不同方法测定瘤胃非降解蛋白质小肠消化率及相关性分析

Small Intestinal Digestibility of Rumen Undegraded Protein Measured by Different Methods and Correlation Analysis

本试验分别采用移动尼龙袋法、改进三步体外法、原始三步体外法和酸性洗涤不溶氮(ADIN)估测法测定13种精料的瘤胃非降解蛋白质(RUP)小肠消化率,并对移动尼龙袋法与其他方法的测定结果进行相关性分析,同时对常规营养成分和RUP小肠消化率作回归分析,旨在寻找替代移动尼龙袋法测定RUP小肠消化率更简单快速的方法。试验采用单因素试验设计,选取3头装有永久瘤胃瘘管和十二指肠T型瘘管的奶牛。结果表明:移动尼龙袋法测得的豆粕、棉籽粕、菜籽粕、葵花粕、芝麻粕、玉米胚芽粕、玉米、米糠、米糠粕、米糠饼、大麦、麦麸和玉米麸质饲料的RUP小肠消化率分别为98.13%、87.37%、88.47%、82.60%、85.73%、75.40%、93.23%、69.27%、77.83%、92.10%、91.27%、72.37%和79.03%。改进三步体外法测定结果与移动尼龙袋法测定结果的相关系数为0.838 3;原始三步体外法测定结果与移动尼龙袋法测定结果的相关系数为0.789 9;ADIN估测法预测结果与移动尼龙袋法测定结果无显著相关(P>0.05);饲料RUP小肠消化率与饲料常规营养成分含量显著相关(P<0.05)。改进三步体外法比原始三步体外法替代移动尼龙袋法测定饲料RUP小肠消化率效果更好。应用体外法替代移动尼龙袋法测定蛋白质饲料RUP小肠消化率比测定能量饲料RUP小肠消化率效果更好。用饲料的常规营养成分含量可较好地预测RUP小肠消化率。

In this experiment,small intestinal digestibility of rumen undegraded protein(RUP) in 13 kinds of concentrates were measured by mobile nylon bag method(MBT),original three-step in vitro method(TSP),modified three-step in vitro method(MTSP) and acid detergent insoluble nitrogen(ADIN) estimation method,and correlation analysis of measured results between MBT and other methods and regression analysis between conventional nutrient contents and small intestinal digestibility of RUP were carried out.The purpose of this experiment was to find out a simple way to replace the MBT to determine small intestinal digestibility of RUP.Three cows with permanent rumen fistulas and duodenal T-fistulas were chosen and single-factor experimental design was selected in this experiment.Test materials were soybean meal,cottonseed meal,rapeseed meal,sunflower meal,sesame meal,corn germ meal,corn,rice bran,rice bran cake,rice bran meal,barley,wheat bran,wheat bran,corn fiber feed.The results showed that small intestinal digestibility of RUP measured by MBT were 98.13%,87.37%,88.47%,82.60%,85.73%,75.40%,93.23%,69.27%,77.83%,92.10%,91.27%,72.37% and 79.03% in soybean meal,cottonseed meal,rapeseed meal,sunflower meal,sesame meal,corn germ meal,corn,rice bran,rice bran meal,rice bran bread,barley,wheat bran and corn fiber feed,respectively.Correlation coefficient of measured results between MTSP and MBT was 0.838 3,correlation coefficient of measured results between TSP and MBT was 0.789 9,and there was no significant correlation of measured results between MBT and ADIN estimation method(P>0.05).The small intestinal digestibility of RUP was significantly correlated with conventional nutrient contents(P<0.05).The effect of small intestinal digestibility of feed RUP measured by MTSP replacing MBT was better than that measured by TSP replacing MBT.The effect of small intestinal digestibility of protein feed RUP measured by in vitro method replacing MBT was better than that of energy feed.The small intestinal digestibility of RUP can be predicted by feed conventional nutrient contents.