Lecture 12 Exam 3

Protein (amino acids)

Under high-growth conditions, glycine and serine may need to be supplied to the diet. -In general, methionine is the first, and lysine the second limiting amino acid in corn-soybean-based poultry rations. Birds slightly deficient in amino acids will over-consume energy. -This principle used in some finisher rations. The concept of an ideal amino acid ratio is based on lysine as a reference, with all other essential acids expressed as a percentage of lysine. There are several reasons for choosing lysine as the reference amino acid for poultry: 1. Dietary lysine is used only for protein accretion and maintenance. 2. Lysine is the second limiting amino acid after methionine. 3. Synthetic lysine supplementation is economically feasible. 4. Lysine analysis in feedstuffs is straightforward. 5. Lysine requirement data for dietary, environmental, & body composition and other circumstances are readily available

Feedstuffs: General Considerations

Unheated soybeans contain trypsin inhibitors & rapeseed contains glucosides and goitrogens. Cottonseed meal contains gossypol & sterculic acid which adversely affect albumen & yolk color. Yellow corn & alfalfa contain yellow nonnutritive pigments (xanthophylls) effective in enhancing pigmentation of egg yolks and broiler skin.

Energy Sources: Grains

Grains primarily serve as sources of energy, mainly from starch, and also provide some protein, vitamins, and minerals. -High-energy grains suitable for poultry are corn, milo, wheat, rice, triticale, and oat groats. -Medium-energy grains are barley and heavy oats. -Low-energy grains are oats, spelt & wheat-milling by-products. Grains, in general, are low in protein and are deficient in lysine and tryptophan. -Also low in calcium and available phosphorus.

Energy Sources: Vegetable or Animal Fats and Vegetable Proteins

Fats are frequently used as energy sources in synchrony with feed grains, especially when higher levels of energy are needed in the ration. -In addition to energy, fat provides linoleic acid, the essential fatty acid of primary concern for poultry. Vegetable protein concentrates commonly used include oil meals from soybean, cottonseed, canola (rapeseed) meal, sunflower seed, safflower, and peanuts. -To a lesser extent, corn gluten meal and pea meal are also used as protein supplements.

Supplemental Ingredients

Feed ingredients particularly rich in vitamins, amino acids, and minerals tend to fall in the category of supplemental ingredients. -Sun-cured and dehydrated alfalfa meals. -Corn gluten meal; Distillery and brewery by-products. -Fish solubles; Brewer's yeast. Synthetic amino acid sources include: -Methionine; Methionine hydroxy analog. -Lysine; Threonine. A variety of mineral supplements used containing Ca, P, Na, Mn, and Zn. -Common mineral sources: Curaçao rock phosphate, dicalcium phosphate, rock phosphate, steamed bonemeal, limestone, oyster shell, and salt. Molasses is a good source of energy, but has an adverse laxative effect that limits use. Granite grits of various sizes are a mechanism for grinding feed and whole grains in the gizzard. -Optional in modern production, providing grit to birds raised on wood chip litter prevent impacted gizzards.

Non-nutritive ration components (cont)

Numerous enzymes are now available that promise to make ration nutrients more available. -Proteases; Glucanases; Amylases. -Cellulases; Pentoases, etc. Amylolytic enzyme supplements are beneficial to growth in diets containing western barley. -These barleys are known to be lacking in beta-glucanase that is present in most other grains. -based on starch Phytase is added to rations to make phosphorus, which is bound to phytin in feedstuffs, available to the animal. Xanthophylls can come from natural sources such as corn, corn gluten meal, and alfalfa meal. -Some nutritionists add commercial sources of xanthophylls derived from marigold petals. Xanthophylls provide yellow pigmentation to the skin & egg yolks, a market preference. -Xanthophylls do not add nutritional value to the product. Chemotherapeutic agents Mold inhibitors Pellet binding agents Antioxidants

Nutrient requirements of poultry cont.

Some nutrients act antagonistically to the metabolism & development of meat and eggs. -Especially when in excess, containing a toxic component, or are improperly balanced. -Nutrient requirements vary depending on the type of poultry enterprise involved. Advancements in genetics have resulted in birds that grow rapidly or lay eggs at high levels. -Modern birds are very sensitive to proper nutrient specifications nutrient requirements have to be perfect, small changes will drastically affect the birds Methionine is the first limiting amino acid in chickens Lysine is second limiting For flock replacement chickens, nutrients of particular concern include: -Protein level & limiting essential amino acids. -Methionine, lysine, arginine, cysteine, and tryptophan. -Vitamins A, D, riboflavin, pantothenic acid, and niacin. -Ca, available P (for skeleton and eggs), Na (salt), and Mn.

Nutrient Requirements

An important concept to remember is that animals are fed to meet nutrient requirements. -Not certain feed ingredients. Poultry nutrient requirements are more precisely defined than many other domestic animals. -The bird is relatively easy to research, with economic incentive to define nutrient requirements of the animal. Nutrients in the ration do not act independently. -When properly balanced, each component works to provide materials for metabolism & development of meat and eggs.

Non-nutritive ration components

Antibiotics USED TO BE added to poultry diets to reduce subclinical bacterial infections & improve growth and feed efficiency. -Antibiotics should be used sparingly to reduce the possibility of resistant organisms. -Bacitracin; Bambermycin; Chlortetracycline. -Erythromycin; Lincomycin; Oleandromycin. -Penicillin; Tylosin: Virginiamycin. *Remember Veterinary Feed Directive* Anthelmintic agents are included in poultry diets in which there is a problem with worms. -Worms are problem if the birds have access to soil. -Caged birds do not usually have the problem. -Piperazine and hygromycin B are examples of deworming agents. Coccidiosis is a serious protozoan disease for poultry that is characterized by enteritis and diarrhea. -Common to birds that are raised on the floor. -To prevent the problem, coccidiostats such as amprolium & zoalene are commonly added to feeds.

Classes of Ration Components (poultry)

Classes of ration components that are provided for the animals include: -Oxygen; Water; Carbohydrates (energy). -Protein (amino acids); Fat (energy). -Vitamins; Minerals. -Factors considered nonnutritive. -Enzymes, xanthophylls (make skin yellow), coccidiostats, antibiotics, etc.

Vitamins (poultry)

Commercial vitamin premixes are usually added to poultry rations without regard for vitamins present from other ingredients. -Such as corn, soybean, alfalfa meal, etc. In making up a vitamin premix, stability of the vitamins is a concern. -In absence of information concerning stability characteristics of supplements, suggested allowance factors are: -Vitamin A, 66%; Vitamins D and E, 50%; Vitamin K, 25%. -B-complex vitamins, 15% to 20%

Protein Sources (cont)

Cotton seed meals contain 41% to 43% protein. Use is restricted because of gossypol and sterculic acid content. -Gossypol can depress growth in chicks & is detrimental to yolk color for laying hens fed cottonseed meal. Alfalfa meals used in poultry rations as source of vitamins, xanthophylls, & some protein. -Because of high fiber content, alfalfa meal is usually not used in excess of 5% to 7% of the poultry ration. Alfalfa meals also contain toxic substances related to saponins, which negatively influence growth and increase mortality of chicks when levels exceed 10% of the diet. Animal Protein Sources commonly used include fish meal, meat meal, meat & bone meal, poultry by-products meal, and hydrolyzed feather meal. -Except for feather meal, these feedstuffs are generally considered excellent sources of amino acids. -Use limitations are based on cost, availability, salt content and variability of phosphorus With a protein level of 60% to 70%, fish meal is frequently used at 2% to 5% of the ration. -Due to favorable amino acid profile and as a source of unidentified factors. Fish meal should not exceed more than 10% of the ration. -It can produce fishy flavors in poultry products.

Energy

Of feed fed to poultry, about 3/4 (75%) of feed energy is required for the maintenance of the body. -And 1/4 is for production. It is generally recognized that birds eat to satisfy their energy needs. -Nutrients of the diet are generally formulated in relation to the energy content of the ration.

Feeding poultry

Poultry rations constitute about 54% of the feed that is annually mixed in the United States. Cost of feeding represents approximately 75% of the cost of poultry production. -As a result, producers have considerable interest in effectively formulating poultry feeds. Feeding is not an isolated activity. -Interactions of genetics, physiology, management, disease, and environmental conditions influence animal nutrition. vertically integrated industry competitive pricing In general, objectives of feeding poultry are: -Transform nonedible materials into an edible product. -To meet the physiological requirements of the bird. -Carry out these objectives in an economical manner. The modern poultry industry consists of vertically integrated companies. -A company may own everything from the genetics of the birds to the restaurants serving finished products. The majority of poultry, broilers, laying hens, and turkeys are raised in confinement.

Protein sources

Soybean meal is an excellent source of protein. -It may vary in protein content from 44% to 50%, with the higher levels resulting from the removal of hulls. -Soybean meal is a good source of lysine Such meals are often used in broiler rations due to their low fiber and high energy content. -Methionine may be marginal and requires a supplemental source in corn- and soybean-based rations. Raw soybeans contain a trypsin inhibitor and other substances that are growth inhibitors. -Inactivated when soybeans are properly heated. -Unextracted soybeans are sometimes used in broiler rations, but must be processed by either extruding or roasting. A crop genetically related to rapeseed varieties, Canola is grown in colder climates that makes it prohibitive to grow high-protein oil seeds such as soybean meal. -Canola has reduced levels of goitrogens & erucic acid. -used in poultry rations. -It has sinapines that produce eggs with a fishy flavor and an offensive odor when fed to brown-egg birds. Canola meal contains less lysine than soybean meal but slightly higher sulfur amino acid levels. -Levels equal to 8% canola meal used in laying diets, but egg size may be reduced as much as 1 g.

Minerals

The major minerals present in poultry rations are calcium and phosphorus. -Limestone and oyster shell are common sources. -Steamed bonemeal, Curaçao phosphate, defluorinated rock phosphate, monosodium phosphate, and dicalcium phosphate are commonly added as sources of calcium and phosphate. Important trace minerals are generally added as trace mineral mixes (premix) for poultry: -Magnesium; Potassium; Sulfur; Iron; Copper. -Manganese; Zinc; Iodine. Selenium is sometimes added, although levels are closely regulated in the U.S & Canada. -Selenium at high levels can be toxic.