[Vitamin E and selenium in the feed of farm animals (author's transl)].

A survey is given of vitamin E and selenium deficiency syndromes in farm animals. Some syndromes can be attributed to the exclusive deficiency of one of the above-mentioned feed components. In some cases with practically complete lack of both componentspathological symptoms can be cured by the addition of one of them to the feed in sufficient amount. A synergistic effect of vitamin E and selenium is sometimes found to recur. The most important theory about the functioning of vitamin E is that it acts as an antioxidant. This theory presumes that, in case of a vitamin E deficiency, peroxidation of unsaturated lipids can occur everywhere in the body leading to oxidative chain reactions. The free radicals thus produced might participate in non-specific reactions with functional and structural compounds. Vitamin E is considered able to reduce lipid peroxides or scavenge free radicals from chain reactions. The pros' and cons' of this theory are discussed. The role of vitamin E has further been associated with thenium is part of the enzyme glutathione peroxidase. This enzyme catalyses the reaction of reduced glutathione with peroxides, whereby hydroxy-acids and oxidized glutathione are generated. Most probably the glutathione peroxidase has its antioxidative action in the cytosol, whereas vitamin E is mainly located in the membranes of the cell.