SeleniumSelenoprotein PSelenomethionineGlutathione PeroxidaseSelenious AcidYeast, DriedOrganoselenium CompoundsDietary SupplementsSelenoproteinsAntioxidantsSodium SeleniteSelenic AcidVitamin ESelenium RadioisotopesDietPlasmaCross-Sectional StudiesAnimal FeedSelenocysteineRisk FactorsSelenium OxidesLiverAnimal Nutritional Physiological PhenomenaVitamin E DeficiencyDose-Response Relationship, DrugNailsBody WeightTrace ElementsRandom Allocation