INFLUENCE OF DIET ON LIPID OXIDATION AND MEMBRANE-STRUCTURE IN PORCINE MUSCLE MICROSOMES

The effect of oxidized dietary lipid (corn oil) and dietary vitamin E (cu-tocopherol) on the fluidity of porcine muscle microsomal membranes was investigated. Using the membrane probe diphenylhexatriene, fluore scence anisotropy measurements showed that microsomal membrane fluidit y decreased during FeCl2-induced lipid peroxidation. Microsomes from p igs fed an alpha-tocopherol-supplemented diet (200 mg of alpha-tocophe ryl acetate/kg of diet) were significantly less susceptible (P < 0.05) to FeCl2-induced lipid peroxidation and to changes in membrane fluidi ty compared to muscle microsomes from pigs fed a basal diet (10 mg/kg of diet). Compared to unoxidized dietary corn oil, consumption of oxid ized oil (4.5 mequiv of peroxide/kg of diet) did not significantly aff ect the rate of peroxidation of the microsomal lipids but led to a sig nificant decrease in membrane fluidity. Results suggested that the red uced exudation in pork steaks from pigs fed supplemental alpha-tocophe rol, observed in this study and in an earlier study, did not appear to be directly related to oxidation-induced changes in membrane fluidity . However, further studies are needed to more adequately evaluate this observation.