Evaluation of Antioxidant Circulatory Lipid-Soluble Vitamins and Sodium as Non-invasive Indicators of Chronic Copper Exposure and Toxicity in Rainbow Trout, Oncorhynchus mykiss

Abstract

Measurement of circulatory indicators of copper (Cu) exposure and toxicity in rainbow trout revealed elevated Cu concurrent with reduced sodium (Na) concentrations in plasma of Cu-exposed fish. Using a new normal phase high performance liquid chromatography (HPLC) method developed and validated for simultaneous extraction of lipid-soluble antioxidant vitamins we found that, contrary to our original hypothesis, plasma antioxidant status was enhanced as evidenced by a linear increase in vitamin E concentration. This suggests that vitamin E was mobilized from other metabolic pools to enhance circulatory antioxidant status possibly for delivery to Cu-sensitive locales. On the other hand, plasma vitamin A was not affected by the Cu exposure although its level decreased with time concurrent with an increase in fish size suggesting increased demand for growth. Thus circulatory Cu, Na, and vitamin E, but not vitamin A, can be used as non-lethal biomarkers of chronic Cu exposure and toxicity in fish.

Hepatic retinoid levels in seven fish species (teleosts) from a tropical coastal lagoon receiving effluents from iron‐ore mining and processing

“…This finding is supported by the significant positive relationships between retinol and retinyl palmitate with lipid peroxidation (measured as malondialdehyde, Table 2). In an experiment with rainbow trout exposed to Cu, Kamunde et al [30] also observed enhancement of the antioxidant status (in their case, vitamin E) with a prooxidant metal (Cu) in plasma.…”

“…Although these lagoons were initially selected to be reference lagoons, previous studies have shown that they may have been affected by anthropogenic sources of trace elements, probably from atmospheric deposition [20]. In order to sample the main components of the fish community in the lagoons, samples were collected using gill nets of various mesh sizes (20,25,30,40, and 50 mm). Fish were killed by a blow to the head, wrapped in aluminum foil, transported on ice to the lab, and preserved frozen (À208C) for one week.…”