Abstract
At this stage of research, the primary focus in species-specific ex situ conservation is on long-term preservation strategies for germplasm, particularly cryopreservation and freeze-drying of male gametes (spermatozoa). Therefore, the primary objective of the present study was to determine the influence of boar semen cryopreservation and freeze-drying techniques on the molecular quality of spermatozoa as assessed by the proteomic profile and the degree of nuclear chromatin disintegration (SCSA). Semen samples collected from 4 Polish Landrace boars (3 ejaculates/boar) were used for experiments. The extent of inter-specimen differences in cryopreserved and freeze-dried boar spermatozoa was assessed based on semi-quantitative expression levels of selected acrosomal (SPACA1, AFAF) and mitochondrial (UQCRC2) proteins, which may also be valuable predictors of cytophysiological status, metabolic activity and fertilizing capacity of male gametes. The present study has confirmed that the cryopreservation and freeze-drying procedures used did not impair sperm quality, as verified by the degree of sperm nuclear chromatin integrity. Furthermore, considerable individual variability was identified between semi-quantitative proteomic profiles associated with the relative expression of AFAF, SPACA1 and UQCRC2 proteins, depending on the applied method of boar semen preservation.