牦牛尿嘌呤衍生物排出量对皱胃注射酵母RNA水平的响应

摘要

本研究对3头牦牛施以皱胃瘘管手术,以酵母RNA为嘌呤碱基供体,连续注射4期,以期测定牦牛吸收嘌呤的回收率,为尿嘌呤衍生物估测牦牛瘤胃微生物氮产量的模型积累数据.结果表明,牦牛皱胃连续注射酵母RNA可使尿囊素(564～1 426 μmol/kg BW0.75)、总嘌呤衍生物(purine derivative,PD)排出量(629～1 507 μmol/kgBW0.75)及尿囊素占总PD比例线性提高(0.90～0.95)(P＜0.01)；嘌呤碱基注射水平对尿酸、肌酐及尿氮排出量影响不显著(P＞0.05).回归分析发现,牦牛皱胃嘌呤注射量(X,mmol/d)与尿嘌呤衍生物排出量(Y,mmol/d)间存在线性关系:Y=0.85X+33.02 (R2 =0.96,P＜0.001),牦牛吸收嘌吟在尿中的回收率为85％.%Three castrated yaks fitted with T-shaped abomasum cannulae were used to study the recovery rate of urinary purine derivative after abomasum infusion with incremental amounts of purine bases. As the infusion RNA levels increased, excretion of urinary allantoin (564-1 426 μmol/kg BW0.75), total purine derivative (629 - 1 507 μmol/kg BW0.75) and the ratio of allantoin to total purine derivative (0. 90 - 0. 95) increased linearly (P<0. 01), although excretion of uric acid, creatinine and nitrogen were not significantly (P>0. 05) affected by infusion levels. The relationship between daily urinary purine derivative excretion (Y, mmol/d) and exogenous purine supply via abomasums infusion (X, mmol/d) was Y=0. 85X+33. 02 (R2 =0. 96), suggesting that 85% of the supplied exogenous purine was excreted in the urine of the yaks.