SUPRANUTRITIONAL VITAMIN-E SUPPLEMENTATION IN PIGS - INFLUENCE ON SUBCELLULAR DEPOSITION OF ALPHA-TOCOPHEROL AND ON OXIDATIVE STABILITY BY CONVENTIONAL AND DERIVATIVE SPECTROPHOTOMETRY

The influence of three levels of vitamin E (30, 200 and 1000 mg kg(-1) ) in the diet of pigs on the subcellular deposition of alpha-tocophero l in muscle and on the oxidative stability determined by conventional and first derivative spectrophotometry was studied. The content of a-t ocopherol in m. gluteo biceps and in mitochondrial and microsomal frac tions of the muscle significantly increased (p < 0.01) with increasing levels of dietary vitamin E. Concentrations of a-tocopherol in muscle , mitochondria and microsomes of pigs fed diet supplemented with 1000 mg kg(-1) alpha-tocopheryl acetate were 3.2-, 6.1- and 5.6-fold greate r, respectively, than those in their counterparts from the control ani mals. These differences in alpha-tocopherol concentration in the subce llular fractions and intact muscle resulted in enhanced stability of t he membranes and the tissue when exposed to iron-ascorbate induced per oxidation. When lipid oxidation in the same samples was further measur ed by the first derivative method, the resultant MDA-TBA values were 5 9-69% lower in tissue samples, 16-19% lower in mitochondria and 6-9% l ower in microsomes than the conventional TEARS values. (C) 1997 Elsevi er Science Ltd. All rights reserved.