Homemade Nucleic Acid Preservation Buffer Proves Effective in Preserving the Equine Faecal Microbiota over Time at Ambient Temperatures.
Authors: Ward Ashley B, Harris Patricia A, Argo Caroline McG, Watson Christine, Neacsu Madalina, Russell Wendy R, Ribeiro Antonio, Collie-Duguid Elaina, Heidari Zeynab, Morrison Philippa K
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Faecal microbiota analysis has become increasingly important in equine practice as a window into colonic health and disease states, yet the microbial community can shift dramatically during sample storage, potentially invalidating results. Researchers at the University of Glasgow tested four preservation methods on faecal samples from ten horses stored at room temperature for up to 150 hours, using 16S rRNA gene sequencing to track changes in microbial diversity and bacterial composition at 0, 24, 72, and 150 hours. A homemade nucleic acid preservation (NAP) buffer proved superior to conventional methods—whilst cold storage, chlorhexidine (CLX), and Whatman FTA cards all adequately preserved samples for 24 hours, only NAP prevented the overgrowth of opportunistic "bloom" taxa and maintained both microbial diversity and community structure up to 150 hours at ambient temperature, with CLX and cold packs showing significant shifts by 72 hours. For practitioners relying on faecal analysis for clinical decision-making, these findings suggest that NAP buffer offers a practical, cost-effective solution for sample preservation when immediate laboratory processing isn't possible, whilst conventional cool packs become unreliable beyond 24 hours at room temperature—critical information for field sampling protocols and regional referral logistics.
Read the full abstract on PubMed
Practical Takeaways
- •If collecting equine faecal samples for microbiota analysis, use NAP buffer for storage up to 150 h at room temperature rather than cool packs or FTA cards, which fail to preserve community structure beyond 24 h
- •For routine sample collection and transport, COLD or CLX treatments are acceptable for up to 24 h, but NAP buffer is the only suitable option if processing will be delayed beyond 72 h
- •Proper sample preservation is critical for microbiota-based health assessments in horses, as inadequate preservation leads to loss of diversity and overrepresentation of unstable taxa
Key Findings
- •NAP (nucleic acid preservation) buffer effectively preserved faecal microbiota diversity and community structure for up to 150 h at room temperature
- •COLD, CLX, and NAP treatments were effective for up to 24 h storage, but only NAP prevented community shifts by 72 h
- •FTA card samples showed significantly lower diversity (p = 0.001) and under-representation of Fibrobacterota compared to other treatments
- •NAP buffer inhibited the overgrowth of bloom taxa that occurred in other treatments by 72 h at room temperature