日粮蛋白质水平对6．6～10千克仔猪整体蛋白质周转代谢的影响

Effects of Dietary Protein Levels on Performance and Whole-Body Protein Turnover of 6.6～10 kilogram Piglets

本文旨在研究日粮蛋白质水平对6．6～10kg仔猪整体蛋白周转代谢的影响。选用25头（6.64±0．5）kg，（21±1）d的DLY（杜洛克×长白×大白，Duroc×Landrace×Yorkshire）断奶仔猪，随机分为5个处理，每处理5个重复，每个重复1头猪。采用单因子试验设计，分别饲喂14％、17％、20％、23％和26％蛋白质水平的饲粮，各倒粮蛋白质组成及氨基酸模式保持一致。试验期14d。结果表明：蛋白质水平在23％以下时，整体氮流量、蛋白质合成量、蛋白质降解量和蛋白质沉积量以及蛋白质沉积效率都随日粮蛋白质水平的增加而增加，但当日粮蛋白质水平超过23％后各项参数下降（P〉0．05）。仔猪整体蛋白质周转代谢对口粮蛋白质水平作出的反应存在“临界值”，临界蛋白质水平为23％。

This single factorial designed experiment was conducted to investigate the effects of dietary protein levels on wholebody protein turnover of 6.6～10 kg piglets. Twenty-five （6.64 ± 0.5） kg, （21 ± 1） d, DLY （Duroc × Landrace × Yorkshire） weaning piglets were randomly allocated into five treatments （5 replicates per treatment, 1 piglet per replicate） and fed five graded levels （14%, 17%, 20%, 23% and 26%） of protein diets respectively. The protein composition and amino acid pattern in five diets were kept the same. And whole experiment lasted for 14 days. The experimental results showed that whole-body nitrogen flux（WBNF）, protein synthesis（WBPS）, protein breakdown（WBPB）, protein accretion（WBPA） and PA/PS increased, while after dietary protein level reached 23%, whole-body protein turnover parameters were decreased with the elevation of dietary protein levels（P：〉0.05）. It indicated that threshold exists in the response of wholebody protein turnover of 6.6～10 kg piglet to dietary protein level and the ＂threshold＂ protein level is 23%. EChinese Journal of Animal Nutrition, 2006,18（4） ： 223-227 ]