الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The present study aimed to sex reverse of some genotypic female O. niloticus into phenotypic males after hatching by two experiment. The first reared in aquaria using different water temperatures (28°C the Control, 32°C, 34°C and 36°C). The aquaria were supplied with air pump and with a thermostat to adjust the water temperature. The experimental period was 30 days post hatching (W=0.008g/fish, L=0.6 cm/fish), Total number was 1200 fish (100 fish per aquaria) and fish were fed on the basal diet 40% crude protein at rate of 20% of the body weight and 12% of body weight for another 50 days at 28oC the final weight, male % and survival rate of fish indoor aquarium were recorded. Highly significant increase (P<0.0001) in final body weight, body length, and weight gain after 30 and 80 days was recorded in control group as compared with other treatments 32, 34 and 36°C, while, body weight of fry exposed to 36°C, decreased significantly after both 30 and 80 days when compared with fry in the control group (28°C). The mean survival rates of the fry reared at the treatment 36°C was significantly lower compared to the control groups after 30 and 80 days. The percentages of males reared over the first 30 days of exogenous feeding at 36, 34, 32 and 28°C were 80, 75.3, 70.3 and 52.3%, respectively. The second experiment fed diet containing 17α- methyltestosterone hormone and/or tamoxifen reared in hapas (1*1*1 m) suspended in concrete pond. The experiment contained 1800 fries at a yolk sac larvae stage and was distributed in 18 hapas, each hapa stocked with 100 fry and sex fed treatments (control, 200 mg Tamoxifen /kg diet, 100 mg Tamoxifen /kg diet, 60 mg (17α MT) hormone/kg diet, 30 mg (17α MT) hormone + 200 mg Tamoxifen /kg diet and 30 mg (17α MT) hormone + 100 mg Tamoxifen /kg diet. After sex reversal identify of the phenotypic sex of 50 fish from each hapa was determined by microscopic examination of the gonads when the fish reached 4 - 5cm length. Investigated the growth performance and survival rate of fry. The results of the second experiment indicated that highly significant differences in final body weight, body length, and weight gain between treated fish with 60 mg (17 α MT), tamoxifen 100 mg / kg diet and untreated fish (control) after 30 and 80 days. While, the survival rates decreased significantly for all treated groups with tamoxifen and 17α- methyltestosterone hormone. High male percentage (97.33 %) was obtained in groups treated with Hormone (17 α MT) followed by Tamoxifen 200 mg + 30 mg Hormone. It could be concluded that, using of tamoxifen 200 mg/kg diet and high temperature 36 for male sex reversal of Oreochromis niloticus fry better than hormone of 17α-methyltestosterone because it was the best and safety for human.