Microbiota in different digestive tract of paddlefish (Polyodon spathula) are related to their functions

Paddlefish has high economic and ecological value. In this study, microbial diversity and community structure in intestine, stomach, and mouth of paddlefish were detected using high-throughput sequencing. The results showed that the diversity and richness indices decreased along the digestive tract, and significantly lower proportion of those were observed in intestine. Firmicutes, Bacteroidetes and Proteobacteria were the dominant phyla. In top 10 phyla, there was no significant difference in mouth and stomach. But compared with intestine, there were significant differences in 8 of the 10 phyla, and Firmicutes and Bacteroidetes increased significantly, while Proteobacteria decreased significantly. There was no dominant genus in mouth and stomach, but Clostridium _sensu_stricto_1 and uncultured_bacterium_o_ Bacteroidales was predominant in intestine. In conclusion, the species and abundance of microbiota in the mouth and stomach of paddlefish were mostly the same, but significantly different from those in intestine. Moreover, there was enrichment of the dominant bacteria in intestine.