不同添加量混合菌对体外发酵的影响

The Influence of Different Additive Amount of Mixed Bacteria on Fermentation in Vitro

为研究添加混合菌对体外发酵的影响,将混合菌(兼性纤维素分解菌L5和兼性固氮菌LC-5,比例为4∶1)添加于发酵培养液中进行体外培养,按照混合菌添加量设1个对照组(CK)(添加灭活菌液)和5个试验组(4.0×107、4.0×108、4.0×109、4.0×1010和4.0×1011CFU·L-1)。体外培养过程中,测定2~48 h产气量,并分别在12 h和48 h测定培养液中氨态氮(NH3-N)、挥发性脂肪酸、微生物蛋白(MCP)等指标。结果表明,各试验组产气量均呈逐渐增加趋势。与CK相比,12 h时,4.0×1010CFU·L-1组的NH3-N、MCP含量以及滤纸酶活性均有显著提高,但其他各项发酵指标则显著降低;4.0×1010CFU·L-1组的丙酸与丁酸含量显著高于其他试验组,乙酸、总挥发性脂肪酸、MCP、NH3-N含量以及滤纸酶活性在数值上均略高于其他试验组。48 h时,4.0×1010CFU·L-1组除丁酸含量、pH值与滤纸酶活性外,其他各指标与CK相比均有显著提高;随着混合菌添加量的增加,乙酸、丙酸、丁酸、总挥发酸、甲烷以及NH3-N含量均呈上升趋势,但4.0×1010CFU·L-1组与4.0×1011CFU·L-1组间差异不显著(P>0.05)。综上,混合菌添加量以活菌数为4.0×1010CFU·L-1时效果最佳。本研究为纤维素分解菌与固氮菌在反刍动物生产中的应用提供了理论依据。

In order to study the influence of different additive amount of mixed bacteria on internal environment of rumen,mixed bacteria was added in diet of cow（live bacteria number of facultative cellulose bacteria L5; live bacteria number of facultative azotobacter LC-5 = 4∶ 1） in this experiment. One control group（CK） and five test groups（4. 0× 107,4. 0 × 108,4. 0 × 109,4. 0 × 1010 and 4. 0 × 1011 CFU·L^（-1）） are included in this study. The fermentation last for48 h. The indexes of NH3-N,microbial crude protein（MCP）,pH value and so on of in vitro fermentation were measured at 12 h and 48 h,respectively. The result showed that the gas production of each test group had an increased trend. At 12 h,the contents of NH3-N and MCP in 4. 0 × 1010 CFU·L^（-1） group were significantly higher than those in control group. The other fermentation indexes of control group were significantly lower than the 4. 0 × 1010 CFU·L^（-1） group（P 〈0. 05）. The propionic acid and butyric acid content of 4. 0 × 1010 CFU·L^（-1） group were significantly higher than other test groups（P 〈0. 05）. And 4. 0 × 1010 CFU·L^（-1） group was a little higher than other groups in value of acetic acid,total volatile acid,MCP,NH3-N content and filter paper enzyme activity（P 〈0. 05）. At 48 h,the fermentation indexes of 4. 0 × 1010 CFU·L^（-1） group were higher than control group（P 〈0. 05）,except the content of butyric acid,the pH value and filter paper enzyme activity. The content of acetic acid,propionic acid,butyric acid,total volatile acid,methane and NH3-N were on the rise with the addition amount raising,and there was no difference between 4. 0 × 1010 CFU·L^（-1） group and 4. 0 × 1011 CFU·L^（-1） group. In summary,the group of 4. 0 × 1010 CFU·L^（-1） was the best addition on improving rumen environment. This study provides a theoretical support for the application of cellulose decomposing bacteria and azotobacter used in ruminal production.