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

LOZANO, ISMAEL ESTEBAN; SANTILLÁN DEIU, ANTONELLA; LO NOSTRO, FABIANA; DE LA TORRE, FERNANDO

Santos

Encuentro; SETAC Latin America 12th Biennial Meeting; 2017

Thousandsof active ingredients of mass-use drugs are produced commercially to improveanimal and human health. These substances are considered contaminants ofemerging concern and their presence in the aquatic environment -fromagricultural and industrial wastewater- has raised concern regarding toxiceffects on non-target aquatic organisms. Ivermectin (IVM) is one of the mostwidely used macrocyclic lactones and has been known as a potent, effective andsafe antiparasitic drug, commonly used for treatment and prevention of internaland external parasites of livestock and humans. IVM is excreted largelyunchanged in dung of treated animals. IVM residues may affect non targetaquatic organisms close to cattle breeding areas such as feedlots. In fish, thepharynx is a major site through waterborne pollutants can enter the body, andgills are often among the organs most affected by such compounds. The effect ofIVM was assessed on gill oxidative stress biomarkers responses of a native fishspecies Cyphocharax voga (Characiformes),after ex vivo exposure. Fish weresacrificed, and the branchial arches were dissected and assigned to fourtreatment groups: saline solution as control (C); methanol (0.05%) as vehiclecontrol (Sv); and two nominal concentrations 50 µg.L-1(C1) and 500µg.L-1(C2) based on environmental data. Branchial arches were keptunder continuous shaking for 1h at 25°C. The biomarkers evaluated were:enzymatic activities of catalase (CAT) and superoxide dismutase (SOD), totalantioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation levels(thiobarbituric acid reactive substances, TBARS), and reduced glutathionelevels (GSH). Statistical differences between treatments were determined usinga one way analysis of variance (p<0,05) followed by Tukey?s test. Nosignificant differences were found between all the analyzed parameters for Cand Sv groups. Both IVM concentrations showed a significant increase (20.4% forC1 and 25.4% for C2) for SOD. In addition, in case of C2 concentration, asignificant increase (46.3%) for ACAP and a significant increase for TBARSlevels of both treatments (102.2% for C1 and 41.3% for C2) were detected. Nosignificant differences for CAT and GSH were found. These results suggestedthat an ex vivo exposure of C. voga gills to IVM would promotechanges at biotransformation and oxidative stress levels, indicating that theinner response seems not to be enough to prevent oxidative damage to lipid.