The effect of ammonium nitrogen and phosphorus of phosphates on the biochemical parameters of juvenile rudd (Scardinius erythrophthalmus Linnaeus, 1758)

Purpose. To study the physiological and biochemical state of juvenile rudd (Scardinius erythrophthalmus L.) under the chronic effect of high concentrations of ammonium nitrogen and phosphorus of phosphates. Methodology.The study was conducted at the Bila Tserkva Experimental Hydrobiological station of the Institute of Hydrobiology of the NAS of Ukraine. Ammonium chloride and potassium monophosphate were applied in 14-day experiments. During the experiments, we did not violate the bioethics principles. The activities of lactatdehydrogenase and alkaline phosphatase were determined using appropriate test kits. The succinate dehydrogenase activity was determined by a spectrophotometric method. Glutamate dehydrogenase activity was determined by the Khokhlov. The total protein content in the muscles and gills was determined according to the Lowry method, the total lipid content was determined using the “Total lipids” test kit, and the glycogen content was determined by the anthrone method. Findings.Ammonium ions enhance both aerobic and anaerobic respiration processes as evidenced by SDH and LDH activities. On the contrary, the activity of these enzymes decreases due to the action of phosphorus of phosphates. According to ALP activity, it was found that the studied compounds weaken de-phosphorylation processes. These processes significantly increase only at a concentration of ammonium ions above 5.0 mg N/dm3. Only ammonia nitrogen changes the activity of glutamate dehydrogenase, which is actively involved in nitrogen metabolism, orthophosphate ion is not involved in these processes. The glycogen content due to the action of ammonium nitrogen showed a tendency to accumulate at low concentrations, which is obviously associated with the activation of gluconeogenesis processes to ensure the homeostasis of the body under such conditions. The action of phosphorus of phosphates resulted in the use of glycogen to ensure the energy needs of the body. At higher concentrations, a decrease in the processes of its accumulation was observed, probably as a result of its parallel use for adaptation processes. As a result of the enzymatic regulation of metabolic processes, the contents of lipids and protein in the tissues of juvenile rudd change significantly due to the actions of the studied compounds. Originality. The obtained data supplement and expand the existing scientific knowledge on the patterns of changes in enzymatic activities of energy and protein metabolisms as well as dephosphorylization processes in the tissues of juvenile fish species under the effect of high concentrations of nutrients, in particular ammonium nitrogen and phosphorus of phosphates. Practical value. Similar changes in the amount of enzyme activity and the content of energy-intensive substances (proteins, lipids, glycogen) can be used as a biochemical marker indicating the presence of a toxic load in a water body. It can include elevated levels of ammonium nitrogen and phosphorus of phosphates, which is possible as a result of the irrational use of ammonium and phosphorus fertilizers on agricultural areas and runoff from them, effluents from livestock complexes and volley of discharges from the industry.