Assessment of the composition of peripheral blood cells and red bone marrow in preclinical studies is a key component of program for analysis of biologically active compounds obtained from the plant materials. Current study concerns effect of the complex extract from Rumex plants (R. confertus, R. tianschanicus, R. thyrsiflorus) on parameters of blood cells and bone marrow of laboratory animals. During the study, data were obtained on the effect of the extract on hematopoiesis when administered at 100 mg/kg of animal weight. The results obtained show that application of the extract is accompanied by a statistically significant increase in the number of neutrophil precursors, such as myeloblasts and band neutrophils (p≤0.05). According to our results the extract we obtained from Rumex plants does not cause inhibition of early bone marrow precursors and is safe and non-toxic.

The article was written as part of the Ministry of Science and Higher Education of the Republic of Kazakhstan’s project AP 23486220, titled “Study of the important organ systems reactivity in the main commercial fish species of the Ile-Balkhash basin under anthropogenic load.” (2024-2026). The article represents the study investigating the long-term effects of polyethylene terephthalate (PET) microplastics on zebrafish (Danio rerio). Zebrafish exposed to PET microplastics at concentrations of 1.9 mg/l and 5.64 mg/l exhibited significant kidney and gill damage. This included necrosis, circulatory disorders, and tissue damage. Histological analysis revealed specific pathological changes such as vacuolization and hyaline-droplet degeneration in kidneys, and destruction of epithelium and lamellae in gills. Notably, no compensatory-adaptive reactions in gills were observed, indicating a lack of adaptation to prolonged exposure. These findings suggest that microplastics may migrate through the bloodstream, disrupting normal kidney and gill structures. The study highlights the severe impact of microplastic pollution on fish organs, emphasizing the urgent need for further research to develop strategies for mitigating microplas-tic pollution in aquatic ecosystems. Additionally, the observed lack of adaptive responses underscores the potential for significant ecological consequences, urging immediate attention to address this critical environmental issue.

The gills of teleost fish are multifunctional organs involved in respiration, osmoregulation, and immune defense, and are highly sensitive to environmental stressors. This study evaluated the histological and ultrastructural condition of the gill epithelium of common carp (Cyprinus carpio Linnaeus, 1758) inhabiting the middle reaches of the Ile River (Kazakhstan) under chronic anthropogenic pressure. Although hydrochemical parameters remained within permissible limits for fishery waters, all examined specimens (n = 10) exhibited pronounced structural alterations. Histological analysis revealed edema, epithelial hyperplasia, lamellar fusion, necrosis, and desquamation, indicating substantial impairment of gill integrity. Ultrastructural examination demonstrated advanced developmental stages of rodlet cells, mast cell degranulation, and increased activity of mucous and chloride cells, accompanied by mitochondrial alterations and autophagosome formation. Alongside destructive changes, moderate compensatory reactions were observed, reflecting tissue-level adaptation to prolonged environmental stress. These findings demonstrate that gill histopathology provides a sensitive tool for detecting sublethal effects of chronic anthropogenic impact, even when conventional hydrochemical indicators suggest acceptable water quality. The results support the use of cellular and tissue-level biomarkers in freshwater environmental monitoring programs.

In recent decades, there has been an increase in the pollution of the waters of the Ile-Balkhash basin by agricultural, industrial and domestic discharges, which has negative consequences for the ichthyofauna. The aim of this study was a histopathological analysis of the condition of the gills, which are the most sensitive to contamination of fish organs, due to their direct and constant contact with water. 7 specimens of three main fish species of commercial fish fauna were caught: bream (Abramis brama) and carp (Cyprinus carpio), both as typical benthophages with some specific feeding features and pike perch (Sander lucioperca). Microscopic analysis of the gills of the common bream (Abramis brama) revealed epithelial hypertrophy and hyperplasia, mucosal and chloride cell changes, epithelial detachment, necrosis, hyperemia, and aneurysms, which were quantified using a semi-quantitative approach. It was found that epithelial hypertrophy, hyperplasia, epithelial detachment and necrosis significantly varied between seasons, while the severity of necrosis was significantly higher in one of the seasons. Comparative analysis showed that in the carp (Cyprinus carpio), adaptive changes in the gills predominate, while in the pike perch (Sander lucioperca), as a more sensitive species, pronounced destructive lesions indicate a high level of environmental stress. Discriminant canonical analysis confirmed that epithelial hyperplasia, mucosal cell changes, epithelial detachment and necrosis are the main factors of seasonal differentiation. The results obtained demonstrate the high informative value of histopathological biomarkers of fish gills for assessing the seasonal dynamics of water quality within a single aquatic ecosystem.

The article presents the results of 2021 research on the bream (Abramis brama) population of the Kapchagay Reservoir and notes the changes that have occurred in its population compared to earlier studies. Modern sustainable use of natural biological resources presupposes the mandatory preservation of their natural reproduction, while taking into account the need to preserve each type of resource not only within its natural range, but also in each habitat. One of the valuable natural bioresources is the commercial ichthyofauna of inland waters. The Kapchagay Reservoir is one of the main fishery reservoirs in the country. The main share of the industrial catch in this reservoir falls on the bream (Abramis brama). Studies of the bream population of the Kapchagay Reservoir conducted in 2021 showed that the age structure of this species is represented by twelve age groups (from 1+ to 12+). At the same time, 4-year-old fish predominate,their share in the catches amounted to 22.03%. The main fishing load falls on fish older than five and six years, the share of which in the catches was 13.28% and 10.73%, respectively. Visualization of the spatial distribution data of bream in the Kapshagay Reservoir showed that despite the fact that bream is found throughout the water area in relatively large quantities, there is a seasonal accumulation in certain areas of the reservoir. The rejuvenation of the bream population in the Kapshagay Reservoir compared to the catch records of previous years indicates overfishing, which is due to its IUU fishing

The article was written as part of the Ministry of Science and Higher Education of the Republic of Kazakhstan’s project AP 23486220, titled “Study of the important organ systems reactivity in the main commercial fish species of the Ile-Balkhash basin under anthropogenic load.” (2024-2026). The ecological condition of the Ili-Balkhash Basin raises serious concerns due to increasing anthropogenic pressure, accompanied by the influx of heavy metals, pesticides, and other organic pollutants into water bodies. Fish gills, as a highly sensitive organ of external respiration, serve as a reliable bioindicator of water toxicity. As part of this study, morphological and histological analyses of the gill apparatus were conducted on three commercially important fish species – Cyprinus carpio, Abramis brama, and Sander lucioperca — caught in different areas of the Ili-Balkhash Basin. In fish inhabiting zones with elevated pollutant concentrations, pronounced pathological changes in gill tissue were observed, including epithelial hyperplasia, lamellar fusion, destruction of the capillary network, and inflammatory infiltration. The severity of these alterations correlated with the level of aquatic pollution. Cyprinus carpio demonstrated the highest sensitivity to pollutants, whereas Sander lucioperca showed relative resistance. The findings indicate a significant impact of waterborne pollutants on the morphofunctional condition of the gill apparatus, and consequently, on the viability and productivity of fish populations. These results highlight the urgent need for regular ecological monitoring and the implementation of protective measures to preserve the aquatic ecosystem of the Ili-Balkhash Basin, safeguard biodiversity, and ensure sustainable fisheries. Keywords: Ili-Balkhash Basin, aquatic pollutants, gill pathologies, Cyprinus carpio, Abramis brama, Sander lucioperca, histomorphology.