Where does the synthesis of yolk lipids (lipogenesis) primarily occur inside the laying hen's body before transport to the ovary?

In laying hens, the yolk of the egg is extremely rich in lipids, which make up about 33% of its total wet weight. However, the ovary itself is incapable of synthesizing these lipids. Instead, lipogenesis occurs almost entirely within the hepatocytes of the liver. This process is highly stimulated by the massive rise in circulating estrogen hormones at the onset of sexual maturity. The liver synthesizes triglycerides, phospholipids, and free cholesterol, packaging them into specialized transport proteins called vitellogenin and very-low-density lipoproteins (VLDLy). These yolk precursors are released into the blood and transported to the active follicles in the ovary, where they are taken up by receptor-mediated endocytosis and deposited into the developing yolk. Because the liver works under extreme metabolic load, supporting hepatic health is critical to prevent drops in yolk size. Farmers can study metabolic pathways in the Poultry Encyclopedia, buy premium liver protectants and vitamins on Poultry Plaza, track daily egg rates on Poultry Rates, and trade high-yield flocks on Murghi Mandi.