A study was made of the amounts and fatty acid compositions of the cholesterol esters, phospholipids, and triglycerides present in the yolk of the fertile unincubated egg and in the yolk, liver, and extrahepatic tissues of the chick embryo at various stages of development. Esterification of cholesterol, mainly with oleic acid, occurred in the yolk during incubation. There appeared to be a preferential absorption from the yolk sac of phospholipids rich in docosahexaenoic acid. Considerable amounts of cholesterol esters, of which 80% was cholesterol oleate, accumulated in the embryonic liver. The liver phospholipids contained more stearic, arachidonic, and docosahexaenoic acids, and less palmitic and oleic acids, than did the yolk phospholipids. Docosahexaenoic acid occurred in a surprisingly high concentration in the liver triglycerides. The extrahepatic triglycerides contained more palmitic and C18polyunsaturated acids, but less docosahexaenoic acid, than did the liver triglycerides. The concentration of oleic acid in the extrahepatic cholesterol esters was much less than in the liver cholesterol esters. The extrahepatic phospholipids contained more arachidonic and docosahexaenoic acids, but less oleic acid, than did the yolk phospholipids. The implications of these findings are discussed in relation to the general lipid metabolism of the chick embryo.
Production of Oleic Acid Ethyl Ester Catalyzed by Crude Rice Bran (Oryza sativa) Lipase in a Modified Fed-batch System: A Problem and its Solution
