Authors : J.S. Ruwaan, P.I. Rekwot, P.A. Abdu, B.O. Omontese, J.A. Obidi and N.P. Chiezey
Abstract: About fifty 20 weeks old Shika Brown (SB) cocks were used in this study. Five cocks consisting of three Red Shika-Brown (RSB) and two White Shika-Brown (WSB) were bled for serum samples for testosterone assay at weeks 1, 3 and 6 pre and post-infection with a Velogenic Newcastle disease virus. Blood samples were collected at 30 min interval for 3 h from each cock on the days of sampling. The blood samples were centrifuged in a Hermle Z364 centrifuge at 251.6x g for 15 min with the sera obtained stored in serum vials and kept in a deep freezer at -20°C until analysis using the Enzyme Linked Immunosorbent Assay (ELISA) technique. At the end of the study, twenty control (n = 20) and twenty infected (n = 20) cocks were slaughtered. Their testicles were removed, measured, minced and ground for the determination of gonadal sperm reserves. The mean testosterone concentration of both the control SB cocks and the pre-infected SB cocks had no particular pattern. The mean testosterone concentration post infection showed a decrease from week 1-6. The mean testosterone concentration peak for the control red SB cocks was 1, 2 and 2.5 nmols mL-1 at weeks 1, 3 and 6, respectively while the white SB cocks had 12.5, 5.5, 3 nmols mL-1 at weeks 1, 3 and 6, respectively. The infected red SB cocks had mean testosterone concentration peaks of 9.7, 6.3 and 2.7 nmols mL-1 at weeks 1, 3 and 6 post-infection, respectively while the white SB cocks had a mean testosterone concentration peak of 6.5, 14.5 and 6.5 nmols mL-1 at weeks 1, 3 and 6 post-infection, respectively. The gonadal sperm reserves of the control red and white SB cocks were not significantly different but the gonadal sperm reserves of the control white SB cocks was significantly (p>0.05) higher than the gonadal sperm reserves of the infected red and white SB cocks. The total gonadal sperm reserve of the control white cocks was significantly (p>0.05) higher than the total gonadal sperm reserves of the infected red and white SB cocks.
J.S. Ruwaan, P.I. Rekwot, P.A. Abdu, B.O. Omontese, J.A. Obidi and N.P. Chiezey, 2010. Effect of a Velogenic Newcastle Disease Virus on Testosterone Concentration and Gonadal Sperm Reserves of Vaccinated Shikabrown Cocks. Research Journal of Poultry Sciences, 3: 48-53.