Vitamin D Is Not an Essential Nutrient for Rora (Labeo rohita) as a Representative of Freshwater Fish.

Abstract

SummaryThis investigation was directed towards finding the need of vitamin D for fish. The freshwater column feeder fish Labeo rohita (Rora) was used for the study. Early fry stage fish were divided into four experimental groups of 350 each: two groups were kept in natural light, while the other two were maintained under total darkness. One each of the light and dark-grown groups was supplied dietary vitamin D3 [1,650 i.u/kg diet], whereas the other groups were fed a vitamin D-deficient diet for six months. The known vitamin D-related functions and growth parameters were studied in these four experimental groups of fish. The results showed that fish reared on vitamin D-deficient diet and in dark did not have even traces of liver vitamin D, indicating a state of vitamin D deficiency in these fish. No significant differences were observed in percent bone to body weight or dry matter of the vitamin D-deficient/ supplemented groups of fish grown in light/dark. Further, it was also observed that there were no significant changes in bone and carcass ash or calcium and phosphorus content in response to vitamin D3 sup plementation as compared to the groups which did not receive vitamin D3 (grown both in light and dark). Also, there was little change in several other parameters like carcass protein and lipid, mortality rates, hepatosomatic index, and feed efficiency between the vitamin D-deficient/ supplemented groups of fish. Thus, these findings suggest that vitamin D may not be an essential nutrient for Rora (Labeo rohita) as a representa tive of freshwater fish.

Vitamin D impacts on the intestinal health, immune status and metabolism in turbot (Scophthalmus maximus L.)

“…For example, the dietary VD 3 requirement of freshwater aquaculture species Wuchang bream (initial weight was 17.71 ± 0.22 g) was estimated to be around 5000 IU/kg by using the second-order polynomial regression model (Ref12). In contrast, no significant difference in Accepted manuscript the growth and body composition was detected when the 21-day-old fry of freshwater species Rora (Labeo rohita, initial weight was around 0.1 g), were fed with VD 3 deficient or 1,650 IU/kg VD 3 supplemented feeds (41) . Another report on orange-spotted grouper showed that whereas the maximum VD 3 concentration of Atlantic salmon (Salmo salar) diet reached 57,000 IU/kg (16) .…”

“…As predicted by the broken-line model based on the weight gain, the dietary VD 3 requirement of juvenile black carp (Mylopharyngodon piceus, initial weight 4•73 ± 0•13 g) and tilapia (initial weight around 0•80 g) was 534•2 IU/kg (41) and 374•8 IU/kg (42) , respectively. Surprisingly, no significant difference in the growth and body composition was detected when the 21-d-old fry of freshwater species Rora (Labeo rohita, initial weight around 0•1 g), were fed with VD 3 deficient or 1650 IU/kg VD 3 supplemented feeds (43) . In addition, the study on the marine fish orange-spotted grouper (initial weight 81•5 ± 0•1 g) showed that the optimum addition level of dietary VD 3 was 750•19 IU/kg estimated by the broken-line model based on WGR (13) .…”

The significance of vitamin D for fish: a review

“…In contrast to mammals, plasma 25(OH)D 3 values are not an important indicator of vitamin D 3 status in fish. In rora ( Labeo rohita ) fry (∼100 mg) fed a (supposed to be) vitamin D 3 and D 2 free diet for 180 days showed no signs reduced growth (Ashok et al . 1998, 1999).…”

Vitamin D3 and Its Metabolites Have No Role in Calcium and Phosphorus Metabolism in Tilapia mossambica.

“…It is shown by the lack of any effect of vitamin D3/metabolites (given at various doses) on the various parameters studied: (i) maintenance of serum calcium-phosphorus levels; (ii) stimulating intestinal calcium absorption; (iii) inducing whole-body 45Ca/32P uptake and (iv) gill CaBP activity. Our earlier studies in Rora (Labeo rohita) have shown that fish deficient in vitamin D (vitamin D-deficiency was judged by the absence of any detectable vitamin D in the liver of fish, grown in darkness and fed a diet devoid of vitamin D for six months) showed no significant differences in the vitamin D-related (bone and carcass mineral stores) and growth (carcass protein and lipid, hepatosomatic index, feed efficiency, and mortality rates) parameters when compared with the controls fed vitamin D3, suggesting that this vitamin may not be an essential nutrient for fishes (27). This observation is contrary to similar studies in terrestrial verte brates, where decreased calcification of bone and hypocalcemia is the classical manifestation of vitamin D deficiency (28)(29)(30).…”