title: The biological activity of 25-hydroxycholecalciferol and 1,25--dihydroxycholecalciferol for rainbow trout (Salmo gairdneri).
abstract: Dietary 25-hydroxycholecalciferol (25-hydroxycholecalciferol (25-OH-D3) and 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] showed vitamin D activity in rainbow trout. However, inclusion of dietary cholecalciferol (vitamin D3 or D3), ergocalciferol (vitamin D2 or D2), 25-OH-D3 or 1,25-(OH)2D3 did not result in the presence of detectable levels of vitamin D or 25-OH-D in the blood plasma of the fish. Fish fed the diet devoid of vitamin D over an extended period of time showed symptoms of a droopy-tail or "lordosis-like" syndrome that appeared to be related to muscle weakness since x-ray examination indicated no abnormality in vertebral development. The requirement for vitamin D as cholecalciferol was in excess of 1600 IU/kg diet and may be as high as, or higher than 2400 IU/kg diet.
mesh_terms: D000818:Animals; D001823:Body Composition / Q000187:drug effects; D002112:Calcifediol / Q000494:pharmacology*; D002117:Calcitriol / Q000494:pharmacology*; D002762:Cholecalciferol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004872:Ergocalciferols / Q000494:pharmacology; D006887:Hydroxycholecalciferols / Q000097:blood; D009751:Nutritional Requirements; D012487:Salmonidae / Q000502:physiology*; D013746:Tetany / Q000378:metabolism; D014337:Trout / Q000254:growth & development / Q000502:physiology*; D014807:Vitamin D / Q000378:metabolism*
chemical_list: D004872:Ergocalciferols; D006887:Hydroxycholecalciferols; D014807:Vitamin D; D002762:Cholecalciferol; D002117:Calcitriol; D002112:Calcifediol