玉米和大麦体外瘤胃发酵氢气、甲烷和挥发性脂肪酸产量差异研究

Differences in Hydrogen,Methane and Volatile Fatty Acids Production between Corn and Barley in in Vitro Rumen Fermentation

本试验旨在研究玉米和大麦体外瘤胃发酵氢气、甲烷和挥发性脂肪酸产量的差异。以玉米和大麦为发酵底物,选用3只安装永久性瘤胃瘘管的湘东黑山羊作为瘤胃液供体动物,利用全自动体外模拟发酵系统进行48 h体外瘤胃发酵试验。结果表明:1)与玉米相比,大麦的粗蛋白质和中性洗涤纤维含量较高,而淀粉含量较低。2)与玉米相比,大麦的干物质降解率显著降低(P<0.05),产气速率、起始底物降解速率均显著升高(P<0.05);氢气的产气量、降解每克底物的产气量、潜在最大产气量、产气速率均显著升高(P<0.05);甲烷的产气速率显著升高(P<0.05)。3)与玉米相比,大麦的氨态氮浓度、乙丙比以及丁酸、异丁酸和戊酸浓度及比例均显著升高(P<0.05)。结果提示,大麦的前期底物降解速率显著高于玉米,促进更多氢气累积,有助于丁酸生成。

This present study was conducted to investigate the hydrogen,methane,volatile fatty acids produc tion in corn and barley in in vitro rumen fermentation.Rumen fluid was collected from three Xiangdong black goats fitted with permanent rumen fistula.The 48 h in vitro ruminal incubation was performed using automatic fermentation system.The results showed as follows:1)compared with corn,barley had greater crude protein(CP)and neutral detergent fiber(NDF)contents and lower starch content.2)Compared with corn,dry mat ter degradation(DMD)of barley significantly decreased(P<0.05),and the fractional rate of gas production and initial fractional rate of degradation significantly increased(P<0.05);hydrogen production,gas produced by degradation per gram of substrate,the final asymptotic volume of hydrogen production and the fractional rate of production significantly increased(P<0.05);fractional rate of methane production significantly in creased(P<0.05).3)Compared with corn,ammoniacal nitrogen concentration,acetate to propionate ratio,the concentrations and percentages of butyrate,isobutyrate and valerate significantly increased(P<0.05).In conclusion,barley has greater initial fractional rate of degradation than that of corn,which produces a large a mount of hydrogen and favors butyrate production.