Biomarker responses elicited by a commercial formulation of Fipronil in a native species (Cyphocharax voga) after branchial ex vivo exposure

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

Buenos Aires

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

SETAC Latinoamerica

Fipronil is a currentuse pesticide whose toxicity is still unknown in many non-target organisms (eg,fishes). Gills are considered the first organ where insecticidesimpact in aquatic organisms, therefore gill biomarker responses could be indicativeof the immediate damage produced in fish. In this context, the biomarkerresponses promoted by a commercial formulation of the insecticide fipronil(CLAP) were evaluated in juveniles of C.voga using a branchial ex vivoexposure model. After sacrificing the animals, gill arches of each individualwere dissected and arches were grouped in pairs. A number was assigned to eachpair and subsequently were randomly assigned to the following experimentaltreatments: fish saline solution (C); two nominal concentrations (10 and500 µg/L) of a commercial formulation of fipronil dissolved in saline solution (C1 and C2, respectively). Gills remained submerged in thesolutions under continuous agitation for 1 h at 25 °C in glass containers.After incubation period, enzymatic activities of catalase (CAT) andglutathione-S-transferase (GST) as well as the levels of lipid peroxidation byTBARS and antioxidant capacity against peroxyl (ACAP) were determined.Differences between groups were analyzed using one way ANOVA and Tukey'smultiple comparisons. Gill exposure to C1 promoted an increase of 90% in GSTactivity respect to C group, however this raise was not significant in C2.Regarding the CAT activity, only C2 group showed a significant decrease (54%) respectto C. In terms of oxidative damage, exposition to both C1 and C2 fipronilconcentrations promoted an increase in TBARS levels (87 and 116%,respectively). In the same way, an important decrease in total antioxidantcapacity was also verified after gill exposure in C1 (246%) and C2 (450%) fipronilmedia. These results indicate that the assayed fipronil formulation proved tobe an inducer of a significant oxidative stress in gills. In addition, thesensibility of this native species in combination with this fast test constitutesa useful tool in evaluating toxicity of formulated insecticides.