An experiment was conducted with the objective of evaluating the levels digestible lysine for chickens in the starting phase (1 to 21 days of age), using two eletrolytes balances. Eighty hundred male Cobb broilers were used, allotted in a randomized complete design in a 2 × 5 factorial arrangement consisting of five levels digestible lysine levels (1.021; 1.276; 1.531; 1.786; 2.042) and two electrolyte balances (190 and 255 mEq/kg), with four replications and 20 chicks per experimental unit. There was interaction for final weight, weight gain and feed intake, and for the electrolyte balance of 190 mEq/kg the best final weight and weight gain were observed with a 1.515% of digestible lysine. For the eletrolyte balance of 255 mEq/kg, the best final weight and weight gain were observed with 1,801% digestible lysine. The feed:gain ratio increased linearly when the digestible lysine was increased. The uric acid and total protein values did not differ, however the calcium levels presented interaction significant between electrolyte balances and level lysine. The digestible lysine requirement for the starting phase, from 1 to 21 days of age ranges with the electrolyte balance in the feed.
amino acids; arginine; broiler chickens; electrolyte balance; lysine
