A multi-biomarker approach to lambda-cyhalothrin effects on the freshwater teleost matrinxa Brycon amazonicus: single-pulse exposure and recovery

Effects of the pyrethroid lambda-cyhalothrin (LCH) were investigated in matrinxa Brycon amazonicus, a non-target freshwater teleost. The fish were submitted to a single-pulse exposure (10% of LC50; 96h, 0.65gL(-1)), followed by 7days of recovery in clean water. Hematologic parameters indicated impairments in oxygen transport, which were not recovered. Plasma [Na+], [Cl-], and protein were diminished, and only [Na+] remained low after recovery. Gill Na+/K(+)ATPase activity was increased and recovered to basal values. Brain acetylcholinesterase activity was not responsive to LCH. Liver ascorbic acid concentration was not altered, and reduced glutathione levels remained augmented even after recovery. LCH inhibited hepatic superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities, while glutathione-S-transferase (GST) and glucose-6-phosphate dehydrogenase (G6PDH) activities were steady. After recovery, SOD remained low, and GPx was augmented. Liver depicted lipid peroxidation, which was not observed after recovery. Hepatic morphology was affected by LCH and was not completely recovered. These responses, combined with the persistence of changes even after recovery span, clearly show the feasibility of these biomarkers in evaluating LCH toxic potential to non-target organisms, highlighting the importance of pyrethroids' responsible use.