Effect of using plant - Rosa-sinensis' extracts and Methyltestosterone in a fry diet for Oreochromis niloticus (L.)'s growth, survival and sex ratio

The effectiveness of plant extracts (PE) and Methyltestosterone (MI) for male production and growth promotion in Oreochromis niloticus were studied in concrete tanks for 60 days. Fry were fed at two feeding levels, initially 20% and later 10% of body weight dally with diet treated with 60mg/kg. Tilapia treated with MT for 60 days attained an average weight of 10.13~c1.32g, those treated with PE attained an average weight of 11.15~c0.55g compared to 6.95~c0.32g for untreated (control) fish reared under similar conditions. The percentage of males among the untreated tilapia was 39.28%, 68.75% for PE fed tilapia, more than 88.88% of the tilapia in MT treatment group were male. The experiments demonstrated that the anabolic and sex reversal effects of MT on tilapia are proportional to the duration of treatment and quantity of hormone administered Histological sections of the testes of fry fed MT and P E diets showed deformed, clustered, swollen nuclei. Higher concentrations of MT and PE can be used to control prolific breeding and increase yield in fish production