Abstract: The present study was conducted to investigate lipid and fatty acid compositions, differential lipids, potential biomarkers and metabolic pathways in the muscles of two indigenous donkey breeds in Dezhou, Shandong, Sanfen (SF) and Wutou (WT), using liquid chromatography-mass spectrometry (LC-MS)-based lipidomics. The results showed that a total of 1 101 lipid molecules belonging to 13 subclasses were identified in both donkey breeds. Triglycerides were the dominant lipids in donkey muscle, followed by phospholipids. The relative content of diacylglycerol in SF muscle was significantly higher than that in WT muscle (P < 0.05), while no significant difference in fatty acid composition was found between SF and WT muscle (P > 0.05). A total of 37 differential lipid molecules were identified (variable importance in the projection above 1, P < 0.05), of which 32 were up-regulated and five were down-regulated in SF muscle compared with WT muscle. Among them, 11 lipid molecules were considered as potential lipid markers to distinguish SF and WT from receiver operating characteristic curve analysis. These differential lipids were involved in glycerophospholipid metabolism, glycosylphosphatidylinositol-anchor biosynthesis, linoleic acid metabolism, alpha-linolenic acid metabolism, and arachidonic acid metabolism. This study analyzed the lipid differences of Dezhou donkey in different breeds at the level of lipid molecules and metabolism, screening of potential biomarkers.

Key words: Dezhou donkey breeds; muscle; lipid composition; lipidomics