Influence of increased saturated fatty acid intake from beef tallow on antioxidant status and plasma lipids in atherosclerosis-susceptible Japanese quail

Abstract

In this study, the relationship between tissue antioxidant status and atherogenesis was examined using the atherosclerosis-susceptible Japanese quail model. Male Japanese quail were fed commercial poultry diets containing two levels of beef tallow (i.e. 6.0 or 12.0% w w ) that were balanced for endogenous cholesterol (i.e. 0.05% w w ) or supplemented to a high level of cholesterol (i.e. 0.5%), for 9 weeks to examine the effects of increased SFA and cholesterol intake on plasma lipids, tissue antioxidant status and atherosclerotic plaque development in quail. Diets containing 12% beef tallow resulted in lower diet 18:2n-6 14:0 fatty acid ratios. Hypercholesterolemia ( P < 0.001) obtained in birds fed high cholesterol diets led to lower ( P < 0.01) LDL HDL ratios and greater severity of atherosclerotic plaques. No dietary treatment interaction was observed for plasma total cholesterol or LDL HDL cholesterol ratios, albeit a significant (P ≤ 0.05) interaction between dietary cholesterol and fat intake was recorded for plasma triacylglycerols. Liver cholesterol content was affected by dietary cholesterol ( P < 0.01) intake, while triacylglycerol ( P < 0.01) content was influenced only by the intake level of dietary fat. Elevated plasma TC, and in particular plasma TG, associated with diets containing increased SFA and cholesterol content resulted in enhanced development of aortic plaque. Antioxidant enzymes (catalase, glutathione peroxidase, glutathione reductase, superoxide dismutase) and tissue glutathione levels of red blood cell, heart and aortae were not affected by dietary treatment and did not correspond with aortic plaque deposition. Hepatic superoxide dismutase activities were lower ( P= 0.002) in birds fed high cholesterol diets. Differences in susceptibility to oxidative challenge with H 2O 2 were observed in heart and liver tissue. Forced production of lipid peroxidation, as measured by tissue thiobarbituric reactive substances (TBARS), was lower ( P < 0.05) in heart and liver tissues from birds fed atherogenic diets.