Effect of zinc on boar sperm liquid storage

MARINI, P. E; FERNÁNDEZ BEATO, L; CANE, F; TEIJEIRO, JM

Frontiers in Veterinary Science

Lausanne : Frontiers Media S.A.

Año: 2023

2297-1769

Storageand transport of liquid boar sperm for artificial insemination (AI) requiresthe addition of solutions called extenders, which increase the volume of theejaculate and help preserve its functional characteristics. Yet, the quality ofsperm decreases over time primarily due to the increased production of reactiveoxygen species (ROS) that damage the plasma membrane. Many commercial extendersare supplemented with additives that mitigate this effect. In semen, zinc issupplied at high concentration on the seminal plasma and helps protect theplasma membrane of sperm. However, zinc in the seminal plasma is diluted andchelated upon addition of extenders for storage, potentially reducing itsantioxidant effect. Here we characterize viability, motility, mitochondrialactivity, DNA integrity and ROS content of boar sperm diluted with Sus (MediNova, Italy) extender supplemented with different concentrations of ZnCl2,at intervals after dilution during 3 days. The ability of sperm supplementedwith 2 mM ZnCl2 to fertilize oocytes in vivo of was also tested. Sperm viability wasover 82% for all treatments. Mitochondrial integrity analysis, measured by Cytochromec activity, indicated a protector effect of Zn, noted as a reduced number of spermwith extensive loss of mitochondrial activity. Acrosomal integrity was improvedby treatment with all concentrations of ZnCl2 tested. Spermkinematics were affected by treatment with ZnCl2, showing higherpercentage of progressive and rapid sperm in doses supplemented with 2mM ZnCl2.ROS levels and chromatin integrity did not show differences between ZnCl2-supplementeddoses and the control. Fertilization rate, total number, live, still born andmummified piglets did not change when sperm were diluted with extendercontaining 2 mM ZnCl2. The presentedcharacterization indicates that Zn addition to Sus extender have a protectiveeffect on mitochondrial sheath and acrosomal membranes; and provides the basisfor further studies aimed to optimize sperm performance in AI