Comparison of bacterial diversity in large intestine of Xiangxi yellow cattle (Bos taurus) associated with different diet: Fresh Miscanthus sinensis and mixed forage

Ruminants harbour a complicate ecosystem consisting mostly of microorganisms which have the ability to digest the fibrous cell walls of plant materials from host's food. To discover the novel enzyme from ruminant's digestive tract for exploration of the new biofuel plant-Miscanthus sinensis, we comparatively analyzed the distribution of microbiome in the large intestine of two groups of local cattle fed with either M. sinensis[M. sinensis (+) group] or mixed forage [M. sinensis (-) group]. Two libraries of 16S rRNA gene from intestinal microbiome of two groups of local cattle were constructed respectively, and subjected to restriction fragment length polymorphism (RFLP) and sequence analysis. After analyzing the sequences of 16S rRNA genes, our results indicated that the intestinal bacteria of M. sinensis (+) group were composed ofFirmicutes (48.89%), Bacteroidetes (6.67%), rumen bacteria (10%) and uncultured bacteria (34.44%), and the intestinal bacteria of M. sinensis (-) group were composed ofFirmicutes (52.87%), Bacteroidetes (1.27%), rumen bacteria (9.55%), uncultured rumen bacteria (4.46%) and uncultured bacteria (31.21%). As expected, we found that five species of potential cellulolytic becteria can only be detected in the library of M. sinensis(+). Besides, through phylogenetic tree analysis, we found that the ratio of uncultured genus which were lack of recognized sequences in M. sinensis (+) library and M. sinensis (-) library were 55.96 and 51.56%, respectively, indicating that the cattle fed onM. sinensis will produce more novel uncultured genus which probably have specific metabolic effect on decomposition of M. sinensis.   Key words: Cattle, bacterial diversity, large intestine, Miscanthus sinensis, 16S rRNA gene library, phylogenetic analysis.