Development of a model of excess fat soluble vitamins : a tool to study malformation of hatchery-raised fishes

Abstract

It has been suggested that fat soluble vitamins are involved in the occurrence of both skeletal and pigment disorders of fish. Since it was noted that fat soluble vitamins affected both skeletal and pigment development, a model for excess fat soluble vitamins was developed. The critical stages were demonstrated for the skeletal and pigment disorders of metamorphosing flounder by using the model. This study also suggested that the retinoic acid receptor pathway is a major pathway to induce skeletal deformity and that the inhibition of vitamin D receptor, pitx-2 and sonic hedgehog expression is concomitant with the occurrence of skeletal deformity. A previous study reported that feeding a diet containing excessive amounts of vitamin D_3 elevated the possible risk of hypermelanosis. Because feeding a diet including 1,25 (OH) vitamin D_3 promoted the occurrence of hypermelanosis, dietary vitamin D_3 possibly was metabolized into 1,25 (OH) vitamin D_3 and then promoted the occurrence of hypermelanosis.