Change in the activity of enzymes of energy and carbohydrate metabolism in pink salmon smolts Oncorhynchus gorbuscha (Walb.) with change in environmental salinity

The activity of key enzymes of energy and carbohydrate metabolism (cytochrome c oxidase (CO), lactate dehydrogenase (LDH), aldolase, glucose-6-phosphate dehydrogenase (G6PDH) and 1-glycerophosphate dehydrogenase (1-GPDH)) was studied in smolts of pink salmon Oncorhynchus gorbuscha (Walb.) from the White Sea in a cage experiment simulating its transition from freshwater to marine environment. A decrease in the activity of CO, G6PDH, 1-GPDH and an increase in LDH and aldolase in juveniles with increasing water salinity were revealed. The obtained results allow us to assume that in the studied pink salmon there is a redistribution of energy substrates between the reactions of aerobic and anaerobic metabolism towards an increase in anaerobic ATP synthesis. This may indicate the realization of adaptive mechanisms of metabolic restructuring in pink salmon juveniles, aimed at providing energy for the osmoregulation process when the salinity regime of the habitat changes.