Evaluation of antioxidant status, oxidative stress and serum trace mineral levels associated with Babesia ovis parasitemia in sheep.

Ovine babesiosis is a fatal disease characterized by severe progressive hemolytic anemia. In order to clarify the causal mechanisms implicated in anemia, this study was aimed to assess the antioxidant status and erythrocyte oxidative stress in sheep suffering from ovine babesiosis. Babesia infection was confirmed both with Giemsa's staining blood smears and semi-nested PCR amplified region of 18S rRNA gene. Thirty-eight Iranian sheep, naturally infected with Babesia spp., were considered as the infected group and divided into four subgroups according to parasitemia rates (<1%, 1-2%, 2-3% and >3%), and the same number non-infected animals were selected as the control group. Blood samples were taken and hematological parameters, activities of antioxidant enzymes including erythrocyte glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), glucose-6-phosphate dehydrogenase (G6PD), total antioxidant capacity (TAC), median corpuscular fragility (MCF), and serum concentrations of some trace minerals (copper, iron, zinc, manganese, and selenium) were measured. In addition, as an index of lipid peroxidation, the level of malondialdehyde (MDA) was measured. The results revealed a significant decrease (P<0.01) in RBC count, packed cell volume (PCV) and Hb concentration as well as the activities of erythrocyte GSH-Px, SOD, CAT, G6PD, TAC, MCF and serum concentrations of Cu, Zn, Mn and Se in the infected sheep. In contrast, significantly increased (P<0.01) levels of MDA and erythrocyte osmotic fragility as well as serum concentration of iron were recorded in the infected animals. Overall, the observed remarkable decrease in the antioxidant enzyme activities, median corpuscular fragility and substantial elevated levels of lipid peroxidation associated with the notable increase in parasitemia indicate high exposure of RBCs to oxidative damage in Babesia infected sheep. These results indicate that the disturbed antioxidant defense mechanisms in ovine babesiosis can promote the development of anemia.