Rudd (Scardinius Erythrophthalmus L., 1758) as a bioindicator of anthropogenic pollution in freshwater bodies
Abstract
A. Sliusarenko, H. Makhorin, V. Prus, L. Bozhyk, L. Yevtukh, V. Honcharenko, P. Pukalo, B. Gutyj*, O. Dunaievska, M. Prychepa*, L. Kytsokon, O. Rud, O. Khomiak, O. Vodianitskyi, О. Potrokhov, V. Martseniuk and N. Hrynevych
We studied the changes in morphophysiological (gonadosomatic index, hepatosomatic index, spleen index) and biochemical (protein, glycogen, lipids, malonic dialdehyde, thyroxine, triiodothyronine, and cortisol) parameters in redfish under the action of toxic loading. Two lakes were chosen as model zones. These reservoirs differ significantly in anthropogenic impact and water quality (oxygen content and mineralization). The high content of toxicants (heavy metals) in Lake Kyrylivske significantly affected the physiological status of the studied fish. In the case of intensive toxic pollution of the reservoir, the indicators of the liver and spleen in redfish increase by 1.9 and 1.6 times, respectively that testified to the increasing functional activity of these organs. Changes in energy substrates accompanied enhancement of the functional activity of internal organs. The protein and glycogen content in the tissues of the liverwort from the contaminated lake was lower by 24.5% and 36.0%, respectively, compared with the conditional control. We found that the anthropogenic load on the reservoir protein content in the gills of fish increases by 18.2% (p≥0.05). However, under these conditions, its content in the muscles is significantly reduced by 24.5% compared to fish from relatively clean water. Confirmation of chronic stress at the time of the study was the high value of malonic dialdehyde in liver tissue. In fish from Lake Kyrylivske (dirty reservoir), its content was higher by 40.7% (p ≥ 0.05) than the same indicator for conditional control. Significant changes in hormone content also occurred during the stay of the Rudd in unstable hydro- ecological conditions. Thus, we found that the content of triiodothyronine in the blood plasma of fish under the influence of toxic contamination was 2.9 times lower (p≤0.05) compared to fish from control conditions. However, the content of thyroxine in the blood plasma of redfish from the contaminated lake was higher by 40.0% (p≤0.05) relative to the conditional control. The content of thyroxine and triiodothyronine in the blood plasma allows assessing the strength of anthropogenic impact on fish adequately. The obtained data on the physiological state of the Rudd allows monitoring (by changes in internal organs, by the content of hormones, malonic dialdehyde) the ecological state of water bodies located in geographically urbanized areas. This will further help minimize the harmful effects of toxic loads on the aquatic ecosystems of the city and its environs.