Regional gastric pH measurement in horses and foals.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This study investigates the pH levels in various regions of the stomach in horses and foals, revealing differences between regions and between adult horses and young foals. The study shows an observable directional gradient in the pH levels of adult horses’ stomach surfaces and indicates that gastric acid secretion is functioning properly in young foals.
Methods Used in the Study
The research involved a total of 45 horses including 18 foals (average age of 20 days) and 27 adult horses (average age of 2.9 years). A pH electrode was inserted through an endoscope biopsy channel to measure the pH on the surface of the gastric mucosa and the gastric content. A reference electrode was attached to a shaved area on the neck of each subject. The regions where pH was measured included:
- The dorsal squamous fundus (SF)
- Squamous mucosa near the margo plicatus (MP)
- Glandular fundus (GF)
- Fluid or feed contents of the stomach
The measurements in these regions were recorded twice for each animal.
Findings in Adult Horses
Among the adult horses, the highest pH was found in the SF region (average pH 5.46) with a lower pH noted towards the ventral regions, i.e., towards the MP (average pH 4.12) and finally to the glandular fundic mucosa (average pH 3.09). The fluid contents of the stomach showed the lowest pH of 2.72. The variance in pH at each site within the stomach was statistically significant.
Findings in Foals
In foals, mean pH measurements displayed a different trend. The SF showed an average pH level of 4.88, while the MP region showed an average of 4.92. Proceeding towards the GF region, the average pH dropped to 2.10. For milk and fluid contents, the pH was found to be 1.85 in six foals, whereas the feed contents revealed an average pH of 3.39 in 12 foals. The pH of the SF and MP were statistically significantly higher than that of the feed contents which, in turn, was significantly higher than the glandular mucosal surface and fluid content pH values.
Conclusions of the Study
The results gathered from this study highlight a dorsal to ventral pH gradient on the gastric mucosal surface in adult horses. In other words, the researchers found a significant pattern of pH decrease from the upper (dorsal) to the lower (ventral) regions in the horses’ stomachs. Furthermore, the study concluded that gastric acid secretion is functioning as expected in young foals.
Cite This Article
Publication
Researcher Affiliations
- Marion duPont Scott Equine Medical Center, Virginia-Maryland Regional College of Veterinary Medicine, Leesburg 22075, USA.
MeSH Terms
- Aging / physiology
- Animals
- Animals, Newborn / physiology
- Electrodes / veterinary
- Gastric Mucosa / physiology
- Horses / physiology
- Hydrogen-Ion Concentration
- Reproducibility of Results
- Stomach / physiology
Citations
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- Murray MJ. Equine model of inducing ulceration in alimentary squamous epithelial mucosa. Dig Dis Sci 1994 Dec;39(12):2530-5.
- Cao J, Zhang J, Wu H, Lin Y, Fang X, Yun S, Du M, Su S, Liu Y, Wang N, Bao T, Bai D, Zhao Y. Probiotic Potential of Pediococcus pentosaceus M6 Isolated from Equines and Its Alleviating Effect on DSS-Induced Colitis in Mice. Microorganisms 2025 Apr 22;13(5).
- Hodgson E, Thirouin M, Narayanan P, Romano TR, Wise J, Bond S. A novel placement method of a calibration-free pH capsule for continuous wireless measurement of intragastric pH in horses. J Vet Intern Med 2025 Jan-Feb;39(1):e17273.
