Ovine malignant theileriosis: The status of antioxidant vitamins, serum lipid profile, lipid peroxidation and erythrocyte antioxidant defense

Abstract

In order to investigate more aspects of the erythrocytic antioxidant defense and the lipid content of the serum during ovine malignant theileriosis, 50 Iranian fat-tailed sheep, about 1–2 years old, naturally infected with Theileria lestoquardi, were selected and divided into three subgroups according to their parasitemia rates (< 1%, 1–3%, 3–5%). Also, ten non-infected sheep served as controls. Blood samples were collected, and hematological parameters, the activities of antioxidant enzymes including superoxide dismutase (SOD), gluthatione peroxidase (GPX) and catalase, osmotic fragility of the RBCs, the level of malondialdehyde (MDA) as an index of lipid peroxidation, phosphatidylserine, antioxidant vitamins (A, E and C) and the concentrations of serum lipid composition (cholesterol, triglyceride and lipoproteins including HDL, LDL and VLDL cholesterol) were measured. A significant decline in the activities of antioxidant enzymes and also remarkable increases in the concentration of MDA, osmotic fragility and phosphatidylserine were evident in infected sheep, along with significant correlations with the hematological parameters. The results showed that the antioxidant agents could be important factors in the prevention of erythrocytic membrane damage during parasitemia. In addition, the unaltered level of antioxidant vitamins in the infected animals showed that such vitamins did not elicit effective responses to the oxidative damages. The level of the major lipid components of the serum remained unchanged during infection, which implied that the infection with T. lestoquardi did not induce important changes in lipid metabolism, and these components are unlikely to have a major role in the process of anemia. In conclusion, the antioxidant defense of the RBCs has a considerable role to prevent the occurrence of anemia in malignant ovine theileriosis.