Effects of vitamin E, selenium and vitamin C on various biomarkers following oxidative stress caused by diazinon exposure in rainbow trout

Abstract

Biochemical parameters are appropriate biomarkers to assess the effects of pesticides on an aquatic ecosystem. Diazinon is an organophosphate pesticide whose metabolism in fish body produces reactive oxygen species that can cause oxidative stress. In this study, Oncorhynchus mykiss were allocated into four treatment groups (with three replicates): control; Diazinon; vitamin C + diazinon, and vitamin E,selenium + diazinon. Blood samples were obtained after two and four weeks and superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and malondialdehyde (MDA) were measured. SOD activity was significantly lower in diazinon-exposed fish than in the control group. However, there were no differences between the two supplemented groups and the control group in this regard. CAT activity was significantly higher in all three diazinon-exposed groups compared to the control group. However vitamin E, selenium had the least difference with the control group. Maximum and minimum TAC were observed respectively in fish supplemented with vitamin E, selenium and those only exposed to diazinon. The diazinon group also had the highest MDA levels. The two supplemented groups and the control group had no significant differences in MDA levels. These findings highlighted the antioxidant effects of supplementation with vitamin E, selenium or vitamin C against free radical produced during the metabolism of diazinon. Meanwhile, the combination of vitamin E, selenium had higher antioxidant effects than vitamin C. Moreover, SOD, the first defensive barrier against superoxide radicals, and MDA, an index of cellular damage induced by hydroxyl radicals, are the most suitable indicators to assess the effects of diazinon.