日粮蛋白质水平对断奶仔猪氮代谢的影响

试验研究了日粮不同蛋白质水平对断奶仔猪氮代谢的影响。试验采用完全随机设计,将72头35日龄断奶的仔猪分为4组,每组3个重复,每个重复6头。4个组分别饲喂24%、22%、20%、18%蛋白水平的日粮。结果表明:粪氮排泄随日粮蛋白水平的升高而增加,24%蛋白组粪氮排泄量显著高于其它3组(P<0.05),尿氮变化不显著;22%、20%、18%蛋白组氮表观消化率无显著差异,24%蛋白组氮表观消化率显著低于其它3组(P<0.05);氮代谢率随蛋白水平上升而下降;血清总蛋白浓度与日粮蛋白水平无显著的相关性;血清尿素氮浓度随日粮蛋白水平的降低而降低。总之,考虑到仔猪生长和氮排出,仔猪日粮蛋白水平应以20%~22%为好,18%的日粮蛋白水平影响仔猪日沉积氮量。

Effects of dietary protein level on metabolism of N of weaned pigs

The experiment was conducted to evaluate the effects of dietary protein level of weaned pigs on metabolism of N. This experiment was in a complete randomized design. 72 healthy piglets were divided into four groups with three replicates, each of which including 6 piglets. The four groups were of-fered diets containing 24%、22%、20% and 18% CP respectively. The results showed that fecal nitrogen excretion enhanced with dietary CP increase. Fecal nitrogen excretion was(P<0.05) higher in group containing 24% CP than that of other three groups.There were no significant changes in urine nitrogen excretion. There was no significant difference in apparent nitrogen digestibility among groups containing 22%、20% and 18% CP, whereas the apparent nitrogen digestibility in group containing 24% CP was significantly lower(P<0.05) than that of other groups. Apparent nitrogen metabolism rate reduced with dietary CP increase. There was no significant correlation between the concentration of plasma total protein and the level of dietary CP. The concentration of plasma urea N decreased with CP reduction. In con- clusion, based on the consideration of performance and nitrogen excretion , the optimal protein level for weaned piglets is 20% to 22%.Reducing protein level to 18% affects N retention.