Comparative Morphological Studies on Testes and Seminal Vesicles of African Catfish (Clarias gariepinus) and Nile Tilapia (Tilapia nilotica)

Abstract

Comparative morphological studies on the testes and seminal vesicles in African catfish and Nile Tilapia were conducted with the aim of comparing morphological and their architectural differences using anatomical, histological and biometric techniques. A total of the 50 fishes comprising of 25 African catfish and 25 Nile Tilapia fishes were captured and used, their live bodyweights and standard body lengths of the fish were measured using weighing balance in grams (g) and Tape rule in centimeter (cm), respectively. Thereafter, a midline incision was made on the ventral surface of the abdominal column. The positions of the organs were carefully examined in situ with representative samples of each of the testes and the seminal vesicle taken for routine histological evaluations with histomorphometry of the spermatozoa structural index assessment. The findings of this work showed that, the testicular structure and seminal vesicles of both African catfish (Clarias gariepinus) and Nile tilapia (Tilapia nilotica) are morphologically different in sizes, shapes and weight but have some similarities in their colors and locations. The testicular lengths of the African catfish were longer than that of the Nile tilapia (p<0.05). However, the spermatozoa structural index did not differ statistically even though there was higher is catfish when compared with tilapia with exception of the spermatozoa tail length. Therefore, apart from the contribution of the present study to the knowledge of comparative anatomy in these species of fish, it has equally put forward a baseline data for further comparative studies on the testicular and seminal vesicular morphology in these species.