Chapters authored
Relationship between Plasma Proteins and Boar Semen Freezability
Currently, there is great interest in using frozen boar semen to enhance pig-breeding processes. Yet semen freezability, as well as its limited lifespan in the uterus, limits the efficacy of such a procedure. Pig spermatozoa membrane is less stable and more sensitive to low temperatures as it contains lower levels of cholesterol. It is also highly susceptible to lipid peroxidation (LPO) during freezing, since it is rich in polyunsaturated fatty acids (PUFA). Seminal plasma (SP) has beneficial effects on post-thaw semen quality and its composition may have a genetic basis, specifically in protein content. To date, studies on boar semen freezability have focused on sperm cell proteins with very little attention having been paid to SP proteins. In boar SP, there are 82 identified proteins with spermadhesins (90%) and fibronectins (FN) the most abundant. The only plasma protein thus far identified as a freezability marker is FN1. Other plasmatic proteins of recognized importance in the freezing of porcine semen are: DQH, HSP90AA1, NPC2, L-PGDS, ß-HEX, SOD, and PON-1. The purpose of this chapter is to examine the most efficacious elements of the above plasma proteins with regard to their role as biological or potential biological markers of porcine semen freezability.
Part of the book: Animal Genetics
Biological Signals of Sperm Membrane Resistance to Cryoinjury in Boars
Despite the great progress achieved in the cryopreservation of boar semen, it has not been possible to effectively counteract the negative effects on fertility and prolificacy. The boar sperm membrane (SpM) has a particular composition of phospholipids, cholesterol, and proteins that make it highly sensitive to freezing. Just at the beginning and during the freezing protocol, the sperm are exposed to factors that destabilize the membrane and increase the sensitivity to cholesterol efflux and lipid peroxidation. This is a series of events similar to physiological capacitation; they are commonly called cryocapacitation. All the molecules reported as freezability marker and those considered potential markers are directly or indirectly related to the physiology of the SpM. The above gives rise to intensify studies tending to assess their importance as facilitators of the boar semen freezing.
Part of the book: Cryopreservation Biotechnology in Biomedical and Biological Sciences