 wk 12 wk 100 190 240 500 300 600 50 24 200 110 600 320 850 450 900 500 1100 500 50 28 230 120 600 300 500 240 50 28 450 250 600 350 600 350 These figures indicate approximate water usage values and will vary with the stage of production, health and feed consumption. SECTION 2.6 Water

CHAPTER 2 117 INGREDIENT EVALUATION AND DIET FORMULATION The contribution of feed is not usually heat loss takes place mainly through the considered in calculating water balance, yet respiratory tract. The fowl has no sweat glands, most feeds will contain around 10% of free consequently evaporation via the skin is water. Other bound water may become minimal. Evaporation overwhelmingly occurs available during digestion and metabolism, via the moist surface layer of the respiratory such that 7 – 8% of total requirements can tract to the inspired air which is ‘saturated’ with originate from the feed. water vapor at body temperature. Evaporation rate is therefore proportional to respiratory rate. Water is created in the body as a by-product Heat loss through evaporation represents only of general metabolism. If fats are broken down, about 12% of total heat loss in the broiler chicken then about 1.2 g of water are produced from each housed at 10ºC, but this increases dramatically gram of fat. Likewise protein and carbohydrate through 26 – 35ºC where it may contribute as will yield about 0.6 and 0.5 g per gram respec- much as 50% of total heat loss from the body. tively. Total metabolic water can be more At high temperatures, evaporative water loss will easily estimated from the bird’s energy intake approximate water intake and so this obviously because on average 0.14 g of water is produced imposes major demands on the ventilation systems. for each kcal of energy metabolized. This means that for a laying hen, consuming 280 kcal c. Water balance and ME/day, about 39 g of metabolic water will be dehydration produced. Feed and metabolic water together therefore account for about 20% of total water Under normal physiological conditions for needs, and so are very important in the calcu- adult birds, water intake and output are controlled lation of water balance. to maintain a constant level of water in the body. A positive water balance is found in the b. Water output growing bird to accommodate growth. With drinking water being supplied ad libitum under The quantities of water excreted in the feces most commercial conditions, dehydration due and urine are dependent on water intake. Broiler to lack of drinking water should not occur. The chickens produce excreta containing about 60 adverse effects of short term reduced water – 70% moisture, while that produced by the intake are often a result of a concomitant laying hen contains about 80% moisture. For the reduction in feed intake. laying hen at least, the quantity of water excreted in the feces is about four times that The turkey poult is most susceptible to dehy- excreted as urine. Undoubtedly, this loss is dration resulting from drinking water deprivation, subject to considerable variation with the amount and mortality occurs when drinking water is and nature of undigested feed. re-introduced to the poults. Poults 11 days of age, subjected to a 48-hour period of water deprivation, Evaporation is one of four physical routes by showed 83% mortality following reintroduction which poultry can control their body tempera- of ad libitum cold water, and in most cases ture. Due to its molecular structure and bonding, death occurred within 30 minutes. Poults 18 days water has an unusually high latent heat of of age showed less mortality which was some- vaporization. Some 0.5 kcals of heat are required what delayed (2 –34 hours) while older turkeys to vaporize one gram of water. Evaporative subjected to the same conditions showed no SECTION 2.6 Water

118 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION mortality. The exact reason for this mortality is When birds received cool water for a 4-week not fully understood. Poults deprived of water period, they were able to maintain peak egg pro- show reduced body temperature, and when duction, possibly due to higher feed intake. water is introduced, body temperature continues Under commercial conditions, with long runs of to decrease for 30 minutes or so. Poults often water pipe, it is obviously very difficult to dupli- drink large amounts of water following dehydration, cate these conditions. However, it does show the and it has been suggested that the problem importance of trying to keep the water as cool as relates to simple water intoxication and associated possible, and in this regard, the usual practice of dilution of electrolytes in the body. If young poults placing water tanks on high towers in direct sun- are dehydrated for whatever reason, then light should be seriously questioned. administration of electrolytes in the water may be beneficial. This problem does not seem to occur e. Water restriction with chickens. Most birds should have continuous access to d. Drinking water temperature water. Some breeders recommend water restric- tion of laying hens as a means of preventing wet Water offered to birds is usually at ambient manure, especially in hot climates, although temperature. This means that for laying birds serious consideration should be given to other pre- housed under controlled environmental condi- ventative measures prior to this last resort. tions, the temperature of drinking water is held Production may drop as much as 30% when fairly constant, while for broiler chickens, water hens are deprived of water for 24 hours, and it may temperature decreases with age corresponding take as long as 25 to 30 days before production to a reduction in brooding temperature. It is only returns to normal. Similar results have been for the first few days of a chick’s life that drinking reported for broilers where decreases in water sup- water temperature is specified, where traditional ply have resulted in marked depressions in weight management recommendations suggest the use gain. Table 2.31 shows the results of a con- of ‘warm’ water. However, there is little documented trolled test where water restriction was imposed evidence supporting this recommendation. on broilers. There was a marked drop in feed intake- Birds drink more water at higher environmental with the greatest reduction occurring with the first temperatures, yet the cooling of water may 10% reduction in water intake, causing a 10% result in even higher intakes. Table 2.30 outlines decline in feed intake. the results of a small scale study conducted with layers housed at 33ºC. Table 2.31 Effect of water restric- tion on relative weekly feed con- Table 2.30 Layer performance at 33ºC sumption of broilers with hot vs cold drinking water Age (weeks) Degree of water restriction (%) Water temperature 0 10 20 30 40 50 84 84 75 84 71 Feed/bird/day (g) 33ºC 2ºC 2 100 99 102 90 85 80 Egg production (%) 63.8 75.8 4 100 88 81 78 73 71 Egg weight (g) 81.0 93.0 6 100 86 83 79 74 67 49.0 48.5 8 100 90 87 81 77 73 Total 100 * All birds receive water ad libitum for first week. (Data from Kellerup et al. 1971) SECTION 2.6 Water

CHAPTER 2 119 INGREDIENT EVALUATION AND DIET FORMULATION The effect of an accidental 48-hour cut in Fig. 2.3 Effect of a 48-hour period of water deprivation on egg numbers. water supply to layers is shown in Fig. 2.3. f. Water quality Production dropped off very quickly to virtu- Water quality should be monitored with ally 0%, although interestingly a few birds assays conducted at least each 6 months. Chemical contaminants are the most serious maintained normal production. Most birds problem affecting water quality. However, poultry usually adjust to high levels of certain that resumed production within 28 d achieved minerals after a period of time, and so only in a relatively small number of cases does the normal output for their age, and there was an mineral content of water significantly affect the performance of a flock. There are certain areas indication of improved shell quality. where water salinity is high enough to adversely For certain classes of stock, intentional water affect flock performance. In such cases, it may be necessary to remove some of the supplemental restriction is used as a management tool. To date, salt from the diet. However, this should be this is most common with broiler breeders fed done only after careful consideration to ensure on a skip-a-day program. Water restriction may that there will be a sufficient salt intake because occur on both feed-days and off-feed days. performance can be severely reduced if salt Restriction on off-feed days is done because it intake is too low. is assumed that birds will over-consume water on these days due to hunger or boredom. Any bacterial contamination of water is an However, it seems as though breeders do not drink indication that surface water is entering the that much water on an off-feed day (Table 2.32). water supply and steps should be taken to cor- rect the situation. Alternatively, the water may Table 2.32 Water intake of 13 be chlorinated to eliminate contamination. week-old broiler breeders Another problem that can exist with water is a (ml/bird/day) Feeding day Water restricted Ad-lib Non-feed day water Average each only on day feed days 270 36 175 182 153 108 109 141 145 All birds drank the same average amount of water over a 2 day feeding schedule regardless of water treatment. When birds are given free-choice water, they obviously over-consume on a feed-day, but drink little on an off-feed day. These data suggest the need for water restriction of skip-a-day fed birds, although special attention on feed-days rather than off-feed days will be most advantageous in preventing wet litter. SECTION 2.6 Water

120 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION build-up of nitrates or nitrites. Such contamination age and class of stock, but in general these is usually an indication of run-off from animal values can be used as guidelines to indicate the wastes or fertilizers leaching into the water possibility of toxicity with birds consuming system. Although the standard for human water such water over prolonged periods. supply is 10 to 20 ppm of nitrate nitrogen, higher levels can usually be tolerated by animals. In the last few years, there has been an Levels beyond 50 ppm need to be present before interest in the treatment of water for poultry. In water is suspected as a factor in the poor per- large part, this is carried out in an attempt to formance of poultry. As nitrites are 10 times more prevent problems of mineral deposits occurring toxic than nitrates, and because bacteria in the in pipelines, boilers and automatic waterers, intestinal tract and in the water supply can rather than preventing toxicity problems per convert nitrates to nitrites, levels of these two se. Such treatments involves orthophosphates, contaminants in the water supply must be kept which sequester calcium and magnesium, there- to a minimum. Superchlorination of the water by preventing precipitation in the water supply. will quickly oxidize nitrites to nitrates thereby In most situations, these systems will not reducing their toxicity. Before initiating a super- unduly alter the water composition in terms of chlorination program, check with a local the bird’s nutritional requirements. As a last resort, pathologist to ensure a proper level of chlorination some producers use water softeners, and in in order not to interfere with the performance or these situations, there is some cause for concern, efficiency of vaccines or other drugs. regarding the bird’s health. These softeners contain an active column of resin, that has Table 2.33 Concentration of water the ability to exchange one ion (mineral) for minerals above which problems another. Over time, the resin column becomes may occur with poultry (ppm) saturated with the absorbed minerals (usually calcium and magnesium salts) that are extracted Total soluble salts (hardness) 1500 from the water, and so it must be flushed and Chloride 500 re-charged with the donor mineral. In most Sulphate 1000 softeners, this recharging process involves Iron 50 sodium from NaCl. This means that sodium is Magnesium 200 replacing other minerals in the water, because Potassium 500 sodium salts readily dissolve, and will not leave Sodium 500 mineral scale in the equipment. The amount of Nitrate 50 sodium that is pumped into the water supply is Arsenic 0.01 therefore in direct proportion to the hard pH 6.0 – 8.5 minerals extracted from the water. In areas of very hard water, one can expect higher levels of Table 2.33 outlines standards for drinking water sodium in water reaching the birds, and vice-versa in terms of mineral levels. Toxicity and loss of in areas of lower water hardness. Problems in performance will vary dependent upon bird water sodium will likely occur if softener salt use exceeds 40 kg/40,000 litres of water. SECTION 2.6 Water

CHAPTER 2 121 INGREDIENT EVALUATION AND DIET FORMULATION g. General management sufficient water to sustain maximum production. considerations with water When the lower beak of the bird is too long, up to 20% loss in egg production can occur, com- Where continuous flow water troughs are used pared with properly beak-trimmed birds. When for caged birds, one must be sure that birds at disease or stress occur, a decrease in water con- the end of the trough obtain sufficient water. sumption is usually noted a day or two before a A rise in house temperature will result in decrease in feed consumption. For this reason, increased water consumption, and unless the water managers should consider installing water meters supply can be adjusted accordingly, shortages on all water lines to each pen or cage row and of water may result for the birds at the far end of have the attendant keep a daily record of water the line. It has also been demonstrated that poor- consumption. Such records can give early warn- ly beak-trimmed birds may not be able to drink ing of potential problems with the flock. SECTION 2.6 Water

122 CHAPTER 2 INGREDIENT EVALUATION AND DIET FORMULATION Suggested Reading Angel, R. et al. (2002). Phytic acid chemistry: National Academy of Sciences, (1974). In: Nutrients Influence on phytin phosphorus availability and and Toxic Substances in Water for Livestock and phytase efficacy. J. Appl. Poult. Res. 11:471-480. Poultry. NAS Washington, D.C. Bedford, M.R., (2002). The foundation of conducting National Academy of Sciences, (1980). In: Mineral feed enzyme research and the challenges of explain- Tolerances of Domestic Animals. NAS Washington, D.C. ing the results. J. Appl. Poultry Res. 11:464-470. National Academy of Sciences, (1987). In: Vitamin Coelho, M.B., (1994). Vitamin stability in premixes Tolerance of Animals. NAS Washington, D.C. and feeds: A practical approach. BASF Technical Symposium. Indianapolis. May 25. pp 99-126. National Academy of Sciences, (1994). In: Nutrient Dale, N., (1997). Metabolizable energy of meat and Requirements of Poultry. 9th Rev. Ed. NAS Washing- bone meal. J. Appl. Poultry Res. 6:169-173. ton, D.C. Kersey, J.H. et al., (1997). Nutrient composition of Novus, (1994). In: Raw Material Compendium. 2nd spent hen meals produced by rendering. J. Appl. Edition. Publ. Novus Int., Brussels. Poultry Res. 6:319-324. Pesti, G.M. and B.R. Mitter, (1993). In: Animal Feed Lane, R.J. and T.L. Cross, (1985). Spread sheet Formulation. Publ. Van Nostrand Reinhold, N.Y. applications for animal nutrition and feeding. Shirley, R.B. and C.M. Parsons, (2000). Effect of pres- Reston Publ., Reston, Virginia. sure processing on amino acid digestibility of meat Leeson, S., G. Diaz and J.D. Summers, (1995). In: and bone meal for poultry. Poult. Sci. 79:1775-1781. Poultry Metabolic Disorders and Mycotoxins. Publ. Sibbald, I.R., (1983). The TME system of feed eval- University Books, Guelph, Ontario, Canada uation. Agriculture Canada 1983-20E. Animal Mateos, G.G., R. Lazaro and M.I. Garcia, (2002). Research Centre, Ottawa, Canada. The feasibility of using nutritional modification to Sibbald, I.R., (1987). Examination of bioavailable replace drugs in poultry feeds. J. Appl. Poult. Res. amino acids in feedstuffs for poultry and pigs. A 11:437-452. review with emphasis on balance experiments. Can. McDowell, L.R., (1989). In: Vitamins in Animal J. Anim. Sci. 67:221-301. Nutrition. Academic Press, N.Y. Valdes, E.V. and S. Leeson, (1992). Near infrared Moritz, J.S. and L.D. Latshaw, (2001). Indicators of reflectance analysis as a method to measure metabo- nutritional value of hydrolysed feather meal. lizable energy in complete poultry feeds. Poult. Sci. Poultry Sci. 80:79-86. 71:1179-1187. National Academy of Sciences, (1973). In: Effect of Wiseman, J., F. Salvador and J. Craigon, (1991). Processing on the Nutritional Value of Feeds. NAS Prediction of the apparent metabolizable energy con- Washington, D.C. tent of fats fed to broiler chickens. Poult. Sci. 70:1527-153.

FEEDING PROGRAMS 3CHAPTER 123 FOR GROWING EGG-STRAIN PULLETS Page 3.1 Diet specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 3.2 Strain specific nutrient requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 3.3 Feeding management of growing pullets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 a. General considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137 b. Manipulating nutrient intake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141 c. Suggested feeding program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143 d. Manipulation of body weight at sexual maturity . . . . . . . . . . . . . . . . . . . .146 e. Nutrient management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .148 f. Prelay nutrition and management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149 i. considerations for calcium metabolism ii. prelay body weight and composition iii. early eggsize iv. pre-pause v. urolithiasis g. Lighting programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 h. Feed restriction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 3.1 Diet specifications example, the pullet will eat less and so nutrients, such as amino acids, will have to T able 3.1 shows diet specifications be increased accordingly. Pullets grown for Leghorn pullets, while Table 3.2 on the floor, rather than in cages, will eat more provides comparable data for brown feed, and so amino acid levels can be egg birds. These nutrient specifications are reduced. The diet specifications are based intended for guidelines in diet formulation on using conventional ingredients where when general growth and development (as nutrient digestibility is fairly predictable. outlined by the primary breeders) is the goal When non-standard ingredients are used, it of the rearing program. Pullets are grown under is essential to formulate to more stringent stan- a range of environmental conditions and dards of digestibility, such as for digestible housing systems and these can influence amino acids. Tables 3.3 – 3.6 show exam- nutrient needs. In most situations, variable ples of diet formulations using corn, wheat management conditions influence energy or sorghum with and without meat meal. needs, and so it is important to relate all other nutrients to energy level. In hot climates for SECTION 3.1 Diet specifications

124 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.1 Diet specifications for leghorn pullets Starter Grower Developer Pre-lay (0 to 6) (6 to 10) Age (weeks) (10 to 16) (16 to 18) Crude Protein (%) 20.0 18.5 Metabolizable Energy (kcal/kg) 2900. 2900. 16.0 16.0 Calcium (%) Available Phosphorus (%) 1.00 0.95 2850. 2850. Sodium (%) 0.45 0.42 0.17 0.17 0.92 2.25 Methionine (%) Methionine+cystine (%) 0.40 0.42 Lysine (%) Threonine (%) 0.17 0.17 Tryptophan (%) Arginine (%) 0.45 0.42 0.39 0.37 Valine (%) 0.78 0.72 0.65 0.64 Leucine (%) 1.10 0.90 0.80 0.77 Isoleucine (%) 0.72 0.70 0.60 0.58 Histidine (%) 0.20 0.18 0.16 0.15 Phenylalanine (%) 1.15 0.95 0.86 0.80 0.75 0.70 0.65 0.60 Vitamins (per kg of diet): 1.30 1.10 0.92 0.88 Vitamin A (I.U) 0.70 0.60 0.51 0.48 Vitamin D3 (I.U) 0.35 0.32 0.29 0.26 Vitamin E (I.U) 0.65 0.60 0.53 0.49 Vitamin K (I.U) Thiamin (mg) 8000 Riboflavin (mg) 2500 Pyridoxine (mg) Pantothenic acid (mg) 50 Folic acid (mg) 3 Biotin (µg) 2 Niacin (mg) 5 Choline (mg) 4 Vitamin B12 (µg) 12 0.75 Trace minerals (per kg of diet): 100 Manganese (mg) 40 Iron (mg) Copper (mg) 500 Zinc (mg) Iodine (mg) 12 Selenium (mg) 60 30 6 60 0.5 0.3 SECTION 3.1 Diet specifications

CHAPTER 3 125 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.2 Diet specifications for brown egg pullets Starter Grower Developer Prelay (0 to 5) (5 to 10) Age (wks) (10 to 15/16) (15/16 to 17) Crude Protein (%) 20.0 18.0 Metabolizable Energy (kcal/kg) 2900 2850 15.5 16.0 Calcium (%) Av. Phosphorus (%) 1.00 0.95 2800 2850 Sodium (%) 0.45 0.42 0.17 0.17 0.90 2.25 Methionine (%) Methionine+cystine(%) 0.45 0.38 0.42 Lysine (%) 0.78 Threonine (%) 1.10 0.17 0.17 Tryptophan (%) 0.72 Arginine (%) 0.20 0.41 0.35 0.34 Valine (%) 1.15 0.71 0.63 0.61 Leucine (%) 0.75 0.90 0.75 0.73 Isoleucine (%) 1.30 0.68 0.60 0.57 Histidine (%) 0.70 0.18 0.15 0.15 Phenylalanine (%) 0.35 0.95 0.86 0.80 0.65 0.70 0.65 0.60 Vitamins (per kg of diet): 1.10 0.92 0.88 Vitamin A (I.U) 0.60 0.51 0.45 Vitamin D3 (I.U) 0.32 0.27 0.24 Vitamin E (I.U) 0.60 0.50 0.45 Vitamin K (I.U) Thiamin (mg) 8000 Riboflavin (mg) 2500 Pyridoxine (mg) Pantothenic acid (mg) 50 Folic acid (mg) 3 Biotin (µg) 2 Niacin (mg) 5 Choline (mg) 4 Vitamin B12 (µg) 12 0.75 Trace minerals (per kg of diet): Manganese (mg) 100 Iron (mg) 40 Copper (mg) 500 Zinc (mg) 12 Iodine (mg) Selenium (mg) 60 30 6 60 0.5 0.3 SECTION 3.1 Diet specifications

126 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.3 Examples of chick starter diets (kg) 1 2 3 456 544 555 Corn 628 643 578 568 Wheat 100 105 100 100 Sorghum 50 100 100 50 Wheat shorts 310 258 30 27 250 Meat meal 10 10 227 191 10 10 Soybean meal 10 10 Fat 1.1 1.3 1.7 1.6 DL-Methionine* 3.1 2.8 1.5 1.6 3.4 2.9 Salt 18 13.2 2.7 2.3 18.5 13.3 Limestone 12.8 3.7 19.3 16.1 11.4 3.2 Dical Phosphate 1 1 10.5 5 1 1 Vit-Min Premix** 1000 1000 1 1 1000 1000 1000 1000 Total (kg) 21.0 21.0 2930 2930 20.6 20.6 20.0 21.0 Crude Protein (%) 2900 2930 2930 2930 ME (kcal/kg) 1.05 1.05 Calcium (%) 0.47 0.47 1.00 1.05 1.05 1.05 Av. Phos. (%) 0.18 0.18 0.45 0.45 0.45 0.47 Sodium (%) 0.46 0.47 0.18 0.18 0.18 0.18 Methionine (%) 0.78 0.78 0.45 0.46 0.45 0.45 Meth + Cys. (%) 1.16 1.17 0.78 0.78 0.81 0.81 Lysine (%) 0.89 0.87 1.10 1.10 1.10 1.20 Threonine (%) 0.29 0.28 0.76 0.74 0.78 0.80 Tryptophan (%) 0.31 0.30 0.27 0.27 * or eqivalent MHA ** with choline SECTION 3.1 Diet specifications

CHAPTER 3 127 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.4 Examples of pullet grower diets 1 23 45 6 Corn 550 555 590 558 Wheat 620 150 Sorghum 150 160 20 Wheat shorts 165 150 20 568 234 Meat meal 256 50 180 150 10 Soybean meal 10 200 188 23.5 Fat 10.5 10 1.3 238 1.6 DL-Methionine* 1.2 2.5 10 3.2 Salt 3.3 1.3 1.3 15.6 15.4 Limestone 17.3 2.7 2.7 6.1 1.7 6.8 Dical Phosphate 11.2 12.5 18 1 3.4 1 Vit-Min Premix** 1 2 9 1000 17.9 1000 1000 1 1 10 Total (kg) 1000 1000 1 19.5 19.0 1000 2930 Crude Protein (%) 2930 ME (kcal/kg) 19.0 19.4 19.5 18.9 0.97 Calcium (%) 0.97 2930 2900 2930 2930 0.43 Av. Phos. (%) 0.43 0.18 Sodium (%) 0.18 0.97 0.97 0.97 0.97 0.42 Methionine (%) 0.43 0.43 0.42 0.43 0.42 0.76 Meth + Cys. (%) 0.72 0.18 0.18 0.18 0.18 1.1 Lysine (%) 1.0 0.45 0.42 0.42 0.42 0.74 Threonine (%) 0.8 0.72 0.73 0.72 0.75 0.26 Tryptophan (%) 0.26 1.0 1.0 1.0 1.0 0.78 0.7 0.7 0.72 * or eqivalent MHA 0.25 0.29 0.28 0.25 ** with choline SECTION 3.1 Diet specifications

128 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.5 Examples of pullet developer diets 1 23 4 56 534 535 Corn 649 Wheat 239 648 Sorghum 200 Wheat shorts 186 240 197 20 572 580 Meat meal 10 20 96 205 203 Soybean meal 167 114 10 20 Fat 1.1 10 10 181 161 DL-Methionine* 3.3 1.4 10 10 Salt 16 1.2 1.4 2.4 1.3 Limestone 9.6 3.1 2.7 15.4 3.5 1.3 Dical Phosphate 1 16.4 17.5 4.8 17 3.2 Vit-Min Premix** 1000 6.3 8.4 1 9.2 15 1 1 1000 1 5.5 Total (kg) 1000 1000 1 16.5 1000 1000 Crude Protein (%) 16.5 16.5 16.5 2850 ME (kcal/kg) 2855 2855 2850 16.5 16.5 Calcium (%) 0.92 2850 2850 Av. Phos. (%) 0.92 0.92 0.92 0.39 Sodium (%) 0.39 0.39 0.39 0.18 0.92 0.92 Methionine (%) 0.18 0.18 0.18 0.38 0.39 0.39 Meth + Cys. (%) 0.39 0.39 0.38 0.63 0.18 0.18 Lysine (%) 0.63 0.63 0.63 0.79 0.35 0.35 Threonine (%) 0.82 0.83 0.79 0.56 0.64 0.64 Tryptophan (%) 0.69 0.68 0.57 0.24 0.86 0.86 0.22 0.22 0.24 0.62 0.61 0.22 0.21 * or eqivalent MHA ** with choline SECTION 3.1 Diet specifications

CHAPTER 3 129 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.6 Examples of prelay diets 1 2 3 4 56 527 481 Corn 615 629 574 593 Wheat 227 306 180 180 Sorghum 50 180 180 60 Wheat shorts 168 100 34 167 105 Meat meal 10 10 122 90 11 10 Soybean meal 1.4 1.6 16.7 11 1.6 1.5 Fat 3 2.4 1.4 1.4 3.2 2.7 DL-Methionine* 51.6 46.6 2.5 2 51.3 46.8 Salt 11 1.4 51.5 48.2 10.9 Limestone 1 1 9.9 3.4 1 1 Dical Phosphate 1000 1000 1 1000 1000 Vit-Min Premix** 1 1000 16.0 16.0 1000 16.0 16.2 Total (kg) 2850 2850 17.0 2850 2900 2.25 2.25 16.6 2850 2.25 2.30 Crude Protein (%) 0.42 0.42 2850 2.25 0.42 0.42 ME (kcal/kg) 0.17 0.17 2.25 0.42 0.17 0.18 Calcium (%) 0.41 0.42 0.42 0.17 0.37 0.37 Av Phosphorus (%) 0.64 0.64 0.17 0.39 0.66 0.65 Sodium (%) 0.78 0.78 0.38 0.64 0.82 0.84 Methionine (%) 0.66 0.63 0.64 0.84 0.60 0.58 Meth + Cystine (%) 0.22 0.20 0.81 0.58 0.21 0.20 Lysine (%) 0.58 0.24 Threonine (%) 0.25 Tryptophan (%) * or eqivalent MHA ** with choline 3.2 Strain specific nutrient requirements T here are often questions about the need for strain-specific diets in growing white ple, amino acid levels in the starter diet are or brown egg pullets. Such differences 10-15% higher for this smaller strain. would most likely be induced by differential growth Starter diets are shown in Table 3.7 where there rate and/or different mature body weight. As shown is a fairly consistent energy base for all strains, in Table 3.12 there are differences in growth rate although the diet for the smallest body weight of commercial pullets throughout the 18 week strain, namely Lohmann, is much higher in grow-out period. At 4 weeks of age, there is a lysine and threonine. This same trend continues 14% difference in body weight between the for the grower diets (Table 3.8). Interestingly, for lightest and heaviest strain, while at 18 weeks this the developer diets (Table 3.9), the highest difference is 10%. This differential growth rate amino acid needs are for the heaviest pullet is reflected in nutrient needs, where for exam- SECTION 3.2 Strain specific nutrient requirements

130 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.7 Starter diets for white egg pullets Age fed (wks) Shaver Hyline 36 Hyline 98 Lohmann Bovan (0 to 6*) (0 to 6) (0 to 6) (0 to 3) (0 to 6) Protein (%) 19.5 20 20 21 20 ME (kcal/kg) 2900 2960 2960 2900 2980 Calcium (%) Av. Phosphorus (%) 1.0 1.0 1.0 1.05 1.0 Sodium (%) 0.47 0.50 0.5 0.48 0.5 Linoleic acid (%) 0.16 0.19 0.19 0.16 0.18 1.2 1.0 1.0 1.4 1.3 Methionine (%) 0.42 0.48 0.48 0.48 0.45 Methionine+cystine (%) 0.73 0.8 0.8 0.83 0.8 Lysine (%) 0.95 1.1 1.1 1.2 1.1 Tryptophan (%) 0.20 0.20 0.20 0.23 0.21 Threonine (%) 0.68 0.75 0.75 0.8 0.75 * Extrapolated from Management Guide Information Table 3.8 Grower diets for white egg pullets Age fed (weeks) Shaver Hyline 36 Hyline 98 Lohmann Bovan (6 to 12*) (6 to 8) (6 to 8) (3 to 8) (6 to 10) Protein (%) 17.5 18 18 19 18 ME (kcal/kg) 2800 3025 2960 2800 2970 Calcium (%) Av Phosphorus (%) 0.95 1.0 1.0 1.03 1.0 Sodium (%) 0.47 0.47 0.48 0.46 0.48 Linoleic acid (%) 0.16 0.18 0.18 0.16 0.17 1.0 1.0 1.0 1.44 1.3 Methionine (%) 0.38 0.44 0.44 0.39 0.4 Methionine+cystine (%) 0.66 0.73 0.73 0.69 0.72 Lysine (%) 0.86 0.9 0.9 1.03 1.0 Tryptophan (%) 0.18 0.18 0.18 0.22 0.19 Threonine (%) 0.62 0.7 0.7 0.72 0.7 * Extrapolated from Management Guide Information SECTION 3.2 Strain specific nutrient requirements

CHAPTER 3 131 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.9 Developer diets for white egg pullets Age fed (weeks) Shaver Hyline 36 Hyline 98 Lohmann Bovan (12 to 17) (8 to 15) (8 to 16) (8 to 16) (10 to 15) Protein (%) ME (kcal/kg) 16.5 16.0 16.0 14.9 16.0 Calcium (%) 2750 3075 2940 2800 2960 Av Phosphorus (%) Sodium (%) 1.15 1.0 1.0 0.92 1.0 Linoleic acid (%) 0.45 0.45 0.46 0.38 0.45 0.16 0.17 0.17 0.16 0.17 Methionine (%) 1.0 1.0 1.0 1.03 1.3 Methionine+cystine (%) Lysine (%) 0.36 0.39 0.39 0.34 0.36 Tryptophan (%) 0.63 0.65 0.65 0.58 0.65 Threonine (%) 0.81 0.75 0.75 0.67 0.88 0.16 0.16 0.16 0.16 0.17 0.58 0.60 0.60 0.51 0.60 Table 3.10 Prelay diets for white egg pullets Age fed (weeks) Hyline 36 Hyline 98 Lohmann Bovan (15 to 19*) (16 to 18) (16 to 18*) (15 to 17) Protein (%) 15.5 15.5 18 15 ME (kcal/kg) 3040 2940 2800 2930 Calcium (%) Av Phosphorus (%) 2.75 2.75 2.05 2.25 Sodium (%) 0.4 0.45 0.46 0.45 Linoleic acid (%) 0.18 0.18 0.16 0.18 1.0 1.0 1.03 1.2 Methionine (%) 0.36 0.36 0.37 0.36 Methionine+cystine (%) 0.60 0.60 0.70 0.63 Lysine (%) 0.75 0.75 0.87 0.8 Tryptophan (%) 0.15 0.15 0.21 0.16 Threonine (%) 0.55 0.55 0.62 0.55 * Extrapolated from Management Guide Information SECTION 3.2 Strain specific nutrient requirements

132 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.11 Feed intake for white egg pullets (grams) Starter Shaver1 Hyline 36 Hyline 98 Lohmann Bovan Grower 1099 1085 1141 350 931 Developer 2072 621 665 1258 1239 Pre-lay 2702 2645 3241 3327 2023 Layer 860 980 1048 924 Total (to 18wks) 5873 448 476 1 No prelay diet. 5659 6027 5983 5593 Table 3.12 Body weight of white egg pullets (grams) Week Shaver Hyline 36 Hyline 98 Lohmann Bovan 1 70 65 65 70 70 2 135 110 110 115 105 3 205 180 180 170 175 4 280 250 260 240 250 5 365 320 350 320 320 6 450 400 450 400 395 7 535 500 550 470 475 8 620 590 650 540 560 9 700 680 750 614 650 10 775 770 850 682 735 11 845 870 930 749 820 12 915 950 816 900 13 975 1000 878 975 14 1030 1070 941 15 1035 1100 1130 998 1045 16 1095 1160 1180 1110 17 1165 1210 1230 1056 1170 18 1235 1250 1270 1118 1225 1300 1280 1320 1181 1270 (Shaver) while the smaller Lohmann apparent- tion, and so it is somewhat surprising that there is ly need much lower amino acid intake. There a considerable range of calcium (2.05 to 2.75%) is considerable variation in the specifications for and available phosphorus (0.4 to 0.5%) given for strain-specific prelay diets (Table 3.10). the various strains. At this time, the Lohmann seems to have higher amino acid needs. The various strains To some extent, variable diet specifications for of pullets consume anywhere from 5.6 to 6.0 kg prelay diets relate to age of bird. Prelay diets are of feed to 18 weeks, and this is somewhat influ- most beneficial in terms of optimizing calcium accre- enced by diet energy level (Table 3.11). SECTION 3.2 Strain specific nutrient requirements

CHAPTER 3 133 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Body weight of pullets are shown in Table 3.12. For critical nutrients such as vitamin E there are six-fold differences in suggested specifications. There are significant differences in vitamin- mineral premixes suggested for the various Comparable diet specifications for brown egg strains of commercial pullets (Table 3.13). In some pullets are shown in Tables 3.14 to 3.20. There instances, the breeding companies do not give seems to be more consistency in strain specif- a specification for a certain nutrient, and pre- ic specifications for brown egg pullets, although sumably this means that the natural ingredi- it should be emphasized that the feeding ents provide adequate levels for this strain of bird. schedule in terms of bird age is more variable. Table 3.13 Vitamin-mineral premix for white egg pullets units/kg Shaver Hyline 36,98 Lohmann Bovan feed Vitamin A 12000 8000 12000 8000 Vitamin D3 IU 2500 3300 2000 2500 Vitamin E IU Vitamin K IU 30 66 20* 10 IU 3 5.5 3 3 Thiamin mg 2.5 0 1 1 Riboflavin mg 7 4.4 4 5 Pantothenic acid mg 12 5.5 8 7.5 Niacin mg 40 28 30 30 Pyridoxine mg 5 0 3 2 Biotin µg 200 55 50 100 Folic acid mg 1 0.22 1 0.5 Vitamin B12 µg 30 8.8 15 12 Choline mg 1000 275 200* 300 Iron mg 80 33 25 35 Copper mg 10 4.4 5 7 Manganese mg 66 66 100 70 Zinc mg 70 66 60 70 Iodine mg 0.4 0.9 0 1 Selenium mg 0.25 0.3 0.3 0.2 * Extrapolated from Management Guide Information SECTION 3.2 Strain specific nutrient requirements

134 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.14 Starter diets for brown egg pullets Age fed (weeks) Shaver ISA Hyline Bovan (0 to 4) (0 to 5) (0 to 6) (0 to 6) Protein (%) ME (kcal/kg) 20.5 20.5 19.0 20.0 Calcium (%) 2950 2950 2870 2980 Av Phosphorus (%) Sodium (%) 1.07 1.07 1.0 1.0 Linoleic acid (%) 0.48 0.48 0.48 0.5 0.16 0.16 0.18 0.18 Methionine (%) 1.0 1.3 Methionine+cystine (%) 0.52 0.52 Lysine (%) 0.86 0.86 0.48 0.45 Tryptophan (%) 1.16 1.16 0.8 0.8 Threonine (%) 0.21 0.21 1.1 1.1 0.78 0.78 0.2 0.21 0.75 0.75 Table 3.15 Grower diets for brown egg pullets Age fed (wks) Shaver ISA Hyline Lohmann Bovan (4 to 10) (5 to 10) (6 to 9) (0 to 8) (6 to 10) Protein (%) ME (kcal/kg) 19.0 20.0 16.0 18.5 18.0 Calcium (%) 2850 2850 2890 2775 2940 Av Phosphorus (%) Sodium (%) 1.0 1.0 1.0 1.0 1.0 Linoleic acid (%) 0.42 0.44 0.46 0.45 0.5 0.16 0.17 0.18 0.16 0.17 Methionine (%) 1 1.4 1.3 Methionine+cystine (%) Lysine (%) 0.45 0.47 0.44 0.38 0.4 Tryptophan (%) 0.72 Threonine (%) 0.76 0.80 0.70 0.67 1.0 0.19 0.98 1.03 0.9 1.0 0.7 0.19 0.2 0.18 0.21 0.66 0.69 0.7 0.7 SECTION 3.2 Strain specific nutrient requirements

CHAPTER 3 135 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.16 Developer diets for brown egg pullets Age fed (wks) Shaver ISA Hyline Lohmann Bovan (10 to 16) (10 to 16) (9 to 16) (8 to 16) (10 to 15) Protein (%) ME (kcal/kg) 16.0 16.8 15.0 14.5 15.5 Calcium (%) 2750 2750 2830 2775 2840 Av Phosphorus (%) Sodium (%) 0.95 1.0 1.0 0.9 1.0 Linoleic acid (%) 0.36 0.38 0.44 0.37 0.45 0.16 0.17 0.16 0.16 0.17 Methionine (%) 1.0 1.0 1.2 Methionine+cystine (%) Lysine (%) 0.33 0.35 0.39 0.33 0.35 Tryptophan (%) 0.60 0.63 0.60 0.57 0.63 Threonine (%) 0.74 0.78 0.70 0.65 0.85 0.16 0.17 0.15 0.16 0.16 0.50 0.53 0.60 0.50 0.60 Table 3.17 Prelay diets for brown egg pullets Age fed (wks) Shaver ISA Hyline Lohmann Bovan (16 to 17) (16 to 17*) (16 to 18*) (16 to 18*) (15 to 17) Protein (%) 17.0 17.0 16.5 17.5 14.8 ME (kcal/kg) 2750 2750 2850 2775 2820 Calcium (%) Av Phosphorus (%) 2.05 2.05 2.75 2.0 2.25 Sodium (%) 0.45 0.45 0.44 0.45 0.45 Linoleic acid (%) 0.16 0.16 0.18 0.16 0.18 1.0 1.0 1.2 Methionine (%) 0.36 0.36 0.35 0.36 0.35 Methionine+cystine (%) 0.65 0.65 0.60 0.68 0.63 Lysine (%) 0.80 0.80 0.75 0.85 0.80 Tryptophan (%) 0.17 0.17 0.17 0.20 0.16 Threonine (%) 0.54 0.54 0.55 0.60 0.55 * Extrapolated from Management Guide Information SECTION 3.2 Strain specific nutrient requirements

136 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS All poultry breeding companies recommend where from 6.3 to 6.8 kg feed (Tables 3.18 and prelay diets for their brown egg pullets, and 3.19). As for the white egg pullets, the strain spec- while most nutrient specifications are similar, there ifications for vitamin-mineral premixes for the brown are again major differences in recommendations pullets show tremendous variation, and again for for calcium. These brown egg pullets weigh from some strains, certain nutrients are not deemed essen- 1475g to 1580g at 18 weeks, and consume any- tial within these premixes (Table 3.20). Table 3.18 Feed intake1 for brown egg pullets (grams) Shaver ISA Hyline Lohmann Bovan 840 1099 1148 Starter 600 1694 966 1764 1351 2758 3346 3577 2170 Grower 2100 525 1163 1029 1015 480 539 Developer 3000 6297 6574 6370 6223 Pre-lay 588 Layer 600 Total (to 18 wks) 6888 1Dependent on diet energy level Table 3.19 Body weight of brown egg pullets (grams) Week Shaver ISA Hyline Lohmann Bovan 70* 1 60 50 70 75 110* 180* 2 100 100 115 130 290 370 3 200 190 190 195 450 530 4 300 280 280 275 610 690 5 380 380 380 367 770 850 6 480 480 480 475 935 1020 7 570 580 580 580 1110 1200 8 650 675 680 680 1300 1400 9 760 770 770 780 1500 10 850 850 870 875 11 940 950 960 960 12 1030 1040 1050 1040 13 1120 1130 1130 1120 14 1220 1220 1210 1200 15 1320 1300 1290 1265 16 1400 1390 1360 1330 17 1490 1475 1430 1400 18 1580 1560 1500 1475 * Extrapolated from Management Guide Information SECTION 3.2 Strain specific nutrient requirements

CHAPTER 3 137 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.20 Vitamin-mineral premix for brown egg pullets units/kg Shaver ISA Hyline Lohmann Bovan feed Vitamin A IU 13000 13000 8800 12000 8000 Vitamin D3 2000 2500 Vitamin E IU 3000 3000 3300 10-30 Vitamin K 10 IU 25 25 66 3 3 Thiamin Riboflavin IU 2 2 5.5 1 1 Pantothenic acid 6 5 Niacin mg 2 2 0 8 7.5 Pyridoxine 30 30 Biotin mg 5 5 4.4 3 2 Folic acid 50 100 Vitamin B12 mg 15 15 5.5 1.0 0.5 Choline 15.0 12 mg 60 60 28 300 300 Iron Copper mg 5 5 0 25 35 Manganese 5 7 Zinc µg 200 200 55 100 70 Iodine 60 70 Selenium mg 0.75 0.75 0.22 0.5 1 0.2 0.25 µg 20 20 8.8 mg 600 600 275 mg 60 60 33 mg 5 5 4.4 mg 60 60 66 mg 60 60 66 mg 1 1 0.9 mg 0.2 0.2 0.3 3.3 Feeding management of growing pullets Da) General considerations ment problems. Similarly, first egg appearing at iet formulation and feeding management 15-17 weeks means that we must critically are now critical aspects of growing review our rearing programs. The key to successful pullets to the onset of sexual maturity. nutritional management today is through opti- Age at maturity is getting earlier although it is ques- mizing (maximizing) body weight of the pullet. tionable that this has changed suddenly in just Pullets that are on-target or slightly above target a few years. In fact, what has been happening weight at maturity will inevitably be the best pro- is that age at maturity has slowly been decreas- ducing birds for the shell egg market. ing by almost 1 d per year, and this is especial- ly true for many strains of brown egg pullets. The traditional concern with early maturity Moving birds to laying cages at 19-20 weeks is has been too small an egg size. Results from our no longer feasible and often results in manage- early studies indicate the somewhat classical SECTION 3.3 Feeding management of growing pullets

138 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.21 Pullet maturity and egg characteristics Age at Lighting Egg production (%) Egg size (% large) (wk) 18-20 wk Mean 30 wk 63 wk (to 35 wk) 15 18 32 92 17 44 21 21 65 12 92 37 69 0 91 effect of early maturity in Leghorns without standards are now rarely given in the breeder man- regard to body weight (Table 3.21). agement guides. It is known that most (90%) of the frame size is developed early, and so by 12- There seems little doubt that body weight and 16 weeks of age, the so-called ‘size’ of the pul- perhaps body composition at this time are the let is fixed. While this parameter is useful as anoth- major factors influencing egg size both at matu- er monitoring tool, we have had little success in rity and throughout the remainder of the laying affecting frame size without also affecting body period. Summers and Leeson (1983) conclud- weight. It therefore seems very difficult to pro- ed that body weight is the main factor control- duce, by nutritional modification, pullets that are ling early egg size (Table 3.22). below target weight, yet above average frame size and vice versa. Since shank length and ‘frame Table 3.22 Effect of body weight on size’ are so highly correlated with body weight, egg size their measurement or monitoring is no longer con- sidered necessary. However, an exception to this 18 wk wt (g) Early egg wt (g) rule occurs in hot weather conditions where high 1100 46.9 temperatures seem to stimulate leg bone growth 1200 48.4 independent of body weight. It is not clear 1280 48.8 why birds held at higher temperatures have 1380 49.7 longer shank bones, although there is a possibility of altered hormone balance. For example, thy- Although there is some evidence to indicate roid hormones are known to influence bone devel- that nutrients such as protein, methionine and linole- opment through mediation of somatomedins ic acid can influence egg size throughout the lay- and it has been shown that even though birds held ing cycle, these nutrients have only moderate effects at 30 vs. 22ºC have reduced thyroid size, their on early egg size. This is probably related to the circulating T4 levels are increased by 100%. pullet producing at maximum capacity at least up Another factor that may be of importance is to the time of peak egg mass. blood flow to the feet and legs during heat stress. It is well known that birds divert more blood Although it is fairly well-established that to the legs during heat stress as a means of body weight is an important criterion for adequate countercurrent cooling between the arterial early production, there is still insufficient evidence and venous supply. In some types of birds, regarding optimum body structure and com- heat loss from the legs can be the largest con- position. Frame size is still discussed, although tributor to overall heat loss, and it is interesting that this has been recorded to occur at 30ºC since SECTION 3.3 Feeding management of growing pullets

CHAPTER 3 139 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS at higher tempertures evaporative losses become body composition is most likely the stimulus to more important. Since the hind limbs are appar- maturity. There may, in fact, be a need for ently more heavily supplied with blood at 30 vs. attainment of a minimum lean body mass prior 18ºC, and even though nutrient intake is reduced to sexual maturation. With most mammals, at higher temperatures, it is conceivable that the attainment of minimum fat reserves are essen- active growth plate receives a greater supply of tial for puberty, and so it seems likely that body nutrients related simply to increased blood flow. composition is as important as total body mass It would be interesting to see if environmental in influencing the onset of egg production. In temperature influences development of other parts studies involving a relatively small number of birds, of the skeleton and especially the keel. we have seen no correlation between age at first egg and either percentage or absolute levels of While pullets are maturing earlier, there has body fat. While no clear picture has yet emerged been little change in body weight at time of first with respect to body composition and maturi- egg. As will be discussed in section 3.3g), light- ty, it seems likely that birds having some ener- ing program is the most important stimulus to matu- gy reserve, as they approach peak egg produc- rity. Pullets as young as 8 weeks of age will be tion, are less prone to subsequent production influenced by light stimulation, and regardless problems. A production curve as shown in of body weight or composition, will produce eggs Figure 3.1 is often observed in flocks, related to earlier than normal. Without any light stimulation, inadequate body size or energy reserves at the then a minimum threshold body weight and/or time of maturity. Fig. 3.1 Reduction in egg production after peak, associated with small appetite and body weight. SECTION 3.3 Feeding management of growing pullets

140 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS When this type of production loss is not due er maturity is desired or when adverse to an identifiable disease and/or management prob- environmental conditions prevail. Leeson and lem, then it most likely relates to birds being Summers (1981) suggested that energy intake of deficient in energy. It is perhaps not too surpris- the pullet is the limiting factor to growth rate, since ing that birds are in such a precarious situation with regardless of diet specifications, pullets seem to respect to energy balance. Dairy cows and sows consume similar quantities of energy (Table invariably lose body weight during peak lactation 3.23). In this study, all pullets had a similar body in order to meet energy requirements. Perhaps the weight at 15 weeks even though diet specifications most classical case of energy deficiency at this time were dramatically variable. As seen in Table 3.23, is seen with the turkey breeder. Due to a decline birds consumed similar quantitities of energy even in feed intake from time of first lighting through though protein intake varied by 85%. These data to peak egg production, the turkey breeder nec- suggest that if protein and amino acid intake are essarily loses considerable body mass in an adequate, additional diet protein does little to attempt to maintain energy balance. It is likely stimulate growth rate. that the same situation applies to Leghorn pullets and in some cases, to brown egg birds. Obviously, In other studies, we have reared Leghorn pul- the effect is most pronounced for underweight flocks lets on diets varying in protein or energy, and again, with small appetites where energy intake is min- energy intake seems to be the major factor imal. In fact, with many flocks exhibiting production influencing body weight (Tables 3.24 and 3.25). characteristics as shown in Figure 3.1, it is body These studies indicate that growth rate is more weight at housing that deserves immediate inves- highly correlated with energy intake than with tigation rather than factors occurring at the actu- protein intake. This does not mean to say that al time of the production loss. protein (amino acid) intake is not important to the growing pullet. Protein intake is very impor- The key to optimizing layer performance tant, but there does not seem to be any measurable would seem to be attainment of body weight goals return from feeding more than 800 g of protein at time of maturity. It is likely that body condi- to the pullet through 18 weeks of age. On the tion will be a factor of the flock in question, being other hand, it seems as though the more ener- influenced by stocking density, environmental gy consumed by the pullet, the larger the body temperature, feather cover, etc. Unfortunately weight at maturity. Obviously, there must be a attainment of desired weight for age is not fine line between maximizing energy intake always easy to achieve especially where earli- and creating an obese pullet. Table 3.23 Nutrient intake of pullets (8-15 weeks) Diet energy-protein 15 wk Body wt. Energy intake Protein (g) (Mcal) intake (g) 2950 kcal – 15% CP 3100 kcal – 24% CP 1272 9.77 464c 3200 kcal – 20% CP 1267 9.17 718a 1291 9.51 597b SECTION 3.3 Feeding management of growing pullets

CHAPTER 3 141 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.24 Effect of diet protein level (0-20 wks) on pullet growth and nutrient intake Diet Protein Body wt. Energy intake Protein intake (%) (g) (Mcal) (kg) 24.3 1.28d 15 1445 22.9 1.28d 22.9 1.37cd 16 1459 22.0 1.39c 22.9 1.53b 17 1423 23.0 1.62a 18 1427 19 1444 20 1480 All diets 2850 kcal ME/kg Table 3.25 Effect of diet energy level (0-20 wks) on pullet growth and nutrient intake Diet energy Body wt. Energy intake Protein intake (kcal ME/kg) (g) (Mcal) (kg) 2650 1320c 20.6c 1.40a 2750 1378bc 21.0bc 1.37a 2850 1422ab 21.8ab 1.37a 2950 1489a 22.1ab 1.35ab 3050 1468a 21.4abc 1.26c 3150 1468a 22.5a 1.29bc All diets:18% CP, 0.36% methionine aand 0.9% lysine b) Manipulating nutrient intake In order to maximize nutrient intake, one must consider relatively high nutrient dense diets, If one calculates expected energy output in terms although these alone do not always ensure opti- of egg mass and increase in body weight, and relates mum growth. Relatively high protein (16-18% this to feed intake, then it becomes readily appar- CP) with adequate methionine (2% CP) and ent that the Leghorn must consume at least 90 lysine (5% CP) levels together with high energy g/bird/day and the brown egg bird close to 100 levels (2800-3000 kcal/kg) are usually given to g/bird/day at peak production. Because feeding Leghorn pullets, especially in hot weather is ad-libitum, management programs must be situations. However, there is some evidence to geared at stimulating early appetite. The practi- suggest that high energy diets are not always help- cal long-term solution is to rear birds with opti- ful under such warm conditions. (Table 3.26) mum body weight and body reserves at maturity. This situation has been aggravated in recent Leghorn pullets were heavier at 126 d when years, with the industry trend of attempting to rear fed the high energy diet in the cool environment, pullets on minimal quantitites of feed. Unfortunately, but diet had no effect at 30ºC. As expected, pul- this move has coincided with genetically lets ate less of the high energy diet, and because smaller body weights and hence smaller appetites, together with earlier sexual maturity. SECTION 3.3 Feeding management of growing pullets

142 CHAPTER 3 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Table 3.26 Influence of diet energy on growth and nutrient intake of leghorn pullets maintained at 30 or 18ºC to 18 weeks of age Body wt 126 d Total feed intake ME intake Protein intake (g) (kg) (Mcal) (g) Temperature 18ºC 1398 7.99 20.04 1330 2500 kcal ME/kg 1434 6.98 21.07 1160 3000 kcal ME/kg 1266 6.05 15.17 1010 Temperature 30ºC 1218 5.19 15.69 870 2500 kcal ME/kg 3000 kcal ME/kg all other nutrient levels were fixed, this result- ative to management guide values (Table 3.12) ed in reduced intake of all nutrients except at 4-6 weeks of age. This situation can arise for energy. Pullets therefore ate less protein and amino a variety of reasons such as sub-optimal nutri- acids when fed 3000 vs. 2500 kcal ME/kg, and tion, heat stress, disease, etc. For such flocks it this can be critical where intake per se is less at is inappropriate to change from starter to grow- 30ºC. The pullets fed 3000 kcal/kg are border- er diet, merely because the flock has reached some line in intake of balanced protein at 870 g vs. our arbitrary age. It is more appropriate to feed the requirement for 800 g to this age. High energy higher nutrient dense starter until the target diets may therefore not always be beneficial weight is reached. For example, Figure 3.2 under heat stress conditions, and intake of other shows an underweight flock at 6 weeks. For this nutrients such as protein and amino acids must flock to receive a grower at 6 weeks of age will be given priority during formulation. The Leghorn cause problems because the flock will likely stay pullet eats for energy requirement, albeit with some small until maturity, be late maturing, and then imprecision, and so energy:protein balance is crit- produce a sub-optimal number of eggs that will ical. All too often there is inadequate amino acid also be small. This type of flock can most effec- intake when high energy corn-based diets are used, tively be ‘corrected’ in growth by prolonged the result of which is pullets that are both small feeding of the starter diet. In this situation, the and fat at maturity. birds reach the low end of the guide weight at almost 10 weeks of age (Figure 3.2). At this time, One of the most important concepts today a grower diet could be introduced. Since the flock in pullet feeding, is to schedule diets according is showing a growth spurt, then feeding to to body weight and condition of the flock, rather almost 12 weeks could be economical. The flock than according to age. For example, tradition- is now slightly over-weight and so ideally suit- al systems involve feeding starter diets for about ed to realizing maximum genetic potential dur- 6 weeks followed by grower and then developer ing peak production. Some producers, and diets. This approach does not take into account especially contract pullet growers, are sometimes individual flock variation, and this will be inap- reluctant to accept this type of program, since they propriate for underweight flocks. It is becom- correctly argue that feeding a high protein starter ing more difficult to attain early weight for age. diet for 10-12 weeks will be more expensive. This means that flocks are often underweight rel- Depending upon local economic conditions, SECTION 3.3 Feeding management of growing pullets

CHAPTER 3 143 FEEDING PROGRAMS FOR GROWING EGG-STRAIN PULLETS Fig. 3.2 Pullet growth in relation to feeding program. feeding an 18% protein starter diet for 12 vs. 6 According to the standard schedule, the starter weeks of age, will cost the equivalent of 2 eggs. and grower are each fed for 6 weeks, followed A bird in ideal condition at maturity will produce by developer. In Scenario #1, the body weight far in excess of these 2 eggs relative to a bird that is below standard at 3 weeks, and pullets are only is underweight at maturity. 400 g at 6 weeks relative to the standard of 450 g at this time. If this flock is changed to the c) Suggested feeding program lower nutrient dense grower diet at 6 weeks, the birds will not likely achieve target weight at Diet specification, together with approximate maturity. For this reason in Scenario #1, the starter ages for feeding, are given in Tables 3.1 and 3.2 diet is continued until weight-for-age is achieved for Leghorns and brown egg birds respectively. at 9 weeks of age. In Scenario #2 there is even In practice, flocks may not grow according to greater cause for concern since the flock suddenly expected standards, and for Leghorns at least, they slows down in growth at 9 weeks of age. This are more likely to be underweight than on tar- type of growth depression is seen in situations get. Brown egg strains on the other hand, of disease challenge, with severe beak trim- because of their inherently higher feed intake, ming or when there is sudden increase in envi- sometimes achieve weights that are greater than ronmental temperature. For this flock, it is standard goals. For these reasons, there needs essential to re-introduce the higher nutrient to be flexibility in time of change from, for dense starter diet in order to stimulate growth. example, starter to grower etc. Table 3.27 In this extreme situation, the grower diet is shows various scenarios for the feeding sched- introduced at 12 weeks since the pullets seem uling of a Leghorn strain to 17 weeks of age. to be making acceptable weekly gains in growth. SECTION 3.3 Feeding management of growing pullets