Digestible lysine requirements of female broilers from 1 to 15 days of age

Abstract

Two experiments were conducted to determine digestible (dig) Lys requirements of female Ross × Ross 708 and Hubbard × Cobb 500 broilers from d 1 to 15. In each experiment, 1,600 female broilers were randomly distributed into 64 floor pens and fed 8 experimental diets consisting of 7 concentrations of dig Lys ranging from 0.95 to 1.43% in increments of 0.08% and a positive control diet containing 1.27% dig Lys. A true Lys digestibility assay was conducted with cecectomized roosters to determine Lys digestibility of the negative control diets. True dig Lys of the negative control diets was determined to be 0.92 and 0.91% in experiments 1 and 2, respectively. In experiment 1, the dig Lys requirement for female Ross × Ross 708 broilers was determined to be 1.35 and 1.27%, for BW gain from 1 to 7 d and 1 to 14 d of age, respectively. The dig Lys requirement was 1.38% for 1- to 7-d feed conversion. In experiment 2, dig Lys requirements for female Hubbard × Cobb 500 broilers were estimated to be 1.26 and 1.18% for BW gain from 1 to 7 d and 1 to 14 d of age, respectively. The dig Lys requirement was 1.26% for 1- to 14-d feed conversion, but a requirement could not be estimated for feed conversion from 1 to 7 d of age. Therefore, dig Lys requirements for modern broilers are higher than previously reported based on growth performance. © 2012 Poultry Science Association, Inc.