A New Approach of Sperm Motility Subpopulation Structure in Donkey and Horse

Sustainable Alternatives to the Reduction of Plastic Straws Used with Chilled Equine Semen

Currently, plastic is used being without any limitations. The livestock sector is no stranger to its use. For example, artificial insemination involves the use of different plastic materials, including semen straws and insemination catheters, which increase the levels of waste in our environment. Finding a sustainable solution to avoid plastic materials is a challenge. The aim of this study was to examine different biodegradable materials as alternatives to conventional syringes used for refrigerated equine semen. The materials tested were bamboo, avocado, grass, paper, Kraft paper, wheat, and rice. Bamboo and avocado were selected to continue testing with the refrigerated semen with a lifespan extended by INRA 96®; the rest of the materials did not meet the requirements necessary for preservation. Motility and movement kinetics tests were performed at 24 and 96 h of refrigeration to evaluate semen quality; relative to the control, significantly better results were displayed in regard to the total and progressive motility avocado straws. The kinetic parameters were comparable to the control for both materials and within normal ranges. After performing a microbiological control process for both straws, it was confirmed that there was no bacterial growth in either straw. We can confirm that avocado straws can be used to preserve chilled equine semen, guaranteeing seminal quality while being respectful to the environment.

Comparative Study on the Sperm Proteomes of Horses and Donkeys

The reproductive performance of horse sperm and donkey sperm has been reported to differ. Sperm proteins play a crucial role in sperm viability and fertility. Although differences between species are known, no prior study has investigated disparities in the sperm proteome between horses and donkeys. Therefore, this study characterized and compared the sperm proteomes of horses and donkeys using 4D-DIA mass spectrometry technology. We identified 3436 proteins in horse sperm and 3404 proteins in donkey sperm. Of these, 3363 proteins were expressed in both horse and donkey sperm, with 73 proteins being specifically expressed in horse sperm, and 41 in donkey sperm. According to data analysis, donkeys exhibited a greater percentage of motility and progressive movement in straight-line sperm than horses, as well as lower percentages of static and slow sperm than horses. Joint analysis of the results from the horse and donkey sperm proteomes and their CEROS II-read parameters demonstrated a possible association between sperm proteins and their sperm viability patterns. These findings suggest that there are discrepancies in the expression levels and protein compositions of horse and donkey sperm and that certain specific proteins may be responsible for the differences in performance between these two species.

ProAKAP4 as Indicator of Long-Lasting Motility Marker in Post-Thaw Conditions in Stallions

ProAKAP4, a precursor of AKAP4 (A-kinase anchor protein) found in the flagellum of mammalian and non-mammalian spermatozoa, serves as a structural protein with established correlations to motility parameters across diverse species. This study aimed to determine the proAKAP4 level evolution in thawed stallion semen over a 3 h period, examining its correlation with motility descriptors and mitochondrial membrane potential. Utilizing sixteen ejaculates from four French warmblood stallions, this study involved maintaining thawed samples at 37 °C for 3 h, conducting proAKAP4 enzyme-linked immunosorbent assays (ELISA), computer-assisted sperm analysis (CASA), and mitochondrial membrane potential by JC-1 probe and flow cytometry at 0, 1, and 3 h post-thawing. The findings indicate significant positive correlations (p ≤ 0.05) between proAKAP4 levels and sperm total or progressive motility at all time points analyzed. Spermatozoa velocity descriptors (VAP, VCL, VSL) and spermatozoa lateral head displacement (ALH) display positive correlations (p ≤ 0.05) with ProAKAP4 at the 0 h post-thawing. ProAKAP4 concentration exhibits no discernible difference between batches with or without a cryoprotectant. Notably, proAKAP4 consumption remains insignificant within the initial hour after thawing but becomes significant (p ≤ 0.05) between 1 and 3 h post-thawing. In summary, proAKAP4 demonstrates positive correlations with total and progressive motility in stallion semen for up to 3 h after thawing, albeit showing a noticeable decrease starting from the first hour post-thawing, indicating a progressive consumption as a result of spermatozoa motile activity.

The impact of Origanum Vulgare essential oil supplementation on sperm motility and subpopulation alterations in bulls, dogs, and rabbits

Artificial insemination is a widely adopted method in livestock production for various reasons such as health security and genetic improvement. Although sperm motility is of paramount importance in this technique as it directly influences the sperm's ability to fertilize the oocyte. In previous research on human sperm, we observed that in vitro supplementation with Origanum Vulgare essential oil significantly improved sperm motility and antioxidant activities, all without negatively affecting the integrity of their DNA. Based on these promising results, we considered it crucial to explore the potential effects of supplementation with this essential oil on sperm of other species. In this study, we studied the effects of oregano essential oil supplementation on sperm motility of (bulls = 15) (dogs = 15) and (rabbits = 9) and the changes that in vitro incubation with this oil could induce on sub-motile sperm populations of different species. The results of the study showed that in vitro oregano essential oil supplementation had a significant impact on sperm motility in the three species studied. This improvement in sperm motility was accompanied by an increase in the proportion of subpopulations with high velocity and progressivity: an increase of (2.16%, 10% and 4.84%) for subpopulation 1, (6.50%, 5.5% and 3.17%) for subpopulation 4 in bulls, dogs and rabbits respectively. While the subpopulations representing low motile and non-progressive sperm have decreased. These results suggest that the use of oregano essential oil can be a beneficial approach to improve sperm motility in different species, which can have important implications for the success of artificial insemination.

The ability of donkey sperm to induce oocyte activation and mule embryo development after ICSI

Members of the Equus genus exhibit a fascinating capacity for hybridization, giving rise to healthy offspring. Mules, resulting from the mating of a mare with a jack, represent the most prevalent equid hybrid, serving diverse roles in our society. While in vitro embryo production, particularly through Intracytoplasmic Sperm Injection (ICSI), has rapidly gained significance in domestic horses, the in vitro production in other equids remains largely unexplored. Utilizing donkey sperm for fertilizing horse oocytes not only addresses this gap but also provides an opportunity to investigate donkey sperm's fertilization capability in vitro to further improve donkey ICSI. In this work, we initially studied the localization of donkey sperm Phospholipase C zeta (PLCζ) and assessed the sperm's capacity to induce pronuclear formation and maternal SMARCA4 recruitment upon injection into pig oocytes through ICSI. Subsequently, we investigated the injection of donkey sperm into horse oocytes, evaluating in vitro production up to the blastocyst stage using sperm from different jacks, including frozen and refrigerated samples. Distinct patterns of PLCζ localization were observed for donkey sperm cells compared to their horse counterparts. Additionally, donkey sperm exhibits a reduced ability to induce porcine oocyte activation. However, when injected into horse oocytes, donkey sperm demonstrated sufficient capability to induce oocyte activation as no discernible differences in cleavage or blastocyst rates are observed between in vitro produced mules and horse ICSI embryos. Our study not only delineates PLCζ localization in donkey sperm but also suggests potential differences in the ability to induce oocyte activation in pigs compared to horses while observing no distinctions in pronuclear recruitment of SMARCA4. Interestingly, donkey sperm remains sufficiently capable of inducing horse oocyte activation for in vitro mule blastocyst production.

ProAKAP4 as a motility long-lasting marker in Catalan donkey spermatozoa

ProAKAP4 is identified within the flagellum of spermatozoa in various mammalian species, serving as a structural protein associated with motility parameters. This investigation focuses on the presence of proAKAP4 in donkey sperm, elucidating its localization, molecular characteristics, and its correlation with motility descriptors and mitochondrial membrane potential. Twelve ejaculates from Catalan donkeys were analyzed in this study. The initial steps involved proAKAP4 sequencing and detection through Western blotting and immunofluorescence. Post-thaw assessments were conducted at 0, 1, and 3 h, encompassing proAKAP4 levels, sperm motility analyzed via Computer-Assisted Sperm Analysis (CASA), and mitochondrial membrane potential determined by flow cytometry using the JC-1 stain. The findings reveal that proAKAP4 in donkeys exhibits a characteristic localization at the principal piece of the flagellum, consistent with observations in other mammals. The molecular weight of proAKAP4 is determined to be 100 kDa. Significantly, a positive correlation (p ≤ 0.05) is established between proAKAP4 concentration and both total and progressive motility. The presence of cryoprotectant is associated with a lower proAKAP4 concentration. Notably, proAKAP4 experiences a substantial decrease (p ≤ 0.05) during the initial hour post-thawing. In conclusion, proAKAP4 is identified in donkey sperm, akin to its presence in other mammals. It exhibits a positive correlation with total and progressive motility, its concentration is notably affected by the presence of cryoprotectant with significant consumption observed during the initial hour following thawing. These findings contribute to our understanding of proAKAP4 dynamics in donkey sperm, providing insights that may have implications for semen preservation and reproductive technologies in equids.

A new computational approach, based on images trajectories, to identify the subjacent heterogeneity of sperm to the effects of ketanserin

The identification of kinematic subpopulations is of paramount importance to understanding the biological nature of the sperm heterogeneity. Nowadays, the data of motility parameters obtained by a computer-assisted sperm analysis (CASA) system has been used as input to distinct algorithms to identify kinematic subpopulations. In contrast, the images of the trajectories were depicted only as examples of the patterns of motility in each subpopulation. Here, python code was written to reconstruct the images of trajectories, from their coordinates, then the images of trajectories were used as input to a machine learning clustering algorithm of classification, and the subpopulations were described statistically by the motility parameters. Finally, the images of trajectories in each subpopulation were displayed in a way we called Pollock plots. Semen samples of boar sperm were treated with distinct concentrations of ketanserin (an antagonist of the 5-HT2 receptor of serotonin) and untreated samples were used as a control. The motility of sperm in each sample was analyzed at 0 and 30 min of incubation. Six subpopulations were found. The subpopulation 2 presented the highest values of velocities at 0 or 30 min. After 30 min of incubation, the ketanserin increased the values of the curvilinear velocity at high concentrations, whereas the linearity and the straight velocity decreased. Our computational model permits better identification of the kinematic subpopulations than the traditional approach and provides insights onto the heterogeneity of the response to ketanserin; thus, it could significantly impact the research on the relationship between sperm heterogeneity-fertility.

Assisted Reproductive Technologies (ARTs) in Domestic Mammals

As guest editors, we are pleased to present this Special Issue entitled "Assisted Reproductive Technologies (ARTs) in Domestic Mammals", comprising 10 articles of relevant interest in the field of animal reproduction [...].

Extracellular Reactive Oxygen Species (ROS) Production in Fresh Donkey Sperm Exposed to Reductive Stress, Oxidative Stress and NETosis

Jenny shows a large endometrial reaction after semen influx to the uterus with a large amount of polymorphonuclear neutrophils (PMN) migrating into the uterine lumen. PMN act as a sperm selection mechanism through phagocytosis and NETosis (DNA extrudes and, together with proteins, trap spermatozoa). While a reduced percentage of spermatozoa are phagocytosed by PMN, most are found to be attached to neutrophil extracellular traps (NETs). This selection process together with sperm metabolism produces a large amount of reactive oxygen species (ROS) that influence the reproductive success. The present study aimed to determine the extracellular ROS production in both sperm and PMN. With this purpose, (1) donkey sperm were exposed to reductive and oxidative stresses, through adding different concentrations of reduced glutathione (GSH) and hydrogen peroxide (H₂O₂), respectively; and (2) PMN were subjected to NETosis in the presence of the whole semen, sperm, seminal plasma (SP) or other activators such as formyl-methionyl-leucyl-phenylalanine (FMLP). Extracellular ROS production (measured as H₂O₂ levels) was determined with the Amplex^® Red Hydrogen Peroxide/Peroxidase Assay Kit. Donkey sperm showed more resilience to oxidative stress than to the reductive one, and GSH treatments led to greater H₂O₂ extracellular production. Moreover, not only did SP appear to be the main inducer of NETosis in PMN, but it was also able to maintain the extracellular H₂O₂ levels produced by sperm and NETosis.