This work is licensed under Creative Commons Attribution–NonCommercial International License
(CC BY-NC 4.0).
The activities of PO and P5CD enzymes of proline catabolism have been studied in different organs of trout (Parasalmo mikiss) before spawning and during spawning, as well as the effect of citruline on the activity of these enzymes again before spawning and during spawning. PO and P5CD activities have been determined according to the generated amount of glutamate. The obtained data were compared with different organs of carp fish (Cyrpinus carpio) with the activities of these enzymes up to spawn and during spawn. The studies have shown that the activities of enzymes of proline catabolism of both trout and carp fish significantly increase, and citruline has a stimulating effect on the activities of these enzymes in both organisms.