Why does a deficiency of dietary choline lead to excessive fat accumulation in the liver (Fatty Liver Syndrome) of brown layers?

The liver of a laying hen is a highly active lipid factory, synthesizing massive amounts of triglycerides daily for transport to the growing yolk follicles in the ovary. For these lipids to be exported from the liver cells (hepatocytes) into the bloodstream, they must be packaged into water-soluble transport vesicles known as Very-Low-Density Lipoproteins (VLDL). The structural shell of VLDLs is composed of phosphatidylcholine (lecithin). Choline is the essential precursor required for the synthesis of phosphatidylcholine. If dietary choline is deficient, the liver cannot synthesize phosphatidylcholine, halting the assembly and export of VLDL. Consequently, synthesized triglycerides become trapped inside the hepatocytes, leading to severe fatty liver degeneration, hepatocyte rupture, and Fatty Liver Hemorrhagic Syndrome (FLHS). Supplementing feed with Choline Chloride (at 500 to 1000 mg/kg) or betaine ensures continuous fat export and liver protection. Farmers can read hepatic metabolism in the Poultry Encyclopedia, buy high-concentration Choline Chloride on Poultry Plaza, monitor daily raw grain rates on Poultry Rates, and list healthy flocks on Murghi Mandi.