~ 358 ~  International Journal of Fisheries and Aquatic Studies 2016; 4(1): 358-363  ISSN: 2347-5129 (ICV-Poland) Impact Value: 5.62  (GIF) Impact Factor: 0.352 IJFAS 2016; 4(1): 358-363 © 2016 IJFAS www.fisheriesjournal.com Received: 14-11-2015 Accepted: 16-12-2015 Indranath Ghosal Fish Endocrinology Research Unit, Department of Zoology, University of Calcutta, Kolkata. Debosree Mukherjee Fish Endocrinology Research Unit, Department of Zoology, University of Calcutta, Kolkata. Csaba Hancz Faculty of Agricultural and Environmental Sciences, Kaposvár University, Kaposvár, Hungary. Suman Bhusan Chakraborty Fish Endocrinology Research Unit, Department of Zoology, University of Calcutta, Kolkata. Correspondence Suman Bhusan Chakraborty Fish Endocrinology Research Unit, Department of Zoology, University of Calcutta, Kolkata. Production of monosex Nile tilapia, Oreochromis niloticus by dietary and immersion treatment with Basella alba leaves and Tribulus terrestris seeds Indranath Ghosal, Debosree Mukherjee, Csaba Hancz, Suman Bhusan Chakraborty Abstract In the present study mixed sex juveniles of Nile tilapia were subjected to dietary treatment with powdered Basella alba leaves and Tribulus terrestris seeds (0.0, 5.0, 10.0, 15.0 g/kg feed) and immersion treatment with aqueous extracts of both plant materials (0.05, 0.1, 0.15 g/l). There was no significant difference (P>0.05) in survival percentage among different treatment categories for both dietary and immersion experiments. Dietary treatment with both plant materials produced significantly higher percentage (P<0.05) of males compared to that of control. There was no significant difference (P>0.05) in male percentage between treatments with B. alba and T. terrestris during feeding and immersion experiments. For dietary treatment, the highest percentage of males (76.6±0.5) was observed with T. terrestris at the concentration of 15.0 g/kg, while treatment with T. terrestris aqueous extract at a concentration of 0.15 g/l showed the highest percentage of males (81.4±0.5) during immersion experiment. Keywords: Phytochemicals, Dietary treatment, Immersion treatment, Sex reversal, Methyl testosterone 1. Introduction The Nile tilapia, Oreochromis niloticus (Linnaeus) is a well-studied, fast-growing and widely cultured fish species. It is currently ranked second only to carps in global production and is likely to be the most important cultured fish in the 21 st century [1] . Rapid growth, high tolerance to low water quality, efficient food conversion, resistance to disease, ease of spawning and good consumer acceptance makes tilapia a suitable fish for culture [2] . Females of tilapiine species have a high fecundity, generally reproducing at a small size and exhibiting stunted somatic growth at higher densities, while male tilapias exhibit faster growth rates and are often the preferred gender for monosex aquaculture [3] . Synthetic steroids are commonly used to induce sex reversal in tilapia but because of the potential hazards of such steroids; the use of new chemicals is a potential alternative to be explored [4] . Plant extracts containing diverse bioactive principles such as alkaloids, flavonoids, pigments, phenolics, terpenoids, steroids and essential oils which have been reported to promote various activities like antistress, growth promotion, appetite stimulation, tonic and immunostimulation, and antimicrobial properties in fish culture [5, 6] . Phytochemicals are also reported to block biosynthesis as well as action of estrogen by acting as aromatase inhibitors and antagonists to nuclear estrogen receptor in gonad germ cells [7] and hence may be considered as potential mean for inducing sex reversal in fish. However, there are significant variations regarding the efficacy of different phytochemicals for production of all-male fish population and the potential anabolizing and virilizing effects of such plant extracts needs to be clearly documented. Aqueous and methanol extracts from the dry leaves of Basella alba, a fast growing vegetable, probably originating from India [8] , has been reported to possess active components that increase testosterone production in adult male rat testes during in vitro studies [9, 10] . This edible plant has been found to possess nutritional values including androgenicity in traditional medicines of several countries [11] . Moreover, few studies have indicated a positive effect of the methanol extract of B. alba leaves on sex reversal, growth and immunostimulation in Poecilia reticulata and O. niloticus [12, 13] . The herb, Tribulus terrestris has been reported to