日粮中添加维基尼亚霉素对肉牛瘤胃发酵参数及微生物数量的影响

试验旨在研究日粮中添加维吉尼亚霉素对瘤胃发酵参数及瘤胃微生物的影响，为阐述维吉尼亚霉素通过调节瘤胃微生物数量进而改变瘤胃发酵参数奠定基础。试验选用4头装有瘤胃瘘管的肉牛(559.4 kg±30.1 kg)进行重复交叉试验设计，维吉尼亚霉素添加量为30 mg/kg精料（干物质基础）。结果发现，维吉尼亚霉素对淀粉降解菌和蛋白降解菌有抑制作用（P<0.01）；维吉尼亚霉素能提高瘤胃pH（P<0.05）和瘤胃氨氮的利用程度（P<0.01）；维吉尼亚霉素对L-乳酸产生有抑制作用，但差异不显著（P=0.304）。维吉尼亚霉素对总挥发性脂肪酸的影响不大（P=0.864）。因此， 认为维吉尼亚霉素通过对淀粉降解菌和蛋白降解菌的选择性抑制,使得L-乳酸含量出现差别，进而改变瘤胃pH。

Influence of Adding Virginiamycin to Diets of Steers on Ruminal Fermentation Parameter and Microbial Populations

The purpose is to investigate the influence of virginiamycin on rumen fermentation parameter and ruminal microbial populations of steers. Four ruminally cannulated steers(559.4 kg±30.1 kg) were used in a repeated cross-over design. The addition dose of virginiamycin was 30 mg/kg concentrates (DM). It was indicated that virginiamycin could suppress Amylolytic bacteria populations and Proteolytic bacteria populations (P<0.01).Virginiamycin increased ruminal pH (P<0.05) and the utilization rate of ruminal NH₃-N (P<0.01). Viginiamycin inhibit the concentration of L-lactic acid (P=0.304). TVFA showed no difference (P=0.864). We presume that the virginiamycin inhibit Amylolytic bacteria populations and Proteolytic bacteria populations, which lead to the decrease of lactic acid concentration and consequently the pH value.