Effect of different levels of supplemented dietary Selenium nanoparticle and vitamin E on growth indices, survival and maturation in Convict cichlid fish (Amatitlania nigrofasciata)

Convict cichlid fish (Amatitlania nigrofasciata) of the most famous ornamental fresh water fish and one of the Cichlidae family which is native to Central America. In this experiment, 216 fry of Convict cichlid fish with average weight of 0.26±0.008g to martyr Nasser Fazli barabadi laboratories of Gorgan university of agricultural sciences & natural resources in six groups, include control group (no additives), one group (100 mg.kg-1 diet of vitamin E) , two group (0.1 mg.kg-1 diet of Nano Selenium ), three group (0.2 mg.kg-1 diet of Nano Selenium), four group (100 mg.kg-1 diet of vitamin E and 0.1 mg.kg -1 diet of Nano Selenium ) and five group (100 mg.kg-1 diet of vitamin E and 0.2 mg.kg-1 diet of Nano Selenium) were stored in triplicate. At the end of 85 days, some indices of growth, maturation and survival were evaluated. The Result showed that fish fed in groups of two and five better performance in terms of growth indices with other groups and the control groups respectively. The survival rate of the control group was not significant between groups ( P > 0.5 ). The results showed that fish fed rations number four showed better performance on some indicators of sexual maturation, so that the fishes of this group has maximum diameter of longitudinal and transverse ovum, maximum diameter of ovum yolk space, maximum diameter of longitudinal and transverse of green egg and maximum diameter of green egg yolk space are the most significant difference between the control group and other groups ( P < 0.5 ). It was also found that the minimum time of maturation and the highest percentage of hatching rate in the group one, which has significant difference with other treatments and the control ( P < 0.5 ). The results of this study found that diets supplemented with 100 mg of vitamin E in addition to 0.2 mg.kg-1 of diet Nano selenium, have better performance on growth indices of Convict cichlid fish which can be extended to other fishes of cichlid family including farmed tilapia. The results also showed that diet number four improved reproductive indicators (related to ovum and egg) in Convict cichlid fishes. Also feeding fish with diet of number one can strengthen the hatching percentage of larvae and the sexual maturity of Convict cichlid fish and other fishes of cichlid family, including tilapia farmed to be effective.