High-starch diets alter equine faecal microbiota and increase behavioural reactivity

Area of Science:

• Equine Science
• Microbiology
• Animal Behavior

Background:

• Gut microbiota influences host health, disease, and behavior, acting as a key link in the gut-brain axis.
• Diet significantly impacts gut microbial composition, with high-starch diets altering hindgut microbiota in horses.
• High-starch diets in horses are linked to increased behavioral reactivity, suggesting a potential connection with microbial changes.

Purpose of the Study:

• To compare the fecal microbiota and behavior of naïve ponies fed high-starch versus high-fiber diets.
• To investigate the relationship between dietary-induced changes in gut microbiota and equine behavior.

Main Methods:

• A cross-over study design was employed with 10 naïve ponies.
• Ponies were fed either a high-starch (HS) or high-fiber (HF) diet.
• Fecal microbiota composition was analyzed using 16S rRNA gene sequencing, and behavioral responses were recorded.

Main Results:

• Ponies exhibited increased reactivity and reduced settling behavior on the HS diet compared to the HF diet.
• While Firmicutes and Bacteroidetes dominated the phyla irrespective of diet, multivariate analysis revealed significant diet-induced alterations in microbial community structure at lower taxonomic levels.
• The abundance of 85 operational taxonomic units (OTUs) differed significantly between the dietary groups, with correlative relationships observed between microbiota changes and behavior.

Conclusions:

• Dietary interventions significantly impact equine fecal microbial community structure.
• Alterations in gut microbiota composition induced by diet play a role in modulating host behavior in horses.
• A clear link exists between diet, gut microbial composition, and behavioral outcomes in ponies, underscoring the gut-brain axis relevance.