The Usefulness of Selected Physicochemical Indices, Cell Membrane Integrity and Sperm Chromatin Structure in Assessments of Boar Semen Sensitivity

The effects of a glyphosate-based herbicide on the bovine gametes during an in vitro embryo production model

Roundup® (R), while it is the most used herbicide globally, and its residues are ubiquitous in urban and suburban areas, its impact on vertebrates' safety remains highly debated. Here, in three in vitro experiments, we investigated the effects of a very low dose (1 ppm) of R on the fertilization capacity and embryo development in cattle. In the first experiment, frozen-thawed bull semen exposed to R for 1 h exhibited reduced motility parameters but unaffected fertilization ability. However, after in vitro fertilization, the rates of embryo formation were significantly lower compared to the untreated controls. In the second experiment, oocytes exposed to R during in vitro maturation showed reduced cleavage rates, and the embryo yield on days 7, 8, and 9 of embryo culture was significantly lower than that of the controls. In the third experiment, oocytes were matured in the presence of R and in a medium containing both R and Zinc, chosen to offer antioxidant protection to the oocytes. Day-7 blastocysts were analyzed for the expression of genes associated with oxidative stress, apoptosis, and epigenetic reprogramming. Exposure to R markedly suppressed embryo formation rates compared to the controls. The combination of R with Zinc restored the blastocyst yield, which on days 8 and 9 was comparable to that of the controls and higher than the groups exposed only to R on all days. The gene expression analysis revealed that R promotes oxidative stress development, triggers apoptosis, and induces epigenetic changes in developing embryos, while zinc presence alleviates these adverse effects of R. These findings imply that even at very low doses, R could be highly toxic, leading to functional abnormalities in both gametes, potentially affecting fertility in both genders.

Analysis of changes in the morphological structures of sperm during preservation of liquid boar semen in two different seasons of the year

Animal fertility is the result of a combination of genetic, physiological and environmental factors. Assessment of semen quality plays a key role in determining the reproductive performance of boars. The aim of the study was to determine the effect of two seasons of the year on the morphology, morphometry, cell membrane integrity and mitochondrial activity of sperm during storage of liquid boar semen at 17 °C. The study was carried out using 20 boars. Four ejaculates were collected from each boar in each of two seasons of the year. All tests were carried out five times: at 1, 24, 48, 96 and 168 h during storage. The results showed that sperm in ejaculates collected in summer are more sensitive to storage conditions than those from ejaculates obtained in winter. The percentage of sperm with morphological defects was shown to increase with the storage time of the diluted ejaculates, particularly between 96 and 168 h of preservation. In summer, the percentage of sperm with an intact cell membrane and the percentage with high mitochondrial membrane potential are much lower than in winter, at every hour of semen preservation. In the case of boars used for artificial insemination, it is worth taking into account the season when the semen is collected, especially if it is to be stored in liquid form. Assessment of sperm cell structures during storage of liquid semen should be implemented at insemination stations and should be carried out more often in summer.

Integrity of Sperm Cell Membrane in the Semen of Crossbred and Purebred Boars during Storage at 17 °C: Heterosis Effects

Simple Summary

The cell membrane of spermatozoa is the main structural element of these gametes. In boars, due to its structure, it is most susceptible to various types of damage induced by various factors. Artificial insemination in pigs mainly involves the use of liquid semen preserved at 17 °C. Thus, it is important to monitor this semen during its storage. In practice, the changes that can take place in sperm during the preservation and storage of boar semen are not analysed. Furthermore, considerable variation is observed in the characteristics of boar semen, which may depend on the breed or crossbreeding variant of the boar. Crossbred boars are often used in artificial insemination, because they not only easily produce ejaculates with good parameters, but also have good libido characteristics. However, despite the benefits of artificial insemination with semen of crossbred boars, there is insufficient knowledge of the sensitivity of cell structures to conditions associated with semen storage in comparison with boars of the parent breeds. For this reason, a study was conducted to analyse changes in the integrity of sperm cell membranes taking place during the storage of semen collected from Duroc × Pietrain crossbred boars and purebred boars of the parent breeds. The sperm of Duroc × Pietrain crossbred boars were found to be less sensitive to the conditions of semen storage and to better retain cell membrane integrity than the sperm of purebred males, which was confirmed by calculating the heterosis effects for semen assessed at different hours of storage at 17 °C.

Abstract

The aim of the study was to assess changes in the integrity of sperm cell membranes during the storage of semen collected from Duroc × Pietrain crossbred boars and purebred boars of the component breeds. To compare the cell membrane integrity of sperm heads in crossbred and purebred boars, heterosis effects were estimated. The study was conducted on 48 ejaculates collected from Duroc × Pietrain crossbred boars and from purebred Duroc and Pietrain boars used for artificial insemination. Microscope slides were prepared from each ejaculate for the evaluation of the cell membrane integrity of the sperm, at 1, 24, 48, 72, and 96 h after collection of the ejaculate. Diluted ejaculates were stored at 17 °C. Sperm membrane integrity was analysed by two methods: SYBR-14/PI and eosin–nigrosin. Our results showed that the cell membrane integrity of sperm heads changed with storage time, but the extent of the changes varied depending on the genetic group of boars. The semen of Duroc × Pietrain crossbreds was clearly seen to be less sensitive to storage conditions than that of boars of the parent breeds, which was confirmed by the calculated heterosis effects. The percentage of sperm with an intact cell membrane was higher in crossbred boars than in purebred boars (p ≤ 0.05). In addition, significantly fewer moribund sperm spermatozoa and spermatozoa with a damaged cell membrane were observed in crossbred boars (p ≤ 0.05). In the semen of purebred Duroc and Pietrain boars, the cell membrane integrity of the sperm should be assessed more often during storage than in the semen of Duroc × Pietrain crossbred boars. This study provides valuable information for the development and implementation of semen quality monitoring in crossbred boars and boars of the parent breeds during storage at 17 °C with respect to the cell membrane structure of sperm heads. The evaluation methods used effectively identify damage to the cell membranes of the sperm during semen storage.

Effect of sperm concentration on boar spermatozoa mitochondrial membrane potential and motility in semen stored at 17 °C

The aim of the study was to assess the effect of sperm concentration in the ejaculate on the mitochondrial membrane potential and motility of Landrace boar spermatozoa during storage of diluted semen at 17 °C. The study was conducted on ejaculates collected from 10 boars aged 1.5–2 years. Based on sperm concentration measurements, two groups of boars were identified: Group 1 – boars providing ejaculates with a sperm concentration of at least 500 × 103/mm3 and Group 2 – boars providing ejaculates with a sperm concentration of less than 500 × 103/mm3. Four ejaculates were collected manually from each boar. Each ejaculate was diluted with Biosolvens Plus diluent, and insemination doses were prepared and stored at 17 °C. Mitochondrial membrane potential and motility of spermatozoa were evaluated at each insemination dose. The tests were carried out after 1, 24, 48, 96 and 168 h of storage. Based on the results, it was found that ejaculates with a sperm concentration ≥ 500 × 103/mm3 have a lower share of spermatozoa with high mitochondrial membrane potential than ejaculates with a sperm concentration below 500 × 103/mm3. A high correlation between the share of spermatozoa with a high mitochondrial membrane potential and motility of spermatozoa was demonstrated in the first 24 h and after 96 h of semen storage, which was confirmed by the calculated phenotypic correlation coefficients. Sperm cells in ejaculates with a higher sperm concentration are more sensitive to storage time than spermatozoa in ejaculates with a lower concentration.

Utilization of bull fertility-associated antigen to improve the quality of frozen bull semen

Background and Aim:

The implementation of artificial insemination (AI) is one of the strategies to use superior male semen optimally to improve the genetic quality of livestock. One of the factors that influence AI is a fertility-associated antigen (FAA). This research aimed to examine the effects of FAA extracted from the accessory sex glands of a bull from a slaughterhouse that was added in bull semen freezing medium to increase cattle (bull) fertilization.

Materials and Methods:

This research used a randomized complete block design. It consisted of two research phases, namely, explorative and experimental phases. The first phase involved determining the FAA molecular weight using the SDS-PAGE method, and the second phase consisted of laboratory and field testing, including testing the quality of frozen semen supplemented with FAA extracted from the accessory glands of a bull’s genital organ from a slaughterhouse with various doses (0, 5, 10, and 15 μg in every 200 million progressively motile spermatozoa).

Results:

The results showed that the percentages of bull sperm motility between the groups without and with the additional administration of FAA with a dose of 5 μg did not significantly differ. However, there was a difference between the groups without and with the additional administration of FAA with doses of 10 and 15 μg. After further testing, the highest percentage of sperm progressive motility occurred at a dose of 15 μg/200 million progressively motile spermatozoa (P3), which was equal to 2.59±46.88b (%).

Conclusion:

This research found that not all of the accessory glands (seminal vesicles) of bulls taken from the slaughterhouse contain the FAA. An FAA level between the accessory glands (seminal vesicles) of one cattle to another is different. The addition of the FAA protein from the accessory sex glands of a bull’s organ in cattle semen can improve fertility by increasing the percentage of viability, motility, intact plasma membrane of spermatozoa, and pregnancy rate of bulls and decreasing the sperm capacitation post-thawing.

Dependence of the frequency of sperm defects and dimensions on sperm motility in ejaculates of Polish Landrace boars

An attempt was made to determine the dependence of the frequency of sperm defects and dimensions on sperm motility in ejaculates of Polish Landrace boars. The study was conducted on 393 ejaculates collected from 33 Polish Landrace boars. Ejaculates were grouped according to the percentage of sperm with progressive motility, distinguishing ejaculates in which the percentage of motile sperm was 70% and 80%. In each ejaculate, the frequency of morphological changes in the sperm was determined and morphometric measurements of the sperm were made. Ejaculates with a higher proportion of sperm with progressive motility were found to contain more sperm. The ejaculate volume and sperm concentration in the ejaculate were not found to be directly associated with sperm motility. The frequency of primary defects was linked to sperm motility. Ejaculates with higher sperm motility contained fewer sperm with primary defects. The frequency of minor morphological changes, however, shows no significant dependence on sperm motility in the ejaculate. The primary morphological sperm defects most often found in ejaculates are a proximal droplet and the Dag defect. Both of these morphological forms are more common in ejaculates with lower sperm motility. The most common secondary sperm defects include sperm with a simple bent tail, sperm with a free normal head, and sperm with a distal droplet. These defects were not found to depend on sperm motility in the ejaculate. Sperm cells in ejaculates with greater sperm motility had slightly larger dimensions than sperm in ejaculates with lower sperm motility. Ejaculates with higher sperm motility are preferable for use in practice, not only because more insemination portions can be prepared from them, but also due to the lower frequency of primary defects.

The Effect of Omega-3 Fatty Acids, EPA, and/or DHA on Male Infertility: A Systematic Review and Meta-analysis

The objective was to evaluate the effect of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on sperm parameters including total sperm concentration, sperm motility, sperm DHA, and seminal plasma DHA concentration in infertile men. The literature search was conducted in PubMed, Google Scholar, and Scopus from January 1, 1990 to December 20, 2017. The systematic review and meta-analysis were based on randomized controlled trials in infertile men with DHA or EPA treatments, either alone or in combination with other micronutrients. Three studies met the inclusion criteria: 147 patients in the intervention group and 143 patients in the control group. The analysis showed that omega-3 treatments significantly increased the sperm motility (RR 5.82, 95% CI [2.91, 8.72], p <. 0001, I² = 76%) and seminal DHA concentration (RR 1.61, 95% CI [0.15, 3.07], p =. 03, I² = 98%). Compared with the controls, the interventions did not affect the sperm concentration (RR 0.31, 95% CI [-8.13, 8.76], p =. 94, I² = 95%) or sperm DHA (RR 0.50, 95% CI [-4.17, 5.16], p =. 83, I² = 99%). The observed heterogeneity may be due to administration period and dosage of omega-3 fatty acids across the studies. Funnel plot shows no evidence of publication bias. This meta-analysis indicates that supplementing infertile men with omega-3 fatty acids resulted in a significant improvement in sperm motility and concentration of DHA in seminal plasma.