One experiment was conducted to evaluate the performance and carcass yield of two strains of male broilers fed the diets with different profiles of amino acids from 43 to 56 days of age. Data of performance (weight gain, feed intake and feed conversion), carcass yield (dressing, breast, wing, legs, head, back percentage, abdominal fat) and edible bowels (gizzard, liver and heart) were collected. The experimental design involved eight treatments in a factorial 2x4 (two strains - Hubbard and HI-Yield and four amino acid profiles), with 4 replicates of 50 broilers each. The amino acid recommendations were based on NRC (1994), Rostagno et al. (1992), Degussa (1997) and AEC (1993). When the different recommendations were compared, the lysine level was maintained constant, using NRC (1994) level as standard. No interaction of carcass yield was observed among the treatments. Broilers fed diet based on NRC (1994) recommendations showed smaller weight gain and worst feed conversion. Hubbard broilers showed better weight gain, but feed intake and feed conversion were not affected. Dressing percentage did not differ between treatments. However, the results showed that Hubbard broilers had a higher legs yield and HI-Yield a higher breast yield. Abdominal fat percentage was affected by treatments and also by strains. Edible bowels did not differ between treatments.
amino acid profile; broiler; carcass yields; performance
