Phospholipids Composition of Freshwater Fishes' Tissues under Increased Concentrations of Cobalt Ions

The paper deals with content of phospholipids and ratio of their individual fractions in the gills, liver, and muscles of silver carp (Carassius gibelio Bloch.) and common pike (Esox lucius L.) exposed to 0.1 and 0.25 mg/dm3 of cobalt ions for 14 days. It has been shown that changes in the phospholipid profile in fish organs under the toxic impact depended on the metal concentration and were species- and tissue-specific. Thus, phospholipid profile in gills was similar in both species, whereas in liver and muscles it differed. The dynamics of the phospholipid fractions' content and the phosphatidylcholine/sphingomyelin and phosphatidylcholine/phosphatidylethanolamine ratio in pike tissues were more pronounced. Instead, crucian carp showed greater resistance to the cobalt ions, which was reflected in the efficiency of absorption and detoxification of cobalt in liver and muscles, preventing oxidative damage. The obtained data indicate remodeling of phospholipids and modulation of the cell membrane fluidity as an adaptive response to the environmental factors, in particular cobalt ions' impact.