Boar Semen Preservation: A Proteomic Perspective on Liquid Storage at -17°C

The preservation of boar semen following dilution presents a multifaceted challenge, profoundly influenced by a constellation of external factors, including the boar's intrinsic physiology, husbandry practices, and semen handling procedures. Environmental variables such as temperature, vibration, and microbial contamination further complicate this delicate process. Within a stable environment, the judicious use of artificial insemination (AI) dosages reveals two primary intrinsic determinants of semen preservation elasticity: the sperm's inherent storage capacity and the composition of seminal plasma.

Individual boar sperm exhibit varied sensitivities to their own seminal plasma, reflecting a dynamic interplay between sperm and seminal plasma that regulates the functionality of the sperm membrane, ultimately shaping the semen's quality and longevity. Recent advancements in omics technologies have unearthed an abundance of potential biomarkers within sperm and seminal plasma, offering valuable insights into enhancing semen quality and preservation.

Proteomics, the comprehensive study of protein identification and characterization, holds immense potential for elucidating the intricate processes underlying semen preservation and the molecular mechanisms governing sperm function and preservation. Existing research has established a direct correlation between the preservation ability of boar semen and the abundance and quantity of proteins found in sperm and seminal plasma.

Seminal plasma, the primary milieu for sperm survival, is a complex mixture secreted by the testes, epididymis, and various accessory glands – the seminal vesicles, prostate gland, and bulbourethral gland – and is notably rich in proteins. The fertilization potential, cryopreservation resistance, and storage capacity of sperm are intricately linked to the presence of seminal plasma proteins, with studies in cattle, sheep, stallions, and pigs demonstrating the involvement of specific seminal plasma proteins in safeguarding sperm and maintaining its function.

Sperm proteins themselves are designated as putative biomarkers for intrinsic properties such as fertilization ability, longevity, cryopreservation resistance, and antioxidant stress resistance. Despite these insights into the molecular underpinnings of semen preservation, the inherent instability of sperm during preservation has led to a focus on sperm freezeability and seminal plasma in proteomic studies. The specific changes in sperm protein levels within boar semen preserved in a liquid state at different -17°C remain unclear.