Poor semen quality is associated with impaired antioxidant response and acute phase proteins and is likely mediated by high cortisol levels in Brucella-seropositive dromedary camel bulls

Abstract

Brucellosis in dromedary camel bulls leads to either temporary or permanent loss of fertility. Camel brucellosis is associated with both orchitis and epididymitis. However, the clinical signs of camel brucellosis are not clear as those in cattle. Therefore, this study aimed to diagnose camel brucellosis based on a serological screening using Rose Bengal plate test (RBPT) followed by competitive ELISA. To understand the impact of brucellosis on camel bull fertility, this study aimed to examine the semen characteristics, evaluate the testicular histopathology, examine hormonal profile, antioxidants and acute phase proteins (APP). A total of 150 mature bulls were used in this study. Blood samples were collected for serological, hormonal, and biochemical analysis. This study revealed that 6.6% and 7.3% of the examined bulls were Brucella-seropositive using RBPT and competitive ELISA, respectively. The Brucella-seropositive dromedary bulls showed poor semen quality, pathological changes orchitis, and lower testosterone. Moreover, our findings showed a higher cortisol level, and significant impairments in the measured APP and antioxidants in Brucella-seropositive bulls. In conclusion, the Brucella-seropositive dromedary bulls showed lower fertility due to poor semen quality and lower testosterone levels. Such lower fertility is likely mediated by high cortisol levels, and impaired APP and antioxidants' defense response.

Keywords: Antioxidants; Brucellosis; Camels’ infectious disorders; Dromedary bulls infertility.

Fig. 1

Semen analysis of epididymal semen in both Brucella-seropositive and seronegative dromedary bulls. (a) Spermatozoa vitality (%). (b) Spermatozoa abnormalities (%). (**) means significant at < 0.01, (***) means significant at < 0.001.

Fig. 2

Serum levels of the measured steroid hormones in both Brucella-seropositive and Brucella-seronegative dromedary bulls. (a) Testosterone hormone concentration (ng/ml), (b) cortisol hormone concentration (ng/ml). (*) means significant at < 0.05.

Fig. 3

Representative images for the histopathological changes in the testes of a Brucella-seropositive dromedary bull showing subacute orchitis. (A) Widespread infiltration of inflammatory cells in the interstitial tissues (arrows), interstitial edema (arrowhead) and decreased size of seminiferous tubules (bended arrow). (B) Heavy infiltration of the interstitial tissue with inflammatory cells (asterisk) and degeneration of the epithelium lining of seminiferous tubules (arrow). (C) Heavy infiltration with inflammatory cells in the interstitial tissue with (asterisk) and in the lumen of seminiferous tubules (arrow). (D) Degeneration of germ cell layer (thin arrow), infiltration of macrophages (thick arrow), lymphocyte (bended arrow) and Neutrophils (arrowhead) in the lumen of seminiferous tubules. H&E stain.

Fig. 4

Representative images for the histopathological changes in the testes of a Brucella-seropositive dromedary bull showing chronic fibrosed orchitis. (A) Widespread interstitial fibrosis (asterisk) between atrophied seminiferous tubules (arrow). (B) Widespread interstitial fibrosis (asterisks) and atrophied seminiferous tubules with degeneration and necrosis of the lining epithelium (arrows). (C) Intensive fibrosis in the interstitial tissue (asterisks), peritubular fibrosis (arrowhead) and necrosis of tubular lining epithelium (arrows). (D) Peritubular fibrosis (arrowhead), necrosis of tubular lining epithelium (arrows) and lymphoid cells’ infiltration in the tubular lumen (bended arrow). H&E stain.