Evaluation of physiological preparedness for reproductive function of domesticated beluga females and females grown from eggs in artificial conditions

Abstract

The article highlights the problem of significant reducing the number of beluga at the beginning of the XXI century, which resulted in restoring its population artificially. The formation of repair and brood stocks is slowing down due to a significant shortage of producers of natural generation. Artificial reproduction of beluga is currently carried out due to domestication of fish, as well as by growing mature individuals on “from eggs to eggs” principle. Producers grown in the hatcheries often have metabolic disturbances, signs of physiological exhaustion, and a modified biochemical composition of oocytes. All these deteriorate the reproductive functions of the producers. There have been presented the results of studying physiological preparedness of beluga producers to spawning campaign carried out by the Caspian branch FSBO “Glavrybvod” at the Sergievsky sturgeon hatchery. The objects of the study were females caught in the natural environment and domesticated in the hatchery, as well as sixteen-eighteen-year-old females from their own broodstock. Physiological readiness for spawning was assessed by a complex of physiological and biochemical parameters of blood and the amount of accumulated plastic and energy substances in oocytes in the form of proteins and lipids. It was revealed that domesticated females were better prepared for pituitary injections than females from the broodstock. This was justified by both physiological and biochemical parameters, as well as by the coefficient of polarization of oocytes. Eggs of females grown in the hatchery conditions are smaller (1.3 times smaller) and the number of triglycerides in them is 4.35 times less than in those of domesticated fish. In addition, the accumulation of protein and lipids by oocytes differs greatly in broodstock female species due to heterogeneity of their functional state.