Dietary features are associated with differences in the urinary microbiome in clinically healthy adult dogs

Nutrition plays an important role in shaping gut microbiome composition, but the impact of diet on the urinary microbiome (i.e., urobiome) remains unknown. The aim of this project was to discover how nutritional features affect diversity and composition of the urobiome in dogs. This was a cross-sectional study. Dietary histories were obtained for 15 clinically healthy adult dogs, including limited nutrient profiles (protein, fat, crude fiber), commercial diet brand, and dietary diversity. Urine samples were collected via cystocentesis, followed by V4 amplicon sequencing of the bacterial 16S rRNA gene. Data were analyzed to determine the association between major nutrients and dietary sources with urobiome composition. Protein, fat, and crude fiber content had no statistically significant effect on alpha or beta diversity. However, beta diversity based on Bray Curtis distances differed (PERMANOVA; P = 0.017, R2 = 0.10) between dogs fed one commercial diet brand compared to dogs consuming any other brand, characterized by lower alpha diversity (P = 0.018) and lower relative abundances of Staphylococcus, Bacillus halodurans, and Paracoccus. Beta diversity also differed (P = 0.019, R2 = 0.10) between dogs consuming more diverse daily diets (greater than or equal to 3 unique food sources) as compared to those consuming less diverse diets (less than 3 unique food sources). Due to overlap between diet brand and dietary diversity groups, it is unclear whether one or both variables drove urobiome differences. Overall, the results of this study suggest that diet impacts the canine urobiome and support further exploration of the relationship between diet and urobiome composition in dogs.