Dogs Are a Poor Taxonomic Model for Human Inflammatory Bowel Disease, but Are Potentially Functionally Relevant for Human Ulcerative Colitis

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory condition affecting the gastrointestinal tract. Human IBD consists of two major subtypes, Crohn’s Disease (CD) and Ulcerative Colitis (UC) which continue to have large global health and economic implications. Although dogs have previously been investigated as a potential research model for human IBD, their utility for specific subtypes has not been adequately considered. In this study, we explored the microbial diversity, abundance, and functional pathways of the gut microbiota in IBD dogs against UC and CD humans, to investigate if IBD dogs may serve as a research model for a particular human IBD subtype. Comparative analysis of combined 16S ribosomal RNA data from IBD dogs and humans revealed a difference in gut microbial composition between dogs and humans, further supported by a lack of common taxonomic groups in both core microbiome and indicator species analyses. Despite significant species-driven compositional differences, predictive functional pathway analysis displayed similarities in shared metabolic pathways of IBD dogs and UC humans. These findings suggest that while dogs may not serve as relatable taxonomic models for human IBD subtypes, they may hold functional relevance for human ulcerative colitis.