体外培养发酵法和体内法测定绵羊混合日粮的可利用赖氨酸和可利用色氨酸的研究

Determination of Utilizable Lysine and Utilizable Tryptophan of Mixed Rations for Sheep Using an in Vitro Incubation Technique

本试验分别用体内法和体外法,测定12种典型绵羊日粮的可利用赖氨酸(utilizable lysine,uLys)和可利用色氨酸(utilizable tryptophan,uTrp),研究体内法和体外法的回归关系,从而通过该回归关系,利用体外法测定的结果估测体内到达十二指肠的uLys和uTrp。体内法用3只体重(46.00±1.30)kg,装有瘤胃瘘管和T型十二指肠瘘管的成年杂交绵羊羯羊(小尾寒羊×无角多赛特)作为试验动物,12种日粮粗蛋白质(CP)水平递增。12种日粮和3只试验动物4个设计3×3拉丁方试验。每个拉丁方试验分为3个试验期,每期10 d,预试期7 d,正试期3 d。正试期收集十二指肠食糜,分别用聚乙二醇(PEG,分子量4 000)和三氧化二铬(Cr2O3)作为液相和固相指示剂计算十二指肠食糜流量。通过测定食糜样品的赖氨酸和色氨酸,根据食糜流量计算到达十二指肠的可利用赖氨酸(in vivo-uLys)和可利用色氨酸(in vivo-uTrp)。体外法用Zhao等的体外培养技术测定日粮的可利用赖氨酸(in vitro-uLys)和可利用色氨酸(in vitro-uTrp)。结果表明,in vitro-uLys和in vivo-uLys存在显著的回归关系(R2=0.4 9,P<0.0 5,RSD=0.0 7);in vitro-uTrp和in vivo-uTrp回归关系极显著(R2=0.6 0,P<0.0 1,RSD=0.03)。

The objective of the present experiment was to study the regression relationship between uLys and uTrp of mixed rations determined using in vitro incubation technique （in vitro-uLys, in vitro-uTrp） and uLys and uTrp supply to duodenum of sheep （in vivo-uLys, in vivo-uTrp）, and to predict in vivo-uLys and in vivo-uTrp of rations for sheep based on the regression relationship between in vitro-uLys and in vivo-uLys and between in vitro-uTrp and in vivo-uTrp. Twelve typical rations with graded levels of crude protein （CP） three adult male sheep, weighing （46.00 -＋ 1.30） kg, fitted with rumen cannulas and simple T-type duodenal cannulas, were allocated in four 3 × 3 Latin square designs. Polyethylene glycol （PEG） and chromium oxide （Cr2O3） were used as dual markers for the measurement of the intestinal digesta flow and the calculation of in vivo-uLys and in vivo-uTrp of duodenal digesta. The in vitro-uLys and in vitro-uTrp of the 12 rations were determined using the in vitro incubation technique of Zhao et al.. The results indicated that there was a significant linear regression relationship between in vitro-uLys （x, % DM） and in vivo-uLys （y, % DM） （R2 = 0.49, P〈0.05） and between in vitro-uTrp （x, % DM） and in vivo-uTrp （y, % DM） （R^2 = 0.60, P〈0.01）. [Chinese Journal of Animal Nutrition, 2007,19（6） ：671- 677]