饲料原料蛋白质二级结构对奶牛瘤胃降解特性的影响

试验通过尼龙袋法研究豆粕、棉粕、菜粕、DDGS和玉米5种饲料在奶牛瘤胃内粗蛋白的降解特性,并通过傅里叶红外光谱法测定了5种饲料的蛋白质二级结构,研究主要饲料原料蛋白质二级结构对奶牛瘤胃降解特性的影响。结果表明:在5种饲料中,α螺旋最高的为豆粕30.52%,最低的为DDGS 18.77%。β折叠最高的为玉米35.89%,最低的为棉粕28.36%。饲料蛋白质二级结构α螺旋与β折叠比值与有效降解率呈显著强度正相关(r=0.952 8,P=0.012 2),与蛋白质慢速降解组分呈强度正相关(r=0.798 7,P=0.105 1),与非降解组分呈高度负相关,相关性趋于显著(r=-0.866 7,P=0.057 2)。

Study on protein secondary structures on the protein degradability of feeds in rumen of dairy cows

In this study,the degradation properties of crude protein of soybean meal,cotton seed meal,rape seed meal,DDGS and corn in cows’ rumen were studied by the nylon bag method,and five kinds of feed protein secondary structures were determined by FTIR.The results showed that the highest α-helix of five kinds of feed is soybean meal 30.52%,the lowest one is DDGS 18.77%.The highest β-sheet of five kinds of feed is corn 35.89%,the lowest one is cotton seed meal 28.36%.Forage protein secondary structures(α-helix/β-sheet) had significantly positive correlation with the forage crude protein effective degradation rates(r=0.952 8,P=0.012 2),it showed a strong correlation with the degradation rate of the slow degradation of part(r=0.798 7,P=0.105 1),and had strong negative correlation with the non-degradable,which tendency was significant(r=-0.866 7,P=0.057 2).