Coconut oil induces short-term changes in lipid composition and enzyme activity of chick hepatic mitochondria

We studied the short-term effects of a 20% coconut oil supplementation to t he chick diet on lipid composition of liver and hepatic mitochondria, and c hanges that occurred in mitochondrial-associated enzymes as a result of thi s diet. No significant differences were observed in the lipid contents of l iver when young chicks were fed the experimental diet, whereas hepatic mito chondria rapidly changed in response to this diet. Total cholesterol signif icantly increased in mitochondria at 24 hours of coconut oil diet feeding a nd decreased when dietary treatment was prolonged for 5 to 14 days. Changes in total mitochondrial phospholipids showed an inverse profile. A signific ant decrease in phosphatidylethanolamine and an increase in sphingomyelin w ere found at 24 hours. The cholesterol/phospholipid molar ratio significant ly and rapidly (24 hours) increased in mitochondria from treated animals. C ytochrome oxidase activity drastically increased after 24 hours of experime ntal diet feeding and lowered to the control values when dietary manipulati on was prolonged for 5 to 14 days. ATPase activity showed an inverse profil e. Changes in cytochrome oxidase activity were parallel to changes in the c holesterol/phospholipid molar ratio, whereas changes in ATPase activity sho wed an inverse correlation with changes in this molar ratio. To our knowled ge, this is one of the first reports on the very rapid response (24 hours) of mitochondrial lipid composition and function to saturated fat feeding. ( J. Nutr. Biochem. 10:325-330, 1999) (C) Elsevier Science Inc. 1999. All rig hts reserved.