SEX REVERSAL IN PIKEPERCH, Stizostedion lucioperca (L.), BY ORAL ADMINISTRATION OF METHYLTESTOSTERONE

Abstract

Oral administration of 17α-methyltestosterone (MT) was used to sex inverse juvenile pikeperch reared under intensive culture conditions (from D42 to D154). Fish (W=2.3 g) were stocked into six circular flow-through tanks (200 liters, 600 fish per tank).MTwas mixed into the feed in dose 30 mg/kg of the diet; the treatment and post-treatment phase lasted 21 and 90 days respectively. Administration of 30 mg MT/kg of the diet produced about 83.3% males and 10% females. Approximately 6.7% of all the examined pikeperch were classified as fish with abnormal gonads. In hormone treated group, no morphological changes were observed in the kidney, liver and skin. The hepato-somatic index (HSI) of androgen treated fish was not significantly different from the control (P>0.05). The analysis of variance showed that there were no significant differences in growth, condition factor and survival between the MT-treated group and the control, both in treatment (D63 - D84) and post-treatment (D85 - D154) phase (P>0.05).