Effects of subchronic manganese chloride exposure on tambaqui (Colossoma macropomum) tissues: oxidative stress and antioxidant defenses.

This study aimed to evaluate oxidative stress parameters in juvenile tambaqui (Colossoma macropomum) exposed to 3.88 mg l−1 Mn2+ for 96 hours. Biomarkers of oxidative stress, such as thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) activities, as well as content of reduced glutathione (GSH), were analyzed in gill, liver, brain, and kidney. The presence of Mn2+ in the water corresponded to increased levels of Mn2+ accumulation according to the following sequence: gill > kidney > brain > liver. There was a significant increase in TBARS levels (40 %) and SOD activity (80 %) in addition to a significant decrease in GSH content (41 %) in gills of fish exposed to waterborne Mn2+. In hepatic tissue of the exposed animals, TBARS levels decreased significantly (35 %), whereas SOD (82 %) and GST activities (51 %) as well as GSH content (43 %) increased significantly. In brain of exposed juvenile fish, only significant decreases in SOD (32 %) and CAT activities (65 %) were observed. Moreover, the kidney of exposed fish showed a significant increase in TBARS levels (53 %) and a significant decrease in SOD activity (41 %) compared with the control. Thus, the changes in biomarkers of oxidative stress were different in the tissues, showing a specific toxicity of this metal to each organ.Fil: Gabriel, Diogo. University of Santa Maria; BrasilFil: Riffel, Ana Paula K.. University of Santa Maria; BrasilFil: Finamor, Isabella A.. University of Santa Maria; BrasilFil: Saccol, Etiane M. H.. University of Santa Maria; BrasilFil: Ourique, Giovana M.. University of Santa Maria; BrasilFil: Goulart, Luis O.. University of Santa Maria; BrasilFil: Kochhann, Daiani. National Institute for Research in the Amazon; BrasilFil: Cunha, Mauro A. . University of Santa Maria; BrasilFil: Garcia, Luciano O.. Universidade Federal do Rio Grande do Sul; BrasilFil: Pavanato, María A.. University of Santa Maria; BrasilFil: Val, Adalberto Val. National Institute for Research in the Amazon; BrasilFil: Baldisserotto, Bernardo. University of Santa Maria; BrasilFil: Llesuy, Susana Francisca. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular; Argentin