Characterization of the gastrointestinal microbiome of the Syrian hamster (Mesocricetus auratus) and comparison to data from mice.

Syrian hamsters (Mesocricetus auratus) have been increasingly used as rodent models in recent years, especially for SARS-CoV-2 since the pandemic. However, the physiology of this animal model is not yet well-understood, even less when considering the digestive tract. Generally, the gastrointestinal microbiome influences the immune system, drug metabolism, and vaccination efficacy. However, a detailed understanding of the gastrointestinal microbiome of hamsters is missing. Therefore, we analyzed 10 healthy 11-week-old RjHan:AURA hamsters fed a pelleted standard diet. Their gastrointestinal content was sampled (i.e., forestomach, glandular stomach, ileum, cecum, and colon) and analyzed using 16S rRNA gene amplicon sequencing. Results displayed a distinct difference in the bacterial community before and after the cecum, possibly due to the available nutrients and digestive functions. Next, we compared hamsters with the literature data of young-adult C57BL/6J mice, another important animal model. We sampled the same gastrointestinal regions and analyzed the differences in the microbiome between both rodents. Surprisingly, we found strong differences in their specific gastrointestinal bacterial communities. For instance, Lactobacillaceae were more abundant in hamsters' forestomach and ileum, while Muribaculaceae dominated in the mouse forestomach and ileum. Similarly, in mouse cecum and colon, Muribaculaceae were dominant, while in hamsters, Lachnospiraceae and Erysipelotrichaceae dominated the bacterial community. Molecular strains of Muribaculaceae in both rodent species displayed some species specificity. This comparison allows a better understanding of the suitability of the Syrian hamster as an animal model, especially regarding its comparability to other rodent models. Thereby, this work contributes to the characterization of the hamster model and allows better experimental planning.