Seasonal Changes in the Distinct Taxonomy and Function of the Gut Microbiota in the Wild Ground Squirrel (Spermophilus dauricus)

SIMPLE SUMMARY: Gut microbiota is a large number of microbes colonized in the gut tract, and it plays a certain role in regulating the host’s immunity, metabolism, and nervous system. Recent studies have shown that the gut microbiota also has a close relationship with reproduction. The wild ground squirrel (Spermophilus dauricus) is a typical seasonal breeding animal. The purpose of this study was to explore the distinct taxonomy and function of the gut microbiota in the breeding and non-breeding seasons of the wild ground squirrel using 16S rRNA gene sequencing technology. The results show that the taxonomy of gut microbiota was different between the breeding season and non-breeding season. Functional prediction of the gut microbiota indicated that the relative abundance of metabolic pathways was differentially enriched between the breeding season and non-breeding season. This study further revealed the potential relationship between gut microbiota and reproduction and expanded our understanding of the function of gut microbiota. At the same time, it provided a new direction for research on the breeding strategy of seasonal breeding animals. ABSTRACT: Seasonal breeding is a normal phenomenon in which animals adapt to natural selection and reproduce only in specific seasons. Large studies have reported that the gut microbiota is closely related to reproduction. The purpose of this study was to explore the distinct taxonomy and function of the gut microbiota in the breeding and non-breeding seasons of the wild ground squirrel (Spermophilus dauricus). The 16S rRNA gene sequencing technology was utilized to sequence the gut microbiota of the wild ground squirrel. PICRUSt analysis was also applied to predict the function of the gut microbiota. The results suggested that the main components of the gut microbiota in all samples were Firmicutes (61.8%), Bacteroidetes (32.4%), and Proteobacteria (3.7%). Microbial community composition analyses revealed significant differences between the breeding and non-breeding seasons. At the genus level, Alistipes, Mycoplasma, Anaerotruncus, and Odoribacter were more abundant in the non-breeding season, while Blautia and Streptococcus were more abundant in the breeding season. The results of a functional prediction suggested that the relative abundance of functional categories that were related to lipid metabolism, carbohydrate metabolism, and nucleotide metabolism increased in the breeding season. The relative abundance of energy metabolism, transcription, and signal transduction increased in the non-breeding season. Overall, this study found differences in the taxonomy and function of the gut microbiota of the wild ground squirrel between the breeding and non-breeding seasons, and laid the foundation for further studies on the relationship between the gut microbiota and seasonal breeding.