中文摘要：

以3只瘘管山羊为瘤胃液供体，研究体外培养条件下不同纤维素水平底物对微生物的分离获得率及DNA提取率的影响。底物可溶性淀粉与纯纤维素比例设计为：100：0，70：30，50：50，30：70，0：100。结果表明：总微生物分离获得率与DNA提取率随底物纤维素含量的增加，总体上呈现下降趋势；分离获得率为53．29％，总微生物DNA提取率为51．0％；细菌DNA的提取率（45．4％）显著低于原虫DNA的提取率（56．1％）（P〈0.05）；所提得DNA片段在20kb以上，PCR扩增效果较好，适合于后续研究的分子操作。

英文摘要：

Three goats which fisted with permanent rumen cannulas were used to provide rumen fluid to harvest microbes in vitro, and to investigate the effects of rations in different starch to cellulose ratio on recovery rate of microbes from tureen fluid after detaching and rate of DNA extraction from rumen microbes. Substrates were designed by varying the ratio of starch to cellulose （NSC： SC） as follows： 100： 0, 70 ： 30, 50 ： 50, 30 ： 70, 0：100. Results showed that the recovery rate of microbes from rumen fluid after detaching and the rate of DNA extraction from ru- men microbes generally decreased with the increase of dietary cellulose ratio. The average recovery rate of microbes was 53.29 %, and the average rate of DNA extraction from mixed microbes was 51.0%, it was further observed that the rate of DNA extraction from bacteria （45.4%） were significantly less than those samples from protozoa （56.1%） （P〈0.05）. The results also showed that the molecular size of DNA fragment were larger than 20 kb, and the DNA which extracted from all the samples were fit for further studies.