Gut microbiome composition is related to anxiety and aggression score in companion dogs

Abstract Background There is mounting evidence for a link between behaviour and gut microbiome composition in several animal models and human health. However, the role of the gut microbiota in the development and severity of behavioural issues in companion dogs is not yet fully understood. In this work, we investigated the relationship between gut microbiome composition and aggression or anxiety in pet dogs. Pet dogs (n = 48) were assigned to higher or lower anxiety and aggression groups based on their owner’s responses to the Canine Behavioral Assessment & Research Questionnaire (C-BARQ). Then the gut microbiome of each animal, sequenced from microbial DNA extracted from fecal samples, was assessed for association with the dog’s assigned behavioural group using multiple approaches. Results While minimal differences in relative abundance were seen between behavioural groups, we were successful in predicting behavioural group based on gut microbiome composition using machine-learning based approaches and compositional balances. The generated models were particularly successful when distinguishing higher and lower anxiety dogs. The genus Blautia was identified across all our analyses, suggesting a strong link between this genus and anxiety in pet dogs. Conclusions This study builds on a growing area of research of great interest to dog owners, trainers, and behaviour professionals, and provides insight into specific bacteria that are linked to increased anxiety and aggression in pet dogs. Further research is required to identify bacteria to the species level, and to better understand the specific role of Blautia in the canine gut-brain axis.