Cryopreservation of ram-sires semen with usage of synthetic extenders

Abstract

The retrospective analysis of the invention of synthetic extender for ram’s semen cryopreservation, developed by different authors, is presented in the article. It has been shown, that in order to ensure the biological usefulness of the extenders for semen, they should contain phospholipids, electrolytes, non-electrolytes, cryoprotectants, biologically active substances and other ingredients, due to the many physical and chemical processes that occur in the process of cooling and deep freezing of spermatozoa. Researchers have established the protective role of phospholipids from chicken egg in protecting sperm from cold stroke. It has been proven that the usage of dried yolk and egg powder in extenders during the cryopreservation of sperm provides a high protective effect of sperm at the level of natural yolk. The degree of effectiveness of different electrolytes in preventing cold shock has been indicated. Their protective function not only for the creation of buffer properties of extender, but also for the reduction of freezing point of aqueous solutions has been emphasized. The importance of sugars in the composition of ram’s semen cryopreservation extenders has been proven. They reduce the conductivity of semen, thereby reducing sperm agglutination, act as antioxidants, inactivate spermolysins, increase the viscosity, structure water, prevent excessive hydration of proteins and organelles are used by sperm for respiration and glycolysis. It has been experimentally proven by a number of researchers, who studied the protective effect of antioxidants for the development of synthetic extender, that the process of cryopreservation intensifies the lipids peroxidation, which disrupts the orderliness of the sperm membranes structure and thereby the oxidation products damage the plasma membrane and adversely affect on the energy of sperm. A perspective direction in the development of new extenders for animal reproduction biotechnology has been highlighted, both for in vitro fertilization of oocytes and for freezing and thawing of semen using the metal nanoparticles.