Sex Reversal in Carp (<i>Cyprinus carpio</i>) 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