体外产气法研究丁酸梭菌对瘤胃发酵特性的影响

Effect of Clostridium butyricum on rumen fermentation characteristics by gas production in vitro

试验旨在采用体外产气法研究全混合饲粮(TMR)中补充不同水平的丁酸梭菌对产气量、发酵参数与养分消化率的影响,确定丁酸梭菌在肉牛饲粮中的适宜添加量。试验选用选择装有永久性瘘管的荷斯坦阉牛作为瘤胃液供体,以TMR为培养底物。对照组(CON组)只含有培养底物,丁酸梭菌试验组在培养底物的基础上添加浓度为2×10^(8)(CB1组)、4×10^(8)(CB2组)、6×10^(8)(CB3组)、8×10^(8)(CB4组)、10×10^(8)CFU/kg(CB5组)的丁酸梭菌,每个水平设6个重复。结果显示:发酵时间为2 h和4 h时,CB1组体外产气量显著低于其他组(P<0.05),发酵时间为12 h时,CB3组、CB2组、CB4组和CB5组体外产气量显著高于CON组和CB1组(P<0.05)。各试验组的pH值显著低于CON组(P<0.05),氨态氮(NH3-N)含量显著高于CON组(P<0.05),且各试验组间无显著差异(P>0.05)。CB3组、CB4组和CB5组的乙酸、丙酸、总酸含量显著高于CON组(P<0.05)。CB1组、CB2组和CB3组异丁酸含量显著高于CON组(P<0.05)。各试验组干物质消化率(DMD)、中性洗涤纤维降解率(NDFD)均显著高于CON组(P<0.05)。CB2组酸性洗涤纤维降解率(ADFD)显著高于CON组(P<0.05)。研究表明,添加丁酸梭菌可以提高产气量、NH3-N、乙酸、丙酸、总挥发酸含量以及DMD,丁酸梭菌的适宜添加量为6×10^(8)CFU/kg。

The purpose of this experiment was to study the effects of different levels of Clostridium butyricum supplementation on the gas production,fermentation parameters,and nutrient digestibility in TMR diet by in vitro gas production method,so as to determine the appropriate amount of Clostridium butyricum supplementation in beef cattle diet.Holstein steers with permanent fistula were selected as rumen fluid donors and TMR as culture substrate.The control group(CON group)only contained the culture substrate,while the Clostridium butyricum test group added Clostridium butyricum with the concentrations of 2×10^(8)(CB1 group),4×10^(8)(CB2 group),6×10^(8)(CB3 group),8×10^(8)(CB4 group)and 10×10^(8) CFU/kg(CB5 group)on the basis of the culture substrate,with six replicates at each level.The results showed that the in vitro gas production of CB1 group was significantly lower than that of other groups when the fermentation time was 2 h and 4 h(P<0.05).When the fermentation time was 12 h,the in vitro gas production of CB3 group,CB2 group,CB4 group,and CB5 group was significantly higher than that of CON group and CB1 group(P<0.05).The pH value in each experimental group were significantly lower than those in CON group(P<0.05),while the content of ammonia nitrogen(NH3-N)was significantly higher than that in CON group(P<0.05),and there was no significant difference among the experimental groups(P>0.05).The concentrations of acetic acid,propionic acid,and total acid in CB3 group,CB4 group and CB5 group were significantly higher than those in CON group(P<0.05).Isobutyric acid content in CB1 group,CB2 group and CB3 group was significantly higher than that in CON group(P<0.05).Dry matter digestibility(DMD)and neutral detergent fiber degradation(NDFD)of each experimental group were significantly higher than those of CON group(P<0.05).The degradation rate of acid detergent fiber(ADFD)in CB2 group was significantly higher than that in CON group(P<0.05).The study indicates that the addition of Clostridium butyricum can increase gas production,NH3-N,acetic acid,propionic acid,total volatile acid content and DMD.The suitable addition of Clostridium butyricum is 6×10^(8) CFU/kg.