In this paper

we concentrated on masculinization of larvae Nile Tilapia（Oreochromis niloticus）by immersion the larvae in androgens MT（17α-methyltestosterone）or MDHT（17α-methyldihydrotestosterone）. The three factors were considered: treatment period（1

7

13 DPH

Days Post Hatching）

hormone dose（200

600

1 800

5 400 μg·L

-1

）

and treatment duration（2

4

8 h）. All these three factors were taken into account by simple comparison orthogonal experimental design. The main results are as follows: the 7 DPH larvae induced by MT at a dose of 600 μg·L

-1

 with 4 h treatment duration is the best result of masculinization

male rate is 98.81%

while at a dose of 1 800 μg·L

-1

or 5 400 μg·L

-1



male rate greatly decreased（P＜0.05）; 600 μg·L

-1

 or 1 800 μg·L

-1

dose of MDHT present the best results of masculinization

male rate is 98.34% and 98.39% respectively

at a dose of 200 μg·L

-1

or 5 400 μg·L

-1



male rate are not significantly decreased（P＞0.05） When 7 DPH larvae were induced by MT at a dose of 600 μg·L

-1



4 h is the best treatment duration

8 h presents greatly decreased result（P＜0.05）; When MDHT was used

three treatment durations（2

4

8 h）got consistent results（P＞0.05）. The conclusion is that MT and MDHT can both achieve masculinization goals for application of production

but MDHT is more stable and show a better application value.