INFLUENCE OF SECONDARY METABOLITES OF MICROMYCETES ON THE LIPID PROFILE OF CURLY FISH

Abstract

The problem of pollution of aquatic ecosystems, in particular by anthropogenic pollutants and xenobiotics, is one of the most urgent in modern fish farming. A particular threat to the health of aquatic organisms is posed by secondary metabolites of micromycetes, known as mycotoxins, which can enter water bodies through contaminated feed and other sources. These compounds are able to accumulate in the body of fish and cause significant disruptions in their physiological and biochemical functions. It has been established that one of the most sensitive systems to toxic effects is lipid metabolism, which plays a key role in energy supply and structural organization of cells. In this regard, the study of the influence of mycotoxins on the lipid profile and lipid peroxidation processes in fish is an important task for understanding the mechanisms of toxicosis and developing measures to protect the health of aquatic organisms.The aim of this work was to study the effect of mycotoxin T2 on key indicators of lipid metabolism, the intensity of lipid peroxidation (LPO) and the state of antioxidant protection in carp (Cyprinus carpio L.). Research methods. The experiment was conducted for 14 days, using four groups of fish: a control group (without toxin) and three experimental groups with different concentrations of mycotoxin T2 in water (1.0 μg/l, 2.0 μg/l and 5.0 μg/l). Samples of liver and white skeletal muscle tissues were taken for biochemical analyses.The content of total lipids and their fractions (triglycerides, phospholipids, cholesterol) was determined. The intensity of LPO was assessed by the level of malondialdehyde (MDA) and the content of diene conjugates. Additionally, the activity of antioxidant defense enzymes (superoxide dismutase, catalase, glutathione peroxidase) and the key enzyme of lipid metabolism – lipase were analyzed.Results. Studies have shown that the effect of mycotoxin T2 causes significant disorders of lipid metabolism, which had a pronounced dose-dependent nature. A significant increase in the content of total lipids and their triglyceride fraction in liver tissues was established in all experimental groups, which indicates the development of fatty dystrophy. At the same time, an intensive increase in the level of MDA and diene conjugates was observed, especially in the liver, which indicates an increase in lipid peroxidation processes and massive damage to cell membranes. The reaction of the antioxidant system had a two-phase nature: at low concentrations of the toxin, the activity of enzymes increased as a compensatory reaction, while at high doses its inhibition was noted, which indicated the depletion of protective mechanisms. In addition, a significant decrease in lipase activity was recorded, which explains the mechanism of triglyceride accumulation in tissues.Conclusions. The results obtained confirm that mycotoxin T2 is a powerful inducer of oxidative stress and leads to profound disturbances in lipid metabolism in cyprinid fish. These data are important for assessing the environmental risks associated with water pollution and have practical significance for developing strategies for protecting aquatic organisms in aquaculture.