【摘要】 根据基础日粮+待测氨基酸法,由十二指肠瘘管连续灌注DL-Met,通过日增重、氮平衡试验、小肠营养物质消化率指标和血浆游离氨基酸含量确定基础日粮条件下十二指肠氨酸最佳灌注量。试验结果表明:III组日增重最高,比I组提高15.27%(P<0.05)II组和III组沉积氮、沉积氮/可消化氮显著高于I组(P<0.05),其中III组高于II组;III组尿中尿素氮显著低于I组(P<0.05)。III组小肠氮的表观消化率最高,比I组高5.72%(P<0.05)。III组血浆氨氮显著低于I组(P<0.05)。血浆Cys和MetIV组显著高于其它3组(P<0.05),而Ser和Ile则相反。III组血浆Leu、Lys、BCAA和EAA显著低于其它各组(P<0.05)。肉牛十二指肠蛋氨酸最佳灌注量为13g/d。更多还原

【Abstract】 According to the method of basal diet plus infused amino acid,we conducted duodenal DL-Met gradient infusion experiment to quantify the optimal infusion dose of DL-Met under a basal diet in terms of average daily gain(ADG),nitrogen balance experiment,digestibility of nutrient and plasma amino acid(PAA) in the small intesine of steers.The experiment used 4×4 Latin square design.The treatments were basal diet plus infusion dose of 0(I),9(II),13(III)and 17(Ⅳ)g/d DL-Met.The results showed that ADG of group III were the highest and 15.27% increase than group I(P<0.05);RN of groups II and III were significantly higher than group I(P<0.05),but group III was higher than group II;RN/DN of group II and group III were extremely significantly higher than group I(P<0.05),group III was higher than group II;Urine urea nitrogen of group III was significantly lower than group I(P<0.05).Digestibility of N of group III were highest and 5.72% increase than group I.The results also showed that plasma NH3-N content of group II were significantly higher than that of guoup I(P<0.05).The content of plasma Cys and Met of group Ⅳ were significantly higher than that of the rest(P<0.05),but Ser and Ile was the vice versa.Plasma Leu,Lys,BACC and EAA contents of group III were significantly lower than that of the rest(P<0.05).The optimal infusion dose of DL-Met under present experiment was 13g/d.更多还原