Early gonadal development and sex differentiation in rosy barb (Puntius conchonius)

Abstract The main objective of this study was to describe the early gonadal development and to examine the process of sex differentiation in male and female P. conchonius under laboratory conditions. First evidence of primordial germ cells was observed on the day of hatching. The sex differentiation in leptotene, zygotene, pachytene and diplotene stages was clearly detected. Differentiation started from the mid-mid posterior part of the gonads. Actual sex differentiation occurred between 18-21 days and 36-40 days post-hatching in females and males, respectively. Histological sex differentiation differences were clear between males and females; in males, gonads had a smooth surface, were less stained, arrow-shaped, with germ cells located alone in the stroma, and number of germ cells ranging from two to ten per section, whereas in females, gonads had a rough surface, were more stained, wider, with germ cells multiplying rapidly and forming clusters, and number of germ cells ranged from 2 to 58 per section. The numbers of germ cells within the two gonad types were significantly different in favour of females (P < 0.05). Here early developmental stages of the gonads from 0 to 56 days post-hatch are explained.