Increasing the biopotential of juvenile muksun Сoregonus muksun by ultra-weak pulsed magnetic fields in fish farming conditions

The results of a production experiment with juvenile muksun carried out at the Sob fish hatchery (Kharp village, Yamal-Nenets Autonomous Okrug) are presented. The purpose of the experiment, as an important element in the compensatory measure for the reproduction of valuable fish species, was to increase the biopotential of juveniles for their release into the Ob. For several days before hatching, the embryos were treated with ultra-weak pulsed magnetic fields in a specific frequency range. In the postembryonic period, control and experimental muksun juveniles were studied using morphometric and cytological-histological methods. It was established that the experimental juveniles during the entire growing period exceeded the control ones in most parameters, and before release into the Ob River for feeding, the weight of the experimental muksun fry significantly exceeded the weight of the control juveniles. When assessing the nature and degree of connection between morphometric parameters using cluster analysis, it was shown that by the time the experiment was completed, a higher correlation between traits was observed in the experimental juveniles, which is additional confirmation of its increased balance in the development process. The level of formation of the gonads of the reproductive system in the experimental individuals also exceeded the development of the gonads of the control ones - in terms of size and rate of sexual differentiation, number and cytometric indicators of germ cells. The data obtained allow us to consider it advisable to apply this approach in the practice of compensatory fish farming.

1. Isakov P.V., Selyukov A.G. (2005). The state of ovaries and osobennosti of the aquarium species of muksun (Coregonidae, salmon-like) in the winter in the Gulf of Ob // Questions of Philosophy. Vol.45. No. 2. Pp.242-250. (In Russ).

2. Isakov P.V., Selyukov A.G. (2010). Whitefish in the ecosystem of the Gulf of Ob. Monograph / Tyumen: TSU. 184 p. (In Russ).

3. Lukin A.A. (2000). Coregonus lavaretus whitefish production system in the republic of multi-factor pollution // Environmental issues. Vol.40. No. 3. Pp.425-428. (In Russ).

4. Lukin A.A., Sharov A.N. (2002). Pathological microstructures of genetic organisms of female whitefish Coregonus lavaretus oz. Imandra // Questions of ichthyology. Vol.42. No. 1. Pp.114-120. (In Russ).

5. Mikodina E.V., Sedova M.A., Chmilevsky D.A. [et al.] (2009). Histology for ichthyologists: Experience and advice. M.: VNIRO. 112 p. (In Russ).

6. Matkovsky A.K. (2006). Obvious patterns of the dynamics of the abundance of the muksun Coregonus muksun of the Ob river // Questions of fisheries. Vol.7. No. 3(27). Pp. 505-521. (In Russ).

7. Pak I.V., Moiseenko T.I., Sergienko L.L. [et al.] (2013). Variability of cytogenetic parameters of whitefish of the Ob-Irtysh basin // Ecology. No. 4. Pp. 310-312. (In Russ).

8. Reshetnikov Yu.S., Popova O.A., Kashulin N.A. [et al.] (1999). Assessment of the well-being of the fish part of the aquatic community based on the results of morphopathological analysis of fish // Successes of modern biology. Vol.119. No.2. Pp. 165-177. (In Russ).

9. Romeis B. (1953). Microscopic technique. M.:Publishing House of Foreign Literature. 718 p. (In Russ).

10. Selyukov A.G. (2002). Reproductive system of whitefish (Coregonidae, Salmoniformes) as an indicator of the O. B. II constellation. Muksun's genitals Coregonus muksun // Questions of philosophy. Vol. 42. No.2. Pp. 225-235. (In Russ).

11. Selyukov A.G. (2007). Morphofunctional status of fishes of the Ob-Irtysh basin in modern conditions. Tyumen: Tyumen State University. 184 p. (In Russ).

12. Selyukov A.G. (2012). Morphofunctional changes in fish of the Middle and Lower Ob basin under conditions of increasing anthropogenic influence // Questions of ichthyology. Vol. 52. No. 5. Pp. 581-600. (In Russ).

13. Selyukov A.G., A.A. Bogdanova, S.A. Selyukova (2019). Early gametogenesis of whitefish in aquaculture outside the natural range. Second. Gametogenesis and formation of the germ cell fund in muksun and chira fingerlings // Fish farming and fisheries. No. 12(167). Pp. 62-70. (In Russ).

14. Selyukov A.G., Efremova E.V., Selyukova S.A., Shuman L.A. (2020 a). Problems of compensatory fish farming: increasing the adaptive potential of Coregonus nasus (Pallas) in early ontogenesis by weak magnetic fields. 1. Morphometric analysis //Fish farming and fisheries. No. 11. Pp. 32-46. (In Russ).

15. Selyukov A.G., Selyukova S.A., Shuman L.A., Yefremova E.V. (2020 b). Problems of compensatory fish farming: increasing the adaptive potential of Coregonus nasus (Pallas) in early ontogenesis by weak magnetic fields. 2. Histological analysis // Fish farming and fisheries. No. 12. Pp. 28-40. (In Russ).

16. Solodilov A.I. (2000). Patent No. 2155081. A method of processing a substance with a magnetic field and a device for its implementation. M. 2000.

17. Ding Y., Lin Z., Qifeng Z., [et al.]. Abundance of early embryonic primordial germ cells promotes zebrafish female differentiation as revealed by lifetime labeling of germline. Marine Biotechnology. 2019. 21, Pp.217228.

18. Kurokawa H., Saito D., Nakamura S. [et al.]. (2007). Germ cells are necessary for sexual dimorphism in the gonads of the medaka. Proceedings of the National Academy of Sciences of the USA. 104, 43. Pp.16958-16963.

19. Lewis Z.R., McClellan M.S., Postlethwaite J.H. [et al.]. (2008). Female-specific increase in primary germ cells marks sexual differentiation in the three-walled stickleback (Gasterosteus aculeatus). J. Morphol. 269, 8. Pp. 909-921.

20. Tanaka M., Saito D., Morinaga S., Kurokawa H. (2008). The crosscurrent between germ cells and somatic gonad cells is crucial for the sexual differentiation of gonads in bony medaka fish (Oryzias latipes) // Dev Growth Difference. 50, 4. Pp.273-278.