活性干酵母与酵母培养物对体外瘤胃发酵参数影响的比较

Comparison of the Effects of Active Dry Yeast and Yeast Culture on Rumen Fermentation Parameters

本研究采用体外产气量法,以全日制混合日粮(TMR,精粗比60∶40)为发酵底物,比较了两种典型酵母制剂活性干酵母(active dry yeast,ADY)和酵母培养物(yeast culture,YC)对体外产气量、产气动力学参数、甲烷(CH4)含量及瘤胃发酵参数的影响,同时根据24h产气量预测了酵母制剂对底物代谢能(ME)、有机物消化率(OMD)及微生物蛋白(MP)产量的影响,旨在比较二者在体外瘤胃发酵影响上的差异,为进一步揭示其应用效果的差异机制及其合理应用奠定基础。结果显示,ADY及YC组产气量相近,但YC组12、24、48h的产气量均高于ADY组;ADY组发酵前期的产气速率较对照组降低了15.3%(P>0.05),YC组较对照组升高了19.4%(P>0.05),YC组较ADY组升高了41.0%(P<0.05);与对照组相比,YC显著增加了CH4气体含量(P<0.05),显著降低了H2及CO2的含量(P<0.05)。ADY显著降低了H2含量(P<0.05),但对CH4及CO2气体无显著影响(P>0.05);与对照组相比,ADY和YC对发酵液的pH、总挥发性脂肪酸均无显著影响(P>0.05),但均显著升高了发酵液中氨态氮(NH3-N)的浓度(P<0.05)。ADY对个别挥发性脂肪酸比例无显著影响(P>0.05),YC有升高乙酸比例、降低异丁酸比例的趋势;与对照组相比,ADY及YC对预测的底物OMD、ME及MP产量无显著影响(P>0.05),但YC组各预测指标均显著高于ADY组(P<0.05)。综上所述,YC与ADY在对发酵底物的体外瘤胃产气量、气体成分含量、产气速率及发酵参数的影响上存在差异。

This study was conducted to compare the effect of active dry yeast（ADY）and yeast culture（YC）on gas production,dynamics of gas production,methane content and rumen fermentation parameters by in vitro gas production technique,and the values of ME,OMD and yield of MP were also predicted according to 24 hgas production,in order to further reveal the mechanism of the difference effect and lay a foundation for those reasonable application.The results showed that ADY and YC had similiar effect on gas production,however,the gas production of YC group at12,24 and 48hwere higher than that of ADY;Compared to CON group,the rate of gas production in earlier fermentation period was increased by 19.4%in YC group and decreased by 15.3%in ADY group（P〉0.05）,and that of YC group was significantly increased by 41.0% than that of ADY group（P〈0.05）;The content of CH4 of YC group was significantly increased and con-tent of H2 and CO2 were significantly decreased（P〈0.05）.The content of H2 in ADY group was significantly decreased（P〈0.05）,while the content of CH4 and CO2 were not significantly changed（P〉0.05）;The pH and total VFA of rumen fermentation fluid in ADY and YC groups were not significantly changed（P〈0.05）,while the concentration of NH3-N of the two groups was significantly increased（P〈0.05）.ADY had no significant effect on individual VFA（P〈0.05）,whereas YC tended to increase the ratio of acetic acid and decrease the ratio of isobutyric acid;Comparing to CON group,the OMD,ME and MP of ADY and YC groups were not significantly affected（P〉0.05）,while that of YC group were all significantly increased than ADY group（P〈0.05）.In conclusion,there were certain differences in the effect of ADY and YC on gas production,concentrate of gas,the rate of gas production and parameter of rumen fermentation.