VITAMIN-D IS NOT AN ESSENTIAL NUTRIENT FOR RORA (LABEO-ROHITA) AS A REPRESENTATIVE OF FRESH-WATER FISH

This investigation was directed towards finding the need of vitamin D for fish. The freshwater column feeder fish Labeo rohita (Rora) was us ed for the study. Early fry stage fish were divided into four experime ntal groups of 350 each: two groups were kept in natural light, while the other two were maintained under total darkness. One each of the li ght and dark-grown groups was supplied dietary vitamin D, [1,650 i.u/k g diet], whereas the other groups were fed a vitamin D-deficient diet for six months. The known vitamin D-related functions and growth param eters were studied in these four experimental groups of fish. The resu lts showed that fish reared on vitamin D-deficient diet and in dark di d not have even traces of liver vitamin D, indicating a state of vitam in D deficiency in these fish, No significant differencestvere observe d in percent bone to body weight or dry matter of the vitamin D-defici ent/supplemented groups of fish grown in light/dark. Further, it was a lso observed that there were no significant changes in bone and carcas s ash or calcium and phosphorus content in response to vitamin D, supp lementation as compared to the groups which did not receive vitamin D, (grown both in light and dark). Also, there was little change in seve ral other parameters like carcass protein and lipid, mortality rates, hepatosomatic index, and feed efficiency between the vitamin D-deficie nt/supplemented groups of fish. Thus, these findings suggest that vita min D may not be an essential nutrient for Rora (Labeo rohita) as a re presentative of freshwater fish.