Research into the gut microbiome of companion animals is revealing connections between intestinal bacteria, immune function, behaviour, and welfare that are beginning to inform dietary and health recommendations.
The gut microbiome represents a frontier in companion animal welfare science, with accumulating evidence that intestinal bacterial communities affect not just digestive health but immune function, stress responses, and behaviour. Welfare implications include the recognition that repeated antibiotic courses, highly processed diets, and chronic stress can all degrade microbiome health in ways that compound welfare problems. Dogs with microbiome disruption may show increased anxiety or aggression that is treated behaviourally or pharmacologically without addressing the underlying gut health dimension. Dietary interventions supporting microbiome diversity — including appropriate fibre, variety, and fermented foods where suitable — are emerging as welfare-relevant nutritional recommendations. The field is developing rapidly and pet owners should seek evidence-based guidance rather than relying on marketing claims.