The optimum dose and period of synthetic hormones 17-α methyltestosterone during fry stage on masculinization of Siamese fighting fish (Betta splendens)

Abstract

The objective in study aims to develop the production of a mono-sex population of all male Siamese fighting fish (Betta splendens) by using 17α-methyltestosterone (17α-MT). Five treatments contained in a control of, MT-20, MT-40, MT-60 and MT-100 in triplicates. The study for two periods, supplemented diet with 17α-MT experimental diet for 30 days (4 –34 days after hatching (dah), Period-I) and for 45 days (4 – 49 dah, Period-II). Experiments were set up using completely randomized design (CRD). The control group diet without the use of 17α–MT. The remaining groups MT-20, MT-40, MT-60 and MT-100 were fed with feed containing 20, 40, 60 and 100 mg kg-1 of 17α –MT. Four days old fry were stocked at the rate of 100 fry per tank (Period-I and Period-II). The fry fish with oral administration at first feeding was successfully carried out at four dah. Fish were fed with the experimental diet for two periods (Period-I and Period-II). Gonadal characteristic from Period-I and Period-II reared B. splendens for sex reversal was observed. The highest male population was produced from MT - 60 and MT - 100 mg kg-1 in Period-II. Also demonstrated, there were no significant differences in the survival rates among the experimental groups.In conclusion, the masculinizations of all males were produced from Period-II treatment group 60 and 100 mg kg -1 of 17α-MT successfully produced all-male stocks in Siamese fighting fish.

Keywords

• betta splendens
• siamese fighting fish
• sex reversal
• 17 alpha methyltestosterone