Effect of Olive Oil-Fried Sardine Consumption on Liver Lipid Composition and Fatty Acid Cholesterol Esterification in Hypercholesterolemic Rats

Abstract

PUFA n-3 diets have hypolipemic and cardiovascular protection properties, however their effects on liver lipids are not well established. This work aimed to find out the acceptability and effects of diets containing olive oil-fried sardines on serum cholesterol, liver lipid and fatty acids profile in hypercholesterolemic growing Wistar rats. Hypercholesterolemia was induced for three weeks by a casein plus DL-methionine, olive oil and cholesterol plus bovine bileas cholesterol-raising agent. Rats were later transferred for three weeks to semisynthetic diets containing casein plus DL-methionine and olive oil (CO), casein plus DLmethionine, olive oil and the cholesterol-raising agent (COC), sardines fried in olive oil (S), and sardines friedin olive oil and the cholesterol-raising agent (SC). SC or S diets were well accepted by the rats. The SC-diet markedly blocked and reversed the hypercholesterolemic induction of the cholesterol-raising agent. The cholesterol withdrawal decreased serum cholesterol in CO and S dietsby decreasing the serum non-HDL-cholesterol content but the S-diet totally normalised the serum cholesterol. Fried sardines did not change the triacylglycerol, free, esterified and total cholesterol contents of liver. Although long PUFA n-6 and PUFA n-3 were decreased by the dietary cholesterol, olive oil-fried sardine consumption maintained the docosahexaenoic acid and thedocosahexaenoic acid/linolenic acid ratio in liver and cholesterol ester fraction at a high level. Olive oil fried sardines blocked the hypercholesterolemic effect of the diet containing cholesterol and help normalising lipoprotein profile in a rather short period. The oleic acid esterification of cholesterol was kept high in all experimental diets as a mechanism to maintain the liver cholesterol ester/free cholesterol ratio as high as possible. The fat in the oliveoil-fried sardines was used similarly to the oleic acid by the liver of hypercholesterolemic rats but increased its PUFA n-3 content in the total liver and its cholesterol ester fraction.