The intestinal microbiota and metabolic profiles of Strauchbufo raddei underwent adaptive changes during hibernation

The intestinal microbiota help regulate hibernation in vertebrates. However, it needs to be established how hibernation modulates the gut microbiome and intestinal metabolism. In the present study, we used an artificial hibernation model to examine the responses of the gut microbiota of the Strauchbufo raddei to the environmental changes associated with this behavior. Hibernation significantly lowered the diversity of the microbiota and altered the microbial community of the gut. Proteobacteria, Firmicutes, and Bacteroidota were the major bacterial phyla in the intestines of S. raddei. However, Firmicutes and Proteobacteria predominated in the gut of active and hibernating S. raddei, respectively. Certain bacterial genera such as Pseudomonas, Vibrio, Ralstonia, and Rhodococcus could serve as biomarkers distinguishing hibernating and non-hibernating S. raddei. The gut microbiota was more resistant to environmental stress in hibernating than active S. raddei. Moreover, metabolomics revealed that metabolites implicated in fatty acid biosynthesis were highly upregulated in the intestines of hibernating S. raddei. The metabolites that were enriched during hibernation enabled S. raddei to adapt to the low temperatures and the lack of exogenous food that are characteristic of hibernation. A correlation analysis of the intestinal microbiota and their metabolites revealed that the gut microbiota might participate in the metabolic regulation of hibernating S. raddei. The present study clarified the modifications that occur in the intestinal bacteria and their symbiotic relationship with their host during hibernation. These findings are indicative of the adaptive changes in the metabolism of amphibians under different environmental conditions.