: Effects of the antiparasitic Ivermectin on oxidative stress biomarkers on a native fish species: an ex vivo approach

LOZANO, I.; SANTILLAN DEIU, A; LO NOSTRO, F.; DE LA TORRE F.

Santos, SP

Congreso; 12th SETAC Latinamerica Biennal Meeting; 2017

SETAC

Thousands of active ingredients of mass-use drugs are produced commercially to improve animal and human health. These substances are considered contaminants of emerging concern and their presence in the aquatic environment -from agricultural and industrial wastewater- has raised concern regarding toxic effects on non-target aquatic organisms. Ivermectin (IVM) is one of the most widely used macrocyclic lactones and has been known as a potent, effective and safe antiparasitic drug, commonly used for treatment and prevention of internal and external parasites of livestock and humans. IVM is excreted largely unchanged in dung of treated animals. IVM residues may affect non target aquatic organisms close to cattle breeding areas such as feedlots. In fish, the pharynx is a major site through waterborne pollutants can enter the body, and gills are often among the organs most affected by such compounds. The effect of IVM was assessed on gill oxidative stress biomarkers responses of a native fish species Cyphocharax voga (Characiformes), after ex vivo exposure. Fish were sacrificed, and the branchial arches were dissected and assigned to four treatment groups: saline solution as control (C); methanol (0.05%) as vehicle control (Sv); and two nominal concentrations 50 µg.L-1(C1) and 500 µg.L-1(C2) based on environmental data. Branchial arches were kept under continuous shaking for 1h at 25°C. The biomarkers evaluated were: enzymatic activities of catalase (CAT) and superoxide dismutase (SOD), total antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation levels (thiobarbituric acid reactive substances, TBARS), and reduced glutathione levels (GSH). Statistical differences between treatments were determined using a one way analysis of variance (p