Free Faecal Water: Analysis of Horse Faecal Microbiota and the Impact of Faecal Microbial Transplantation on Symptom Severity.
Authors: Laustsen Louise, Edwards Joan E, Hermes Gerben D A, Lúthersson Nanna, van Doorn David A, Okrathok Supattra, Kujawa Theresa J, Smidt Hauke
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Free faecal water (FFW) remains a frustrating condition affecting hindquarter hygiene and welfare in horses, yet its underlying causes remain poorly understood. Researchers compared faecal microbiota composition between ten horses with FFW and ten healthy controls using molecular prokaryotic analysis, then treated ten affected horses with standardised faecal microbiota transplantation (FMT) and monitored symptom severity and microbial communities over 168 days. Surprisingly, no significant microbial differences existed between FFW-affected and healthy horses at baseline; however, FMT produced measurable symptom improvement by day 14 post-treatment (p = 0.02), with improvements persisting throughout the follow-up period, though individual responses were highly variable. Counterintuitively, this clinical improvement occurred without any detectable changes in faecal prokaryotic diversity or composition post-FMT, and donor inocula consistently showed lower microbial diversity than recipient horses' pre-treatment samples. These findings suggest FFW is unlikely to stem from simple dysbiosis, yet FMT can provide temporary relief in some horses through mechanisms unrelated to microbial community restructuring—possibly via metabolite production, immune modulation, or other non-compositional factors—though robust controlled trials are essential before recommendations can be made for clinical practice.
Read the full abstract on PubMed
Practical Takeaways
- •FFW appears not to be caused by an altered microbiota composition, challenging the assumption that dysbiosis is the primary mechanism
- •FMT may provide short-term clinical symptom relief in some FFW horses, but this appears independent of microbiota changes, suggesting alternative mechanisms (immune, metabolic, or functional)
- •Individual response to FMT is highly variable; controlled trials with appropriate comparisons are needed before recommending FMT as standard FFW treatment
Key Findings
- •FFW horses showed no significant differences in faecal microbiota composition compared to healthy controls (p > 0.05)
- •FFW symptom severity decreased significantly 14 days after FMT (p = 0.02) and remained decreased through 168-day follow-up (p < 0.02)
- •FMT had no effect on faecal prokaryotic alpha or beta diversity in treated horses despite symptom improvement
- •Donor inocula alpha diversity was significantly lower than treated horse microbiota (p < 0.001), indicating microbiota composition alone does not explain clinical response