Comparative Analyses Of Gut Microbiota Of Three Species From The Genus Rhabdophis

The gut microbiota plays a key factor in animal physiology and immunity.However,studies on the composition,energy and nutrient uptake of these bacterial communities in gut of snakes are extremely limited.We investigated the gut microbiota of small intestine,large intestine,and cloaca were characterized in Rhabdophis nuchalis,Rhabdophis subminiatus and Rhabdophis tigrinus by Illumina Hi Seq2500 sequencing of the V4 region of the 16 S r RNA gene.The primary results were shown below:(1)In the diversity and difference analysis of the microbial community,lowest gut microbial richness and evenness was found in R.subminiatus.R.nuchalis had the highest richness,while R.tigrinus had the highest evenness.Evenness of gut microbiota in R.tigrinus was significantly higher than R.subminiatus,and the microbial richness and evenness of the small intestine were significantly higher than large intestine in R.tigrinus.Non-metric multidimensional scale analysis(NMDS),the core bacteria heatmap and Venn diagram at genus level analysis showed that R.subminiatus was significantly different from other species with intestinal microbial community.(2)In the core microbial composition,Proteobacteria,Bacteroidetes,Firmicutes,Tenericutes and Fusobacteria were most prevalent phyla in the three species snakes.Firmicutes in R.nuchalis were significantly higher than other two species snakes,whereas Fusobacteria in R.subminiatus and R.tigrinus were significantly higher than R.nuchalis.Firmicutes and Fusobacteria were important factors that lead to the overall difference of gut microbiota in the three snakes.At genus level of the core microbial composition,Mycoplasmataceae,Serratia and Eubacterium had significantly higher proportions in R.nuchalis than other species,but Aeromonadaceae,Enterobacteriaceae and Fusobacterium in the R.subminiatus and R.tigrinus had a significantly higher proportion than R.nuchalis.In addition,the intestinal microbial composition of the snake was significantly affected by the intestinal sample source.(3)Microbial functions were predicted by PICRUSt,showed the level 1 pathways associated with metabolism was highest expression in all snakes.Among level 2 pathway,the function of gut microbes in R.nuchalis were more different from other two species.Carbohydrate metabolism expression in R.nuchalis was significantly higher than other species.In addition,Microbial functions in R.tigrinus was more strongly affected by intestinal sample source.