How the gut microbiome influences animal behavior, stress response, and welfare, and implications for farm and companion animal management.
The gut-brain axis represents a new frontier in understanding animal welfare. Research across multiple species shows bidirectional communication between the gut microbiome and the brain, meaning that gut health directly affects emotional states and stress responses. Chronic welfare compromise — including stress, poor diet, and antibiotic overuse — alters microbiome composition in ways that further worsen stress resilience and immune function, creating negative feedback loops. Welfare interventions that support microbiome health, including dietary diversity and stress reduction, may have broader benefits than previously recognized.