Institution: | aNational Institute of Nutrition and Seafood Research (NIFES), P.O. Box 176, Sentrum, N-5804 Bergen, Norway bDepartment of Fisheries and Marine Biology, High Technology Centre, University of Bergen, N-5020 Bergen, Norway cDepartment of Pediatrics, Haukeland Hospital, Bergen, Norway |
Abstract: | Plasma vitamin D and vitamin D metabolites were measured in Atlantic salmon parr during smoltification and after transfer to seawater. The fish were fed commercial feed for 5 months under natural light, and Na+/K+ ATPase was measured as an indicator of the smoltification status. No significant differences were recorded in the level of plasma vitamin D metabolites. However, a tendency of increasing plasma concentration of 25OHD3 and also a temporary increase in plasma 1,25(OH)2D3 and 24,25(OH)2D3 were recorded prior to seawater transfer. The minor changes in plasma levels of the metabolites indicate a role of the vitamin D metabolites during parr–smolt transformation, although we do not know whether the increased levels are caused by increased synthesis of the metabolites or by decreased binding to receptors or decreased excretion. |