RadioisotopesPhosphorusPhosphorus IsotopesIsotopesIsotope LabelingPhosphorus, DietaryNitrogen IsotopesOxygen IsotopesCarbon IsotopesPhosphorus CompoundsZinc IsotopesSulfur IsotopesDeuteriumIron IsotopesStrontium IsotopesRadioisotope Dilution TechniquePhosphatesPhosphorus Metabolism DisordersNitrogenMass SpectrometryMineralsIndicator Dilution Techniques6-Phytase