Emerging research on the companion animal gut microbiome is reshaping understanding of nutrition, immunity, and behaviour in dogs and cats.
The gut-brain axis — the bidirectional communication between the gastrointestinal microbiome and the central nervous system — is as relevant in companion animals as in humans. Research suggests that microbiome disruption may contribute to anxiety, stress responses, and problem behaviour in dogs and cats, in addition to gastrointestinal disease. Diet is the primary modifiable influence on microbiome composition, and ultra-processed pet foods with limited fibre diversity may contribute to reduced microbiome health compared to more varied diets. This is an active research area with implications for both physical and psychological welfare. Applying microbiome knowledge in clinical practice requires care to distinguish evidence-based recommendations from oversimplified marketing claims about probiotic supplements.