Targeting the Gut-Brain Axis: Pharmacological Modulation of the Microbiome for Neurological and Behavioural Disorders in Companion Animals.

Abstract

Background: The gut-brain axis (GBA) represents a paradigm shift in veterinary neuropharmacology, offering novel approaches for managing neurological and behavioural disorders in companion animals.

Objectives: This review synthesizes current evidence on the bidirectional communication between the gut microbiome and the central nervous system, examining the neural, endocrine, immune, and metabolic pathways that facilitate this dialogue. We explore the unique aspects of canine and feline microbiomes and their implications for species-specific drug development and critically evaluate emerging pharmacological strategies, including psychobiotics, prebiotics, synbiotics and faecal microbiota transplantation (FMT), highlighting their clinical applications in conditions ranging from anxiety and aggression to cognitive dysfunction and epilepsy.

Methods: This narrative review followed established guidelines for evidence synthesis in veterinary medicine. A comprehensive literature search was performed using PubMed, Google Scholar and Scopus databases covering publications from January 2011 to March 2026.

Results: While promising results have been demonstrated with specific strains, such as Bifidobacterium longum BL999 and Lactiplantibacillus plantarum PS128, significant challenges remain. These include methodological limitations in microbiome research, the predominance of correlative over causal evidence and the need for standardized diagnostic tools.

Conclusions: Future directions must prioritize large-scale longitudinal studies, robust clinical trials and advanced multi-omics approaches to establish causal mechanisms and develop personalized, microbiome-targeted therapies. Realizing this potential requires a shift from correlative data to causal mechanisms, from a one-size-fits-all approach to species-specific therapeutics and from rodent models to rigorous trials in dogs and cats.