The Effect of Formulation Diets Based on Digestible Amino Acids and Lysine Levels on Carcass and Chemical Composition of Broiler

This study was conducted to evaluate the carcass yield, abdominal fat deposition and chemical composi-tions of thigh and breast muscles of male Arian broilers fed three different lysine levels of 1) high lysine (110% NRC), 2) standard level suggested by National Research Council (NRC) and 3) low lysine (90% NRC) based on two expression ways of amino acid contents of feedstuffs, as total amino acids (TAA) or digestible amino acids (DAA). Three hundred one day old male broiler chickens were used in a completely randomized design with 6 treatments of 5 replicates (10 male broilers). All diets were iso-caloric and iso-nitrogenous. The results of this study showed that diet formulation based on DAA significantly influenced breast muscle yield and abdominal fat deposition. High lysine level (110% NRC) significantly improved carcass yield, breast and thigh muscle percentages and weights. The interaction between DAA × lysine lev-els of the feed affects carcass and breast muscle percentages of the broilers. Feeding the broilers with high level lysine containing diets (110% NRC) resulted in significantly high lysine content of the breast and thigh muscles. The results of this study suggest that diet formulation based on digestible amino acids with additional lysine at the level of 110% of NRC in starter and grower diets optimized body weight gain in Arain male broilers.