Two Species of Long-Day Breeding Hamsters Exhibit Distinct Gut Microbial Responses to Photoperiodic Variations

Abstract

The relationship between the gut microbiota and photoperiod has received widespread attention, and it is necessary to explore the probable common mechanisms involved. We tested whether the gut microbiota of animals with similar light-regulated life history traits would also exhibit consistent responses to the photoperiod. Here, two species of long-day breeders, striped hamsters (Cricetulus barabensis) and Djungarian hamsters (Phodopus sungorus), were raised under different photoperiods (long daylight, LD; short daylight, SD), and their cecal contents were collected to assess the gut microbiota. There was no difference in the gut microbial diversity between the groups of striped hamsters; however, in the Djungarian hamsters, lower Chao and Shannon indices were observed in the LD group than in the SD group. The bacterial community variation in the striped hamsters was reflected mainly in the enrichment of the genera Enterorhabdus and Jeotgalicoccus in the LD group; meanwhile, more taxa with significant changes in relative abundance under different photoperiods were found in the Djungarian hamsters, such as the enrichment of the genera Lactobacillus and Faecalibaculum in the LD group and the enrichment of the genera Ruminococcus and Colidextribacter in the SD group. The LD conditions substantially reduced the complexity of the gut microbial network in the Djungarian hamsters and increased the R² value of the striped hamster gut microbiota under fitting with a neutral community model. Moreover, the potential gut microbial functions in the striped hamsters were relatively stable, but variations were observed in multiple pathways between the groups of Djungarian hamsters. These results contribute to the understanding of host species specificity in the response of the gut microbiota to external changes.

Keywords: 16S rRNA gene; gut microbiota; photoperiods; rodents; species specific.

Figure 1

Gut microbial diversity of two hamster species under different photoperiods. (a) Principal coordinate analysis (PCoA) based on Bray–Curtis distances calculated using ASVs; (b,c) Chao and Shannon indices of the two hamster species. Differences between the LD and SD groups were assessed by Wilcoxon rank-sum tests and are denoted as * p < 0.05.

Figure 2

Variations in the gut microbial composition resulting from photoperiods. (a,b) Taxonomic compositions at the phylum and genus levels; (c) cluster heatmap drawn using the 20 most abundant ASVs; (d,e) LEfSe identification of gut microbial taxa with significant differences between the LD and SD groups (LDA > 3, p < 0.05).

Figure 3

Co-occurrence networks of the top 30 abundant ASVs. Each node represents an ASV, and its size indicates the degree. Bold circles represent the nodes with the highest degree. Links represent significant (p < 0.05) and strong (Spearman’s correlation greater than 0.6 or lower than −0.6) correlations (red: positive; green: negative).

Figure 4

Distribution and assembly processes of gut microbial communities in two species of hamsters. (a) UpSet diagram of the ASV distribution among groups; (b) fit of the neutral community model: solid blue lines indicate the best fit to the model, whereas dashed blue lines represent 95% confidence intervals around the prediction.

Figure 5

Differences in gut microbial functions. (a) Principal coordinate analysis (PCoA) based on Bray–Curtis distances of KOs; (b) significant differences in level 2 KEGG pathways between different groups of Djungarian hamsters.