Dynamics of the Posthatching Testicular Development in Japanese Quail (<i>Coturnix coturnix japonica</i>): Histological and Ultrastructural Study

The posthatching development of the testis is a well-organized process comprising the maturation of Sertoli cells, the development of Leydig cells, and the differentiation of germ cells. This study aimed to investigate the posthatching testicular development in the Japanese quail, using light and electron microscope. The current study was performed on 25 healthy Japanese quail chicks at 0, 7, 21, 40, and 50 posthatching days. The results revealed that the testis consists of solid seminiferous cords, and their lining epithelium is composed of two types of cells; immature Sertoli cells and gonocyte or spermatogonia at the early stage, which begins from the day of hatching till 21 days posthatching. The interstitium during this period consisted of different developmental stages of the Leydig cells. However, at the late posthatching developmental stage the testis is characterized by the presence of round and elongated spermatids as well as the initiation of spermiogenesis. The interstitial compartment also showed an increase in the number and size of Leydig cells. The findings of the current study provide comprehensive insights into the posthatching development of the Japanese quail testis, contributing to the understanding of avian reproduction.