Effects of the prebiotic Inuline on functional of reproduction, gonad development, fecundity and sex ratio in Danio rerio

The use of probiotics and prebiotics for increasing the growth and resistance against disease are well documented in aquaculture but work on the effects of probiotics and prebiotics on the reproductive performance of fish, especially on ornamental fish, are lacking. We conducted a study to determine the effects of probiotic on gonad development, reproductive performance of Danio rerio. In this study, a diet based on a control diet (T0) and three experimental diets consisted of three levels of inulin: 1 (T1), 2 (T2) and 3 (T3) and these treatments were done with three replicated. The juveniles were fed experimental diets for eight weeks (until adulthood: average weight: 1.67 gr, average length: 5.4 cm). In this experiment reproductive performance in terms of egg diameter, absolute fecundity, sex ratio, gonadosomatic index, number of larvae, survival of juveniles and gonad development were examined. The results showed that probiotic treatments, reproductive performance including egg diameter, survival larvae, absolute fecundity, Gonadosomatic Index, length and weight of larvae in treatment T2 and T3 were significantly higher than other treatments (P <0.05). Also the results showed that the prebiotic inulin does not have a significant impact on the sex ratio in zebrafish (P> 0.05). According to the histology of the gonads, the use of dietary inulin accelerates the process of gonad development in zebrafish.