Quantitative lipidomic analysis of egg yolk, yolk granule, and yolk plasma

Chicken egg yolk (EY) can be divided into yolk granule (EYG) and yolk plasma (EYP); they develop individually based on their remarkably different nutritional compositions and properties. However, the differences in lipid profiles between EYG and EYP have not been fully revealed. In this study, quantitative lipidomic analyses of EY, EYG, and EYP were implemented through a liquid chromatography-tandem mass spectrometry strategy. The results showed a total of 702 identified lipid species, mainly including 136 triglycerides, 112 phosphatidylcholines, 104 phosphatidylethanolamines, 50 lysophosphatidylcholines, and 41 diglycerides. A quantitative comparison showed that phospholipids were the representative differentially abundant lipids in the contrast of EY and EYG, EY and EYP; while triglycerides were the most representative differentially abundant lipids between EYG and EYP. Docosahexaenoic and eicosapentaenoic acids mainly exist in the phospholipids of EY. The research results provide important information for the systematic understanding of the lipid composition of EY, EYG, and EYP, and provide insights into the differential development of EYG and EYP.