A Comparative Assessment of Hematological Indicators of Paddlefish (Polyodon Spathula Walbaum, 1792) when Obtaining Mature Oocytes for Food and Fish-Breeding Purposes

摘要

This study was aimed at assessing the state of reproductive function according to the fish-breeding, hematological, and morphophysiological parameters of the female paddlefish Polyodonspathula (Walbaum, 1792), which have repeatedly matured and spawned for food and fish breeding purposes. The work was carried out in 2019-2020 at the BIOS experimental aquaculture complex in the Astrakhan region. It has been shown that the age of the fish, the number of maturations, and the interspawning periods are the most important factors that made it possible to compare the fish-breeding and biological parameters of paddlefish females that matured and spawned in 2020. The stability of the coefficient of fatness explains the degree of activity of the reproductive function of female paddlefish. Significant differences in morphophysiological parameters between age groups, as well as between females from which caviar for various purposes was obtained, have not been shown. The leukocyte formula of the blood of the studied paddlefish females showed a lymphoid character and viscoelastic properties of leukocytes, as well as the cell agglutination noted during the separation of individual blood components. The distribution of leukocyte types differed slightly depending on the age composition (CV = 35.55 and 35.23%, P < 0.05; CV = 23.96 and 30.92%, P < 0.05, 23, and 18 years, respectively). The results of hematological studies showed that the younger generation (18 years old) of female paddlefish, from which caviar was obtained for food purposes, is better adapted than the older generation (23 years old), and the development of reproductive function is less susceptible to stress factors during maturation. A different picture is observed for fish that have spawned for fish breeding purposes.