Vitamin E for Swine

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Abstract
A fat-soluble dietary factor (ultimately designated vitamin E) found in wheat germ, lettuce and alfalfa meal was reported in 1922 to be effective in preventing fetal death and resorption in the rat. The multiple nature of vitamin E was defined over the next 44 years, and eight structurally similar, naturally occurring compounds have been identified. Their bio-potency differs appreciably, with α-tocopherol being most effective in supporting normal reproduction in rats. Concentrations of this isomer are proportionately greater in plant than in animal tissue, with highest levels in green leaves and seed oils. Commercial forms of vitamin E used in foods, feeds and pharmaceuticals are principally acetate and hydrogen succinate esters of RRR-α-tocopherol and the acetate of all-rac-α-tocopherol. Absorption from the gut is as the free alcohol (after hydrolysis, if esterified). There is a relatively high correlation between plasma and liver levels of α-tocopherol, and plasma α-tocopherol concentrations can be effectively used to appraise vitamin E status. Vitamin E appears to function as an in vivo antioxidant, but, it also may influence the architecture of membrane phospholipids, inhibit the aggregability of blood platelets and favor the immune response to infection. Deficiency signs in swine, first reported in 1949, include microangiopathy, icterus, edema, skeletal and cardiac muscular degeneration and hepatic necrosis. Certain enzymes leak from damaged tissue into the plasma and have been used in the diagnosis of vitamin E deficiency, although they are probably not pathognomonic. Vitamin E requirements are influenced by a number of other factors, including a variety of stresses and dietary concentrations of Se. When nonstressed swine were fed semipurified diets containing .13 5 mg Se/kg, 15 IU of vitamin E/kg of diet was necessary to sustain tissue tocopherol concentrations. It would appear that when Se supplements are restricted to the currently legal limit of .1 mg/kg, vitamin E supplements for a corn-soybean meal diet should be at least 10 to 20 IU/kg, and possibly 30 IU/kg in problem herds. Copyright © 1981. American Society of Animal Science . Copyright 1981 by American Society of Animal Science

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