Evaluation of the effects of dietary vitamin C, vitamin E and Zinc supplementation on growth and reproductive performances of rohu fish, Labeo rohita (Hamilton, 1822)

Abstract

Rohu fish (Labeo rohita, Hamilton1822) is a popular variety of carp fish species for its highly nourishing quality and prolonged freshness. An experiment was undertaken to evaluate the effects of dietary vitamin C, E and Zinc supplementation on Growth and Reproductive performances of Rohu fish, Labeo rohita (Hamilton, 1822) from 25 February, 2013 to 9 June, 2013 in the aquatic laboratory of Department of Fisheries, University of Dhaka. Use of vitamin C, vitamin E, Zinc (Zn) with different doses and locally available feed ingredients, like fish meal, soya cake, flour, mustard oil cake, salt, molasses and vitamin premix is a useful method of fish culture in the field of culture fishery. Proximate composition of the formulated fish feed and the experimental Rohu fish species has been determined as these factors influence the growth performances, feed utilization and reproductive performances of experimental fish during the rearing and feeding trial in the laboratory condition. Growth and reproductive performances using a formulated control feed, Feed A (without vitamin E, vitamin C and Zn) was compared with other three formulated fish feed titled as Feed B (100 mg/kg vitamin C and vitamin E with 10 mg/kg Zn in diet), Feed C (500mg/kg vitamin C and vitamin E with 10 mg/kg Zn in diet ) and Feed D (1000 mg/kg vitamin C and vitamin E with 10 mg/kg Zn in diet) in eight respective tanks of Feed A1 and Feed A2, Feed B1 and Feed B2, Feed C1 and Feed C2, Feed D1 and Feed D2. Each tank contained 10 numbers of adult Rohu fish (Labeo rohita, Hamilton1822). The average initial weight of Rohu fish (Labeo rohita, Hamilton1822) for Feed A (Control feed), Feed B, Feed C and Feed D was 225.26±0.05 g, 225.36±0.05 g, 225.47±0.07 g and 225.34±0.02 g respectively. Growth performances and survival rate were influenced by formulated feed types. Average final weights were 365.15±0.43 g, 375.9±0.03 g, 406.6±0.52 g and 381.93±0.20 g having an average daily gain (ADG, g/day) of 1.16±0.01, 1.25±0.01, 1.50±0.005 and 1.30±0.005 with a Specific growth rate (SGR, %) of 4.11±0.01, 4.17±0.01, 4.33±0.007 and 4.21±0.00 % in Feed A, Feed B, Feed C and Feed D respectively. The above results showed a typical increasing trend of final body weight gain and Specific growth rate (SGR) for the experimental fish species along with the increase of feed protein level for 120 days study period. There were significant differences (p<0.05) among Feed conversion ratio (FCR) and Protein efficiency ratio (PER). Significant differences (p<0.05) were also observed in case of Feed efficiency (%) and Survival rate (%) during the entire study period. Results of the current study suggest that the diet supplementation of 500 mg/kg vitamin E and vitamin C with additional 10 mg/kg Zinc has positive effects on the reproductive performance of experimental fish. The highest female GSI value (1.51±0.06%) was found for Feed C treatment while the lowest value (1.09±0.06%) was found for control treatment (Feed A).The maximum GSI value for male fish was (0.93±0.04%) which was found in Feed C treatment and the lowest value (0.39±0.05%) was found for Feed A treatment So, the study suggests that suitable protein level and sufficient amount of dietary vitamin C, E and Zinc supplementation is required for proper growth and successful reproduction of fish species.