Characterization and comparison of fecal microbiota in horses with pituitary pars intermedia dysfunction and age-matched controls.
Authors: Wang Wenqing, Gibson Justine, Horsman Sara, Mikkelsen Deirdre, Bertin François-René
Journal: Journal of veterinary internal medicine
Summary
Emerging evidence in human medicine links altered gut microbiota to dopaminergic neurodegeneration, yet comparable research in equine pituitary pars intermedia dysfunction (PPID) has been virtually absent until now. Wang and colleagues characterised the faecal microbiota of nine PPID-affected horses and 13 age-matched controls using 16S rRNA sequencing, with samples collected bimonthly to assess microbial composition at genus and phylum levels alongside diversity metrics. PPID horses demonstrated significantly reduced relative abundances of potentially beneficial taxa—notably Christensenellaceae R-7 group (2.04% vs 2.54% in controls), NK4A214 group (2.21% vs 2.62%), Romboutsia and uncultured Peptococcaceae—whilst Fibrobacter abundance was paradoxically elevated, suggesting a dysbiotic shift rather than simple microbial depletion. The altered microbiota composition (evidenced by significant beta diversity differences, P = 0.004) represents a distinct microbial signature in PPID horses, with seven unique genera identified in affected animals compared to twelve in controls. These findings strengthen the hypothesis that dysbiosis contributes to PPID pathogenesis via the microbiota-gut-brain axis, opening potential avenues for prebiotic, probiotic or dietary interventions to modulate microbial communities and potentially slow neurodegeneration in affected horses.
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Practical Takeaways
- •PPID horses show measurable differences in fecal microbiota composition that may reflect altered gut-brain axis function; consider microbiota assessment as a potential biomarker for disease characterization
- •Seasonal variation in microbial diversity suggests timing of sample collection and management interventions should account for temporal microbial shifts
- •Future targeted probiotic or dietary interventions targeting deficient bacterial groups may offer adjunctive therapeutic opportunities for PPID management
Key Findings
- •Horses with PPID had significantly decreased relative abundance of Christensenellaceae R-7 group (2.04 vs 2.54; P=0.02) and NK4A214 group (2.21 vs 2.62; P=0.05) compared to controls
- •Romboutsia and Peptococcaceae uncultured showed significantly lower abundances in PPID horses (log2FoldChange = -3.54 and -0.89 respectively; P=0.04)
- •Fibrobacter abundance was significantly higher in PPID group (log2FoldChange = 0.74; P=0.04)
- •PPID significantly altered beta diversity (P=0.004) and alpha diversity varied seasonally (P=0.001), with 7 unique genera in PPID horses versus 12 in controls