Preliminary report on the age-related variations in the serum and seminal plasma testosterone, seminal plasma biochemistry and seminal vesicle histochemistry of male broodstock African catfish (Clarias gariepinus)

This study investigated the age-related changes in the concentrations of serum testosterone and seminal plasma testosterone, ions, total protein, glucose concentrations and alkaline phosphatase (AP), amino aspartate transferase (AST) activities and the periodic acid Schiff-Alcian blue histochemistry of the seminal vesicle of cultured male broodstock African catfish of 6, 9 and 12 months of age. Each of these months constituted an age group and had five fish. The mean seminal plasma testosterone concentrations of the 6 months-age group were significantly higher (P < 0.05) than that of the other age groups. The 9 months-age group had significantly higher (P < 0.05) values for calcium and magnesium ions, AP and AST. There were no significant variations (P > 0.05) in the values of serum testosterone, seminal plasma cholesterol, sodium and chloride ions across the groups. The seminal plasma potassium ion, total protein and pH values were significantly higher (P < 0.05) in the 12, 9 and 6 months-age groups respectively. The seminal plasma potassium ion of the 12-month-old fish was significantly (P < 0.05) higher than those of others, while the total protein of the 9-month old was significantly higher (P < 0.05) than those of other groups, and the pH of the 6-month old was significantly higher than those of other age groups. There was no significant variation in the values of the different parameters of the seminal plasma of the left and right testes. The seminal vesicles of the different age groups showed the presence of mucopolysacharides and neutral polysaccharides in varying staining intensities. It was therefore concluded that 9-month-old male catfish may be the most suitable for spawning.