Histological characteristics of the liver of Azov roach (Rutilus rutilus Linnaeus, 1758) as a quality bioindicator of water bodies

Purpose. To assess the variability of histological parameters medial zone roach (Rutilus rutilus) liver. establish level effect transformed conditions existence on fish physiological status. determine prospect using monitoring data in ichthyological practice to morphofunctional state fish. Methodology. Primary materials were obtained different parts Southern Bug River, which differ their degrees pollution. Lab processing samples was performed accordance with generally recognized methods and manuals. Histological studies carried out proprietary equipment original techniques specifically designed for diagnosing tissues. The results processed by variation statistics MS Excel an emphasis errors average values. Findings. Microanatomical hepatic parenchyma allowed establishing that most significant changes occured contrastingly recorded organ, could conditionally be considered a bioindicative zone. With potential toxicants dissolved water, shift cell function observed Visually, this manifested as change structuring cytoplasmic inclusions intensity nucleus staining, simultaneously direct cytological characteristics. An 1.20-fold increase area adequately leads 1.18-fold cytoplasm area, well Hertwig constant or nuclear-cytoplasmic ratio (0,25-0,28), statistically significant. indicate nature intracellular metabolism. number cavities is evidence attenuation glycogen-accumulative hepatocytes. nucleolus/nucleus diameter (0.28) indicates cellular function, occurs through activation lipid synthesis. No typical necrosis foci found liver from places concentration commercial effluents, are moderate accumulation fat-soluble pollutants absence pronounced pathologies individuals reserve-compensatory potencies organ. presence individual hepatocytes two nucleoli nuclei allows judging borderline, i.e. prepathological In some cases, proportion dystrophic large vacuoles filled optically transparent liquid established, identifying irreversible pathology - balloon dystrophy, resulting severe impairment analysis clean polluted waters allowed, parallel, relatively low levels intraspecific populations. revealed fact testifies plasticity organ reserve potencies, under technogenic pressure various origins intended purposes. This perspective provides evolutionary definition body’s universal detoxification system. Originality. New presented, existing normal altered structure roach, live existence, significantly updated. For first time, comparative age-1+ out. Based analysis, information taxonomic features compensatory tissue components water areas renewed Practical walue. value morphophysiological studies, connection modern problem lowering vital status populations, exists degraded aquatic ecosystems. use qualitative assessment order predict environmental hazards origin purpose. Key words: parenchyma, liver, hepatocyte, bioindication, area.