Effect of high fat diets with and without cholesterol on erythrocyte and tissue fatty acids in rats

Male weanling wistar rats were fed synthetic diets containing 20% safflower oil (SFO) or palm oil (PO) with and without cholesterol for a period of six weeks. Erythrocyte membranes were isolated and their fatty acid composition were determined at the end of the experiment. Besides the fatty acid composition of the kidney and spleen lipids were also determined. Erythrocyte membrane, kidney fatty acids of rats fed safflower oil (SFO) had in the majority of variants a higher level of n-6 fatty acids when compared to palm oil group. However, in the spleen, the level of n-6 fatty acids in the palm oil groups were higher than in the safflower oil group. In general the arachidonic acid [20:4 (n-6)] levels were higher in the spleen and erythrocytes particularly in the cholesterol fed groups when compared to the kidney levels. Palm oil fed rats had a higher level of palmitic (16:0) and oleic [18:1 (n-9)] acids. Rats fed diets containing cholesterol significantly reduced the level of stearic (18:0) but increased the level of oleic [18:1 (n-9)], linoleic [18:2 (n-3)], and arachidonic acids [20:4 (n-6)]. The ratios such as 18:1 (n-9)/18:2 (n-6), 18:1 (n-9)/18:0, 18:2 (n-6)/20:4 (n-6) and 20:4 (n-6)/18:2 (n-6) are all indicative of the normal activity of enzymes involved in the desaturation and elongation. Thus these studies indicate that addition of cholesterol can modify the fatty acid composition in erythrocytes, kidney and spleen lipids.