On the Testicular Structures Found in the Ovaries of the “Cobalt” Rainbow Trout

Abstract

Testicular structures were detected in the ovaries of two specimens of the “cobal” rainbow trout, obtained at the Shiga Prefectural Samegai Trout Experimental Station on July 25, 1973. In the ovary of one specimen (fish No. 3), the testicular cysts were occasionally detectable, and the cysts were filled with spermatogonia, spermatocytes and spermatids. Furthermore, in some cysts oocytes were intermingled with male germ cells in various spermatogenic stages. In the other specimen (fish No. 4), testicular structure was detected also, but only in one limited region of a histological preparation of the ovary. In all the three “cobalt” examined, ovarian germ layers were conspicuously hypertrophied and com-posed of many gonial germ cells.