Feed Management in Layers

Nutrition plays a major role in the performance of layer birds. Feed management is the most important practice to get egg production at a right time, maximum peak production, long standing peak production, standard egg size, good cull bird weight and reduced feed cost per egg. Body weight should be taken every week from 1^st week to 18^th week of age, the birds with less body weight should be separated and special care must be taken to those birds to get uniformity in flock (BV-300 Layer Management Guide). The birds fed with standard feed, prepared as per nutrient specifications will attain recommended body weight. The nutritional requirements of birds will vary depending upon the age, climate and difference in breeds. So, feed formulation should be prepared as per the nutritional requirement of birds. In summer, the feed intake is less and the feed formulation will be revised as per the feed consumption.

Carbohydrates, proteins, fats, vitamins, minerals and water are main nutrients in poultry layers that are discussed as follows.

Cereal grains such as maize, bajra, broken rice, rice polish, jowar, ragi, de-oiled rice bran (DORB) and wheat bran, etc., are some of the carbohydrate sources used in layer diet. Most of the carbohydrates of cereal grains occur as starch, which is readily digested by poultry (Nutrient requirements of poultry. 1994). Other carbohydrates occur in varying concentrations in cereal grains and protein supplements. These carbohydrates include polysaccharides such as cellulose, hemicellulose, pentosans and oligosaccharides such as stachyose and raffinose, all of which are poorly digested by poultry (Nutrient requirements of poultry. 1994). Thus, these dietary carbohydrates often contribute little to meet the energy requirement of poultry and some adversely affect the digestive processes of poultry when present in sufficient dietary concentrations (Nutrient requirements of poultry. 1994).

The vegetable protein sources are soya bean meal, sun flower cake, rapeseed meal, cotton seed cake, ground nut cake, guar meal, til cake, and distillers dried grains with solubles (DDGS), etc. Animal protein sources are fish meal, meat and bone meal, blood meal and feather meal etc. Proteins are polymers that are composed of alpha amino acids, which are linked together by peptide bonds. Proteins are broken down and hydrolyzed in the digestive system into amino acids. Then, after absorption, the amino acids will be assembled and metabolized to form proteins that are used in the building of different body tissues (Sleman, S. M., et. al., 2015). They also serve vital metabolic roles as blood plasma proteins, enzymes, hormones and antibodies, each of which has a specific role in the body (Sleman, S. M., et. al., 2015). The concepts of digestible amino acids, ideal amino acid ratios, use of synthetic amino acids and feed consumption based formulations must be considered to get excellent result in layer flocks and saving in feed cost (BV-300 Layer Management Guide).

“Fat” or “Oil” is another source of energy. Besides supplying energy, the addition of fat to animal diet improves the absorption of fat-soluble vitamins, decreases pulverulence, increases diet palatability and the efficiency of utilization of the consumed energy (Baião, N. C. and Lara, L. J. C. 2005). Furthermore, it reduces the rate of food passage through gastrointestinal tract, which allows a better absorption of all nutrients present in the diet (Baião, N. C. and Lara, L. J. C. 2005). The digestion of fat produces less body heat (fat has a relatively low heat increment), which is useful during periods of heat stress (BV-300 Layer Management Guide). Vegetable oils such as soy oil, rice bran oil and animal fat such as tallow are used as the energy sources.

The lipids arrive in the duodenum. The presence of food in the duodenum stimulates the secretion of cholecystokinin, which induces the contraction of gall bladder and secretion of the pancreatic juice, making the chime (Baião, N. C. and Lara, L. J. C. 2005). Colipase binds to the oil-water interface and produces the emulsion. Afterwards, triglycerides undergo hydrolysis under the action of the pancreatic lipase and micelles are formed by monoglycerides, diglycerides and free fatty acids (Baião, N. C. and Lara, L. J. C. 2005). Micelles are absorbed through intestinal villi.

Feed ingredients provide some vitamins for poultry and vitamin premixes are given to achieve the requirement of birds. Vitamins have been divided into two groups based on their solubility in fat solvent or in water (DSM in animal nutrition and health). Thus, fat-soluble vitamins include vitamin A, D, E and K. While, vitamin B complex and vitamin C are classified as water soluble vitamins. Fat-soluble vitamins are found in feedstuffs in association with lipids. The fat-soluble vitamins are absorbed along with dietary fats, apparently by mechanisms like those involved in fat absorption. Water soluble vitamins are not associated with fats. Commonly used vitamins in layers are fat-soluble vitamins such as Vitamin A, D3, E and K. Water soluble vitamins are Vitamin B1, B2, niacin, pantothenic acid, pyridoxine (B6), biotin, folic acid, Vitamin B12, choline, Vitamin C, carnitine and inositol (DSM in animal nutrition and health). Classical added choline levels used for layer diet are usually around 250ppm, but for an efficient action on liver, 500 to 1000 ppm of added choline is recommended. Vitamin B12, folic acid and vitamin E improve the liver condition (BV-300 Layer Management Guide).

The deficiency of vitamins and its effects were described by Simon, M. Shane. and Emeritus (2005) as follows:

Minerals are classified into 2 types:

            Steven Leeson detailed about the mineral deficiency in poultry as follows:

Water is one of the most important nutrient in a laying flock. Hence, shortage of water for few hours results in reduced egg production. Water softens feed and carries it through the digestive tract (Basic Poultry Nutrition. 2013). 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 (Basic Poultry Nutrition. 2013). 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 (Basic Poultry Nutrition. 2013).

While preparing the feed formulation, proper raw materials, cost and availability of raw materials must be considered. Feed formulation should be based on age of the birds, nutritional requirement of the breed and feed intake of the birds. The nutrients in the feed raw materials should be utilized efficiently through proper digestion and absorption of nutrients by using emulsifier and enzymes.