Characterization of gut microbial community of rhesus macaques under the high-altitude extreme environments

Background: The mammal intestinal microbita involved in various physiological processes in host and play a key role in host environment adaption. However, for non-human primate(NHP), little is known about their gut microbial community in high-altitude extreme environment and much less to their adaption to high-altitude environment. In this study, we want to characterize gut microbial community of rhesus macaques from multiple high-altitude environment and by comparing it to low-altitude control group to reveal the differences between altitudes. Results: we collected the fecal samples of rhesus macaques from four high-altitude populations (above 3000m) and one low-altitude population (below 100m). We first analyzed the overlap of operational taxonomic units (OTUs) between populations and found 27.8% of OTUs (core OTUs) were shared by all five population.The majority of these OTUs have a higher abundance, whereas the unique OTUs have a lower abundance. By calculating alpha diversity index, we found high-altitude populations exhibited higher diversity. Statistical analysis of beta diversity indicated there were significant difference between high and low altitude population. Significant difference in composition were detected at phylum and family. At phylum level, high-altitude gut microbial community were dominanted by Firmicutes(63.7%), but low-altitude were dominated by Bacteroidetes(52.2%). At family level, high-alititude population were dominanted by Ruminococcaceae(36.4%), but low-altitude were dominated by Prevotellaceae(43.9%). Additionally, the abundance of Christensenellaceae are significantly higher in all high-altitude populations(3.33%) than low-altitude population(0.77%), despite a low abundance in two altitudes. Finally, function prediction indicated there was a significant difference in gene copy number of 29 level-2 pathway between high and low altitude population; and 26 of them are higher in high-altitude, especially in membrane transport and carbohydrate metabolism. Conclusions: We found the gut microbial community of high-altitude rhesus macaques is significantly distinct from low-altitude population in diversity, composition and function. High-altitude populations were dominanted by Firmicutes and Ruminococcace, but low-altitude population by Bacteroidetes and Prevotellaceae. The difference in gut microbiota between two altitude macaque populations may be caused by different host diet, environmental temperature and oxygen pressure, and gut microbial microorganisms may play an critical role in adaptive evolution of rhesus macaques to high-altitude environment.