Possibilities to raise vitamin D content of rainbow trout (Oncorhynchus mykiss) by elevated feed cholecalciferol contents

Farmed rainbow trout (Oncorhynchus mykiss) is a widely consumed fish specie s. The cholecalciferol content in the muscle of rainbow trout is, however, quite low compared with that in several wild fish species. The present stud y was designed to determine whether it is possible to increase the cholecal ciferol content of rainbow trout (initial weight about 500 g) with the use of cholecalciferol-dosed feeds. Three different cholecalciferol concentrati ons (8.9, 17.4 and 53.9 mu g 100 g(-1) feed) were tested. After 4 months of feeding, the cholecalciferol determinations from samples of muscle and liv er were performed using an HPLC method. Here, we suggest that the cholecalc iferol content of rainbow trout muscle cannot be increased by feeding them with elevated doses of the vitamin. (C) 1999 Society of Chemical Industry.