SeleniumDietary SupplementsInternational System of UnitsSelenomethionineSodium SeleniteSelenium CompoundsGlutathione PeroxidaseFood, FortifiedSelenoproteinsYeast, DriedAnimal FeedVitamin ASelenic AcidSelenious AcidDietRandom AllocationSelenoprotein PDouble-Blind MethodOrganoselenium CompoundsThioredoxin Reductase 1Trace ElementsSelenocysteineThioredoxin-Disulfide ReductaseAnimal Nutritional Physiological PhenomenaAntioxidantsIodide PeroxidaseThyroxineTriiodothyronineDose-Response Relationship, DrugErythrocytesBody WeightSelenium RadioisotopesVitamin ETreatment OutcomeVitaminsAdministration, OralZincSelenium OxidesMicronutrientsFolic AcidNutritional Statusalpha-TocopherolPregnancybeta CaroteneNailsLiverPlacebosTime FactorsAscorbic Acid