Physiological-biochemical status of perch (Perca fluviatilis Linnaeus, 1758) and roach in conditions (Rutilus rutilus Linnaeus, 1758) of excessive anthropogenic pressure on the body of water

Purpose. To establish during the spring and summer period the physiologically-biochemical response of fish to the effect of excessive anthropogenic contamination on the indicators of the maintenance of hormones and glucose in their blood plasma, and the possibility of using these indicators to assess the ecological status of the water body. Methodology. Two Lakes in the city of Kyiv were selected for research, which are characterized by various hydrochemical and toxicological indices. These water objects were Lake Kyrylivske (Opechen Upper) – a water body from the system of Lakes Opechen (polluted by the water body) and Lake Babyne that is on Trukhanov Island (relatively clean Lake, control). Fishing was carried out in the early spring and in the middle of the summer by hook fishing gear. In laboratory conditions, the total content of thyroxine (T4), triiodothyronine (T3) and cortisol in blood plasma of fish was determined by enzyme immunoassay, using commercial T3-EIA, T4-EIA sets (NPL Granum, Ukraine) and DS-EIA-Steroid-Cortisol ("Diagnostic Systems" NGO, Russia) using the Rayto RT-2100C EIA Analyzer. The glucose content was determined by spectrophotometrically glucose oxidase method using standard commercial kits "Filisit-Diagnostika" (Ukraine). Statistical data was processed using the programs Statistica 10.0 and Excel programs from the Microsoft Office suite. Findings. In the spring, excessive anthropogenic pressure on the Lake Kyrylivske causes an energy imbalance in fish, which causes the deceleration of catabolic reactions in their tissues. In this period, the perch and roach react to the conditions of existence in the Lake Kyrylivske increase in the content of cortisol in the blood compared with fish from the Lake. Babyne, what can be their reaction to excessive anthropogenic stress. Also, during this period, the low content of thyroxin and triiodothyronine in the perch from the Lake Kyrylivske was noted compared with the Lake. Babyne, which is probably caused by changes in the oxygen and temperature regime during spawning. Increase of thyroxine content in roach from Lake Kyrylivske during the summer period with respect to fish from the Lake Babyne may indicate an increase in the negative effects of toxic substances on the physiological state of fish as water temperature rises. At the perch from the Lake Kyrylivske content of T3 and T4 in 1.19 and 6.22 times, respectively is higher, than that of fish from the Lake Babyne, which is associated with enhanced processes of generating energy in his body, as a result of increased activity of redox reactions, as well as different degrees of oxygen consumption by tissues under complicated conditions of existence. In the summer, in the roach from the Lake Babyne content of cortisol is 2.05 times higher than that of roach of Lake Kyrylivske, which may be the result of a violation of the mobilization of energy compounds by the organism of this species from the Lake Kyrylivske The content of glucose in the blood plasma of the perch from the Lake Kyrylivske was 10.5 mmol/L in the summer, which is 1.43 times higher than that of fish from the Lake Babyne. Such a buildup of glucose can be a mechanism for counteracting toxic substances in the environment. Decrease of glucose content in roach from Lake Kyrylivske is probably the consequence of increased its utilization to ensure the energy homeostasis of the organism under similar conditions of existence. Originality. Inter-species and inter-season differences in the content of hormones in perch and roach, which were under the influence of anthropogenic loading on the water bodies of the metropolis, were established. Practical Value. The obtained results suggest that the characteristics of the thyroxine, triiodothyronine and cortisol content can be characterized by the physiological state of fish, as well as the ecological state of the most water bodies.