Requirements of lysine, nutritional plans and mathematical models for determination of the requirements of broilers

Abstract

Among the different nutrients that can interfere with performance and carcass quality, lysine appears to exert the most pronounced effect, since this additional supplementation improves weight gain, feed conversion and reduces abdominal fat. Specifically about amino acids, the deficiency in the initial phase prevents the maximum proteic deposition while the excess at the end of the phase, beyond it represents waste, it spends additional energy with excretion in the form of uric acid. The solution proposed for this nutritional impasse has been the recommendation of the adoption of a larger number of diets during the life of birds, known as phase-feeding program, where the differences between required and supplied are lower. In formulating the diets for the phase-feeding, researchers have used mathematical models developed from the requirements set by performance experiments or growth curve and deposition of protein in birds. Among the models available, the Gompertz equation is that best describes the growth of chickens and various tissues. The use of mathematical models to describe the growth of birds allows adequate information of weight versus age and minimizes any random effect caused, for example, by the environment. Predict the performance of birds under different feeding conditions and management or even of different strains is information that the use of the Gompertz equation can provide the professionals of the area. Keywords: Amino acids, Gompertz equations, phase feeding