Histophysiological study of the testis in the Arabian carpet shark, Chiloscyllium arabicum, from the Persian Gulf during the reproductive and nonreproductive seasons

The present study aimed to assess the tissue structure and secretions of the male gonads in Arabian carpet shark, Chiloscyllium arabicum Gubanov, 1980 from the Persian Gulf during the spring and autumn. For this purpose, the tissue structure of the testis and the plasma level of testosterone were evaluated during autumn (August-November) and spring (April-June) seasons in C. arabicum. For this purpose, a total of 30 specimen of C. arabicum were caught at the Bahrakan Port, located at the Hendijan in the north of the Persian Gulf, seasonally. Fish were euthanized and blood samples were taken from caudal vein after biometrical tests and then, centrifuged for 10 min. Fish were dissected after bleeding and samples were taken from the testis and fixed in Bouin solution for 48h. Tissue sections were prepared using routine histological techniques and stained with hematoxylin and eosin. Stained tissue sections were studied under light microscope. The amount of testosterone was also measured in plasma samples. The results showed that, the testis of C. arabicum was lobulated and each lobol consisted of golobolar units called spermatocyst with various spermatogenic cells in different developmental stages such as spermatogonia, spermaytocytes and spermatids. Spermatocysts in seven developmental stages were observed in fish testis during spring season. Only spermatocysts in the first five stages of development were detected in the male fish during autumn.