LIGHT MICROSCOPIC STUDIES ON THE TESTIS OF THE COMMON COOT (FULICA ATRA)

Abstract

The testis of the common coot was examined histologically and histochemically to establish baseline reproductive characteristics. The birds were dissected and testes were located in the abdominal region The testicular tissue were removed, washed and sliced into small pieces and fixed in 10% neutral buffered formalin and were processed. Using a semiautomatic microtome, paraffin sections of 5–6 µm thickness were cut and later subjected to histological analysis. The  testis was enclosed by a tunica albuginea composed of collagen and smooth muscle fibers, with an outer tunica serosa and an inner tunica vasculosa. Seminiferous tubules were irregularly distributed throughout the parenchyma. The germinal epithelium of the tubules contained two types of spermatogonia, primary and secondary spermatocytes, three stages of spermatids, and Sertoli cells. Myoid cells were observed in the peritubular region, while Leydig cells occupied the interstitial connective tissue. Masson’s Trichrome staining demonstrated collagen fibers in the capsule, septa, and peritubular regions. PAS–Alcian Blue staining showed moderate to strong positivity for neutral mucopolysaccharides in testicular tissues. These findings enhance understanding of the gonadal tissue in avian reproductive biology.