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.

营养物质在塑造肠道微生物组组成中发挥着关键作用，但饮食对尿液微生物组（urinary microbiome，即urobiome）的影响仍未明确。本研究旨在探究营养特征如何影响犬类尿液微生物组的多样性与组成。本研究为横断面研究，纳入15只临床健康的成年犬，收集其饮食史信息，包括有限的营养组分（蛋白质、脂肪、粗纤维）、商业化犬粮品牌以及饮食多样性水平。通过膀胱穿刺术采集尿液样本，随后对细菌16S rRNA基因的V4区域进行扩增子测序。对测序数据进行分析，以明确主要营养物质与饮食来源和尿液微生物组组成之间的关联。蛋白质、脂肪及粗纤维含量对α多样性（alpha diversity）与β多样性（beta diversity）均无统计学显著影响。然而，基于Bray-Curtis距离的β多样性存在显著组间差异（置换多元方差分析，PERMANOVA；P = 0.017，R² = 0.10）：饲喂某一商业化犬粮品牌的犬只与饲喂其他品牌的犬只相比，前者的α多样性更低（P = 0.018），且葡萄球菌属（Staphylococcus）、嗜碱芽孢杆菌（Bacillus halodurans）及副球菌属（Paracoccus）的相对丰度均更低。每日饮食多样性更高（大于或等于3种独特食物来源）的犬只与饮食多样性更低（少于3种独特食物来源）的犬只之间，β多样性同样存在显著差异（P = 0.019，R² = 0.10）。由于犬粮品牌与饮食多样性分组存在重叠，目前尚无法明确究竟是单一变量还是两个变量共同导致了尿液微生物组的组成差异。总体而言，本研究结果表明饮食会影响犬类尿液微生物组，为进一步探究犬类饮食与尿液微生物组组成之间的关联提供了研究支撑。