Characterisation of the faecal metabolome and microbiome of Thoroughbred racehorses.
Authors: Proudman C J, Hunter J O, Darby A C, Escalona E E, Batty C, Turner C
Journal: Equine veterinary journal
Summary
# Characterisation of the faecal metabolome and microbiome of Thoroughbred racehorses The equine gastrointestinal microbiota profoundly influences systemic health, yet baseline characterisation of the healthy racehorse gut ecosystem remained limited when Proudman and colleagues undertook this 2015 investigation. Eight Thoroughbreds in active race training provided faecal samples before and six weeks after supplementation with amylase-rich malt extract; researchers employed thermal desorption gas chromatography–mass spectrometry to profile volatile organic compounds and 454 pyrosequencing of 16S rRNA gene amplicons to characterise the bacterial community structure. The faecal metabolome proved remarkably complex, dominated by organic acids, alcohols and ketones with 81 distinct volatile compounds identified, though only 28 appeared consistently across >50% of samples; more significantly, supplementation with malt extract produced measurable shifts in volatile profiles and microbial community composition, with individual horses demonstrating variable responses. Faecal microbiota showed exceptional diversity (1200–3000 operational taxonomic units per animal), characterised by high proportions of Firmicutes and Bacteroidetes alongside considerable numbers of low-abundance taxa. For practitioners implementing dietary modifications, this research demonstrates that feed interventions produce detectable biological effects at both metabolic and microbial levels, providing a valuable baseline against which future investigations of disease, performance or dietary protocols can be evaluated.
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Practical Takeaways
- •Baseline faecal metabolomic and microbiotic profiles are now established for healthy Thoroughbred racehorses, providing a reference point for detecting disease-related changes in your patients
- •Dietary supplements such as malt extract produce measurable changes in gut function within 6 weeks; monitor individual horse responses as variation exists between animals
- •The high diversity and complexity of equine faecal microbiota suggests no single 'ideal' bacterial profile exists, supporting individualized rather than standardized dietary interventions
Key Findings
- •Faecal metabolome dominated by organic acids, alcohols and ketones with 81 different VOCs identified, only 28 present in >50% of samples
- •Faecal microbiota highly diverse with 1200-3000 OTUs per individual, dominated by Firmicutes and Bacteroidetes
- •Dietary supplementation with amylase-rich malt extract significantly altered faecal VOC profiles and microbial community structure
- •Marked interhorse variation in response to dietary intervention detected in both metabolomic and microbiotic measures