Abstract: [Objective] The aim of this study was to investigate the possibility of Real-Time PCR technique for study the mechanism of rumen fermentation. In addition, in order to monitor the change of rumen microbes under different diet, the Real-Time PCR method was applied to quantify cellulolytic bacteria in the rumen of sheep. [ Method] SYBR GreenⅠreal-time PCR technique was used in this experiment. According to the 16S rDNA sequence of three predominant cellulolytic bacteria, three pairs of primers were designed. [Results] Primers and reaction condition applied in this study showed a high specificity and sensitivity. The same change tendency was displayed in the population of cellulolytic bacteria between the real-time PCR technique and the traditional Hungate roll tube technique. Moreover, quantification of rumen cellulolytic bacteria by real-time PCR was faster and more sensitive, as compared with traditional method. This indicated that the method of real-time PCR could accurately reflect the variation of rumen microflora , especially in monitoring the change of specified strains in amounts of samples. [Conclusion]The quantitative method for cellulolytic bacteria in the rumen of sheep by real-time PCR could accurately reflect the variation of rumen cellulolytic bacteria.

Key words: Rumen Cellulolytic Bacteria, Real－Time PCR, Quantification