Histological structure of oocyte and follicular cells in breeding season of Wrestling halfbeak fish, Dermogenys pusillus (Kuhl & van Hasselt, 1823) from Paknam Pranburi Estuary, Thailand

Abstract

Development of oocyte and follicular complex during breeding season of Wrestling halfbeak fish, Dermogenys pusillus was examined in 20 fish individuals with a total length of more than 16 cm from Paknam Pranburi Estuary, Thailand. The histological techniques were carried out with H&E, Periodic-Acid Schiff and Masson’s trichrome staining. The results revealed that the development of oocyte divided into two major stages including primary oogenesis and secondary oogenesis. The primary oogenesis consisted of three stages including one nucleolus, perinucleolar, and oil droplets and cortical alveoli stages. The secondary oogenesis divided into three stages including early secondary growth, late secondary growth, and full-grown oocyte steps. For the development of follicle, an appearance of follicles was firstly observed in the perinucleolar stage characterizing with simple squamous epithelium. The completed structure of the follicular complex was detected in oil droplets and cortical alveoli stage with comprising of thin zona radiata and follicular cells. This research provides a basis for further studies on the ultrastructure and reproductive cycle of this fish species.