Metagenomic Analysis of Fecal Archaea, Bacteria, Eukaryota, and Virus in Przewalski's Horses Following Anthelmintic Treatment.
Authors: Hu Dini, Yang Jianming, Qi Yingjie, Li Boling, Li Kai, Mok Kai Meng
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: Anthelmintic Effects on the Equine Microbiome Anthelmintic treatments are essential for parasite control in horses, yet their broader impact on the intestinal microbiota—particularly beyond bacteria—remains poorly understood in equine medicine. Researchers used metagenomic sequencing to comprehensively map changes across all microbial communities (archaea, bacteria, eukaryotes, and viruses) in Przewalski's horses before and after anthelmintic administration, providing the first complete characterisation of such effects in equines. Treatment substantially shifted microbial composition: methanogenic archaea increased (specifically *Methanobrevibacter*), whilst beneficial bacteria including *Bacteroides* and *Prevotella* declined and potentially pathogenic *Clostridium* and *Eubacterium* increased; eukaryotic and bacteriophage populations also showed significant reductions. Critically, whilst the microbiota's overall metabolic capacity for carbohydrate and amino acid metabolism remained functionally intact, the *specific microbial populations* responsible for these pathways were displaced, raising questions about digestive efficiency and immune resilience during this vulnerable post-treatment period. For practitioners, these findings underscore the value of strategic anthelmintic timing, potential probiotic or prebiotic support during treatment, and monitoring for secondary infections, particularly given the observed increase in pathogen-associated taxa and heightened sensitivity of bacteriophages to anthelmintic exposure.
Read the full abstract on PubMed
Practical Takeaways
- •Anthelmintic treatments cause significant disruption to the entire intestinal microbial ecosystem beyond parasites, not just bacteria—understanding these changes may help clinicians anticipate digestive or immune complications post-treatment
- •Treatment appears to increase pathogenic bacteria abundance, suggesting practitioners should monitor treated horses for secondary bacterial infections or digestive upset and consider supportive care protocols
- •Although overall metabolic capacity is retained, microbial population shifts could affect individual horse responses to treatment, supporting the rationale for individualized parasite management strategies rather than blanket herd treatments
Key Findings
- •Anthelmintic treatment substantially altered archaea, bacteria, eukaryota, and viral communities in fecal microbiota, with increased Methanobrevibacter but decreased Methanocorpusculum archaea
- •Bacterial shifts included increased Clostridium and Eubacterium genera associated with immunity and digestion, while Bacteroides and Prevotella decreased
- •Anthelmintic treatment increased relative abundance of pathogenic bacterial genera potentially associated with clinical disease in horses
- •Overall metabolic function of microbiota was preserved post-treatment, but specific microbial populations performing carbohydrate and amino acid metabolism were displaced