Untargeted GC-MS metabolomics reveals metabolic differences in the Chinese mitten-hand crab (Eriocheir sinensis) fed with dietary palm oil or olive oil

Palm oil (PO) and olive oil (OO) have been widely used in animal diets, but the knowledge of metabolic change in animals fed a diet with different oil sources is limited. Here, we compared the metabolic differences in the Chinese mitten crab fed with PO and OO as the main dietary lipid sources by performing GC-MS-based serum metabolomics assays and traditional nutritional assessments. The crab fed OO displayed lower lipid accumulation and oxidative stress in the hepatopancreas than those in the crab fed PO. In the metabolomics assay, 68 metabolites with high credibility were identified and five metabolites were significantly different between two feeding groups. In these five metabolites, hydroxylamine, 3-hydroxypropionic acid and 2-hydroxypyridine were higher in the OO group, while lysine and citrulline were higher in the PO group. We demonstrate that olive oil can provide comprehensive benefits to the crab by providing more energy, improving cell membrane structure, containing phenols as a natural antioxidant, and improving the composition of intestinal microbiota. On the contrary, palmitic acid-enriched palm oil tended to increase protein degradation and lipid accumulation-induced lipotoxicity. This study illustrates that the metabolic mechanism differs between crabs fed olive oil and palm oil, and OA-enriched olive oil is recommended as an ingredient for crab diet formulation.