体外法研究乙酸发酵型脂肪酸组合对瘤胃细菌乙酸发酵的影响

In vitro study on the effect of acetic acid fermentation type fatty acid combination on acetic acid fermentation of rumen bacteria

为研究乙酸发酵型脂肪酸组合对奶牛瘤胃微生物的影响。试验在体外培养底物中添加1.5%硬脂酸、0.5%油酸、1.0%亚油酸、1.5%亚麻酸的脂肪酸组合为试验组,以培养底物中添加5%的棕榈酸钙为对照组,进行体外培养。结果表明,培养液pH值和氨态氮(NH3-N)浓度的各时间点均值在组间没有显著性的差异,但试验组瘤胃发酵产生的总挥发性脂肪酸(TVFA)浓度及乙酸比例都显著提高(P<0.05),试验组微生物蛋白含量显著高于对照组(P<0.05),而其原虫蛋白/细菌蛋白的比例却显著低于对照组(P<0.05),试验组中嗜淀粉瘤胃杆菌、琥珀酸拟杆菌的相对含量均显著高于对照组(P<0.05),溶纤维丁酸弧菌的相对含量显著低于对照组(P<0.05),而白色瘤胃球菌、黄色瘤胃球菌、蛋白溶解梭菌、降解淀粉瘤胃球菌、埃式巨球菌在两组之间差异均不显著。综上,乙酸发酵型脂肪酸组合将乙酸占TVFA的比例从73.54%提高至75.59%,趋使瘤胃发酵向乙酸型发酵模式变化,这可能是通过影响相关瘤胃细菌数量所致。

In order to study the effect of acetic acid-fermented fatty acid composition on rumen microbial fermentation of dairy cows in vitro.In this experiment,the fatty acid combinations of 1.5%stearic acid,0.5%oleic acid,1.0%linoleic acid and 1.5%linolenic acid were added to the in vitro culture substrates as the experimental group,and 5%calcium palmitate as the control group.The results showed that there was no significant difference in pH value and ammoniacal nitrogen(NH3-N)concentration between the two groups,the concentration of total volatile fatty acids and the ratio of acetic acid in rumen fermentation of the experimental group were significantly increased(P<0.05),the content of microbial protein in the experimental group was significantly higher than that in the control group(P<0.05),but the ratio of protozoa protein/bacteria protein was significantly lower than that in the control group(P<0.05),the relative content of Ruminobacter amylophilus and Fibrobacter succinogenes in the experimental group were significantly higher than that in the control group(P<0.05),and the relative content of Butyrivibrio fibrisolvens in the test group was significantly lower than that in the control group(P<0.05),there was no significant differences of other bacterial species in the test group.In summary,the acetic acid fermentation fatty acid combination increased the proportion of acetic acid in the total volatile fatty acid from 73.54%to 75.59%,resultantly transformed the rumen fermentation pattern to the acetic acid fermentation pattern,which might be attributed to the biomass change of related rumen bacteria.