中文摘要：

为了探讨日粮蛋白质水平对肥育宁乡猪营养物质消化率和氮能代谢的影响，选用平均体重为（65．0±2．5）kg的去势宁乡公猪9头，随机分为3组，每组3个重复，每个重复1头猪，饲喂蛋白质水平分别为10．41％、12．91％和15．43％的日粮，试验期为8d，采用全收粪法。结果表明，日粮干物质和能量的表观消化率以12．91％蛋白质日粮组最高，粗蛋白质消化率随日粮蛋白质水平升高而降低（P〈0．05）；氮摄入量、粪氮、尿氮和总氮排出量、氮表观可消化量和氮沉积量及粪能和尿能排出量均随日粮蛋白质水平升高而升高（P〈0．01），而氮的总利用率、表观消化率、代谢能及代谢能／总能随日粮蛋白质水平升高而降低（P〈0．05）。上述结果提示，日粮蛋白质水平影响能量和粗蛋白质的消化率、氮的沉积和排泄，宁乡猪日粮适宜蛋白质水平为12．91％。

英文摘要：

The experiment was conducted to investigate the effects of different dietary crude protein levels on nutrients digestibility and metabolism of nitrogen and energy. Nine Fattening Ningxiang pig （boar, castration） with an average BW of （65.0±2.5） kg were randomly allocated to 3 treatment groups evenly with 3 duplications in one group. Diets with 10.41%, 12.91% and 15.43% CP levels were given to each pig respectively. The experiment lasted for 8 days, and total feces collection method was adapted. Results showed that the pigs fed with 12.91% CP level diet have the highest apparent digestibility of DM and energy. The CP digestibility decreased with the increasing of dietary CP level （P〈0.05）. Ingestive nitrogen, fecal nitrogen, urinary nitrogen, total nitrogen in excretion, apparent digestible and retention of nitrogen, and fecal and urinary energy increased with the increasing of dietary CP level （P〈0.01）; while the total utilization ratio and apparent digestibility of nitrogen, ME and ME/GE decreased with the increasing of dietary CP level （P〈0.05）. These findings implied that the dietary CP levels had significant effects on the digestibility of energy and crude protein, as well as the deposition and excretion of nitrogen. The appropriate diet CP level for Ningxiang pig was 12.91%.