(E45) Detection of Biomarkers Indicators of Intestinal Health Among the Equine Fecal Microbiota Using Quantitative PCR

Abstract:

Background: DNA sequencing is commonly used to analyze microbiota composition but does not provide absolute bacterial quantification. The quantification of certain bacterial taxa has been used as proxies for dysbiosis in various species.

Objectives: To establish reference values for key fecal bacterial taxa using quantitative PCR (qPCR) as indicators of gut health in horses. Animals: Fecal samples from 50 healthy horses and 30 horses diagnosed with colitis.

Methods: Thirteen bacterial taxa associated with gut health and dysbiosis were selected based on the current literature. qPCR assays were optimized for these taxa and total bacterial load. Each sample was analyzed in duplicate at a standardized DNA concentration (5 ng/µl). Group comparisons were performed using the Student’s t-test.

Results: Healthy horses had significantly higher levels of Turicibacter and Lachnospiraceae (p ≤ 0.01), whereas horses with colitis exhibited significantly higher levels of Escherichia coli, Fusobacterium, and Enterobacteriaceae (p ≤ 0.0001). No significant differences were observed for total bacterial load or other taxa, including Ruminococcaceae, Akkermansia, Lactobacillus, Enterococcus, Fibrobacter, Faecalibacterium, Prevotella, and Streptococcus. Reference values for each taxon in the studied population were established. Conclusions and Clinical Importance: This rapid, quantitative approach enabled the detection of dysbiosis in a population of horses with colitis without requiring complete microbiota sequencing. Future studies applying this method may facilitate early microbiota-based diagnostics for equine intestinal diseases and monitor microbiota recovery following antimicrobial therapy.