A Microbiological Map of the Healthy Equine Gastrointestinal Tract.
Authors: Ericsson Aaron C, Johnson Philip J, Lopes Marco A, Perry Sonja C, Lanter Hannah R
Journal: PloS one
Summary
# Editorial Summary: A Microbiological Map of the Healthy Equine Gastrointestinal Tract Understanding the microbial ecology of the equine digestive tract is fundamental to managing everything from colic prevention to nutritional interventions, yet detailed maps of which bacteria colonise different gut regions have been lacking. Using 16S rRNA gene sequencing, researchers sampled both the luminal contents and mucosal lining across seven regions of the gastrointestinal tract in nine healthy horses, providing the first comprehensive regional comparison of equine gut microbiota. The results revealed a striking compositional divide between the small intestine (stomach, jejunum, ileum) and large intestine (caecum, colon), with the small intestine harbouring far greater microbial variability, whilst the large intestine showed relative uniformity despite hosting a larger number of unique bacterial sequences. A particularly significant finding for practitioners is that faecal samples—commonly used as a proxy for overall gut health—adequately represent the luminal microbiota of the large intestine but provide no meaningful information about the stomach or small intestine microbial communities. Conversely, mucosal microbial communities demonstrated regional continuity throughout the tract, suggesting that localised gut health varies by anatomical region in ways not captured by standard faecal analysis, with important implications for targeted probiotic therapy and diagnostic interpretation.
Read the full abstract on PubMed
Practical Takeaways
- •Fecal sampling alone cannot assess stomach or small intestine health status; site-specific sampling needed for upper GI tract evaluation
- •The naturally high variability in upper GI microbiota should be considered normal rather than indicative of dysbiosis, whereas uniformity changes in large bowel may signal pathology
- •Understanding regional microbiota differences helps interpret microbial analysis results and target interventions to specific gut regions based on clinical signs
Key Findings
- •Distinct compositional divide exists between small intestine and large intestine microbiota in healthy horses
- •Cecum and colon show much higher microbiota uniformity compared to stomach, jejunum, and ileum despite greater sequence diversity in colon
- •Fecal/colonic samples provide reasonable profile of large intestine luminal contents but are not informative for stomach or small intestine microbiota
- •Mucosal microbial communities demonstrate regional continuity throughout the equine gut despite luminal variability