Effects of Silver Nanoparticles on Fish Prochilodus lineatus: Oxidative Stress and Metabolic Responses

ALE, A.; ROSSI, A.; DE LA TORRE, F.R.; CAZENABE, J.

Buenos Aires

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

SETAC Latinoamerica

-newline">Silver nanoparticles (AgNPs) are present in a multitude of consumer and medicalstuff due to their antimicrobial properties. The increase in production andconsumption of silver-containing products leads to the release of AgNPs into theenvironment, therefore safety concerns have raised. The aim of the study was toanalyze oxidative stress responses and metabolic parameters in different tissuesof juvenile Prochilodus lineatus exposed to AgNPs. Fish were exposed to thefollowing AgNPs concentrations (Colloidal nanosilver, Nanotek S.A.): 25 µg·L-1; 2,5 µg·L-1 (0.5 and 0.05 of 96-h LC50 value approximately) and 0 µg·L-1(control) (2 fish per aquarium, with 5 replicates per treatment). The aquariumsolutions were renewed every 48 hours. After 5 and 15 days, liver, intestine, gills,brain and muscle samples were obtained from exposed and control fish.Oxidative stress biomarkers were evaluated in all organs through activities ofantioxidant enzymes (catalase, glutathione S-transferase, glutathione reductaseand glutathione peroxidase) and lipid peroxidation levels (LPO). Glycogen,protein and lipid content were determined in liver and muscle. In the liver of fishexposed to 25 µg·L-1 of AgNPs for 15 days, an induction of all antioxidantenzymes activities was observed in comparison with the control. It wasaccompanied by an increase in LPO levels which duplicated the control values.In regard to gills, all enzymes activities decreased after 5 days of exposure at thelowest concentration of AgNPs with respect to the control. On the contrary, theLPO levels decreased after 5 days at both concentrations. The enzyme activitiesmeasured in intestine and brain showed no differences among the treatments.However, the LPO levels in intestine decreased after 5 days of exposure at bothconcentrations. Regarding the metabolic responses, glycogen content showed asignificant increase in liver and muscle of fish exposed to 25 µg·L-1 of AgNPsfor 15 days, while protein concentration decreased only in muscle. The resultsconfirmed that the presence of AgNPs, in short and subchronic exposures, causeoxidative stress mainly in the liver of fish. Furthermore, energy reserves werealtered under the highest concentration and time of exposure. Thus it couldthreaten the health of fish and generate vulnerability in cases of environmentalstress conditions.