Contaminated Sediments: Biochemical Effects and Oxidative Stress in the Sábalo Prochilodus Lineatus, Exposed to the Antiparasitic Ivermectin

LOZANO, ISMAEL; LAGRAÑA, ALDANA; LO NOSTRO, F; DE LA TORRE, F.R.

Santiago de chile

Congreso; SETAC Latin America 14th Biennial Meeting; 2021

Society of Environmental Toxicology and Chemistry (SETAC)

Ivermectin (IVM) is one of the most widely used antiparasiticsworldwide. It is a potent and effective drug for the treatment andprevention of internal and external parasite infections of both livestockand humans. IVM is excreted unchanged (≈90%) in manure of treatedanimals. Thus, residues of IVM may reach aquatic systems, affectingnon-target organisms such as fish. High concentrations of IVM havebeen detected in sediments of water bodies close to livestock areas(feedlots). In this work, the effect on biochemical and oxidative stressbiomarkers induced by IVM was evaluated in juveniles of the nativefreshwater fish Prochilodus lineatus (Characiformes), an inland fisheryspecies. Fish (4.2 ± 0.9 g b.w; n=27) were exposed during 14 days tosediments spiked with environmental concentrations of IVM: 2 µg/kgand 20 µg/kg; following exposure gills, muscle, liver and brain werecollected. Acetylcholinesterase (AChE) activity was measured in brainand muscle; and the following oxidative stress parameters wereanalyzed in all organs: lipid peroxidation levels (thiobarbituric acidreactive substances, TBARS), antioxidant capacity against peroxylradicals (ACAP), catalase enzyme activity (CAT), glutathione Stransferase activity (GST) and reduced glutathione content (GSH).Differences between treatments were evaluated by one-way ANOVA (α= 0.05) followed by a Holm-Sidak test. The lowest concentration ofIVM produced a significant increase in TBARs levels in brain and asignificant decrease in GSH content in gills. Moreover, the lowestconcentration of IVM also produced a significant decay in ACAP and anincrease in CAT activity in liver. A significant decrease in ACAP levelswas observed for both IVM concentrations in gills, whereas in liver,IVM exposure at both tested concentrations caused a significantreduction in GSH levels. Muscle AChE activity was significantlydecreased at both IVM concentrations. Taken together, these resultssuggest that the exposure of P. lineatus juveniles to environmentalconcentrations of IVM in contaminated sediments could generateoxidative damage in brain (TBARS), and alter the enzymaticbiochemical responses (CAT) in liver as well as the levels ofantioxidants (GSH decay) in gills. On the other hand, the decrease inACAP observed upon exposure suggests that the internal response toreactive oxygen species is unbalanced and seems to not be sufficient toavoid oxidative damage and mortality