Responses of branchial biomarkers of Prochilodus lineatus after prolonged exposure to sublethal concentrations of fipronil

DE LA TORRE, F.R.; SANTILLAN, ANTONELLA; MIGLIORANZA, K.; ONDARZA, P.

santos

Congreso; 12th SETAC Latin America Biennial Meeting; 2017

SETAC Latin America

Fipronil (Fp) is a broad-use pesticide, and exhibits severe toxicity and adverse effects to non-target organisms, including fish. In this context, the presence of biochemicalresponses in fish is an effective tool for detecting sublethal effects frompesticide exposure. The responses of branchial biomarkers wereevaluated on juveniles of Prochilodus lineatus after prolonged exposureto sublethal concentrations of Fp. Fish (n=32) were exposed to twonominal concentration of Fp (0.5 µg/L, C1 and 9 µg/L, C2) where toxicantwas dissolved in methanol. Fish were kept in controlled conditions inaquariums with daily renewal of the media. Control fish remained inunchlorinated water (Ctrl) and water with the maximum methanolconcentration used (CtrlSv). Levels of Fp on water samples were alsoanalyzed with liquid-liquid and GC-ECD extraction. After 21 days ofexposure, fish were sacrificed and the branchial arches were extracted.Enzymatic activity of superoxide dismutase (SOD), antioxidant capacityagainst peroxyles (ACAP), content of reduced glutathion (GSH), levelsof lipid peroxidation by TBARS as well as determination of oxidativelymodified proteins (POx) were evaluated. Statistical differences betweengroups were determined using ANOVA (p< 0.05) followed byTukey?s test. No mortality was observed in either experimental group andno significant differences between the parameters of Ctrl and CtrlSvwere detected. Prolonged exposition to C2 promoted an increase (20%)in enzymatic activity of SOD respect to Ctrl group. Also an increase inACAP values (87%) was observed after exposure to C1, showing adecrease in antioxidant capacity. On the other hand, both concentrationspromoted a decrease (5%) in GSH activity respect to Ctrl. In terms ofoxidative damage, exposition to Fp concentrations promoted an increasein TBARS levels (207%, C1 and 134%, C2); meanwhile, only C2 groupshowed a significant increase (41%) in POx levels. These results suggestthat exposure to Fp promoted an antioxidant response, which was notenough to prevent oxidative damage at the protein level and lipidperoxidation. Also, both concentrations proved to be an inducer ofoxidative stress even at ambient relevant concentrations