Fecal Concentrations of Long-Chain Fatty Acids, Sterols, and Unconjugated Bile Acids in Cats with Chronic Enteropathy

SIMPLE SUMMARY: Chronic enteropathy (CE) is a spectrum of chronic digestive disorders in cats. Understanding the metabolic dysfunction in the gut is crucial for understanding these diseases and developing better treatment options. However, the specific metabolic profiles of cats with CE remain largely unexplored. As fat is an essential energy source that participates in many physiological pathways, we focused on fat-related metabolites in this study. Fecal samples from cats with CE and healthy cats were collected, and concentrations of various fatty acids, sterols, and bile acids were measured. Cats with CE had higher concentrations of fatty acids, increased concentrations of animal-based sterols, and decreased plant-based sterols in their feces. A subset of cats with CE also showed abnormal bile acid metabolism, i.e., an increased percentage of primary bile acids. These findings suggest that cats with CE may have altered fat metabolism in their digestive tracts. ABSTRACT: Chronic enteropathy (CE) in cats encompasses food-responsive enteropathy, chronic inflammatory enteropathy (or inflammatory bowel disease), and low-grade intestinal T-cell lymphoma. While alterations in the gut metabolome have been extensively studied in humans and dogs with gastrointestinal disorders, little is known about the specific metabolic profile of cats with CE. As lipids take part in energy storage, inflammation, and cellular structure, investigating the lipid profile in cats with CE is crucial. This study aimed to measure fecal concentrations of various fatty acids, sterols, and bile acids. Fecal samples from 56 cats with CE and 77 healthy control cats were analyzed using gas chromatography-mass spectrometry, targeting 12 fatty acids, 10 sterols, and 5 unconjugated bile acids. Fecal concentrations of nine targeted fatty acids and animal-derived sterols were significantly increased in cats with CE. However, fecal concentrations of plant-derived sterols were significantly decreased in cats with CE. Additionally, an increased percentage of primary bile acids was observed in a subset of cats with CE. These findings suggest the presence of lipid maldigestion, malabsorption, and inflammation in the gastrointestinal tract of cats with CE. Understanding the lipid alterations in cats with CE can provide insights into the disease mechanisms and potential future therapeutic strategies.