The Effect of Dietary Synbiotics in Actively Racing Standardbred Horses Receiving Trimethoprim/Sulfadiazine.
Authors: Lagounova Maria, MacNicol Jennifer L, Weese J Scott, Pearson Wendy
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Synbiotics and Antibiotic Use in Racing Standardbreds When trimethoprim/sulfadiazine is administered to racehorses, the resulting disruption to hindgut microbiota raises legitimate concerns about digestive health and performance recovery; however, evidence supporting synbiotic supplementation during antibiotic treatment remains sparse. Researchers employed a four-way crossover design in 16 actively racing Standardbreds, assigning each horse sequentially to antibiotic treatment alone (10 days), synbiotic supplementation alone (28 days of PROBIOPlus™), combined antibiotic plus synbiotic, or control. Using 16S rRNA sequencing alongside measurements of faecal dry matter, pH, and consistency scoring, the team identified that synbiotic administration alongside antibiotics produced distinct microbiotal community structures during treatment and persisting into the post-treatment period, with particular effects on fibre-degrading bacteria including elevated Fibrobacter populations and altered Ruminococcaceae abundance. Whilst the clinical significance of these microbiotal shifts remains unclear—as neither faecal consistency nor other measurable parameters showed dramatic changes—these findings suggest that targeted synbiotic products may provide some stabilising effect on the microbial ecosystem during antimicrobial therapy in racing animals, warranting further investigation into whether this translates to improved recovery times or performance outcomes.
Read the full abstract on PubMed
Practical Takeaways
- •PROBIOPlus™ synbiotics show some evidence of supporting microbiome stability in racing Standardbreds receiving trimethoprim/sulfadiazine, though effects are modest and primarily affect community structure rather than dramatic functional changes
- •While synbiotics did not prevent all microbiome shifts during antibiotic therapy, they may help maintain fiber-degrading bacterial populations important for digestive health
- •Consider synbiotic supplementation during antibiotic courses as a relatively low-risk intervention, but manage expectations—this product is not a complete microbiome protectant
Key Findings
- •Synbiotic treatment (PROBIOPlus™) combined with antibiotics produced distinct microbiota community membership differences compared to other treatments during and after antibiotic administration
- •Fibrobacter population was significantly higher in antibiotic-treated horses regardless of synbiotic status compared to control horses
- •Few differences were observed in relative abundance of phyla or predominant genera, suggesting limited overall microbiome disruption by the synbiotic intervention
- •Unclassified Ruminococcaceae abundance was significantly lower in antibiotic-treated groups compared to control, with partial recovery in synbiotic-treated horses post-treatment