The longitudinal effect of a multi-strain probiotic on the intestinal bacterial microbiota of neonatal foals.
Authors: Schoster A, Guardabassi L, Staempfli H R, Abrahams M, Jalali M, Weese J S
Journal: Equine veterinary journal
Summary
# Editorial Summary: Probiotic Effects on Neonatal Foal Microbiota A multi-strain probiotic containing four Lactobacillus species and Bifidobacterium animalis subsp. lactis was administered daily for three weeks to 38 healthy neonatal foals in a randomised placebo-controlled trial, with faecal samples analysed via metagenomic sequencing at two-week intervals over six weeks. Despite supplementation, the probiotic produced minimal detectable changes in the foals' intestinal bacterial communities: neither the targeted lactobacilli nor bifidobacteria showed increased relative abundance in treated animals compared to placebo at any timepoint, and major taxonomic groups (phylum, order, class) remained essentially unchanged between groups. Whilst LEfSe analysis did identify enrichment of Lactobacillus in the probiotic group by week 6, overall bacterial diversity and community structure remained unaffected. These findings suggest that oral probiotic supplementation using this formulation has limited capacity to meaningfully shift the foal microbiota during the critical early post-natal period, questioning the practical utility of such products as therapeutic interventions in neonatal gastrointestinal health. Practitioners should therefore view probiotic administration with appropriate scepticism until evidence demonstrating both microbiotal colonisation and clinically relevant health outcomes becomes available.
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Practical Takeaways
- •This specific multi-strain probiotic formulation shows limited clinical benefit for modifying foal intestinal microbiota and should not be relied upon as a therapeutic microbiota intervention in neonatal foals
- •Probiotics containing lactobacilli and bifidobacteria may not establish well in the equine gastrointestinal tract or may be rapidly cleared, suggesting better evidence is needed before routine use in foal management
- •Consider alternative strategies for supporting foal gut health during early life, as probiotic supplementation alone does not appear to meaningfully shift microbiota composition
Key Findings
- •Multi-strain probiotic administration did not increase relative abundance of lactobacilli or bifidobacteria at any timepoint (Weeks 2, 4, 6; all P>0.05)
- •No changes in bacterial microbiota composition at phylum, order, or class level between treatment and placebo groups
- •Probiotic treatment had no effect on alpha diversity or community structure by parsimony and unifrac analysis (all P>0.6)
- •LEfSe analysis showed weak enrichment of Lactobacillus in probiotic group at Week 6 only (LDA score 0.34, P=0.02)