Dietary Sargassum angustifolium (Macro-Algae, Sargassaceae) extract improved antioxidant defense system in diazionon-exposed common carp, Cyprinus carpio

Abstract

Abstract The effects of different dietary levels of algae (Sargassum angustifolium) extract were investigated on the antioxidant system of common carp, Cyprinus carpio. Fish (30.2 ± 2.1 g) were fed 0 (control), 5, 10 and 15 g/kg basal diet of Sargassum angustifolium extract (SAE) for 60 days and then exposed to an environmentally relevant concentration of diazinon (2 mg/l) for 24 h. The biochemical assays were conducted in two times including at the end of feeding period and after 24 h exposure to diazinon. According to the results, malondialdehyde (MDA) levels in the liver remained unchanged (P>0.01) during feeding period, while significantly increased in response to diazinon in control and fish fed 5 and 10 g/kg diet SAE (P<0.01). The hepatic metabolic enzymes (AST: Aspartate aminotransferase, ALT: alanine aminotransferase, LDH: lactate dehydrogenase, CK: creatine kinase) showed no significant changes in all groups during feeding period, while these enzymes increased in Non-SAE supplemented fish and those fed 5 and 10 g/kg SAE after exposure to diazinon (P<0.01). Although little elevations were observed in the activity of hepatic antioxidant enzymes (CAT: catalase, SOD: superoxide dismutase, GPx: Glutathione peroxidase) in fish fed SAE, these elevations were not significant (P>0.01). After exposure to diazinon, antioxidant enzymes significantly decreased in control and fish fed 5 g/kg diet SAE, while the fish of 10 and 15 g/kg diet SAE treatments showed significant elevations (P<0.01). The antioxidant-related genes (sod, cat, gpx) significantly expressed more in response to dietary SAE compared to control (P<0.01). After exposure to diazinon, all groups showed significant elevations in antioxidant-related genes (P<0.01). In conclusion, the results of the present study revealed the antioxidant enhancing effects of SAE at dietary levels of 10 and 15 g/kg diet, which this effect may be attributed to some antioxidant components in the chemical composition of the macro-algae or to the direct effect of SAE on antioxidant defence system of the fish.