Gut Microbiota and Behavioural Issues in Production, Performance, and Companion Animals: A Systematic Review.
Authors: Homer Bonnie, Judd Jackson, Mohammadi Dehcheshmeh Manijeh, Ebrahimie Esmaeil, Trott Darren J
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Gut Microbiota and Behavioural Issues in Production, Performance, and Companion Animals Poor nutrition has long been implicated in behavioural problems across multiple species, but emerging evidence suggests that the composition of the gut microbiota itself may play a crucial role in the development of aggression, hyperalertness, and stereotypies. This 2023 systematic review examined published literature across production animals (including horses and pigs) and companion species, synthesising findings on how microbial communities relate to abnormal behaviour. Whilst no consistent differences in the number of bacterial species (alpha diversity) were identified between behaviourally normal and abnormal animals, significant compositional variations (beta diversity) emerged consistently: animals displaying behavioural problems showed enrichment of pro-inflammatory and lactic acid-producing bacteria alongside reductions in butyrate-producing species—a pattern mirroring findings in humans with mental health disorders. The current evidence base cannot yet determine whether these microbiota changes cause behavioural abnormalities or result from them; however, the association between microbial diversity, metabolite production, and abnormal behaviour is sufficiently established to warrant targeted investigation of the gut-brain-immune axis. For equine professionals, this suggests that nutritional strategies targeting microbiota restoration—potentially through fibre quality, prebiotic supplementation, or targeted probiotic approaches—may represent a novel avenue for managing behavioural issues, though rigorous research establishing causation is needed before specific interventions can be confidently recommended.
Read the full abstract on PubMed
Practical Takeaways
- •Microbiota composition—particularly the balance of pro-inflammatory versus butyrate-producing bacteria—may offer a modifiable target for addressing behavioural problems; consider nutritional interventions that promote healthy microbiota diversity.
- •Behavioral issues in your animals may have a nutritional/microbiota basis rather than purely psychological or management-related origins; diagnostic assessment of gut health could be warranted before escalating behavioral interventions.
- •Current evidence suggests promise for probiotic or prebiotic therapies to restore the gut-brain-immune axis, but these remain experimental; stay informed on emerging microbiota-targeted interventions as evidence develops.
Key Findings
- •No significant differences in bacterial taxa richness (alpha diversity) between animals with abnormal behaviour and controls, but variability exists in species diversity between groups (beta diversity).
- •Animals with abnormal behaviour show enrichment of pro-inflammatory and lactic acid-producing bacteria with concurrent reduction in butyrate-producing bacteria, similar to patterns observed in humans with mental disorders.
- •An association exists between gut microbiota diversity, microbial metabolite production, and abnormal behavioural phenotypes across pigs, dogs, and horses, but causal relationships remain unestablished.
- •Poor nutrition identified as leading factor in manifestation of behavioural issues, with microbiota composition and gut-brain-immune axis dysfunction as potential mediators.