Stress Preconditioning of Boar Spermatozoa: A New Approach to Enhance Semen Quality*

Abstract

Contents Semen preparation and cryopreservation require finely adjusted procedures. Gametes are sensitive to environmental stresses, so in vitro procedures aim to minimize the inevitable harmful conditions. Applying stress to precondition cells has only been investigated recently. Studies demonstrated that by utilizing a well defined and properly applied hydrostatic pressure (HP) stress treatment to spermatozoa before in vitro storage, cryopreservation or insemination, cell survival and fertility improved compared with untreated controls. The birth of healthy piglets from treated fresh or frozen‐thawed semen demonstrates the in vivo safety of the procedure. Although the biological mechanism is still unclear, several processes incorporating cellular stress response might explain the observations. This paper summarizes results, background, aspects and considerations of HP treatment for porcine semen. The new principle, i.e. to improve the stress tolerance by a defined sublethal stress may outline a new strategy in assisted reproductive technologies with unique theoretical and practical consequences.

Effect of ethanol induced mild stress on post-thawed bull sperm quality

“…Nevertheless, in literature, there are other reports describing cryotolerance improvement of boar and bull spermatozoa following hydrostatic pressure challenge [42,45,46].…”

Upregulation of uncoupling protein Ucp2 through acute cold exposure increases post-thaw sperm quality in zebrafish

“…ROS Mitochondrial uncoupling separates oxidative phosphorylation from adenosine triphosphate 35 (ATP) synthase with energy dissipated as heat, and incomplete or mild mitochondrial uncoupling 36 has been shown to reduce oxidative damage [9]. For example, uncoupling induced by the 37 chemical protonophore 2,4-dinitrophenol (DNP) has been shown to be beneficial for in vitro 38 culture of porcine and bovine embryos [31; 45], and for sperm cryopreservation in rhesus 39 macaques [14] and yellow catfish [19]. Physiological uncoupling is mediated by protein 40 complexes embedded in the mitochondrial inner membrane, most notably the uncoupling 41 proteins (UCPs) [3; 42].…”

Boar management and semen handling factors affect the quality of boar extended semen

“…A study involving 7 hybrid boars has shown that stressing semen with hydrostatic pressure compared to conventional processing resulted in higher progressive motility [103]. In a second part of the latter study, each ejaculate of 14 hybrid boars was split in two and either treated by hydrostatic pressure or processed normally.…”