Abstract: This study aimed to elucidate the effects of different ploidy levels and fattening culture modes on the lipid composition of Crassostrea gigas and to reveal the types and variation patterns of bound lipid molecules. Diploid, triploid, and fattening triploid C. gigas were selected to analyze their fatty acid composition and lipid profiles by gas chromatography (GC) and high performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry (HPLC-Q-Orbitrap MS), respectively. The results showed that the contents of n-3 polyunsaturated fatty acids (n-3 PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) in triploid oysters were significantly higher than those in diploid and fattening triploid oysters (P < 0.05). A total of 1 071 lipid molecules belonging to 29 subclasses within the major categories including glycerolipids, sphingolipids, and glycerophospholipids were identified across the three oysters. Differences in lipid composition were observed among the different oyster groups, with 33 lipids including 11 triglycerides, 6 diglycerides, 2 phosphatidylserines, 2 phosphatidylethanolamines, 2 phosphatidylcholines, and 3 phosphatidylinositols identified as significantly different. The findings of this study provide data support and a reference for the nutritional quality evaluation, consumption, processing, and functional lipid development of C. gigas.

Key words: Crassostrea gigas; lipidomics; different strains; differential lipids