title: Vitamin D fortification of eggs for human health.
abstract: BACKGROUND
  Vitamin D is an essential component of vertebrate nutrition, and epidemiological surveys confirm a chronic vitamin D insufficiency in the human population. Eggs are one of the few natural sources rich in vitamin D, containing both vitamin D₃ (D₃) and 25-hydroxyvitamin D₃ (25(OH)D₃). 25-Hydroxyvitamin D₃ is especially useful because it provides five times the relative biological activity of vitamin D. In order to establish the potential for enrichment of eggs with D₃ and 25(OH)D₃, a total of 162 hens were fed three levels of D₃ in combination with three levels of 25(OH)D₃. Egg yolks were analysed for their D₃ and 25(OH)D₃ contents, and egg production, egg weights and feed efficiencies were recorded.
  
  
  RESULTS
  The contents of D₃ and 25(OH)D₃ in egg yolk increased significantly with increasing dietary concentrations. There were no significant differences in egg mass, egg weight or feed efficiency. Depending on the dietary concentrations used, it was possible to produce eggs with between 100 and 500 IU vitamin D, providing scope to meet the recommended daily requirement of vitamin D for children or adults.
  
  
  CONCLUSIONS
  The addition of higher levels of D₃ and 25(OH)D₃ produced eggs with sufficient vitamin D to meet the recommended daily requirements of adults and children without any detrimental effect on production parameters.
authors.affiliation: Poultry Research Foundation, University of Sydney, Camden, NSW 2570, Australia; Poultry CRC, PO Box U242, University of New England, Armidale, NSW 2351, Australia.
authors.forename: Linda C
authors.initials: LC
authors.lastname: Browning
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Cowieson
mesh_terms: D000328:Adult; D000818:Animals; D017849:Animals, Inbred Strains; D001315:Australia; D001522:Behavior, Animal; D002112:Calcifediol / Q000008:administration & dosage / Q000009:adverse effects / Q000032:analysis* / Q000378:metabolism; D002645:Chickens / Q000502:physiology*; D002648:Child; D002762:Cholecalciferol / Q000008:administration & dosage / Q000009:adverse effects / Q000032:analysis* / Q000378:metabolism; D004032:Diet / Q000662:veterinary*; D004530:Egg Yolk / Q000737:chemistry; D004531:Eggs / Q000032:analysis*; D002149:Energy Intake; D005260:Female; D055951:Functional Food / Q000032:analysis*; D006801:Humans; D009753:Nutritive Value; D052287:Oviparity; D064167:Recommended Dietary Allowances; D015854:Up-Regulation
chemical_list: D002762:Cholecalciferol; D002112:Calcifediol
keywords: 25-hydroxyvitamin D3; eggs; laying hens; vitamin D; vitamin D3