Shotgun proteome analysis of seminal plasma differentiate boars by reproductive performance

Proteomic analysis of sperm from fertile stallions and subfertile stallions due to impaired acrosomal exocytosis

Thoroughbred stallions that carry a double-homozygous genotype A/A-A/A for SNPs rs397316122 and rs69101140 in exon 5 of the FKBP6 gene (chr13; EquCab3.0) are uniquely subfertile due to impaired acrosomal exocytosis (IAE). In this study, the sperm proteome in frozen/thawed semen from subfertile Thoroughbred stallions was studied and compared to that of frozen/thawed sperm from fertile Thoroughbred stallions. A total of 2,220 proteins was identified, of which 140 proteins were found to be differentially abundant in sperm from the subfertile stallions compared to that of fertile stallions (83 less and 57 more abundant). Proteins of differential abundance in sperm from the subfertile stallions were mainly overrepresented in the "metabolism" and the "metabolism of lipids" pathways. One of these proteins, arylsulfatase F (ARSF), was studied by immunofluorescence. A lower proportion of sperm displaying ARSF signal at the acrosome region was observed in sperm from subfertile Thoroughbred stallions. In addition, heterologous zona pellucida binding assays revealed that sperm from subfertile Thoroughbred stallions bound at a lower proportion to zonae pellucidae than sperm from fertile Thoroughbred stallions. In conclusion, a group of differential abundance proteins, including some of acrosome origin, were identified in sperm from subfertile stallions with acrosome dysfunction.

Update on artificial insemination: Semen, techniques, and sow fertility

Over the years, reproductive efficiency in the swine industry has focused on reducing the sperm cell number required per sow. Recent advances have included the identification of subfertile boars, new studies in extended semen quality control, new catheters and cannulas for intrauterine artificial insemination (AI), and fixed-time AI under commercial use. Therefore, it is essential to link field demands with scientific studies. In this review, we intend to discuss the current status of porcine AI, pointing out challenges and opportunities to improve reproductive efficiency.

A novel experimental design for boar sperm cryopreservation

Cryopreservation of sperm is a routine technology in many livestock species, but not in swine. Frozen sperm must result in acceptable conception rates and produce 11-12 piglets/litter to be competitive with traditional cooled semen. The development of an extender that results in high post-thaw sperm quality and acceptable litter size requires identification of factors that markedly impact post-thaw semen quality. The present study aims to first identify factors in boar sperm cryopreservation that significantly impacts post-thaw sperm quality using an efficient, cost-effective, and relatively rapid approach. The Plackett-Burman experimental design is ideal for the screening of factors at their extreme, greatly reducing the amount of time and resources needed for a follow-up, full factorial design. Using commercial semen, a 9 factor, 12 run Plackett-Burman design was used on 10 boars split between 12 treatments. Via this method glycerol concentration, cooling rate, antioxidant supplementation with GameteGuard(Membrane Protective Technologies, Inc. Fort Collins, CO), and straw size were identified as highly influential factors that impact post-thaw sperm quality. Extender type, starting osmolality, sodium dodecyl sulfate addition, and stepwise addition of glycerol were also influential for some but not all post-thaw sperm parameters (p<0.05). Equilibration time in the straws before freezing was determined to have no impact on post thaw sperm quality parameters. Using the Plackett-Burman design, it can be concluded that four of the nine factors warrant detailed investigation in a full factorial experiments in development of boar sperm cryopreservation extenders.

The future of assessing bull fertility: Can the 'omics fields identify usable biomarkers?

Breeding soundness examinations for bulls rely heavily on the subjective, visual assessment of sperm motility and morphology. Although these criteria have the potential to identify infertile males, they cannot be used to guarantee fertility or provide information about varying degrees of bull fertility. Male factor fertility is complex, and the success of the male gamete is not necessarily realized until well after the spermatozoon enters the oocyte. This paper reviews our existing knowledge of the bull’s contribution from a standpoint of the sperm’s cargo and the impact that this can have on fertilization and the development of the embryo. There has been a plethora of recent research characterizing the many molecular attributes that can affect the functional competence of a spermatozoon. A better understanding of the molecular factors influencing fertilization and embryo development in cattle will lead to the identification of biomarkers for the selection of bulls of superior fertility, which will have major implications for livestock production. To see this improvement in reproductive performance, we believe incorporation of modern technology into breeding soundness examinations will be necessary—although many of the discussed technologies are not ready for large-scale field application. Each of the ‘omics fields discussed in this review have shown promise for the identification of biomarkers of fertility, with certain families of biomarkers appearing to be better suited to different evaluations throughout a bull’s lifetime. Further research is needed for the proposed biomarkers to be of diagnostic or predictive value.

Should All Fractions of the Boar Ejaculate Be Prepared for Insemination Rather Than Using the Sperm Rich Only?

Simple Summary

The swine industry is constantly looking for efficiency improvement, especially focusing on the artificial insemination (AI) process. One of the trends in AI centers is to maximize the number of doses obtained from one ejaculate. Seminal doses are usually prepared with the sperm-rich fraction or the whole ejaculate, but further studies are needed to understand how to prepare them properly. Thus, this study aims to analyze how accumulative ejaculate fractions may influence sperm storage, AI performance, and offspring. The results indicate that the presence of all ejaculate fractions within seminal doses does not affect either sperm quality or AI performance and offspring health. Therefore, this study highlights the possibility to use the bulk ejaculate for seminal dose preparation, leading to successful AI. Additionally, it results in a more time-efficient preparation of a greater number of seminal doses providing an economic advantage.

Abstract

Boar ejaculate is released in several well-characterized fractions, differing in terms of sperm concentration, seminal plasma volume, and composition. However, the inclusion of the last part of the ejaculate for artificial insemination (AI) purposes is still under debate due to its controversial effects. Thus, there is a need to study the potential synergistic impact of the different ejaculate fractions. We aimed to evaluate the effect of accumulative ejaculate fractions on sperm conservation, AI performance, and offspring health. Ejaculates (n = 51) were collected and distributed as follows: F1: sperm-rich fraction; F2: sperm-rich + intermediate fractions; F3: sperm-rich + intermediate + poor fractions. Each group was diluted in a commercial extender, packaged in seminal doses (2000 × 10⁶ sperm/60 mL), and stored at ~16 °C. On day 3 of conservation, sperm were analyzed and used for AI (n = 174). High sperm quality was observed after storage without a significant difference between the groups (p > 0.05). Moreover, no differences were obtained for AI performance (pregnancy and farrowing rates, and litter size; p > 0.05) and offspring health (growth and blood analysis; p > 0.05). Conclusively, the presence of all ejaculate fractions within the seminal doses does not impair the reproductive performance, reporting important economic savings according to the economic model included here.

Biochemical and cytotoxic evaluation of latroeggtoxin-VI against PC12 cells

Latroeggtoxin-VI (LETX-VI) is a peptide neurotoxin discovered from Latrodectus tredecimguttatus eggs. In the current study, the action features of the neurotoxin on PC12 cells were systematically investigated. LETX-VI could promote dopamine release from PC12 cells in the absence and presence of Ca2+, involving an even more complex action mechanism in the presence of Ca2+ and when the treatment time was longer. Although LETX-VI enchanced the autophagy and secretion activity in PC 12 cells, it showed no remarkable influence on the proliferation, cell cycle, apoptosis and ultrastructure of the cells. Pulldown combined with CapLC-MS/MS analysis suggested that LETX-VI affected PC12 cells by interacting with multiple proteins involved in the metabolism, transport, and release of neurotransmitters, particularly dopamine. The low cytotoxicity and effective regulatory action of LETX-VI on PC12 cells suggest the potential of the active peptide in the development of drugs for the treatment of some dopamine-related psychotic diseases and cancers.

Seminal Plasma: Relevant for Fertility?

Seminal plasma (SP), the non-cellular component of semen, is a heterogeneous composite fluid built by secretions of the testis, the epididymis and the accessory sexual glands. Its composition, despite species-specific anatomical peculiarities, consistently contains inorganic ions, specific hormones, proteins and peptides, including cytokines and enzymes, cholesterol, DNA and RNA-the latter often protected within epididymis- or prostate-derived extracellular vesicles. It is beyond question that the SP participates in diverse aspects of sperm function pre-fertilization events. The SP also interacts with the various compartments of the tubular genital tract, triggering changes in gene function that prepares for an eventual successful pregnancy; thus, it ultimately modulates fertility. Despite these concepts, it is imperative to remember that SP-free spermatozoa (epididymal or washed ejaculated) are still fertile, so this review shall focus on the differences between the in vivo roles of the SP following semen deposition in the female and those regarding additions of SP on spermatozoa handled for artificial reproduction, including cryopreservation, from artificial insemination to in vitro fertilization. This review attempts, including our own results on model animal species, to critically summarize the current knowledge of the reproductive roles played by SP components, particularly in our own species, which is increasingly affected by infertility. The ultimate goal is to reconcile the delicate balance between the SP molecular concentration and their concerted effects after temporal exposure in vivo. We aim to appraise the functions of the SP components, their relevance as diagnostic biomarkers and their value as eventual additives to refine reproductive strategies, including biotechnologies, in livestock models and humans.

Effects of the classification of boars according to progressive sperm motility and the extender type on the reproductive performance of a single fixed-time insemination

The study aimed to evaluate the fertility of boars according to the resistance of their semen to storage using dilution in either Short- or Long-term extender for single fixed-time insemination. From a total of 32 boars, twelve boars were classified during three semen collection (one collection/boar/week) as Low- (64.5%) or High-preservation (83.9%) capacity for maintaining progressive motility (PM) at 120 h of storage using Short-term extender. After the selection period, six ejaculates (weekly collected) from the Low- and High-preservation boars were diluted in Short- or Long-term extender (2 × 2 factorial design) for insemination and evaluation of fertility. A total of 519 weaned sows were submitted to induction of ovulation with triptorelin (OvuGel®) at 96 h post-weaning. Twenty-four hours later, estrus sows were single fixed-time inseminated (FTAI) with semen doses from the different groups of evaluation. The SAS® software was used for statistical analysis considering the class of boar, type of extender, and interaction as fixed effects. The GLIMMIX procedure was used, considering a binomial distribution for total motility (TM) and PM, binary distribution for pregnancy (PR), and farrowing rate (FR), and the total born (TB) was analyzed assuming a normal distribution with the comparison of means by Tukey-Kramer test. An interaction of class of boars and type of extender was observed for TM and PM at insemination (P < 0.001). Long-term extender increased TM in Low-preservation boars, with no effect in High-preservation boars. The ejaculates from High-preservation boars diluted in Short- or Long-term extender showed higher PM at insemination (86.8 and 87.8%, respectively) compared to those from Low-preservation boars in Short- or Long-term extender (73.2% and 77.9%, respectively). There was no effect of the interaction of boar preservation class and type of extender (P ≥ 0.163) on PR, FR or TB. However, Low-preservation boars presented lower TB (14.1 ± 0.2) compared to High-preservation boars (15.0 ± 0.2; P < 0.01). The PR (93.3 vs. 90.1) and FR (88.8 vs. 88.2) were not affected by class of Low- or High-preservation boars, respectively (P ≥ 0.187). The type of extender did not affect PR, FR, or TB (P ≥ 0.440). In conclusion, Low-preservation boars impaired the reproductive performance of single-FTAI sows by reducing TB with no apparent effect on PR or FR.