Effect of different dietary protein levels and amino acids supplementation patterns on growth performance, carcass characteristics and nitrogen excretion in growing-finishing pigs

作者：Yumei Zhao, Gang Tian, Daiwen Chen, Ping Zheng, Jie Yu, Jun He, Xiangbing Mao, Zhiqing Huang, Yuheng Luo, Junqiu Luo, Bing Yu · 发表于：Journal of Animal Science and Biotechnology/Journal of animal science and biotechnology · 年份：2019 · DOI：10.1186/s40104-019-0381-2 · 被引用次数：60 · 研究领域：Animal Nutrition and Physiology、Animal health and immunology、Animal Behavior and Welfare Studies

Abstract Background This study was conducted to determine the effects of different dietary protein levels and amino acids supplementation patterns in low protein diets on the growth performance, carcass characteristics and nitrogen excretion in growing-finishing pigs. Forty-two barrows (25.00 ± 0.39 kg) were randomly assigned to 7 diets. Diet 1: the high crude protein diet with balanced for 10 essential amino acids (EAAs). Diet 2: the medium crude protein diet with 2% (approx) decreased protein level of Diet 1 and balanced 10 EAAs. Diet 3: the low crude protein diet with 4% decreased protein level of Diet 1 and balanced 10 EAAs. The protein levels of Diet 4, 5, 6 and 7 were the same as that of Diet 3. Diet 4 was only balanced for lysine (Lys), methionine (Met), threonine (Thr) and tryptophan (Trp); Diet 5 and 6 were further supplemented with extra isoleucine (Ile) or valine (Val), respectively; Diet 7 was further supplemented with extra Ile + Val. Results Over the 112 days trial, the reduction of dietary protein by 2% or 4% with balanced10 EAAs significantly decreased nitrogen excretion ( P < 0.05), but had no effects on growth performance and carcass characteristics ( P > 0.05). In low protein diet, Val supplementation significantly increased body weight gain at 25–50 kg phase ( P < 0.05), while Ile supplementation at 75–100 kg phase and 100–125 kg phase significantly reduced the ratio of feed to gain ( P < 0.05). No effect of different dietary protein levels and...