日粮中添加黄芪多糖对锦江黄牛瘤胃体外发酵及养分降解率的影响

Effects of Astragalus Polysaccharides(APS)on Rumen Fermentation and Nutrient Degradability of Jinjiang Yellow Cattle in Vitro

[目的]试验旨在探究不同水平黄芪多糖(astragalus polysaccharides,APS)对锦江黄牛瘤胃体外发酵指标及养分降解率的影响。[方法]选取4头健康并安装永久瘤胃瘘管的锦江黄牛公牛,采集瘤胃液。采用单因素试验设计,试验分为6组,每组4个重复,在基础日粮中分别添加0、0.25%、0.5%、1.0%、2.0%和4.0%的黄芪多糖,体外发酵24 h后测定发酵参数、养分降解率,并评定多项指标综合指数(MFAEI)。[结果]结果表明,与对照组相比,1.0%和2.0%添加组的瘤胃液菌体蛋白(MCP)含量均显著升高(P<0.05);2.0%添加组的氨态氮(NH3-N)含量显著降低(P<0.05);1.0%添加组的丙酸含量显著升高(P<0.05),乙丙酸比值显著下降(P<0.05);0.5%、2.0%和4.0%添加组的粗蛋白(CP)降解率极显著高于对照组(P<0.01);各添加组的总产气量、pH、乙酸含量、干物质(DM)降解率、酸性洗涤纤维(ADF)降解率及中性洗涤纤维(NDF)降解率与对照组相比均无显著变化(P>0.05)。MFAEI指数评定结果为1.0%组>4.0%组>0.5%组>0.25%组>2.0%组。[结论]在体外发酵条件下,添加黄芪多糖可提高瘤胃微生物蛋白含量和丙酸浓度,降低NH_(3)-N浓度和乙丙酸比值,其中1.0%添加量效果最佳。

[Objective]This experiment was conducted to investigate the effects of different levels of Astragalus Polysaccharides(APS)on rumen fermentation and nutrient degradability of Jinjiang yellow cattle in vitro.[Method]Four healthy Jinjiang yellow cattle with rumen fistula were selected to collect rumen fluid,and all fluid samples were mixed in vitro and divided into 6 groups as following:basal diet astragalus polysaccharides by 0(control group),0.25%,0.5%,1.0%,2.0%,and 4.0%.After 24-hour in vitro fermentation,the fermentation parameters and nutrient degradability were determined.The results showed that the content of microbial protein(MCP)in both the 1.0%and 2.0%APS groups were increased significantly.The contents of propionic acid were increased while the ratio of acetic acid and propionic acid was decreased in the 1%APS group compared to the control group(P<0.05).The concentration of ammonia nitrogen(NH_(3)-N)was decreased significantly in the APS 2.0%group,but the digestibility of crude protein(CP)in the 0.5%,2.0%,and 4.0%APS groups was increased significantly compared with the control group(P<0.01).Nevertheless,there was no significant difference in total gas production,pH value,the content of acetic acid and propionic acid,acetic acid/propionic acid,the digestibility of dry matter(DM),neutral detergent fiber(NDF)and acid detergent fiber(ADF)among all groups(P>0.05)using multiple-factors associative?effects?index(MFAEI)analysis.[Result]The results showed the MFAEI value in 1%APS group was highest in all groups.[Conclusion]These results indicated that Astragalus polysaccharide can promote the synthesis of rumen MCP and propionic fermentation in vitro,and the additive level of APS by 1.0%is better.