B12添加对活体外瘤胃发酵和纤维降解的影响

采用体外产气量法研究在高水平玉米秸日粮中添加B12对瘤胃发酵和纤维降解的影响。B12添加对发酵液原虫和细菌的数量、pH、氨态氮浓度、总挥发酸以及各挥发酸的摩尔比无显著影响(P>0.05);但随B12添加水平的增加,发酵液细菌的数量(P=0.086)和总挥发酸的生成量(P=0.081)呈上升趋势。与0ng/ml组相比,30ng/ml、90ng/ml组的乙酸生成量分别提高4.97%、5.76%,丙酸生成量分别提高5.31%、6.4%。B12添加显著提高了发酵液羧甲基纤维素酶、木聚糖酶的活性和72hDM、NDF的降解率(P<0.05),而对微晶纤维素酶活和ADF的降解率无显著影响(P>0.05)。结论:在高水平玉米秸日粮中添加B12对纤维降解有促进作用。

Effects of B12 on Rumen Fermentation and Fibre Degradation in Vitro

An in vitro study was conducted to study the effects of different B_(12) levels on fermentation and fibre degradation.Results showed that: the addition of B_(12) had no significantly effect on the total counts of protozoa and bacteria, the ammonia-N concentration,pH value,the molar percentage of acetate,propionate,butyrate,valerate,isobutyrate,isovalerate,the ratio of acetate to propionate,TVFA concentration(P>0.05),but the number of bacteria(P=0.086) and TVFA concentration(P=0.081) had an increasing tendency with the increase of B_(12) level.The addition of B_(12) significantly increased the activity of CMCase and Xylanas,and the degradation of DM and NDF(P<0.05),but there was no significantly difference in the activity of Avicelase and the degradation of ADF(P>0.05).The current study suggested that the addition of B_(12) had beneficial effects on fibre degradation when the diet(fermentation substrate) contained higher corn stalk.