Sex formation in carp and factors influence on its differentiation

Abstract

The mechanisms that determine and regulate the sex of carp have been discussed in the article. Studies of the mechanisms that determine and regulate sex in fish are of considerable interest from the point of view of the possibility of active exposure such as both on the processes of individual growth and on the possibility of increasing the number of individuals of the sex having economically valuable qualities (growth rate, survival rate, quality and quantity of eggs, etc.). Differentiation underlies morphogenesis and occurs mainly in the process of embryonic development, as well as in postembryonic development and in some organs of the adult organism. The main factor of differentiation is the differences in the cytoplasm of early embryonic cells due to the heterogeneity of the cytoplasm of the egg and the specific infl uence of neighboring cells such as induction. It has been found that both heredity and external factors (temperature and pH of water during incubation, gamete size, feed quality, age selection of producers) influence the sex of carp. When feeding carp brood fish with a low protein diet during their reproduction, females dominated the offspring (62 %), and males dominated the high protein diet (56 %). When reproducing older carp brood fish (10 years or more) males predominated in the offspring, with the selection of middle-aged (7-8 years) males also prevailed, and when selecting young (4-5 years old), females prevailed. Homogeneous selection of gametes, i.e. when fertilizing large-sized eggs with large sperms, significantly more females have been obtained in the offspring, and when using small gametes, males dominated in the offspring. With heterogeneous types of gamete selection, sperm played a crucial role in determining sex.