十二指肠灌注不同必需氨基酸溶液对生长育肥羔羊氮平衡及血浆尿素氮的影响

试验旨在探究实际饲养条件下由十二指肠瘘管灌注不同必需氨基酸溶液对哈萨克羊羔羊氮平衡及血浆尿素氮（plasma urea nitrogen，PUN）的影响。选取5只体况良好、4月龄、体重为（29.40±1.76） kg的哈萨克羊公羔羊，安装永久性十二指肠近端瘘管，代谢笼内单笼饲养。采用5×5拉丁方设计，即不含氨基酸组（对照组）、包含8种必需氨基酸的全灌注组（8EAA）、剔除赖氨酸组（-Lys）、剔除精氨酸组（-Arg）及剔除蛋氨酸组（-Met），处理组采用随机过程进行分配，每期7 d。结果显示，与对照组相比，8EAA组粪氮排出量差异不显著（P>0.05），而尿氮、氮表观消化率、氮沉积和PUN浓度都显著升高（P<0.05）。与8EAA相比，-Arg、-Met、-Lys组氮沉积均显著降低（P<0.05），分别降低30.62%、11.56%、12.99%，日增重分别下降13.89%、7.78%、6.58%，但差异不显著（P>0.05），PUN浓度也有升高的趋势。结果表明，实际育肥条件下Arg、Met、Lys对哈萨克育肥羔羊有限制性作用。

Effects of Duodenal Infusions of Essential Amino Acid on Nitrogen Balance and Plasma Urea Nitrogen of Growing-finishing Lambs

This study was aimed to explore the effects of duodenal infusions of essential amino acid (EAA) on nitrogen balance and plasma urea nitrogen (PUN) of growing-finishing lambs.Five Kazakh male lambs with (29.40±1.76) kg body weights and 4 months old were chosen,fitted with duodenal cannulae and raised in metabolic cage individually. The 5×5 Latin square design was used in this experiment and 7 d for per period. The duodenal infusions in control group contained no EAA,that in 8EAA group contained 8 kinds of EAA,while that in -Arg,-Lys and -Met groups were contained 8 kinds of EAA without Arg,Lys and Met,respectively. The results showed that the fecal N excretion in 8EAA group was no significant difference compared with control group (P>0.05),while the urinary N,N retention,N apparent digestibility and PUN concentration were significantly increased (P<0.05).Compared with 8EAA group,the N retention in -Arg,-Lys and -Met groups were significantly decreased by 30.62%,11.56% and 12.99% (P<0.05),and the daily gain were decreased by 13.89%,7.78% and 6.58% (P>0.05),respectively. PUN concentration was increased in response to the removement of Met,Arg and Lys. In conclusion,Arg,Met and Lys had restricted effect to Kazakh lamb in actual fattening conditions.