POULTRY

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 Animals  eat to acquire the energy and  building materials that they need to live  and grow.  Animals use energy  to perform normal body functions such as  breathing, walking, eating,  digesting, and maintaining body temperature.  Nutrients provide poultry the energy and material needed for the development of   bone, flesh, feathers, and eggs. Each of these compounds is important  in  providing poultry the nutrients they need, and a deficit of even one  can have serious health consequences for poultry.

Feed has six major components:

• Water
• Carbohydrates
• Fats
• Proteins
• Minerals
• Vitamins

Water   is often overlooked, but it is one of the most important nutrients. An   animal can live without food longer than it can live without water. In  a  laying flock, a shortage of water for just a few hours can result in   reduced egg production, so clean water should be available at all  times.  If you do not use automatic waterers, fill the drinkers twice a  day. If  the drinkers are filled only in the morning, birds can run out  of water by midday. A laying hen drinks about 25% of her daily water  intake during the last two hours of daylight.

Water   plays an important role in the body of an animal. Water softens feed   and carries it through the digestive tract. As a component of blood  (90%  of blood content), water carries nutrients from the digestive  tract to  cells and carries away waste products. Water also helps cool  the bird  through evaporation. (Birds do not have sweat glands, so their  heat loss  occurs in the air sacs and lungs through rapid respiration.)

A   baby chick is composed of about 80% water. Even though this percentage   decreases as a bird gets older, the need for water remains. There is  no  precise quantity requirement for water because there are several  factors  that affect the amount of water a bird needs: age, body  condition,  diet, temperature, water quality, and humidity. As a rule of  thumb,  poultry consume twice as much water as feed.

Carbohydrates   (compounds with carbon, hydrogen, and oxygen) are an energy source for   animals and make up the largest portion of a poultry diet.  Carbohydrates  are typically eaten in the form of starch, sugar,  cellulose, and other  non-starch compounds. Poultry typically do not  digest cellulose and the non-starch compounds, referred to as crude  fiber, well. However, poultry are able to use most starches and sugars  well. Important sources of  carbohydrates in poultry diets include corn,  wheat, barley, and other  grains.

Fats   have two and one-quarter times the calories of carbohydrates by  weight.  Fat provides nine calories of energy per gram, while  carbohydrates  while carbohydrates provide only four.  At room  temperature, saturated  fats are solids and unsaturated fats are liquid.  Examples of saturated  fats that can be used in poultry diets include  tallow, lard, poultry  fat, and choice white grease. Examples of usable  unsaturated fats  include corn oil, soy oil, and canola oil. Common  sources of  supplemental fat in commercially produced poultry feeds  include animal  fat, poultry fat, and yellow grease. The high cost of  vegetable oils  makes including these fats in poultry diets  uneconomical.

Fats are composed of smaller compounds called fatty acids.   Fatty acids are responsible for cell membrane integrity and hormone   synthesis. Although there are many different fatty acids, poultry have a   specific requirement for one—linoleic acid—so   it must be included in the diet. Linoleic acid is considered an   essential fatty acid because poultry cannot generate it from other   nutrients (for example, by converting one fatty acid to another). 

Fat   must be present in the diet for poultry to absorb the fat-soluble   vitamins A, D, E, and K. In addition to its role in nutrition, fat is   added to feed to reduce grain dust. Fat addition also improves the   palatability of feed (that is, makes the feed more appetizing).

Fats,  including those incorporated in feed, have a tendency to go bad or  become rancid. This is a year-round problem, but the risk of feed  going  rancid is even greater in the summer. To prevent feed from going   rancid, antioxidants are added to poultry diets containing added fat. A   common antioxidant listed on feed labels is ethoxyquin.

Proteins are complex compounds made up of smaller units called amino acids.   After a bird consumes protein, the digestive process breaks down the   protein into amino acids. The amino acids are then absorbed by the  blood  and transported to cells that convert the individual amino acids  into  the specific proteins required by the animal. Proteins are used in  the  construction of body tissues such as muscles, nerves, cartilage,  skin,  feathers, beak, and so on. Egg white is also high in protein.

Amino acids are typically divided into two categories: essential and nonessential. Essential amino acids are those that cannot be made in adequate amounts to meet the needs of the animal. The nonessential amino acids are those that the body can generate in sufficient quantities as long  as the appropriate  starting material is available. There are 22 amino  acids commonly found  in feed ingredients. Of these, 11 are essential  and must be supplied in  the feed. Poultry diets typically contain a  variety of feedstuffs  because no single ingredient is able to supply  all the necessary amino  acids in the right levels.

Most   feed tags indicate only the percentage of crude protein in a given   feed. This information does not tell you about the quality of the   protein used. Protein quality is based on the presence of the essential   amino acids. For poultry, methionine and lysine are the two most   critical amino acids. Deficiencies of either of these will lead to a   significant drop in productivity and the health of the flock.  Commercial  poultry diets typically contain methionine and lysine  supplements.  Because of these supplements, the feed can contain less  total protein;  without supplements, the feed would have to contain  excessive amounts of the other amino acids in order to meet the  methionine and lysine requirements.

The   main sources of protein in poultry diets are plant proteins such as   soybean meal, canola meal, corn gluten meal, and so on. Animal proteins   used include fishmeal and meat and bone meal. Fishmeal can be   used only in limited quantities (less than 5% of the total composition   of the diet) or it will give poultry meat and eggs a fishy flavor.

Minerals   play a role in bone formation, but minerals are also needed for  several  other important functions, including the formation of blood  cells,  blood clotting, enzyme activation, and energy metabolism and for  proper  muscle function.

Minerals are typically classified as macro- or microminerals. Poultry require higher levels of macrominerals and lower levels of microminerals in their diets. The microminerals include copper, iodine, iron,   manganese, selenium, and zinc. Although poultry have lower requirements   for microminerals, these minerals play essential roles in the body’s   metabolism. Iodine, for example, is required to produce thyroid  hormones  that regulate energy metabolism. Similarly, zinc is involved  in many  enzyme-based reactions in the body, and iron aids oxygen  transportation  within the body. 

The   macrominerals include calcium, phosphorus, chlorine, magnesium,   potassium, and sodium. Many people are familiar with calcium’s role in   proper bone formation and eggshell quality, but calcium’s important  role  in blood-clot formation and muscle contraction is less well known.   Phosphorus is important in bone development, and it is part of cell   membranes and is required for many metabolic functions. Chlorine is   important in the formation of hydrochloric acid in the stomach and thus   plays a role in digestion. Sodium and potassium are electrolytes   important for metabolic, muscle, and nerve functions. Magnesium also   assists with metabolic and muscle functions.

Grains   are low in minerals, so mineral supplements are added to commercial   poultry feeds. Limestone or oyster shell are common sources of calcium.   Dicalcium phosphate is a common source of phosphorus and calcium. The   microminerals are usually supplied in a mineral premix.

Vitamins   are a group of organic compounds that poultry require in small   quantities. Despite the low requirement levels, vitamins are essential   for normal body functions, growth, and reproduction. A deficiency of  one  or more vitamins can lead to a number of diseases or syndromes.

Vitamins   are divided into two categories: fat-soluble and water-soluble. The   fat-soluble vitamins are A, D, E, and K. Vitamin A is required for   normal growth and development of epithelial tissue (skin and the  linings  of the digestive, reproductive, and respiratory tracts) and   reproduction. Vitamin D3 is required for normal growth, bone   development, and eggshell formation. Vitamin K is essential for blood   clot formation.

The  water-soluble  vitamins include vitamin C and the B vitamins. The B  vitamins include  vitamin B12, biotin, folacin, niacin, pantothenic acid,  pyridoxine,  riboflavin, and thiamin. The B vitamins are involved in  many metabolic  functions, including energy metabolism. Poultry can make  vitamin C, so  there is no dietary requirement established for this  vitamin. Vitamin C  supplementation, however, has been shown to be useful  when birds are  stressed. 

Some  vitamins are  produced by microorganisms in the digestive tract. Vitamin  D can be  produced when sunlight hits the bird’s skin. Other vitamins  must be  supplied because they are not formed by the birds. Many  essential  vitamins are partially supplied by feed ingredients such as  alfalfa  meal and distillers’ dried solubles. A vitamin premix is  typically used  to compensate for the fluctuating levels of vitamins  found naturally  in food and to assure adequate levels of all vitamins.