EFFECT OF DIFFERENT TYPES OF DIETARY FAT ON THE LIPID PROFILE OF RATS

Abstract

This study tries to illucidate the biochemical effects of dietary oils and fats commonly available in the local market on the lipid profile of rats. The oils used were com oil, sunflower oil and olive oil, whereas the fats used were hydrogenated com oil, butter fat and palm stearin. Serum TG, TC, HDL-C, LDL-C and NEFA, liver MDA and microsomal fatty acids as well as pattern of fatty acids in used oils and fats were determined. Results showed that olive oil lowers serum TG, TC, LDL: HDL-C and liver MDA as compared to com and sunflower oils. Mean serum TC and LDL: HDL-C in rats fed com oil were significantly lower than in those fed sunflower oil. The highest percentage of 18:1 microsomal fatty acid was observed in rats fed the olive oil diet while the highest percentage of 18:2 microsomal fatty acid was found in the sunflower oil fed group. A significant increase in 20:4 microsomal fatty acid was found in rats fed the com oil diet. Feeding hydrogenated com oil increased significantly LDL: HDL-C more than that observed upon feeding butter fat and palm stearin diets. Feeding palm stearin diet reduced liver MDA level significantly. The lowest percentage of 18:1 microsomal fatty acid and the highest percentage of 18:2 microsomal fatty acid were found in the hydrogenated com oil fed group as compared with butter fat and palm stearin groups. The process of hydrogenation led to a significant increase in the mean serum TG, TC and LDL: HDL-C in hydrogenated com oil fed group than in the com oil fed group. Hydrogenation of com oil led to a significant increase in 16:0 and 18:0 microsomal fatty acids and a significant decrease in 20:4 microsomal fatty acid.Replacement of hydrogenated com oil by olive oil decreased significantly the serum TG, TC and LDL: HDL-C and led to a significant decrease in 18:0 microsomal fatty acid. Replacement of butterfat by olive oil caused a significant decrease in serum TG, TC, LDL: HDL-C and liver MDA concentrations. It also led to a significant decrease in 16:1 microsomal fatty acid. Replacement of palm stearin by olive oil reduced serum TG and liver MDA concentrations and did not show any significant change in the microsomal fatty acids. There were no significant differences between values of serum NEFA among the different groups.