Two experiments were carried out to determine the nutritional requirement of total lysine for Hubbard and Ross broiler chickens of both sexes, from 1 to 21 and from 22 to 40 days of age. The evaluated traits were weight gain, feed intake, feed:gain, carcass yield, breast with bone yield, breast meat yield and fat pad. In each phase, a completely randomized block experimental design in a 2 x 2 x 6 factorial arrangement was used, with two sexes, two trade mark and six dietary lysine levels, with four replicates using a total of 1920 birds. The basal diets with 1.0% of lysine, 22.61% CP and 3050 kcal ME/kg in the first experiment and 0.825% lysine, 19.6% CP and 3200 kcal ME/kg in the second experiment, were supplemented with six lysine levels (0, 0.06, 0.12, 0.18, 0.24 and 0.30%). Considering the traits as weight gain, feed: gain, the dietary requirement estimates for the phase from 1 to 21 days were 1.191% and 1.198% total lysine for males and females Ross and 1.174% and 1.188% of total lysine for males and females Hubbard, respectively. For the period from 15 to 40 days, considering the weight gain, feed:gain ratio, carcass yield, breast with bone yield, breast meat yield and fat pad, the dietary total lysine level of 1.125% was considered adequate for both sexes from the two trade marks.
sex; trademarks; weight gain
