Lysine levels for broilers in the periods from 22 to 42 and 43 to 49 days of age

Two experiments were carried out to determine the requirement of total lysine for male Ross broilers from 22 to 42 and 43 to 49 days of age. A total of 900 broilers with initial body weight of 764 +/- 35g at 22 days and 2520 +/- 73g at 43 days of age. The broilers were distributed in a completely randomized experimental design with six treatments, six replicates and 25 birds per experimental unit. There were six synthetic lysine levels in each phase. Minimum nutritional requirements were attended, except for lysine. Feed intake, body weight gain, feed conversion, carcass yield and the main cuts were evaluated lysine requirements were estimated by using regression models. Considering the performance data, the nutritional requirements of total lysine were 1.111% for maximum performance from 22 to 42 days of age and 1.044% for maximum performance and carcass and breast yields from 43 to 49 days of age.