Background – Colitis is a leading cause of gastrointestinal disease in horses. Evidence from other animals suggests that measurement of fecal concentrations of selected fatty acids (FA) and zoo- and phytosterols may serve as biomarkers of epithelial barrier damage and intestinal inflammation. Little is known about the fecal FA and sterol profiles of horses with colitis and its etiology.
Objective – Determine the fecal FA and sterol concentrations of healthy horses and in those with clinically determined subtypes of colitis.
Animals – Healthy horses (HC, n=31) and those with various subtypes of colitis: antibiotic-associated diarrhea (AAD, n=13), infectious (INFEC, n=22, includes Salmonella and Clostridia), and inflammatory bowel disease (IBD, n=7).
Methods – Targeted metabolomic analysis performed on lyophilized feces with gas chromatography/tandem accurate mass spectrometry. Metabolite concentrations were analyzed using One-Way ANOVA and adjusted for multiple comparisons.
Results – When compared with HC horses, there was a significant (p< 0.05) decrease in myristate (AAD), and significant increases in stearate (INFEC, IBD), nervonate, arachidonate, and total FA (INFEC). Among sterols, campesterol:cholesterol, lathosterol:cholesterol and sitosterol:cholesterol ratios were decreased (AAD, INFEC, IBD) while concentrations of cholestanol, zoosterol, coprostanol, and total sterol (INFEC, IBD) were increased. Compared to colitis horses that survived, those that died had elevated concentrations of coprostanol.
Conclusions and clinical importance – Fecal FA and sterols are altered in horses with colitis, suggesting changes in metabolic processes of the GI tract epithelium. Fecal FA and sterol profiles may be developed as clinical predictors for colitis' presence and severity.
