The canine gut microbiome influences physical health, immune function, and behaviour, with diet being the primary welfare-relevant modifiable factor.
The canine gut microbiome is an emerging welfare consideration with bidirectional relationships to both physical and psychological wellbeing. A diverse, healthy microbiome supports immune function, reduces inflammatory disease risk, and may influence mood and stress responses through the gut-brain axis. Conversely, chronic stress reduces microbiome diversity, creating a feedback loop where poor welfare degrades microbiome health which may further compromise stress resilience. Diet is the primary modifiable determinant of microbiome health: high-quality diets with diverse protein sources and adequate fermentable fibre support diversity, while highly processed diets with limited fibre diversity correlate with reduced microbiome richness. The welfare implication is that nutritional quality affects not only physical health but potentially psychological resilience through microbiome-mediated pathways.