Effects of sublethal copper exposure on muscle energy metabolism of common carp, measured by 31P‐nuclear magnetic resonance spectroscopy

Abstract

AbstractThe effects of shock and subchronic exposure(1 week) to 0.36 ± 0.08 and 1.31 ± 0.22 μM of copper on the energy metabolism of common carp (Cyprinus carpio) were studied by means of in vivo 31P‐nuclear magnetic resonance spectroscopy (31P‐NMRS). During the experiments, fish were submitted to an additional hypoxic challenge and recovery from this challenge was followed for 6 hs. During all experiments adenosine triphosphate (ATP) levels remained stable. Under control conditions, levels of phosphocreatine (PCr) and inorganic phosphate (Pi) recovered rapidly after the hypoxic challenge; however, full recovery was not observed after shock copper exposure. Also, intracellular pH (pHi) did not recover from the hypoxic challenge after shock exposure. After 1 week of exposure the fish had clearly developed an increased tolerance to copper. At both copper concentrations, PCr and Pi levels returned to resting levels after the hypoxic challenge, but at the highest copper concentration PCr to Pi ratios were significantly lower than PCr to Pi ratios in the control group and levels of PCr and Pi were very unstable. At the high copper concentration, pHi was clearly decreased compared to the control group even before the hypoxic challenge.