ABSTRACT
The present study was aimed to evaluate the efficacy of Basella alba and Tribulus terrestris for induction of masculinisation in Nile tilpia. B. alba leaves and T. terrestris seeds were extracted with water, ethanol, methanol, dichloromethane, hexane and successive methanol and mixed sex juveniles of Nile tilapia were subjected to dietary treatment with the extracts at the concentration of 0.5, 1.0 and 1.5 gm/kg feed. Treatment with both the plants showed no adverse effect on general fish health. There was no significant interaction effects (P>0.05) of solvent and concentration, and solvent and plant material for percentage of males. But, significant interaction effect (P<0.05) of concentration and plant material was observed for percentage of males. Also, there was significant interaction effect (P<0.05) of solvent, concentration and plant material for percentage of males. For dietary administration of B. alba leaves, the highest percentage of males (83.2±0.7) was obtained by treatment with ethanol extract at the concentration of 1.0 gm/kg feed. For all the solvents, the highest percentage of males was observed at the concentration of 1.0 gm/kg. But, in treatment with T. terrestris seeds, the highest percentage of males (88.9±1.1) was obtained with ethanol extract at the concentration of 1.5 gm/kg feed, which was also the highest percentage of males for all the treatment categories.
ABSTRACT
The effects of different anti-estrogenic chemicals were evaluated in guppy, Poecilia reticulata on sex differentiation and survival. New-born fry of the fish were fed diets containing genistein (1 gm kg-1), tamoxifen (100 mg kg-1), methanol extract of Basella alba (1 gm kg-1) and 17α-methyltestosterone (60 mg kg-1) for 30 days. The treated groups showed no significant difference (P>0.05) in survival percentage while a significant increase (P<0.05) in percentage of males were observed in all the treatment groups compared to that in control. Control fish showed the lowest percentage (44.49%) of males while 17α-methyltestosterone treatment provided maximum (81.90%) males, followed by tamoxifen (80.09%), genistein (70.59%) and B. alba (63.55%). Intersex fish with male like colouration and gonopodium development, but female gonad structure was observed in all the treated groups. The nonsteroidal compounds evaluated in this study showed potential for affecting sex ratios although their potency was lower compared to 17α-methyltestosterone. Further studies are needed to determine an optimum treatment regime with these agents for induction of 100% sex reversal in guppy.