Influence of Elevated Concentrations of Cobalt Ions on Content of Non-Polar Lipids in Freshwater Fish Tissues

The total lipids content and their individual non-polar fractions in gills, liver, and muscles of crucian carp (<i>Carassius gibelio</i> Bloch.) and pike (<i>Esox lucius</i> L.) under the impact of 0.1 mg/dm<sup>3</sup> and 0.25 mg/dm<sup>3</sup> cobalt ions was studied. The lipid profile dynamics in fish tissues under the toxic influence depended on concentration and was species- and tissue-specific. A general trend was noted to increase of the total lipids content in liver, and its decrease in muscles owing to the lipid reserves' redistribution. In liver, the portion of phospholipids and triacylglycerols decreased, and portion of cholesterol and lipid hydrolysis products increased. Changes of the lipid profiles in gill were more pronounced in pike, especially under higher concentrations. Changes in the nonpolar lipids content in muscles of both species under intoxication had common trends: portion of triacylglycerols decreased and of non-esterified fatty acids increased. The cholesterol/phospholipid ratio in gills under the influence of both concentrations of cobalt ions decreased in both fish species, whereas in liver and muscles it significantly increased in crucian carp only.