Mechanism of Choline Chloride in Alleviating Hepatic Lipid Deposition in Bighead Carp (Aristichthys nobilis): Insights from Glycerophospholipid Metabolism and Choline Metabolic Pathways

This study integrated an in vivo feeding trial (0.00–1.00% choline chloride) with in vitro primary hepatocyte experiments to elucidate the molecular mechanisms by which choline chloride alleviates hepatic lipid deposition in bighead carp. The results showed that dietary supplementation with 0.80–1.00% choline chloride significantly reduced hepatic triglyceride (TG) content and lipid droplet accumulation. At the molecular level, choline markedly downregulated lipogenic genes (g6pd, accα, fas) while upregulating genes involved in lipolysis (cpt1α, acox1) and lipid transport (apob-100, mttp). Non-targeted lipidomics revealed that choline maintains lipid homeostasis primarily via the glycerophospholipid metabolism pathway, significantly increasing levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS). Furthermore, choline intervention enhanced the expression of its own metabolism-related genes (slc44a2, chdh, ck, chpt1), accelerating choline transport and phosphorylation. Overall, based on the results of this experiment, 0.80% is the recommended supplemental level of choline chloride in diets, which can effectively alleviate lipid deposition in bighead carp. The mechanism involves inhibiting lipogenesis and promoting lipid decomposition and transport through glycerophospholipid pathways, while simultaneously enhancing PC synthesis to accelerate hepatic lipid export. These findings provide a theoretical basis for precise feed formulation in bighead carp.