Effects Of Exogenous GnRH Stimulation On Testicular Spermatogenesis And Characteristics Of The West African Dwarf Buck

Abstract

The testis in male domestic animals has two primary functions: spermatogenesis and steroidogenesis, coordinated by testicular cells  under GnRH control. This study examined the features of the testes of the bucks of the West African dwarf breed to assess the effects of  additional GnRH-stimulated levels of FSH, LH, T, and estradiol from 3 to 12 months of age. Twelve 3-month-old bucks were divided in a  random manner into GnRH-treated (n = 6) and control (n = 6) groups. Monthly, bucks were weighed, their testicular diameter measured,  and two blood samples taken (n = 12) at a 1-hour interval to establish peripheral concentrations. The GnRH-treated group received 0.5μg/ kg of GnRH intramuscularly the next day, while the control group received saline subcutaneously. Blood samples were taken 1 and 2  hours later to establish GnRH-stimulated levels. At 12 months, bucks were castrated, and testes were weighed and prepared for histological analysis. Testes diameters showed no significant difference (p<0.05): 24.52±0.43 mm (GnRHtreated group) and 25.92±0.45  mm (control group). However, yearling testicular mass differed significantly (p<0.05): 41.50±5.80g (GnRH-treated group) and 38.80±7.58g  (control group). The number and make-up of seminiferous tubular cells (cells of Sertoli, germ cells in the form of spermatogonia,  developing into spermatocytes, further maturing into spermatids, and ultimately forming spermatozoa) indicated increased spermatogenesis in the GnRH-treated group. It is concluded that GnRH super-stimulation increased spermatozoa production in the West  African dwarf buck.