Sex inversion in gynogenetic carp (Cyprinus carpio L.) females

Abstract

Physiological sex was changed in gynogenetic carp females by feeding the fish between 40th and 80th day of life with the feed containing 100 ppm methyltestosterone. The feed was given ad libitum. At the age of 21 months the control group composed of gynogenetic fish contained only females. In the group fed diets supplemented with hormone, one of the five dissected fish possessed weakly developed female gonads, two did not develop gonads to the extent enabling sex determination, and two had properly developed male gonads. Ten fish were used for reproduction. From among these, five yielded from 0.5 to 27 ml of sperm.