Identification of proteoforms of albumin and kallikrein in stallion seminal plasma and their correlations with sperm motility

The aim of this study was to identify the proteoforms of albumin and kallikrein in stallion seminal plasma (SP), and to determine their correlations with sperm motility parameters. The experimental material consisted of ejaculates from 8 stallions, which were collected during the breeding and non-breeding seasons (BS and NBS, respectively). SP proteins were identified by 2-D PAGE and mass spectrometry (MALDI TOT/TOF MS). Sperm motility parameters were analyzed using the CASA system. Protein expression (integrated optical density-IOD) of albumin proteoforms 1 (ALB 1) and 2 (ALB 2) and kallikrein proteoforms 1 (KAL 1) and 2 (KAL 2) was correlated (p⟨0.05) with sperm motility parameters (total motility and progressive motility) during the BS. No significant correlations were found between the expression of albumin or kallikrein and sperm motility parameters during the NBS. The presence of correlations between the expression of ALB 1, ALB 2, KAL 1, KAL 2 and selected sperm motility parameters could suggest that the analyzed components of the SP belong to the group of fertility-associated proteins (FAPs).

Effect of boar ejaculate fraction, extender type and time of storage on quality of spermatozoa

The aim of this study was to investigate the effect the sperm-rich fraction (F1) and the post-F1 fraction (F2) on the quality of boar spermatozoa stored in a liquid state. Ejaculates were collected from three Polish Landrace boars. Each ejaculate fraction was diluted with BTS short-term extender and Safe-Cell Plus (SCP) long-term extender and stored for seven days (D1-D7) at 17°C. Analyses included sperm motility parameters, normal apical ridge (NAR) acrosomes and plasma membrane integrity (PMI). Prior to the dilution of fractions, marked changes (p<0.05) were noted between F1 and F2 in progressive motility (PMOT), velocity average pathway (VAP) and velocity straight line (VCL). After the ejaculate was diluted, the type of fraction and type of extender significantly affected (p<0.05) PMOT, being markedly higher (p<0.05) for F1 extended in BTS. No marked changes (p<0.05) were observed between F1 and F2 extended in SCP for any of the analyzed sperm quality parameters during seven days of storage. Significantly higher (p<0.05) values of sperm quality parameters were noted in F1 compared with F2 for BTS on D7 of storage. The results of the four-way ANOVA analysis indicate that boar, fraction of ejaculate, extender type and day of storage had significant effects on the quality of boar stored spermatozoa. The F1 was characterised by higher quality of spermatozoa during storage in comparison with F2 in the short-term extender. Using the long-term extender containing the proteins allowed for a better application of F2, which could be important for the pig industry.

Effects of storage in different semen extenders on the pre-freezing and post-thawing quality of boar spermatozoa

The aim of this study was to investigate the effects of storage of semen in different commercial extenders on the pre-freezing and post-thawing quality of boar spermatozoa. Semen was diluted in BTS, Androhep (AH) and Gedil (GD), stored for 24 h at 17°C, and then frozen in accordance with the cryopreservation protocol. Analyses of the quality of spermatozoa included: motility, normal apical ridge (NAR) acrosome, plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), measurements of ATP content and activity of superoxidase dismutase (SOD) and glutathione peroxidase (GPx). Prior to the freezing process, no significant effect of the extender on the sperm quality parameters was noted. After thawing the spermatozoa it was demonstrated that the type of extender used influenced PMI, MMP, ATP content and activity of GPx. In the AH extender the percentage of spermatozoa with PMI and ATP content in spermatozoa was significantly higher (P<0.05) as compared to the BTS or GD extenders. In addition, semen stored in the AH was characterised by a statistically higher (P<0.05) percentage of spermatozoa with MMP and increased activity of GPx as compared with the BTS. The results obtained indicate that for the cryopreservation process, boar spermatozoa stored for 24 hours in liquid state can be used. However, the type of extender used prior to freezing may have a significant effect on the post-thawing quality of the spermatozoa. The AH extender better secured the quality of thawed boar spermatozoa as compared with the BTS or GD.

Effects of the platelet-activating factor (PAF) on selected quality parameters of cryopreserved bull semen (AI) with reduced sperm motility

The aim of the study was to determine the effects of platelet-activating factor (PAF) on selected quality parameters of cryopreserved bull semen with reduced sperm motility used for artificial insemination. The aim of experiment 1 was to identify the optimal concentration of the phospholipid able to preserve sperm viability. Cryopreserved semen was treated with different PAF concentrations: 1×10-5M, 1×10-6M, 1×10-7M, 1×10-8M and 1×10-9M. The experiment demonstrated that PAF at concentration 1×10-9M increased most the sperm viability parameters (motility parameters, plasma membrane integrity and mitochondrial function) after 120 min of incubation of thawed semen at 37°C. Cryopreserved bull semen with reduced sperm motility (below 70%) was supplemented with PAF in a concentration of 1×10-9M. A statistically significant increase in sperm motility, percentage of linear motile spermatozoa and VSL value was observed after 120 min incubation of sperm with 1×10-9M PAF. Sperm supplementation with PAF also had positive effects on plasma membrane integrity and percentage of spermatozoa with preserved mitochondrial transmembrane potential, but the differences were not statistically significant. The results indicated positive effects of PAF supplementation at a concentration of 1×10-9M on the selected sperm quality parameters in cryopreserved bull semen with reduced motility.

Dialysis of boar semen prior to freezing-thawing: its effects on post-thaw sperm characteristics

Low-molecular weight components of the seminal plasma have a detrimental effect on sperm function. The present study was undertaken to evaluate the effect of the removal of low-molecular weight components by dialysis on sperm characteristics prior to and after freezing. Semen, collected from 5 boars, was extended in Kortowo-3 extender (K-3, Poland) and cooled for 3h (control non-dialysis) or dialyzed for 5h in semi-permeable dialysis bags of 12-14kDa molecular weight cut-off prior to freezing. The semen samples were diluted in lactose-hen egg yolk-glycerol extender (lactose-HEY-G) or lactose-lyophilized lipoprotein fractions-glycerol extender (lactose-LPFo-G), packaged into aluminum tubes and frozen in a controlled programmable freezer. Pre-frozen and frozen-thawed spermatozoa were evaluated for motility, plasma membrane (SYBR-14 and propidium iodide) and acrosome integrity, mitochondrial function (Rhodamine 123) and ATP content. The results of the study showed that dialysis significantly improved the sperm characteristics prior to freezing. Dialysis enhanced (P<0.05) post-thaw sperm motility, plasma membrane integrity and mitochondrial function, but had no significant effect (P>0.05) on recovery of spermatozoa with intact acrosomes. Furthermore, dialyzed spermatozoa exhibited higher (P<0.05) ATP content compared with the control after freezing-thawing. Consistent inter-boar variability was detected mainly in dialyzed semen following freezing-thawing. These results indicated that the improvement in sperm quality characteristics prior to freezing and the post-thaw sperm recovery were due to the removal of low-molecular weight components from the seminal plasma. It can be suggested that dialysis is effective in improving the post-thaw quality of boar spermatozoa and has also great practical importance in improving the protocols for cryopreservation of semen. Dialysis may also contribute to a better understanding of different mechanisms underlying cryo-induced damage to boar spermatozoa.