Explore the vast range of titles available.

To elucidate the process whereby sperm arrive at an egg in the female reproductive organs, it is essential to investigate how rheological properties of the fluid around mammalian spermatozoa affect their motility. We examined the motility and flagellar waveform of bovine sperm swimming in a fluid with similar rheological properties as mammalian cervical mucus. The results indicated that the surrounding rheological properties largely affected the flagellar waveform of mammalian spermatozoa; in particular, shear-thinning viscoelastic fluid increased the progressive motility of the sperm. To investigate the influence of flagellar waveform on sperm motility in more detail, the waveform was expressed as a function and the progressive thrust of the sperm was calculated based on the empirical resistive force theory. The results of this study showed that the progressive thrust increased with the curvature of the flagellar tip. Moreover, we calculated the thrust efficiency of motile sperm. Results showed that the thrust efficiency in shear-thinning viscoelastic fluids was larger than that in Newtonian fluids, regardless of viscosity. This suggests that motile sperm in cervical mucus move efficiently by means of a motion mechanism that is suited to their surrounding environment.

Mammalian spermatozoa in organisms with internal fertilization are required to swim in the cervical and oviductal mucus, whose rheological properties differ substantially from those of water. Moreover, on the way to the oviduct, a change in sperm motility called hyperactivation may occur. In the present study, we focused on the motion characteristics of hyperactivated bovine sperm and investigated the effect of the surrounding fluid on motility. We prepared two kinds of polyacrylamide with high-viscosity non-Newtonian fluid properties, similar to the actual cervical and oviductal mucus. Using semen from Japanese cattle, we evaluated curvilinear velocity (VCL), straight-line velocity (VSL), and average path velocity (VAP). Additionally, we estimated linearity (LIN), straightness (STR), and wobble (WOB) as sperm motility parameters for several surrounding fluids. We successfully induced hyperactivation of bovine sperm in high-viscosity non-Newtonian fluid. Hyperactivation resulted in an increase in VCL and a decrease in VSL. In the high-viscosity non-Newtonian fluid, the hyperactivated sperm moved in a zig-zag pattern with regularity, different from the movement observed in a diluted solution. The increase in WOB in the non-Newtonian fluid suggests that hyperactivated sperm efficiently progress along the groove that exists on the oviductal mucus wall. These results improve our understanding of the motility of bovine sperm when they undergo hyperactivation in the actual cervical and oviductal mucus.

Many scientific studies often assumed that the most reliable methods for assessing sperm motility are those that give the highest values, and this leads to misinterpretation of the results. This study aims to propose an objective method to validate sperm motility reliability. Bovine and porcine semen samples were split into two equal fractions. Fraction A was kept alive with a motile population considered at maximum proportion, while fraction B was killed with 0% motile population. A range of motile/non motile sperm was performed by mixing both fractions. The Motility Ratio method, comparing measured and theoretical motility, was validated using LEJA slide and IVOS II and applied to other slides. All slides showed strong Concordance Correlation Coefficient between measured and theoretical motility. However, with IVOS II, LEJA slide showed the lowest bias (< 1) while MAKLER or coverslip showed higher bias (> 2 and > 7 respectively) between measured and theoretical motility. This study shows that the best sperm motility is not always the true motility and highlights the importance of implementing a gold standard methodology for motility reliability such as The Motility Ratio method.

Sperm morphology analysis is critical for assessing bovine fertility, since it provides insight into bull reproductive potential as well as subfertility and infertility. Traditional sperm morphology analysis is time-consuming, subjective, and prone to human error, all of which highlight the need for automated, objective solutions. This study presents the design and implementation of a computer-aided system for bovine sperm morphology analysis, leveraging deep learning models to detect and classify sperm cells based on their morphological characteristics. Using micrographs of bull sperm, we present a sequential deep learning framework that automatically detects morphological sperm aberrations. The model segments and analyzes each cell, identifying defects in the head, neck/midpiece, tail, and residual cytoplasm. Specifically, the system employs the YOLOv7 object detection framework, trained on a dataset of 277 annotated images comprising six morphological categories, to automatically identify and classify sperm abnormalities. The experimental results demonstrate a global mAP@50 of 0.73, precision of 0.75, and recall of 0.71, indicating a balanced tradeoff between accuracy and efficiency. By reducing reliance on manual analysis, this work enhances efficiency and accuracy in animal reproduction laboratories, contributing to veterinary reproduction through a cost-effective and scalable solution for sperm quality assessment.

Objective: The X/Y sperm separation technique plays a crucial role in gender control. The objective of this experiment is to investigate the effect of polyvinylpyrrolidone (PVP) concentration (A: 0%, B: 1%, C: 3%, D: 5%, E: 7%, vol/vol) on Y sperm sorting efficiency, based on the specific binding of Resiquimod (R848) to toll-like receptor (TLR)7/8 receptors on the tail of X sperm.Methods: The different concentrations of PVP were added to the R848 sperm sorting solution to facilitate the separation of Y sperm. Subsequently, the isolated sperm were subjected to quantification and motility assessment using computer-assisted semen analysis system. The X/Y sperm ratio is then analyzed by flow cytometry. The sorted sperm were evaluated for acrosomal and plasma membrane integrity. The spermatozoa were then subjected to immunofluorescent staining through immunofluorescence (IF) techniques, which preceded the quantification of the negative sperm rate. The proportion of male embryos was determined through embryonic sex identification after in vitro fertilization.Results: Flow cytometry analysis results showed that when the PVP concentrations were 3%, 5% and 7%, the proportion of Y sperm was not statistically significant, (p≥0.05). However, these percentages were significantly elevated compared to those obtained with 0% and 1% PVP concentrations (p<0.05). The IF staining results demonstrated that the proportion of TLR7/8-negative sperm remained statistically unchanged across PVP concentrations of 3%, 5%, and 7% (p≥0.05). However, these percentages were significantly elevated compared to those obtained with 0% and 1% PVP concentrations (p<0.05). The generation of male blastocysts was significantly higher at a PVP concentration of 3% compared to 0% and 1% (p<0.05), but showed no significant difference from 5% and 7% (p≥0.05).Conclusion: Selecting a 3% PVP concentration not only ensures sufficient sperm yield but also promotes effective selection of Y-sperm. These findings provide empirical evidence supporting the high-efficiency separation of X/Y sperm in livestock.

The swimming process by which mammal spermatozoa progress towards an egg within the reproductive organs is important in achieving successful internal fertilization. The viscosity of oviductal mucus is more than two orders of magnitude greater than that of water, and oviductal mucus also has non-Newtonian properties. In this study, we experimentally observed sperm motion in fluids with various fluid rheological properties and investigated the influence of varying the viscosity and whether the fluid was Newtonian or non-Newtonian on the sperm motility. We selected polyvinylpyrrolidone and methylcellulose as solutes to create solutions with different rheological properties. We used the semen of Japanese cattle and investigated the following parameters: the sperm velocity, the straight-line velocity and the amplitude from the trajectory, and the beat frequency from the fragellar movement. In a Newtonian fluid environment, as the viscosity increased, the motility of the sperm decreased. However, in a non-Newtonian fluid, the straight-line velocity and beat frequency were significantly higher than in a Newtonian fluid with comparable viscosity. As a result, the linearity of the sperm movement increased. Additionally, increasing the viscosity brought about large changes in the sperm flagellar shape. At low viscosities, the entire flagellum moved in a curved flapping motion, whereas in the high-viscosity, only the tip of the flagellum flapped. These results suggest that the bovine sperm has evolved to swim toward the egg as quickly as possible in the actual oviduct fluid, which is a high-viscosity non-Newtonian fluid.

This study developed an embedded 3D TiN nano-electrode arrays with a strong electric field and high biocompatibility for the effective capture of motile sperms. The chip integrates CMOS fabrication technology with a three-dimensional structural design, exhibiting both electrode-based dielectrophoresis and insulator-based dielectrophoresis characteristics. It provides a stable operating environment under strong electric fields with minimal Joule heating interference. In the experiments, we evaluated the effects of different waveforms and capture spaces on the capture efficiency of boar and bovine sperms. The results showed that square waves improved capture efficiency by approximately10% and confirmed that the capture space must exceed half the sperm length to enhance efficiency. When operated under a 20 Vpp square wave, the chip only generated a temperature rise of 1.7°C, causing no significant damage to the sperms and no notable decrease in viability. Under optimal conditions, the capture efficiencies for boar and bovine sperms reached 65.54% ± 1.07% and 63.25%, respectively. Overall, the results demonstrate that this chip offers high throughput, low Joule heating interference, and good species adaptability, showing potential for use in dynamic cell capture and high-throughput analysis.

The cryopreservation of epididymal sperm is an important technique that allows genetic material to be preserved, even post mortem. However, cryopreservation leads to increased oxidative stress and impaired sperm viability. Polyunsaturated fatty acid (PUFA) supplementation may improve certain sperm characteristics, but it also makes sperm more susceptible to oxidative stress, therefore adding antioxidants that counteract oxidative stress has become an option. In this context, this study aimed to evaluate the effect of the interaction between docosahexaenoic acid (DHA) and antioxidants on the quality after the cryopreservation of epididymal bull sperm. Twenty epididymides were collected after slaughter, and epididymal sperm was cryopreserved with bovine extender supplemented with docosahexaenoic acid (DHA), glutathione peroxidase (GPx) and superoxide dismutase (SOD). We verified an improvement in motility in the group that was treated only with DHA 5 µM and a concentration-dependent effect on susceptibility to lipid peroxidation that was associated with DHA concentration (1 µM, 5 µM or 10 µM). Moreover, treatment with DHA (5 µM) and SOD (20 IU/ml) resulted in higher sperm motility. Thus, the association between DHA (5 µM) and SOD (20 IU/ml) appears to be an option for increased epididymal sperm features in bulls.

The technology available to assess sperm population characteristics has advanced greatly in recent years. Large artificial insemination (AI) organizations that sell bovine semen utilize many of these technologies not only for novel research purposes, but also to make decisions regarding whether to sell or discard the product. Within an AI organization, the acquisition, interpretation and utilization of semen quality data is often performed by a quality control department. In general, quality control decisions regarding semen sales are often founded on the linkages established between semen quality and field fertility. Although no one individual sperm bioassay has been successful in predicting sire fertility, many correlations to various in vivo fertility measures have been reported. The most powerful techniques currently available to evaluate semen are high-throughput and include computer-assisted sperm analysis and various flow cytometric analyses that quantify attributes of fluorescently stained cells. However, all techniques measuring biological parameters are subject to the principles of precision, accuracy and repeatability. Understanding the limitations of repeatability in laboratory analyses is important in a quality control and quality assurance program. Hence, AI organizations that acquire sizeable data sets pertaining to sperm quality and sire fertility are well-positioned to examine and comment on data collection and interpretation. This is especially true for sire fertility, where the population of AI sires has been highly selected for fertility. In the December 2017 sire conception rate report by the Council on Dairy Cattle Breeding, 93% of all Holstein sires (n=2062) possessed fertility deviations within 3% of the breed average. Regardless of the reporting system, estimates of sire fertility should be based on an appropriate number of services per sire. Many users impose unrealistic expectations of the predictive value of these assessments due to a lack of understanding for the inherent lack of precision in binomial data gathered from field sources. Basic statistical principles warn us of the importance of experimental design, balanced treatments, sampling bias, appropriate models and appropriate interpretation of results with consideration for sample size and statistical power. Overall, this review seeks to describe and connect the use of sperm in vitro bioassays, the reporting of AI sire fertility, and the management decisions surrounding the implementation of a semen quality control program.

Mammalian fertilization is accomplished by the interaction between sperm and egg. Previous studies from this laboratory have identified a stable acrosomal matrix assembly from the bovine sperm acrosome termed the outer acrosomal membrane–matrix complex (OMC). This stable matrix assembly exhibits precise binding activity for acrosin and N -acetylglucosaminidase. A highly purified OMC fraction comprises three major (54, 50, and 45 kDa) and several minor (38–19 kDa) polypeptides. The set of minor polypeptides (38–19 kDa) termed “OMCrpf polypeptides” is selectively solubilized by high-pH extraction (pH 10.5), while the three major polypeptides (55, 50, and 45 kDa) remain insoluble. Proteomic identification of the OMC32 polypeptide (32 kDa polypeptide isolated from high-pH soluble fraction of OMC) yielded two peptides that matched the NCBI database sequence of acrosin-binding protein. Anti-OMC32 recognized an antigenically related family of polypeptides (OMCrpf polypeptides) in the 38–19-kDa range with isoelectric points ranging between 4.0 and 5.1. Other than glycohydrolases, OMC32 may also be complexed to other acrosomal proteins. The present study was undertaken to identify and localize the OMC32 binding polypeptides and to elucidate the potential role of the acrosomal protein complex in sperm function. OMC32 affinity chromatography of a detergent-soluble fraction of bovine cauda sperm acrosome followed by mass spectrometry-based identification of bound proteins identified acrosin, lactadherin, SPACA3, and IZUMO1. Co-immunoprecipitation analysis also demonstrated the interaction of OMC32 with acrosin, lactadherin, SPACA3, and IZUMO1. Our immunofluorescence studies revealed the presence of SPACA3 and lactadherin over the apical segment, whereas IZUMO1 is localized over the equatorial segment of Triton X-100 permeabilized cauda sperm. Immunoblot analysis showed that a significant portion of SPACA3 was released after the lysophosphatidylcholine (LPC)-induced acrosome reaction, whereas the IZUMO1 and lactadherin polypeptides remain associated to the particulate fraction. Almost entire population of bovine sperm IZUMO1 relocates to the equatorial segment during the LPC-induced acrosome reaction. We propose that the interaction of OMC32 matrix polypeptide with detergent-soluble acrosomal proteins regulates the release of hydrolases/other acrosomal protein(s) during the acrosome reaction.