Copper-zinc superoxide dismutase (CuZnSOD) in antioxidant deficient pigs

Six piglets, aged 4 weeks (weaning) at the beginning of the experiment, were fed a diet lacking antioxidants (vitamin E and selenium) and enriched with oxidated cod liver oil (the peroxide value of which was 112.54 meqv/kg). Four of the experimental pigs were killed for necropsy at the age of 2 months and the remaining two pigs at the age of 3 months. Two piglets from the same litter served as controls. Myodegeneration of the skeletal muscles was induced in the experimental group. Macroscopically, the condition of nutritional myodegeneration ('white muscle disease') was characterized by a pale, yellowish colour and translucence of the skeletal muscles. The livers were pale and mottled. Light microscopy revealed degenerative alterations in the heart and skeletal muscle and infiltrations by lipidic substances. The ultrastructure of some lipidic droplets was analogous to those of ceroid and lipofuscin. Peroxisomes were frequent in degenerating hepatocytes. In order to elucidate the lysosomal involvement in the residual formation, light and electron microscopical immunocytochemistry using copper-zinc superoxide dismutase (CuZnSOD) was applied. Degradation of mitochondria in the skeletal muscles appeared to be due to the direct coalescence of mitochondria with primary lysosomes. Probably zinc was recruited into the antioxidant protection upon conclusion of the increased erythrocyte superoxide dismutase (E-SOD) activity.