Effect of human menopausal gonadotropin on testicular morphometry, gonadal and extragonadal sperm reserves of rabbit bucks

<p>Testicular morphometry, gonadal and extragonadal sperm reserves of rabbit bucks treated with Human Menopausal Gonadotrophin (Menogon®) were studied. Twenty-four crossbred rabbit bucks weighing 1.3-1.6 kg at 15-17 wk were randomised into 4 treatment doses of 0 (control), 7.5, 15.0, and 22.5 I.U. in a completely randomised design with 6 bucks per group. A vial of Menogon® was reconstituted in 1 mL of physiological saline solution and administered intramuscularly at 72 h intervals for 56 d prior to commencement of sample collection. Parameters evaluated were ejaculate concentration, testicular morphometry, gonadal and extragonadal sperm concentrations. Results for ejaculate concentration (86, 110, 186, and 135×106/mm3) revealed a significantly (P&lt;0.05) higher difference in the 15.0 I.U. group. Gonadal and extragonadal sperm reserve indices were not significantly (P&gt;0.05) affected by the treatment. Testicular morphometry results showed that paired testis volume (cm3), testis circumference (cm), ductus deferens length (cm) and epididymal length (cm) were significantly (P&lt;0.05) different, with a progressive increase that corresponds to increased Menogon® administration. High and positive correlations (P&lt;0.01) were observed between testis weight and gonadal sperm reserves (r=0.99) and body weight and gonadal sperm reserves (r=0.99). Similarly, correlations between epididymal weight and epididymal sperm reserves (r=0.85), testis weight and ejaculate concentration (r=0.97), body weight and ejaculate concentration (r=0.96), body weight and testis weight (r=0.97), testis volume and ejaculate concentration (r=0.97), testis volume and gonadal sperm reserve (r=0.91), testis volume and testis weight (r=0.96), and testis volume and body weight (r=0.90) were positive and significant (P&lt;0.05). Taking all the reported results into consideration, controlling the amount of Menogon® administration at 15.0 I.U. for rabbit bucks could be a promising approach to regulating testosterone synthesis and secretion, thereby affording a potential method of enhancing fertility.</p>