Host habitat is the major determinant of the gut microbiome of fish

Abstract Background Our understanding of the gut microbiota animals is largely based on studies mammals. To better understand evolutionary basis symbiotic relationships between animal hosts and indigenous microbes, it necessary to investigate non-mammalian vertebrate species. In particular, fish have highest species diversity among groups vertebrates, with approximately 33,000 this study, we comprehensively characterized bacterial communities in fish. Results We analyzed 227 individual representing 14 orders, 42 families, 79 genera, 85 The was dominated by Proteobacteria (51.7%) Firmicutes (13.5%), different from dominant taxa reported terrestrial vertebrates ( Bacteroidetes ). microbial community more strongly shaped host habitat than taxonomy or trophic level. Using a machine learning approach trained composition predicted functional profiles, found that exhibited classification accuracy. Principal coordinate analysis revealed differs significantly those other classes (reptiles, birds, mammals). Conclusions Collectively, these data provide reference for future microbiome aquatic as well insights into relationship their bacteria, including key role distinct compositions comparison mammals, reptiles, birds.