Comparative Lipidomics of Chick Yolk Sac during the Embryogenesis Provides Insight into Understanding the Development-Related Lipid Supply.

Yolk sac (YS, include the yolk content) at different chick embryogenesis stages possesses varying lipid distributions, which are nutrition-influencing factors for the health of an early embryo and a later adult. YS lipids can substantially influence embryogenesis metabolism, but a comprehensive understanding of lipid's influence remains unknown. Herein, the effects of embryogenesis on lipid profiling of chick YS were investigated by UHPLC-MS/MS-based lipidomics. A total of 2231 lipid species across 57 subclasses were identified in the YS, and 1011 lipids were significantly different (P < 0.05) at the incubation days of 0, 7, 13, and 18. Specifically, phosphocholine and phosphatidylglycerol in late-stage embryogenesis potentially assist with prehatching gas exchange and infection resistance in the environment after lung respiration. In addition, the accumulated lysophosphatidylcholine at day 18 may induce apoptosis and disturb the membrane structure of YS to enable better absorption by the embryo abdomen. The decreased cardiolipin in late embryogenesis may be due to transportation to the embryo and integration into the mitochondrial membrane to accelerate energy metabolism for the rapidly developing embryo after day 13. Therefore, this study demonstrated the lipid profile alteration of the developing YS, providing theoretical guidance for researching the developmental origins of health and disease.