Oxidative metabolism in Odontesthes nigricans Richardson (Pisces, Atherinopsidae) from the Beagle Channel, Argentina

LATTUCA ME; MALANGA G; PEREZ A; CALVO J; PUNTARULO S

Bahía Blanca, Argentina

Simposio; ECSA 44 Symposium: Science and management of estuaries and coasts: A tale of two hemispheres; 2008

Oxidative metabolism in Odontesthes nigricans Richardson (Pisces, Atherinopsidae) from the Beagle Channel, Argentina. Lattuca, M.1; Malanga, G.1; Pérez, A.1,2, Calvo, J.1 & Puntarulo, S.3 1CADIC (CONICET), Ushuaia, Argentina. 2Departamento de Ecología, Genética y Evolución, FCEN, UBA, Argentina. 3Físico-Química- PRALIB, FFyB, UBA, Argentina. The aim of this work was to study comparatively oxidative metabolism in gills and liver of a silverside, Odontesthes nigricans, in their natural environment. This species can be found, following rising tides, along coastal waters and estuaries of the Beagle Channel. Fish were collected with seine net at Cambaceres Bay (54°52´S, 67°16´W) in September 2007. Oxidative metabolism at the hydrophilic level was assessed as the ratio ascorbyl radical content (A·)/ascorbate content (AH-). The A·content, measured by EPR, showed no significant differences between gills and liver of fish. HPLC determinations of AH- content were 12±2 nmol/mg FW in gills, and 159±28 nmol/mg FW in liver. The ratio A·/AH- was significantly different between organs, (6±2)10-5 and (5±2)10-6, for gills and liver, respectively. Oxidative damage to lipids was evaluated through assessing TBARS and lipid radical content in gills and liver. Gills showed a significantly higher damage than liver. Catalase activity and the content of lipid soluble antioxidants (a-tocopherol and b-carotene) showed significantly higher values in liver than in gills. Taken as a whole, O. nigricans liver exhibited a better control of oxidative damage than gills, allowing minimization of intracellular damage when exposed to environmental stressing conditions. Supported by CONICET, ANPCyT, UBA. Keywords: oxidative metabolism, Odontesthes nigricans, Beagle Channel, antioxidants