RESUMO
Caprine coccidiosis, caused by coccidian parasites from genus Eimeria, is considered as one of the most common and significant diseases in goats worldwide. The aim of this experiment was to investigate the responses of the enzymatic antioxidant systems during experimental coccidiosis. For this purpose, 20 newborn kids were selected. Ten were infected with sporulated oocysts of the most pathogenic species of Eimeria, and the remainder served as the control. Blood samples were taken at 0 (before inoculation), 3, 7, 14, 21, 28, and 35 days post-infection (dpi), and antioxidant-oxidant-related parameters were measured. Our data showed that the activities of the main erythrocyte antioxidant enzymes revealed significant declines at 7 dpi. These decreases were more evident at 14 to 21 dpi and then gradually enhanced to the normal values until 35 dpi; however, total antioxidant capacity revealed a remarkable decrease at 7 dpi and remained on the same level toward the end of the study. By contrast, serum levels of malondialdehyde (a biomarker of lipid peroxidation) and total homocysteine significantly increased at 21 and 14, 21, and 28 dpi, respectively. These observations suggest that caprine coccidiosis can impair the major antioxidant systems leading to remarkable oxidative damages during the infection. Furthermore, oxidative injuries could have a considerable linkage to the pathogenesis of Eimeria parasites.