Comparative nontargeted profiling of metabolic changes in tissues and biofluids in high-fat diet-fed Ossabaw pig

Typical clinical biomarker analyses on urine and plasma samples from human dietary interventions do not provide adequate information about diet-induced metabolic changes taking place in tissues. The aim of this study was to show how a large-scale nontargeted metabolomic approach can be used to reveal metabolite groups for generating new hypotheses of obesity-related metabolic disturbances produced in an animal model. A large spectrum of metabolites in the semipolar region, including small water-soluble molecules like betaine and dihydroxyindole, and a wide range of bile acids as well as various lipid species were detected. The high-fat diet influenced metabolic homeostasis of Ossabaw pigs, especially the lipid metabolome, throughout all the analyzed sample types, including plasma, urine, bile, liver, pancreas, brain cortex, intestinal jejunum and proximal colon. However, even dramatic metabolic changes in tissues were not necessarily observed in plasma and urine. Metabolite profiling involving multiple sample types was shown to be a feasible method for the examination of a wide spectrum of metabolic species extending from small water-soluble metabolites to an array of bile acids and lipids, thus pointing to the pathways of metabolism affected by the dietary treatment.