title: Effect of cholecalciferol-enriched hen feed on egg quality.
abstract: Eggs are one of the most important sources of vitamin D in the human diet, and their vitamin D content can be further increased by adding more vitamin D to hen feed. To investigate this issue more closely, we performed two feeding experiments. In both, zero egg samples were collected while the hens were fed regular feeds with a vitamin D content of 1720 or 4280 IU/kg. In experiment 1, egg samples were collected 2, 4, 7, 9, 11, 13, 16, 23, and 30 days after beginning the high-cholecalciferol (11 200 IU/kg) feeding period. In experiment 2, samples were collected 2, 4, 6, 8, 13, 28, 56, 84, 112, 140, and 168 days after beginning the high-cholecalciferol (12 000 IU/kg) diet. The egg samples were then assayed for their cholecalciferol content, and some samples, also for the presence of 25-hydroxycholecalciferol by an HPLC method. Further, the vitamin D-fortified eggs were compared with the controls by a sensory evaluation, by conducting fatty acid and functional analyses (emulsion capacity, gel forming capacity, foaming properties) and by measuring eggshell strength. Because vitamin D can be toxic in high doses, we also performed histopathological tests on the hens at the end of experiment 2. The top cholecalciferol contents in egg yolk (ca. 30 microg/100 g) were reached 8-13 days from starting the high-cholecalciferol diet. After 112 days feeding the cholecalciferol content gradually decreased to ca. 22 microg/100 g. When added to eggs as described above, vitamin D did not affect their sensory or functional properties or their fatty acid composition. Moreover, the cholecalciferol levels used in this study appeared not to affect eggshell strength or to be harmful for hens.
authors.affiliation: Food Research, MTT Agrifood Research Finland, FIN-31600 Jokioinen, Finland. pirjo.mattila@mtt.fi
authors.forename: Pirjo
authors.initials: P
authors.lastname: Mattila
authors.forename: Timo
authors.initials: T
authors.lastname: Rokka
authors.forename: Karoliina
authors.initials: K
authors.lastname: Könkö
authors.forename: Jarmo
authors.initials: J
authors.lastname: Valaja
authors.forename: Laila
authors.initials: L
authors.lastname: Rossow
authors.forename: Eeva-Liisa
authors.initials: EL
authors.lastname: Ryhänen
mesh_terms: D000821:Animal Feed; D000818:Animals; D001696:Biomechanical Phenomena; D002112:Calcifediol / Q000032:analysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002645:Chickens / Q000502:physiology*; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004528:Egg Shell / Q000502:physiology; D004530:Egg Yolk / Q000737:chemistry; D004531:Eggs / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D011786:Quality Control; D012677:Sensation
chemical_list: D005227:Fatty Acids; D002762:Cholecalciferol; D002112:Calcifediol