酿酒酵母和地衣芽孢杆菌对绵羊瘤胃体外发酵的影响

本试验旨在研究添加酿酒酵母和地衣芽孢杆菌对瘤胃体外发酵的影响。在精粗比为50：50的日粮中添加酿酒酵母6×10¹¹ CFU/kg和5种水平的地衣芽孢杆菌0（C1组）、1×10¹¹（C2组）、2×10¹¹（C3组）、3×10¹¹（C4组）和4×10¹¹CFU/kg（C5组）]，并且设置空白对照组（两种菌均不加）（C组），制成6种发酵底物。测定体外发酵48 h产气参数、CH₄浓度、培养液发酵指标和饲料养分消失率。结果显示：①酿酒酵母和地衣芽孢杆菌共同作用对24、48 h累积产气量、快速发酵部分产气量、慢速发酵部分产气量、潜在产气量和产气速率均有显著影响（P<0.05），且在地衣芽孢杆菌添加量为2×10¹¹ CFU/kg时产气量和各项产气参数均达到最大值。②酿酒酵母和地衣芽孢杆菌共同作用对pH影响不显著（P>0.05），但可显著影响氨态氮（NH₃-N）和微生物蛋白（MCP）产量（P<0.05）。当地衣芽孢杆菌添加量为2×10¹¹ CFU/kg时，NH₃-N浓度最小，MCP含量最大。③酿酒酵母和地衣芽孢杆菌共同作用对干物质消失率（DMD）、有机物消失率（OMD）和代谢能（ME）影响显著（P<0.05），对中性洗涤纤维消失率（NDFD）和酸性洗涤纤维消失率（ADFD）无显著影响（P>0.05），且DMD、OMD、NDFD和ME在地衣芽孢杆菌添加量为2×10¹¹ CFU/kg时最大，ADFD最小。综上所述，酿酒酵母和地衣芽孢杆菌联用能促进绵羊瘤胃体外发酵，整体来看，当酿酒酵母的添加量为6×10¹¹ CFU/kg和地衣芽孢杆菌添加量为2×10¹¹ CFU/kg时，作用效果最好。

Effects of Saccharomyces cerevisiae and Bacillus licheniformis on Rumen Fermentation in Sheep in vitro

The aim of this experiment was to study the effect of Saccharomyces cerevisiae and Bacillus licheniformis on rumen fermentation of sheep by in vitro culture method.Six fermentation substrates were prepared by adding 6×10¹¹ CFU/kg Saccharomyces cerevisiae and 5 levels of Bacillus licheniformis (0 (C1 group)、1×10¹¹(C2 group)、2×10¹¹(C3 group)、3×10¹¹(C4 group) and 4×10¹¹ CFU/kg (C5 group))were added to the diet with a concentrate to forage ratios of 50:50,and the control group was set with no Saccharomyces cerevisiae and Bacillus licheniformis (C group).The gas production parameters,CH₄ concentration,ruminal fermentation parameters and nutrient degradation rates were determined after fermented for 48 h.The result showed as follows:①The combined effects of Saccharomyces cerevisiae and Bacillus licheniformis had significant effects on the cumulative gas production at 24 and 48 h,the gas production of fast fermentation,the gas production of slow fermentation,the potential gas production and the gas production rate (P<0.05),and they reached the maximum at the addition of 2×10¹¹CFU/kg Bacillus licheniformis.②The interaction of Saccharomyces cerevisiae and Bacillus licheniformis had no significant effect on pH value (P>0.05),but they could significantly affect ammoniacal nitrogen (NH₃-N) and microbial proteins (MCP) yields (P<0.05).The concentration of NH₃-N reached the minimum and MCP reached the maximum when the dosage of Bacillus licheniformis was 2×10¹¹ CFU/kg.③The interaction effect of Saccharomyces cerevisiae and Bacillus lichenformis on the dry matter degradation rate (DMD),organic matter degradation rate (OMD) and metabolic energy (ME) were significant (P<0.05),but had no significant effects on neutral detergent fiber degradation rate (NDFD) and acid detergent fiber degradation rate (ADFD) (P>0.05).The DMD,OMD,NDFD and ME reached the maximum while ADFD reached the minimum at the addition of 2×10¹¹CFU/kg Bacillus lichenformis.In conclusion,the Saccharomyces cerevisiae and Bacillus lichenformis supplement had significant interaction effects at 6×10¹¹ and 2×10¹¹ CFU/kg on rumen fermentation of sheep in vitro.