Assessment of the threonine-to-lysine ratio of male broilers from 35 to 49 days of age.

摘要

Dietary amino acid concentration should closely meet maintenance and tissue accretion needs of commercial broilers, especially at the higher feed intake rates at the end of the grow-out period, to avoid costly excesses. For this purpose, a study using 1,248 Ross x Ross 708 male broilers was designed to simultaneously evaluate the dietary needs of Lys and Thr from 35 to 49 d of age. Production of dose-response diets was accomplished via the diet-dilution technique, and diets were formulated to provide a range from 0.70 to 1.15% and 0.40 to 0.85% true digestible Lys and Thr, respectively. The only parameter that allowed for an estimation of Lys and Thr requirements using quadratic regression was BW gain, with recommended estimates of 1.09 and 0.72% true digestible Lys and Thr, respectively. Therefore, we estimated a true digestible Thr-to-Lys ratio of 66 for maximizing BW gain. Additionally, requirement estimates for true digestible Thr of 0.67, 0.72, and 0.74% for feed consumption, feed conversion, and breast meat weight, respectively, were calculated.