Dietary Selenium Levels Research Articles

Methionine-responsive Liver Damage in Young Pigs Fed a Diet Low in Protein and Vitamin E

A combined protein-vitamin E deficiency syndrome causing severe liver damage in the pig was studied by manipulating dietary levels of methionine, choline and selenium. Yorkshire pigs weaned at 3 weeks of age, weighing an average of 5 kg, were used in 4 experiments. During the 8-week experimental period the animals were fed a basal diet containing 3% isolated soy protein and 25% corn oil; it was marginal in vitamin E and selenium but adequate in all other nutrients. Consumption of this diet resulted in the development of liver necrosis which was most obvious histologically at weeks 2 and 4; at week 8 severe postnecrotic scarring of the liver predominated with little evidence of acute necrosis. The liver damage was completely preventable by supplementation with α-tocopherol, or selenium, or both. Choline supplementation aggravated the liver damage; however, methionine supplementation provided considerable, and in some cases, complete protection against necrosis and scarring but did not prevent the appearance of hyaline bodies in the hepatocytes. The methionine effect was not related to contamination of the supplemental methionine with selenium.

The Influence of Selenium on the Development of Nutritional Encephalomalacia

It has been generally accepted that low levels of dietary selenium will prevent the development of exudative diathesis and muscular dystrophy but not encephalomalacia in vitamin E-deficient chicks. Recently, however, Century and Horwitt (1964) demonstrated that under certain conditions selenium may protect against the development of the cerebellar disorder as well. In this laboratory, results obtained from preliminary investigations of a possible selenium-tocopherol synergism in encephalomalacia, reported herein, concur with the observation that selenium may protect against this disorder. The data indicate that the element effectively delays onset of the condition as the vitamin E requirement is approached. EXPERIMENTALFemale, one-day old White Plymouth Rock chicks, obtained from a commercial hatchery, were employed in the initial trials. For later studies, a vitamin E-depleted breeding flock was developed to enable the employment of chicks with low tissue stores of vitamin E. Two basal diets were employed to produce encephalomalacia—(1) basal…

SELENIUM AND VITAMIN E INFLUENCE UPON THE IN VITRO UPTAKE OF SE75 BY OVINE BLOOD CELLS.

Whole blood from ewes being fed a purified diet containing urea as the sole nitrogen source was used to determine the in vitro uptake of selenium by ovine blood cells. Selenium-75 as selenite moved into the ovine blood cell in vitro via an oxygen-dependent transport mechanism. The magnitude of this influx was inversely proportional to the dietary intake of selenium, but was not affected by dietary vitamin E. The uptake of sulfur, zinc, or cesium was not influenced by dietary selenium level. (auth)

Metabolic effects of selenium as related to vitamin E

AbstractTrace amounts of dietary selenium, which prevent certain vitamin E deficiency symptoms, have been found to affect the composition of chick tissues. Both selenium and vitamin E increased liver coenzyme A levels to normal when cystine was omitted from the diet. Liver and plasma total fatty acids were unaltered by selenium but vitamin E increased the arachidonic acid content slightly. There was no effect of either selenium or vitamin E on total lipid, cholesterol, phopholipid or coenzyme Q in liver. Low dietary levels of either selenium or vitamin E, which were insufficient in preventing deficiency symptoms, completely eliminated mortality from toxic amounts of a dietary antioxidant. The ability of dietary selenium to reducein vitro lipid peroxidation in chick liver homogenates was not demonstrable with rat liver.