Sex Reversal in Carp (Cyprinus carpio) by Oral Administration of Methyltestosterone

Abstract

Effects of oral administration of methyltestosterone on sex reversal from female to male in carp (Cyprinus carpio) was evaluated using all-female gynogenetic carp. Methyltestosterone supplemented in the diet at 100 μg/g for 36 d was tested at 20 and 25 °C and for varying times of initiation of treatment. The treatments induced partial and more complete sex reversal at 20 and 25 °C, respectively. At 20 °C hermaphrodites appeared frequently. At 25 °C, the most successful sex reversal occurred, particularly when methyltestosterone was administered starting 44 d and terminating 80 d after hatching.Key words: carp, all-female carp, sex reversal, gynogenesis, methyltestosterone, androgen treatment