In the literature, different equations are used to calculate the energy requirement for birds (Emmans, 1974, Peguri and Coon, 1988, NRC, 1994, Sakomura et al., 1993, 2006), the factorial model has been the basis for the elaboration from these models, estimating the requirements consider the differences in weights, body composition, potential for growth and production of the animals, as well as the environment.
The factorial method is based on the principle that the requirement in energy or nutrients is the quantity to be supplied for the maintenance of the vital processes of the organism, protein and adipose tissue growth, reproduction and egg production, and fractionates the total requirements in maintenance, growth, and production (Sakomura …show more content…
The factorial model to estimate the energy requirement still considers the energy need for growth (Eq. 1), that is, all energy retained for protein and lipid deposition is considered. In the case of laying hens and broiler breeders, the energy need for egg production is also computed, compartmentalized in each component (albumen, yolk, and bark). The energy requirement for birds in production can be determined by the equation below (Eq.2):
Where: Pm body weight at maturity (kg); PBt is the body protein weight in time, RP and RL is the retention of protein and body lipid. 1.63 MJ, which is the energy need per unit of maintenance per day, 50 and 56 MJ are the amounts of energy need for retention of protein and lipids (g/d), respectively. 0.025×YW, 0.0036×AW and 0.0012×SW are the energy required to produce each gram of yolk, albumen, and shell (MJ / g), respectively (Emmans and Fisher, 1986).
The same concept is used to calculate the requirement of amino acids considering maintenance, growth (Eq.3) and egg production in the case of laying hens and breeders
The factorial method is based on the principle that the requirement in energy or nutrients is the quantity to be supplied for the maintenance of the vital processes of the organism, protein and adipose tissue growth, reproduction and egg production, and fractionates the total requirements in maintenance, growth, and production (Sakomura …show more content…
The factorial model to estimate the energy requirement still considers the energy need for growth (Eq. 1), that is, all energy retained for protein and lipid deposition is considered. In the case of laying hens and broiler breeders, the energy need for egg production is also computed, compartmentalized in each component (albumen, yolk, and bark). The energy requirement for birds in production can be determined by the equation below (Eq.2):
Where: Pm body weight at maturity (kg); PBt is the body protein weight in time, RP and RL is the retention of protein and body lipid. 1.63 MJ, which is the energy need per unit of maintenance per day, 50 and 56 MJ are the amounts of energy need for retention of protein and lipids (g/d), respectively. 0.025×YW, 0.0036×AW and 0.0012×SW are the energy required to produce each gram of yolk, albumen, and shell (MJ / g), respectively (Emmans and Fisher, 1986).
The same concept is used to calculate the requirement of amino acids considering maintenance, growth (Eq.3) and egg production in the case of laying hens and breeders