The objective of this experiment was to determine the digestible lysine requirement for male broilers from 1 to 21 days. Six hundred male broiler chicks, Hubbard, with an average weight of 48 g were allotted to randomized blocks experimental design with five treatments, six replicates and 20 chicks per experimental unit. The treatments corresponded to the basal diet, with 20.85% of crude protein and 3000 kcal of ME/kg, attending the requirements of protein, energy, calcium, phosphorus and amino acids, except lysine supplemented with five L-lysine levels, resulting on diets with .84, .93, 1.02, 1.11, and 1.20% of digestible lysine in the diet. The true amino acid digestibility in the basal diet was determined by means of a digestibility trial with cecectomized Leghorn roosters. The digestible lysine levels in the diet influenced the weight gain, feed:gain ratio, lysine intake, the ether extract content of the carcass and the protein and fat deposition rate in the carcass. However, there was no effect on diet intake and the concentration of uric acid in the blood serum and crude protein, dry matter and water of the carcass. Based on the results of WG, F:G and protein deposition rate in the carcass, the digestible lysine requirements were estimated in 1.05, 1.03, and 1.08%, respectively.
lysine; broiler chicks; initial phase; male