Activity of the antioxidant defense system of the carp organism under the influence of stress factors and the use of milk thistle in feeding

Abstract

Intensification measures in carp farming are accompanied by the emergence of stressors, which negatively affects the productive characteristics and functional state of organs and systems of fish. One of the ways to counteract their negative effects on the body is to stimulate the antioxidant defense system. The aim of the study is to analyze the effectiveness of plant additives with antioxidant properties of milk thistle in carp feeding, under optimal housing conditions (Experiment I) and under the influence of stress factors common in fish farming, namely: pollution of the aquatic environment with nutrients (Experiment 2) and this pollution. complexes with a decrease in the content of dissolved oxygen in water (Experiment 3). The studies used one-year-old carp, which were divided into experimental and control groups within each of the three variants of the experiment. Control groups of fish received feed with a protein content of 23%. Carp of the experimental groups in addition to the feed by granulation was introduced crushed seeds of milk thistle in the amount of 5%. Experimental feeding lasted 20 days. In accordance with the generally accepted methods and purpose of the experiment in fish farming, the physicochemical parameters of the aquatic environment are provided. Indicators of lipid peroxidation (LPO) and activity of the body's antioxidant defense system (ANS) were analyzed. It was determined that when feeding thistle carp under annual conditions under optimal growing conditions in the muscles of the experimental group there is some tendency to increase the content of catalase (by 14.6%), and the content of SOD, TBC products and diene conjugates is at the same level as and in control. In the hepatopancreas, on the other hand, the level of catalase decreases somewhat relative to control and there is a tendency to reduce TBA products and the content of diene conjugates is reduced by 75% (p <0.05). When feeding milk thistle for contamination of the aquatic environment with nutrients in the muscles almost three times the content of SOD (p˂0.01). The content of catalase tends to decrease, and the content of TBA products and diene conjugates increases by 51%. In the hepatopancreas there is a tendency to decrease all of the above indicators relative to the control group. It was found that the introduction of milk thistle in the feed under conditions of complex exposure to stressors in the muscles increases the content of SOD (p˂0,001). The content of catalase and TBA products decreases slightly in the hepatopancreas, the content of SOD (p˂0.001) and diene conjugates (p˂0.001) increases. Therefore, the antioxidant properties of milk thistle are more pronounced as a result of use in the feeding of carp in the presence of environmental stressors, compared with optimal growing conditions.