Comparison of the fecal microbiome of Eurasian otter experiencing and not experiencing snowy periods

Eurasian otters are semi-aquatic top freshwater predators, they are bioindicator and flagship species in freshwater ecosystems. Understanding the dietary structure and habits of Eurasian otters under different environmental conditions can provide data support for their in-situ or ex-situ conservation. The fecal microbiota can indirectly reflect information about the species' diet and living environment. Therefore, in this study, 32 fecal samples from Eurasian otters that have experienced a snowy period and 36 fecal samples from those that have not in the Northeast region of China were collected. The V3-V4 region of the 16S rRNA was sequenced using high-throughput sequencing, followed by microbial community comparative analysis. The results revealed that alpha diversity of the gut microbiota of Eurasian otters that have experienced a snowy period was higher than that of those that have not. In the gut microbiota of Eurasian otters that have experienced a snowy period, Firmicutes is the dominant phylum and Romboutsia is the primary genus; while in the gut microbiota of Eurasian otters that have not experienced a snowy period, Proteobacteria is the dominant phylum and Pseudomonas is the primary genus. We believe that this is mainly due to differences in dietary habits between snowy and non-snowy periods for Eurasian otters, with a potentially broader food intake range during snowy periods.