Antioxidant processes of the wild tambaqui, Colossoma macropomum (Osteichthyes, Serrasalmidae) from the Amazon

Colossoma macropomum, locally called tambaqui, is a freshwater migratory te leost that shows good tolerance to oxygen and pH changes in water, and both chemical-physical parameters change markedly during the day time and seaso nal water level oscillations in the Amazon Basin. In order to obtain a gene ral view about the basal levels of antioxidants in different tissues of wil d tambaqui, enzymatic (superoxide dismutase and catalase) and non-enzymatic (alpha-tocopherol, beta-carotene, and glutathione) antioxidants and lipid peroxidation levels were assessed in the liver, blood and plasma of ten spe cimens collected during the dry season (September) in a pond near Manaus-AM , Brazil. Superoxide dismutase, catalase, and lipid peroxidation levels wer e high in the liver and low in the blood and plasma. Confirming previous re sults on tambaqui, catalase was detected in the blood of one specimen only. beta-Carotene was not found in any analyzed tissue, while alpha-tocopherol was found only in the liver (7.8 +/- 7.0 nmol g(-1), mean +/- S.E.M.) and plasma (4.3 +/- 0.9 nmol ml(-1)). Blood glutathione concentrations (2.4 +/- 0.17 mmol l(-1)) of tambaqui were comparable with those found in other Ama zonian teleosts. Antioxidant defenses and lipid peroxidation contents from liver, blood and plasma exhibited interesting correlations. These relations hips suggest that antioxidant defenses located in different tissues and in different sub-cellular compartments act in concert. (C) 1999 Elsevier Scien ce Inc. All rights reserved.