Authors : S. Adamu , M.Y. Fatihu , N.M. Useh , N.D.G. Ibrahim , M. Mamman , V.O. Sekoni and K.A.N. Esievo
Abstract: In order to investigate whether testicular pathologic changes reported in trypanosome-infected animals are related to declining testosterone concentrations or not, four White Fulani bulls (infected group) with similar ages and weights were infected with Trypanosoma vivax (T. vivax), Kudaru stock, by inoculating each, intravenously, with 2 mL of blood from an infected donor calf containing 2�106 T. vivax organisms. Three other White Fulani bulls, with ages and weights similar to those of the infected group, which were uninfected, served as control group. Blood samples were collected from animals in the two groups before and after the infection to determine Packed Cell Volume (PCV) and serum testosterone profile. To carry out histopathological studies on the testes and other organs in the body of these animals, one bull from the infected group was sacrificed on day 14 Post-Infection (PI), while two bulls (one each from the infected and control groups) were sacrificed, each, on days 28, 56 and 84 PI. All animals in the infected group were parasitaemic by day 6 PI. This was followed by a gradual and progressive decrease in the values of Packed Cell Volume (PCV) and serum testosterone concentrations in these animals. PI values of these parameters in the control group remained normal relative to the pre-infection ones. The mean PI testosterone concentrations, measured in ng mL 1, in individual bulls of the infected group sacrificed on days 14, 28, 56 and 84 were 9.6±4.2, 7.8±3.7, 4.9±4.1 and 5.0±3.4, respectively. Histopathologically, severe testicular degeneration was observed in all animals in the infected group characterized by necrosis and depletion of the spermatogenic and sertoli cells in the seminiferous tubules. Leydig cells in the interstitial tissues of the testes were also severely degenerated. Severity of the lesions was related to serum testosterone concentrations as testicular degeneration was progressive from the bull that was sacrificed on day 14 PI moving through to the bull that was sacrificed on day 56 PI which had the least mean PI testosterone concentration and in which both spermatogenic and sertoli cells had undergone karyolysis and so were completely depleted. In contrast, testes of bulls in the control group were normal as both seminiferous tubules and interstitial tissues of the testes contained full complement of the spermatogenic and Leydig cells, respectively. It is concluded from this study that lowering testosterone concentration may be an aggravating factor to the degenerative changes observed in the testes of trypanosome-infected male animals.
S. Adamu , M.Y. Fatihu , N.M. Useh , N.D.G. Ibrahim , M. Mamman , V.O. Sekoni and K.A.N. Esievo , 2006. Testicular Pathologic Changes in Relation to Serum Concentrations of Testosterone in Trypanosoma Vivax-Infected White Fulani Bulls. Journal of Animal and Veterinary Advances, 5: 1165-1171.