Primary Gonocity in the Embryogenesis of Coregonus nasus in the Aquaculture Outside Their Natural Areal

About the authors:

Nadezhda S. Kolosova, Master Student, Department of Ecological Genetics, University of Tyumen; kolosovans21@gmail.ru

Alexander G. Selyukov, Dr. Sci. (Biol.), Professor, Department of Zoology and Evolution Ecology of Animals, University of Tyumen; ags-bios@yandex.ru

Vera A. Bogdanova, Cand. Sci. (Biol.), Leading Researcher, Aquaculture Laboratory, Berg State Research Institute on Lake and River Fisheries (Saint Petersburg); vera-bogdanova@yandex.ru

Abstract:

This article evaluates the state and level of proliferative activity of primary gonocytes (PG) in the embryos and larvae of broad whitefish from aquaculture. The authors have found that the cytomorphological parameters of gonocytes (the size of cells and nuclei, as well as the number of nucleoli) vary insignificantly in such embryos throughout embryogenesis, slightly increasing closer to the beginning of the postembryonal period. When increasing the number of PG cells by the end of embryogenesis, the proportion of polymorphonuclear cells decreased, while the number of mitosis cells increased. Dual-core PG and gonocytes in the composition of syncytial complexes could be observed during the whole embryogenesis. Syncytial formations in the post-embryonic period were absent. There were insignificant cytomorphological differences between primary gonocytes of embryos obtained from domestic stock and natural spawners.

The authors have observed earlier mitotic activity of the primary germ cells by the time of hatching in embryos of broad whitefish from domestical stock. That seems to depend on the difference in incubation temperatures in regions of different climatic zones.

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