Metabolizable energy and digestible lysine levels on the composition and carcass yield of broilers

The aim of this study was to determine the nutritional requirement of digestible lysine and metabolizable energy on carcass yield and protein and fat deposition rates of broilers in the period 35-49 days old. A total of 768 Cobb male broilers were distributed in a completely randomized design, in a 4x4 factorial arrangement, totaling 16 treatments (4 levels of digestible lysine x 4 levels of metabolizable energy) and three replicates of 16 birds each. The digestible lysine and metabolizable energy levels were: 0.800, 0.900, 1.000 and 1.100% and 3000, 3120, 3240 and 3360 kcal.kg(-1), respectively. The different levels of metabolizable energy and digestible lysine did not influence (P>0.05) the carcass yield, parts (breast, thigh, drumstick and wing) and abdominal fat. There was an interaction (P<0.05) between the levels of metabolizable energy and digestible lysine on protein and fat deposition rates and carcass fat of broilers. The rate of fat deposition showed the best result for the level of 1.000% LD and 3000 kcal.kg(-1) ME. The higher fat content occurred in the treatment with the highest level of metabolizable energy (3360 kcal.kg(-1)). The metabolizable energy and digestible lysine levels contained in the diets of broilers in the period 35-49 days of age, do not interfere in the carcass and amount of abdominal fat.