Evaluation of Tribulus terrestris Powdered Seed as Androgenic Agent for Production of All Male Red-Belly Tilapia, Coptodon zillii (Gervais 1848)
Keywords:Sex reversal, Tribulus terrestris, Coptodon zillii.
The study investigated the effect of dietary doses of Tribulus terrestris on the sex reversal and production of Coptodon zillii fry. A total of two hundred and seventy (270) three days old apparent healthy fry of C. zillii (mean weight 0.03 ± 0.0g) were randomly selected and distributed 3 into 18 glass tanks (70x45x45 cm ) at 15 fish per tank representing five treatments in triplicate to contain T. terrestris at different inclusion levels of 0.00 (negative control), 10.0, 15.0, 20.0 and 25.0g/kg T. terrestris seeds powder basal diet and labelled (T1-T5). Areference diet contain 0.06 g/kg of basal diet of 17á methyltestosterone (MT) was also formulated as positive control and labelled (T6). At the end of the experiment, final growth weights were recorded and the carcass composition determined. Gonad squashing method involving aceto-carmine staining was used to determine the sex of the fish. Results indicated that dietary treatment with powdered T. terrestris seeds and MT at different concentrations showed no significant difference (P>0.05) in survival percentage compared to that in control group, and growth parameters were better in fish fed T. terrestris and MT treated groups than in the fish fed T1. The highest weight gain was recorded in fish in T4 while the least value was observed in fish fed control diet. All fish fed diet containing T. terrestris and MT treated groups had significantly higher male proportion than untreated group (36.2%). The percentage of male (78.5%) population in T. terrestristreatments in this study was significantly lower than MTtreated group (92.1%) and significantly higher than untreated group. Carcass protein decreased with increasing levels of T. terrestris in the diet. The study indicated that T. terrestris seed powder might be used as a potential alternative to synthetic steroid for production of all male tilapia population.