Comparison of Fecal Microbiota of Horses Suffering from Atypical Myopathy and Healthy Co-Grazers.
Authors: Wimmer-Scherr Christina, Taminiau Bernard, Renaud Benoît, van Loon Gunther, Palmers Katrien, Votion Dominique, Amory Hélène, Daube Georges, Cesarini Carla
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Fecal Microbiota and Equine Atypical Myopathy Atypical myopathy (AM) remains a significant concern for grazing horses, yet the reason why only some animals develop clinical signs despite shared exposure to toxic Acer seeds remains poorly understood. This Belgian research team hypothesised that differences in intestinal bacterial composition might influence susceptibility to hypoglycin A and methylenecyclopropylglycine toxicity, prompting a comparative microbiota analysis of 59 affected horses (29 survivors, 30 non-survivors) and 26 healthy co-grazers from contaminated spring and autumn pastures. Using 16S rRNA sequencing of fresh faecal samples, they identified significantly greater microbial diversity and evenness in AM-affected horses, alongside notable shifts in bacterial family distribution: increased Ruminococcaceae, Christensenellaceae and Akkermansiaceae populations, but reduced Lachnospiraceae, Bacteroidales and Clostridiales—with the latter changes most pronounced in non-survivors. Whilst these findings suggest a distinct microbiota signature associated with AM, whether these microbial alterations represent consequences of systemic toxicity or predisposing factors remains unclear, though the relationship warrants further investigation given emerging evidence of microbiota influence on toxin metabolism and immune resilience. For practitioners managing at-risk herds, these results hint that microbiota-modulating interventions (dietary, probiotic or prebioticapproaches) might merit exploration, though evidence-based protocols require additional research before implementation.
Read the full abstract on PubMed
Practical Takeaways
- •Fecal microbiota composition differs markedly between horses that develop atypical myopathy and healthy herd-mates on contaminated pastures, suggesting the microbiome may influence individual susceptibility to toxin-induced disease
- •Certain bacterial families associated with poor outcomes in AM cases may represent potential biomarkers for prognosis, though further research is needed to determine if microbiota manipulation could reduce disease risk
- •Not all horses exposed to toxic Acer seeds develop clinical disease; microbiota assessment could potentially help identify at-risk individuals during spring/autumn pasture management
Key Findings
- •Fecal microbial diversity and evenness were significantly higher in AM-affected horses compared to healthy co-grazers (p < 0.001)
- •Ruminococcaceae, Christensenellaceae, and Akkermansiaceae were more abundant in AM-affected horses (p ≤ 0.001), particularly in non-survivors
- •Lachnospiraceae, Bacteroidales, and Clostridiales were significantly reduced in AM-affected horses (p < 0.05), especially in animals with poor prognosis
- •Despite significant microbiota shifts between affected and healthy horses, causality remains unclear—changes may result from disease or contribute to disease pathogenesis