Lipid and protein oxidation in microsomal fraction from turkeys: influenceof dietary fat and vitamin E supplementation

The objectives of this study were to investigate the effects of dietary fat s (6% soya oil or rapeseed oil or tallow) and alpha -tocopheryl acetate sup plementation (30 ppm for control and 200 ppm For supplemented animals), on lipid and protein oxidation, induced by Fe3(+)/iascorbate, of microsomal fr action in turkey muscles (M. pectoralis major and M. sartorius), Supplement ation of turkeys with alpha -tocopheryl acetate increased the vitamin E con tent of microsomal membranes. Vitamin E supplementation strongly decreased lipid oxidation in membranal fractions when animals were fed rapeseed oil o r tallow: this effect was less pronounced in animals fed soya oil. Vitamin E supplementation induced a slight decrease in protein carbonyl content, es pecially in animals fed soya oil. Level of protein free thiols was consider ably enhanced in diet enriched with soya oil. Vitamin E supplementation had a stabilizing effect on glucose-6-phosphatase activity of microsomes when oxidized by Fe3+/ascorbate. No muscle effect was detected on the level of l ipid and protein oxidation in membranal fractions even if M. sartorius is k nown to be more oxidative than M. pectoralis major. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.