Copper and Nickel Induce Changes in the Lipid and Fatty Acid Composition of Anodonta cygnea

The effect of copper and nickel ions on the lipid composition of freshwater mussels Anodonta cygnea was investigated using an aquarium experiment. The contents of the main lipid classes were determined using thin layer chromatography and spectrophotometry, and the fatty acid composition was analysed using gas–liquid chromatography. The results indicated that copper and nickel had different effects on the mussels’ lipid composition, with copper producing less effect on the composition of lipids and fatty acids than nickel. On the first experiment day, excessive copper content in the organism caused oxidative stress and modifications in membrane lipids, which returned to their initial level by the end of the experiment. Nickel accumulated predominantly in gills; however, significant modifications in lipids and fatty acids were seen also in the digestive gland from the first day of the experiment. This indicated the activation of nickel-induced lipid peroxidation processes. Moreover, this study revealed a dose-dependent effect of nickel on lipid composition, which was likely related to the development of compensatory biochemical mechanisms in response to nickel-induced oxidative stress. A comparative study of the lipid composition alteration in mussels in response to copper and nickel action revealed the consequences of the toxic impact of metal ions and the defensive mechanisms that organisms employ to detoxify and remove xenobiotics.