A full-system study of neuroendocrine regulation of fish reproduction

Abstract

The participation of the hypothalamo-hypophysial neurosecretory system (HHNS) in the initiation of energy-consuming migration and spawning behaviors and the completion of spawning by suppressing the hyperactivity of the target glands, which ensures the body transition to energy-saving plastic metabolism was established by ecological-histophysiological full-system studies. The analysis of the HHNS key role in these processes made it possible to develop a constructive working scheme for the neuroendocrine integration of fish reproduction on the principle of self-regulation. In order to increase the fish factory reproduction biotech efficiency new methods for controlling of its biotechnology have been developed on this basis. The technology of preparation and the results of industrial tests of the effectiveness pituitary preparations developed to enhance fish maturation: isolated anterior and posterior pituitary lobes (APL and PPL) of the pituitary gland are presented in this part of the research. The increase degree of the of fish farming producers use average of 15% was proved by production (industrial) tests of the effectiveness of the use of the drug APL at sturgeon fish breeding plants of the lower rivers Volga and Don. To increase the effectiveness of the drug APL usage, its dependence on the degree of preparedness of females for puberty and ovulation was established by the most objective assessment of their individual fish-breeding qualities by the degree of the oocyte nucleus polarization. The most important indicators of the producers physiological state and offspring are stored after the use of APL not only within the production norm, but also qualitatively exceed the “control” — the whole pituitary gland. In order to avoid significant production loss of pituitary dry matter (especially when removing PPL) and the high consumption (35–40%) of the pituitary glands to stimulate the maturation of fish males a “Method for stimulating puberty of male fish” by the isolated posterior pituitary lobe was developed, providing waste-free technology for the preparation and usage of both drugs. Possible prospects for improving methods of stimulating sexual maturity of fish breeders are discussed.