SUMMARY
Background: Total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI), nitric oxide (NO), zinc (Zn), copper (Cu) levels, paraoxonase (PON1), arylesterase (ARES) activities, and biochemical changes were studied on sheep with cystic echinococcosis.Methods: The materials were taken from 2-3 yr old sheep slaughtered in Van Province, Turkey in 2017. Before the slaughter, blood samples were collected from the healthy sheep, while various organs of animals were examined for hydatid cysts after the slaughter. Thirty sheep were protoscolex positive, hydatic group, while 30 sheep that did not have any pathological lesions in organ examinations were accepted as the control group. TOS levels, PON1 and ARES activities, and Zn levels were determined by commercial kits, while Cu levels were determined by atomic absorption spectrophotometer. The collected data were then statistically analyzed.Results: Serum TOS and OSI levels were significantly higher in sheep with cystic echinococcosis compared to the control group (P<0.001). TAS levels (P<0.01), PON1 and ARES activities, on the other hand, were significantly higher in control group compared to the cystic echinococcosis group (P<0.001). There were no significant differences in Zn, NO and Cu levels between the groups.Conclusion: PON1 and ARES activities increased in sheep infected with cyst hydatid. The decline of antioxidant reserves in the metabolism results in excessive amounts of free radicals, along with alterations of the normal histological structure of the cystic organ and changes in trace element metabolism.