Sub-chronic toxicity study of palm kernel oil and soya oil in albino Wister rats

Background: Vegetable oils are commonly used food additives. Aim: To characterize and observe the toxic effect of sub chronic consumption of heated and unheated Palm Kernel oil (PKO) and Soya Oil (S0) after heating at 180 ℃ and at room temperature in albino Wistar rats. Methodology: The physicochemical properties were analyzed, sixty rats were divided into five groups of twelve rats and their baseline weight recorded. Group 1 (controls), received water and feed only, while 10mls of each oil was added (add libitum) to 100 grams of feed in each test group for six weeks and twelve weeks. Group 2 received feed, water and unheated PKO and Group 3 received feed, water and heated PKO. Group 4 were given feed, water and unheated SO while group 5 had feed, water and heated SO. The lipid profile and blood glucose were measured at six weeks exposure while the renal function and liver function were determined at twelve weeks exposure. Result: Heating the oils at 180 ℃ for 15 minutes caused a decrease in relative density, peroxide values, and iodine values in both the PKO and SBO and increased acid values and free fatty acids in both with no effect in the refractive index. Biochemical result showed that both heated and the unheated oil samples significantly increased the LDL levels, HPKO and UHSO caused increase in total cholesterol levels, UHPKO significantly decreased the TAG, HPKO significantly increased the ALT, HPKO significantly decreased the urea level and HSO increased the BG significantly. Conclusion: Heating alters the physicochemical properties of the oils thereby decreasing their qualities, while the oils also demonstrated evidence of hyperlipidemia.