A study comparing the healthy and diseased equine glandular gastric microbiota sampled with sheathed transendoscopic cytology brushes.

This study examines the differences in gastrointestinal bacteria found in healthy horses and those with Equine Glandular Gastric Disease (EGGD), using sheathed transendoscopic cytology brushes for sample collection.

Study Design and Procedures

• The researchers carried out a prospective longitudinal study in which five Thoroughbred racehorses from a single training center were examined due to underperformance.
• They performed gastroscopy on these horses and took samples from both the diseased lesions caused by EGGD and the surrounding healthy tissue.
• These samples were collected using sheathed transendoscopic cytology brushes and were subsequently frozen at -80°C.
• The DNA extracted from these samples was then sequenced and compared to a database to identify the types of bacteria (microbiota) present.
• The same horses were examined again six months later for comparison.

Results

• The researchers found that normal glandular mucosal samples had a higher proportion of Proteobacteria (46.3%) compared to the diseased EGGD lesions (18.9%).
• Conversely, the relative abundance of another type of bacteria, Firmicutes, was higher in EGGD samples (41.2%) compared to healthy ones (20.0%).
• Effect size analysis indicated that a higher proportion of Firmicutes species was common in EGGD samples, particularly due to a significant abundance of the bacteria Sarcina in two studied horses with EGGD.
• However, the team couldn’t comment on the stability of the glandular gastric microbiota, which refers to whether the composition of the bacteria population remains the same over time.

Limitations and Conclusion

• One limitation of the study was the small sample size and the fact that none of the horses studied had entirely normal gastric mucosa.
• The researchers concluded that there is a change in the gastric microbiota in horses with EGGD but are unable to definitively attribute it as a cause of the disease.
• The role of the bacteria Sarcina, found to be plentiful in EGGD samples, can potentially act as a biomarker for the disease and warrants further investigation.
• Finally, the study found that sheathed cytology brushes were an effective method for sampling the gastric mucosa.