title: Effect of 1 alpha,25-dihydroxycholecalciferol on egg shell quality and egg production.
abstract: 1. The effect of replacing dietary cholecalciferol (D3) by 1 alpha,25-dihydroxycholecalciferol (1,25-(OH)2D3) on egg shell quality and egg production was tested on 32-week-old White Leghorn laying hens over 9 weeks. 2. Hens fed on a diet supplemented with 5 micrograms 1,25-(OH)2D3/kg diet, tended to lay more eggs, and the eggs had significantly higher specific gravity and percentage shell than eggs from control hens fed on a diet supplemented with 27.5 micrograms D3/kg diet. 3. The effect became apparent after about 4 weeks of treatment and persisted until the end of the test. 4. Hens fed on a diet without D3 supplement started to lay very thin or soft shelled eggs within 4 weeks, suggesting that the birds' reserves of D3 or its metabolites were depleted within this period. 5. The results suggest that 1,25-(OH)2D3 can be substituted for D3 in layer diets to improve egg shell quality.
authors.affiliation: Animal Research Centre, Agriculture Canada, Ottawa, Ontario.
authors.forename: C P
authors.initials: CP
authors.lastname: Tsang
authors.forename: A A
authors.initials: AA
authors.lastname: Grunder
authors.forename: J H
authors.initials: JH
authors.lastname: Soares
authors.forename: R
authors.initials: R
authors.lastname: Narbaitz
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000494:pharmacology*; D002645:Chickens / Q000502:physiology*; D004528:Egg Shell / Q000187:drug effects*; D005260:Female; D010058:Oviposition / Q000187:drug effects*; D011786:Quality Control
chemical_list: D002117:Calcitriol