Scientific publications

Studies of the mechanisms regulating the ion-salt and acid-base balance in the organism of juvenile sterlet acquire special relevance in connection with its possible acclimation to habitats with varying salinity and acidity. In aquarium conditions, two series of experiments were carried out, investigating the effect of ambient salinity and pH on the activity of Na+/K+-ATPase in the gills and muscles of juvenile sterlet, Acipenser ruthenus L. (average body mass ~ 50 g): in the first series juvenile sterlet were reared in three aquariums with different salt concentrations (control – 0.3, 3, 6 ‰); in the second series juvenile fish were kept in water with 0.3 ‰ salt concentration in three aquariums with different pH values: 7.0, 8.0, and 9.0. A significant (р < 0.05) increase in Na+/K+ -ATPase activity was observed in the gills and muscles of fish under salinity increase to 6 ‰, and when the water pH in the aquariums increased from 7.0 to 9.0, the activity of the enzyme declined significantly (p < 0.05). It is shown that activation / reactivation of Na+/K+ -ATPase in the gills and muscles of fish is one of the important mechanisms of biochemical adaptation in juvenile sterlet, aimed at maintaining homeostasis when acclimating to a change in ambient salinity and pH.