The responses of rainbow trout gills to high lithium and potassium concentrations in water

The objective of this study is to discern the effects of increased waterborne lithium and potassium on rainbow trout gill histology, lipid composition, and enzyme activity. The study aims to elucidate the effects of these ions in the laboratory in concentrations similar to those prevailing in a forest lake Poppalijarvi in a contaminated mining area in NW Russia. Under the lithium and potassium exposure, the fish were further stressed by high pH (8.2 as in Lake Poppalijarvi) and lack of food. These multiple stress conditions altered the gill membrane fluidity by increasing sphingomyelin (5.5 +/- 0.6 compared to 2.9 +/- 0.3% in the control) and reducing cholesterol (4 +/- 1 compared to 17 +/- 3 mg g(-1) in the control). The total ATPase activity tended to be higher in the lithium-potassium-exposed group (46 +/- 6 compared to 34 +/- 2 mu mol Pi h(-1) mg(-1) protein in the control). Lithium toxicity was lowered here by the protective role of higher potassium contents. (C) 2007 Elsevier Inc. All rights reserved.