Degree
Doctor of Philosophy (PhD)
Department
Veterinary Clinical Sciences
Document Type
Dissertation
Abstract
Equine glandular gastric disease (EGGD) is a common disease of athletic horses that can affect performance and welfare. Clinical signs are non-specific and diagnosis is made using gastroscopy after a prolonged fasting period. Effective prevention and treatment strategies for EGGD are lacking despite its widespread prevalence and negative effects. The goal of this research was to investigate the pathophysiology of EGGD. Objectives included: 1) compare the gastric glandular mucosal microbiome in horses with and without EGGD, 2) assess the influence of dietary and management factors on the gastric microbiome, and 3) evaluate the pyloric gastric fluid bile acid profile in horses with and without EGGD. It was hypothesized that alterations in the gastric microbiome and bile acid profiles would be associated with EGGD. Two studies investigating the gastric glandular mucosal microbiome in a small, controlled population of horses and a larger, diverse population of horses found differences in the microbiome community structure associated with EGGD. Analysis of dietary and management factors for the diverse population of horses revealed several factors that influence the gastric microbiome. Increased exercise exposure was the only factor associated with an increased risk of EGGD but was not a factor identified to influence the gastric microbiome. Differences in the bile acid profiles of pyloric gastric fluid and serum were associated with hyperemic EGGD. The alterations in the mucosal microbiome and gastric fluid bile acids indicate an altered gastric environment in horses with EGGD. The serum bile acid differences suggest an altered intestinal environment in horses with EGGD. The association of exercise exposure with increased risk of EGGD, but not with the gastric microbiome suggests another mechanism for its role in EGGD. In conclusion, alterations in the gastric microbiome and bile acid profiles could be contributing to onset or persistence of EGGD. The pathophysiology of EGGD appears to be the interaction of multiple factors including the gastric microbiome, bile acids, and exercise. Further investigations into the chronology of identified alterations is warranted. Therapeutic manipulation of the gastric mucosal microbiome or the composition of bile acids are potential targets for future EGGD treatment and prevention strategies.
Date
8-16-2023
Recommended Citation
Paul, Linda, "The Pathophysiology of Equine Glandular Gastric Disease: Investigating the Role of the Mucosal Microbiome and Bile Acid Reflux" (2023). LSU Doctoral Dissertations. 6260.
https://repository.lsu.edu/gradschool_dissertations/6260
Committee Chair
Heidi Banse