Histological Studies on Gonad and Germ Cell Development of Diploid and Triploid Mud Loach (Misgurnus mizolepis)

A Study was conducted by using a histological method to examine gonadal development in diploid and triploid mud loach, Misgurnus mizolepis. Shape of ovaries from both groups looked like a single mass however, size of triploid ovary was significantly smaller than that of diploid ovary. Testis of triploid was also similar that of diploid in shape, but it was smaller than that of diploid. Ovarian development and oogenesis in diploid were significantly more rapid than those process in triploid, and first matured eggs were observed 100-days after hatching (SL, 5.68cm). Triploid ovary from hatching to 9-month-old had external appearance of undeveloped gonad and a few of oocytes of perinucleolus stage. However, normal matured eggs like those of female diploid were observed in one 5year-old triploid fish ovary examined. Although testicular development and sperrnatogenesis of diploid were prosperous sexually, testicular development of triploid were rather retarded compare to their male diploid counterpart in spermatogenesis.