5种饲料原料在瘤胃中干物质、淀粉及粗蛋白质的降解规律与相关性研究

Study on degradation and correlation of dry matter,starch,crude protein of five feed materials in rumen

试验旨在研究5种饲料原料(玉米皮、玉米胚芽粕、DDGS、豆粕和棉粕)在瘤胃中的降解特性,分析其主要营养成分与干物质(DM)、淀粉(Starch)和粗蛋白质(CP)的相关性。选用3头装有永久性瘤胃瘘管的荷斯坦阉牛,采用尼龙袋法测定原料DM、CP和Starch的瘤胃降解特性,通过测定饲料原料淀粉的动态降解率预测淀粉的有效降解率,分析营养成分的相关性;将装有样品的尼龙袋在瘤胃中分别培养2、4、7、8、16、24、36和48 h,每头牛每个时间点设3个重复。结果显示:棉粕的CP含量显著高于其他4种原料(P<0.05),玉米皮的CP含量最低;玉米皮的Starch含量显著高于其他4种原料(P<0.05),玉米胚芽粕的Starch含量显著高于DDGS、豆粕、棉粕(P<0.05)。豆粕的DM有效降解率显著高于其他4种原料(P<0.05);棉粕的CP有效降解率显著高于其他4种原料(P<0.05);豆粕的淀粉Starch有效降解率显著高于其他4种原料(P<0.05)。5种原料的7 h瘤胃降解淀粉率与其有效降解率相关性最强,R2为0.906;5种原料DM有效降解率与中性洗涤纤维(NDF)含量呈显著负相关(P<0.05)。研究表明,豆粕的瘤胃降解率最好,玉米皮较差。

The experiment studied the degradation characteristics of five feed ingredients(corn husk,corn germ meal,DDGS,soybean meal and cotton meal)in rumen,analyzed the correlation of its main nutrients with dry matter(DM),starch(Starch)and crude protein(CP).The experiment selected three Holstein steers with permanent rumen fistulas,and the rumen degradation characteristics of raw materials DM,CP and Starch were determined by nylon bag method.The effective degradation rate of Starch was predicted by measuring dynamic degradation rate of Starch,and the correlation of nutritional components was analyzed.The nylon bags containing the samples were cultured in rumen for 2,4,7,8,16,24,36 and 48 h,with three replicates per cow at each time point.The results showed that the CP content of cotton meal was significantly higher than that of the other four raw materials(P<0.05),and the CP content of corn husk was the lowest.The starch content of corn husk was significantly higher than that of the other four raw materials(P<0.05),and the starch content of corn germ meal was significantly higher than that of DDGS,soybean meal and cotton meal(P<0.05).The effective degradation rate of DM of soybean meal was significantly higher than that of the other four raw materials(P<0.05),the effective degradation rate of CP of cotton meal was significantly higher than that of the other four raw materials(P<0.05),and the effective degradation rate of starch of soybean meal was significantly higher than that of other raw materials(P<0.05).The 7 h rumen starch degradation rate of the five raw materials had the strongest correlation with the effective degradation rate,with R2=0.906.The effective DM degradation rate of the five raw materials was significantly negatively correlated with NDF content(P<0.05).The study indicates that soybean meal has the best rumen degradation rate,and corn husk is worse.