Lipidomics reveals lipid changes in the hepatic during the late chick embryonic development

The liver undergoes significant metabolic changes during the late stage of chick embryonic development, particularly in lipid metabolism. Lipids are critical energy sources and structural components for the growth and development of chicken embryos. However, the dynamic changes in hepatic lipid composition during this critical developmental window remain unclear. To investigate the lipid composition changes and underlying mechanisms, we conducted a study on chick embryonic livers at two key developmental time points (E14 and D1). The results showed that the liver in the D1 group exhibited greater lipid droplet accumulation compared to the E14 group. Biochemical analysis revealed significantly elevated levels of triglycerides, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol in the liver of the D1 group relative to the E14 group. Furthermore, we performed lipidomics analysis and identified 2274 lipid species in chicken liver, which were predominantly composed of glycerolipids and glycerophospholipids. Score plots of principal component analysis and partial least squares discriminant analysis revealed distinct lipid profiles between the E14 and D1 groups, suggesting potential remodeling of liver lipid composition and metabolism during the late stage of chick embryonic development. Meanwhile, a total of 105 differentially abundant lipid species were identified, with 91 significantly upregulated and 14 significantly downregulated in the D1 group compared to the E14 group. Pathway analysis revealed the enrichment of the glycerophospholipid metabolic pathway, which comprises 37 differentially abundant lipids that may play crucial roles in the growth and development of chick embryos during late stages. In summary, this study characterized the liver lipid profile and explored the changes in lipid composition and species of the developing liver, with the aim of identifying the nutritional requirements of chicken embryos in the late stages of development. These findings could be utilized for improving chick quality and broiler performance.