Abstract :
Oxidative stress arises when there is an imbalance between radical-generating and radicalscavenging
activity; it may therefore cause an increase in oxidation products and cell
damage. This study aimed to determine antioxidant status, lipid peroxidation, and their
relation to anemia of grazing sheep deficient in copper (Cu). For this purpose, 39 male
lambs of native (Balady) breed, aged 6–7 months and reared in El-Dakhla oasis (in the
western Egyptian desert), were divided according to plasma Cu (pCu) concentration into
three groups, marginally deficient (MD, pCu = 4–8 mol/l, n = 12), functionally deficient (FD,
pCu<3 mol/l, n = 12) and control (pCu > 9 mol/l, n = 15). Jugular blood was sampled for
determination of red blood cell count (RBC), packed cell volume (PCV), hemoglobin concentration
(Hb), plasma ceruloplasmin activity (pCp), antioxidant activities of erythrocytic
superoxide dismutase (eSOD), catalase (eCAT), glutathione peroxidase (eGSH-Px), and levels
of erythrocytic malondialdehyde (eMDA, as a biomarker of lipid peroxidation). The
Cu-deficient lambs were characterized by microcytic hypochronic anemia accompanied by
decreased pCp, eSOD, eCAT and eGSH-Px activities and increased eMDA level when compared
to the controls. The indices of anemia, pCp and eSOD were lower and eMDA was
higher in FD compared toMDlambs. The enhanced eMDAwas strongly correlated (P < 0.01)
with the inhibited activity of pCu (r =−0.79), pCp (r =−0.65) and eSOD (r =−0.71) and to
a lesser extent (P < 0.05) with eGSH-Px (r =−0.38) and eCAT (r =−0.41). In addition, eMDA
was negatively correlated (P < 0.01) with RBC (r =−0.75), PCV (r =−0.69) and Hb (r =−0.72).
This study suggests that Cu-deficient lambs incur an erythrocytic oxidative damage secondary
to impaired oxidant defenses, which may be one of the mechanisms underlying Cu
deficiency-induced anemia in grazing sheep
