Study On Cryopreservation Of Boar Semen

Artificial insemination(AI) is an important tool for distribution of the genetic potential of males, the aim of sperm freezing is the production of a bank of sperm cells to be used for it. The ability of fertilizing after cryopreservation is an important factor of high-pregnancy rates in mammalian after insemination, and it being associated with the quality of sperm after freeze-thaw process. However, various biochemical and anatomical compartments in the spermatozoa cells may be altered during cumbersome freeze-thaw process, and the current methods for cryopreservation of boar spermatozoa are unsatisfactory. They have poorer motility, plasma membrane integrity, acrosome integrity and in vitro fertilization capability than fresh sperm. The resulting of low fecundity rates and low litter size have made frozen boar semen impractical for the commercial swine producer.Consequently, the first goal of sperm-freezing protocols, including the use of extenders, the choice of sugars, the cooling and warming processes, is to prevent the formation of lethal intracellular ice crystal and to improve sperm motility and viability,and to reduce acrosome and plasma membrane damage during and after cryopreservation. In order to protect the spermatozoa against cold shock, hen egg yolk is widely used as a cryoprotective agent in domestic animals semen freezing extenders. The protective action of yolk is largely presumed to be due to low density lipoproteins(LDL).The effect of LDL on sperm quality of bull and northern pike(Esox lucius) after freezing-thawing have been reported,but no study has been made to evaluate the effect of LDL on boar sperm motility and other characteristics.The beneficial effect of sugar(glucose or fructose)supplementation of the extender on the past-thaw viability of mammalian sperm cells have been reported in many studies.Until now, some studies have reported results of disaccharides (trehalose, sucrose, lactose) effects on mouse, bull, ram,and goat spermatozoa characteristics of motility, viability, intactness and fertility after freezing and thawing, but no authors evaluated the boar spermatozoa quality after freezing in trehalose-supplementation. Furthermore, during the production of frozen sperm, the sperm cells are exposed to a number of potential hazards. The factors include dilution, incubation, exposure to DNA stains, laser light, centrifugation and freezing. These factors may affect the survival capacity and fertilization potential of sperm. However, little is known about the effect different semen handling procedures and processing techniques may have on the integrity of DNA in boar sperm.In order to improve the quality of frozen-thawed boar semen and protect spermatozoa...