Liquid storage of dromedary camel semen in different extenders

Protective effect of epidermal growth factor on cryopreservation of dromedary camel epididymal spermatozoa: Evidence from in vitro and in silico studies

Epidermal growth factor (EGF) plays a crucial role in maintaining male reproductive capacity in mammals, however, its protective effects on cryopreserved dromedary camel epididymal spermatozoa have not been thoroughly investigated. This study aims to investigate the potential protective role of EGF on cryopreserved camel epididymal spermatozoa, supported by evidence from a molecular docking study. We assessed sperm motility, kinematics parameters, oxidative stress, ultrastructural changes, apoptosis, and molecular docking markers in camel epididymal spermatozoa following cryopreservation. Camel epididymal spermatozoa (n = 30 pairs of testes) were collected from local slaughterhouses. The epididymal spermatozoa were diluted with a freezing medium (SHOTOR extender) supplemented with different concentrations of EGF; 0 (EGF0), 50 (EGF50), 100 (EGF100), 200 (EGF200), and 400 (EGF400) ng/mL in SHOTOR extender and cryopreserved using a standard protocol. All EGF groups showed significant improvements in sperm progressive motility, viability, and sperm membrane function after equilibration at 5 °C for 24 hours. Regarding frozen-thawed samples, sperm progressive motility and some kinematic parameters (DAP, VSL, VCL and AHL) were significantly higher in the EFG400 group compared to the other groups (P < 0.01). A significant increase in the percentage of live/acrosome-intact sperm was observed, accompanied by a significant decrease in malondialdehyde levels in all EGF groups (P < 0.05). Both the EGF200 and EGF400 groups showed significantly higher sperm viability and significantly lower percentages of apoptotic and necrotic sperm compared to the other groups (P < 0.05). EGF supplementation preserved the ultrastructural integrity and cryotolerance of epididymal camel spermatozoa. The docking analysis indicated that EGF exhibited higher binding affinity with apoptosis sperm markers, including caspase-3 and bcl-2-associated X (Bax) proteins, with binding energies of -502.0 and -621.0 kcal/mol, respectively. In conclusion, the addition of EGF to SHOTOR extender was found to have beneficial effects on sperm motility, kinematics parameters, sperm viability, acrosome integrity, sperm ultrastructural features, and reduced oxidative stress and apoptosis-like changes in cryopreserved epididymal camel spermatozoa.

Exploring the full potential of sperm function with nanotechnology tools

Sperm quality is essential to guarantee the success of assisted reproduction. However, selecting high-quality sperm and maintaining it during (cryo)preservation for high efficiency remains challenging in livestock reproduction. A comprehensive understanding of sperm biology allows for better assessment of sperm quality, which could replace conventional sperm analyses used today to predict fertility with low accuracy. Omics approaches have revealed numerous biomarkers associated with various sperm phenotypic traits such as quality, survival during storage, freezability, and fertility. At the same time, nanotechnology is emerging as a new biotechnology with high potential for use in preparing sperm intended to improve reproduction in livestock. The unique physicochemical properties of nanoparticles make them exciting tools for targeting (e.g., sperm damage and sexing) and non-targeting bioapplications. Recent advances in sperm biology have led to the discovery of numerous biomarkers, making it possible to target specific subpopulations of spermatozoa within the ejaculate. In this review, we explore potential biomarkers associated with sperm phenotypes and highlight the benefits of combining these biomarkers with nanoparticles to further improve sperm preparation and technology.

Cryopreservation modifies the distribution of the prostate-derived lectin SL15 on the llama (Lama glama) sperm

Lectin-like molecules play a key role in mammalian sperm functionality. These multifunctional proteins have been proven to be involved in sperm capacitation, sperm motility, and viability, formation of the oviductal sperm reservoir, and in sperm-oocyte interaction. In a previous study, we reported the presence of a novel seminal plasma lectin, sperm lectin 15 kDa (SL15), adsorbed to the llama sperm. In order to gain knowledge in the understanding of SL15 and its functions, the aims of this study were to (a) elucidate the presence and localization of SL15 in the llama male reproductive tract and sperm, and (b) determine whether the sperm cryopreservation process of cooling and freeze-thawing affects the SL15 levels and distribution on llama sperm. We found that SL15 protein was expressed along the male reproductive system: testis, epididymis, prostate, and bulbourethral glands, being the prostate the main site of SL15 secretion. SL15 was localized on the sperm head, following different localization patterns. In order to understand if sperm cryopreservation induces modifications in the SL15 adsorption pattern, immunocytochemistry and flow cytometry analysis were carried out on fresh, 24 h cooled, and frozen-thawed sperm. Both cooled and frozen sperm showed particular SL15 patterns, that were not observed in the freshly ejaculated, indicating loss of SL15. Flow cytometry analysis also exhibited a decrease of SL15 in the cooled sperm (P < 0.05), whereas a tendency to decrease was found in frozen-thawed sperm (P < 0.1) when compared with freshly ejaculated sperm. This study extends the knowledge about the SL15 in the llama male physiology and provides evidence that cryopreservation-related techniques disrupt SL15 adsorption to the sperm membrane, possibly affecting sperm functionality and fertility.

Cooled storage of semen from livestock animals (Part II): Camelids, goats, and sheep

This review is part of the Festschrift in honor of Dr. Duane Garner and provides an overview of current techniques in cooled storage of semen from livestock animals such as camelids, goats, and sheep. Facing worldwide environmental changes and a trend towards more conscious and healthy eating behaviors, the development of a stable animal breeding industry is a significant challenge for the near future. In the present review, factors influencing semen handling in camelids, goats and sheep are described and relevant methods as well as current trends to improve liquid-storage of cooled semen are discussed, including extenders, additives, cooling rates, and storage temperatures. The species-specific physiology and resulting challenges are taken into consideration. While the main problem for camelid semen processing is the relatively greater viscosity as compared with that of some other animals, the deciding factor for successful artificial insemination (AI) in goats and sheep is the site (i.e., cervical or vaginal) of semen placement in the reproductive tract. Due to the type of cervical anatomy, the penetration of the cervix when using AI instruments is rather difficult. Furthermore, the seminal plasma of small ruminants affects the interaction with milk-based extenders and egg yolk which results in species-specific regimens for cooled liquid-preservation. Comparing all three species, the greatest pregnancy rates were obtained by AI with goat semen after cooled liquid-storage for several days.

A preliminary study on the effects of E-Z Mixin® and EquiPlus® extenders supplemented with Edible Bird's Nest on the quality of chilled Arabian stallion semen

The aim of this study was to evaluate the effects of adding different concentrations of edible bird’s nest (EBN) which is secreted by swiftlet birds (Aerodramus fuciphagus), into EquiPlus® and E-Z Mixin® extenders on the quality of chilled Arabian stallion semen at various storage times (0, 24 and 48 h). Ten ejaculates were collected from five stallions, and diluted using the two extenders containing 0% (control), 0.12%, 0.24% and 0.24% of EBN + seminal plasma (SP). All the diluted semen samples were then cooled and stored at 5 °C, and examined at 0, 24 and 48 h. Sperm kinetic parameters were assessed using computer assisted sperm analysis (CASA) and viability were assessed using Hoechst33342/PI stain. In both extenders, total motility (TM) and progressive motility (PM) were significantly higher at 0.12% and 0.24% compared to 0.24% + SP at 24 and 48 h. At 0.12%, E-Z mixin® treated semen had significantly higher TM and PM than EquiPlus^® at 24 and 48 h. At 0.12% and 0.24%, average path velocity (VAP), straight-line velocity (VSL) and curvilinear velocity (VCL) were significantly higher in E-Z mixin® treated semen compared to EquiPlus^® at 24 and 48 h. Comparisons between the two extender types at different concentrations of EBN showed no significant difference in lateral head amplitude (ALH), linearity (LIN), straightness (STR), beat cross frequency (BCF) and viability, irrespective of the storage time. The percentage of viable was significantly higher in E-Z mixin® than EquiPlus® at 0 and 48 h in control and 0.12%. Supplementation of the E-Z mixin^® extender with 0.12% and 0.24% EBN concentrations in the absence of SP provided better CASA parameters such as TM, PM, VAP, VSL, and VCL at 24 and 48 h storage time. In conclusion, the results of this study indicated that chilled semen from Arabian stallion that was extended using E-Z mixin® and supplemented with 0.12% and 0.24% EBN concentrations performed better and yielded superior results in sperm kinetic parameters and % viable compared to EquiPlus® at 24 and 48 h storage time.

Semen extenders: An evaluative overview of preservative mechanisms of semen and semen extenders

Reproduction is fundamental for all living things as it ensures the continued existence of a species and an improved economy in animal husbandry. Reproduction has developed since history, and diverse processes, such as artificial insemination and in vitro fertilization, have been developed. Semen extenders were discovered and developed to protect sperm from harmful factors, such as freeze and osmotic shock, oxidative stress, and cell injury by ice crystals. Semen extenders preserve sperm by stabilizing its properties, including sperm morphology, motility, and viability and membrane, acrosomal, and DNA integrity. Therefore, semen extenders must provide a favorable pH, adenosine triphosphate, anti-cooling and anti-freeze shock, and antioxidant activity to improve semen quality for fertilization. Hence, this review provides precise data on different semen extenders, preservative mechanisms, and essential additives for semen extenders in different animals.

Effects of vitamin C, vitamin E, selenium, zinc, or their nanoparticles on camel epididymal spermatozoa stored at 4 °C

This study determined the effects of antioxidant supplementation and storage time at cool temperatures on the characteristics of epididymal camel spermatozoa. Camel testes were collected at the abattoir after animal slaughtering and kept at 4 °C during transportation and until processing (max 6 h). Spermatozoa were retrieved and diluted with SHOTOR extender, split in aliquots, supplemented with the following antioxidants: 200 μm/mL vitamin E, 1.0 g/L vitamin C, 1 μg/mL selenium nanoparticles, 50 μg/mL zinc nanoparticles, 2 μg/mL sodium selenite, and 100 μg/mL zinc sulfate, and stored at 4 °C for 2, 48, 96, and 144 h. The storage time significantly affected (P < 0.05) the sperms' motility and livability, the sperms' membrane integrity, and the percentages of cytoplasmic droplets as well as the percentage of morphologically normal spermatozoa. Epididymal sperm characteristics (progressive motility, livability, membrane integrity, and abnormalities) were significantly improved (P < 0.05) when the spermatozoa were diluted with antioxidants as compared with the control group, and the best additives were identified as nano-selenium, sodium selenite, nano-zinc, and zinc sulfate. In conclusion, adding nano-sized minerals or inorganic trace elements and vitamins maintained the progressive motility, livability, and membrane integrity, and decreased abnormalities and cytoplasmic droplet percentages of epididymal camel spermatozoa stored at 4 °C up to 144 h.

The Current Trends in Using Nanoparticles, Liposomes, and Exosomes for Semen Cryopreservation

Cryopreservation is an essential tool to preserve sperm cells for zootechnical management and artificial insemination purposes. Cryopreservation is associated with sperm damage via different levels of plasma membrane injury and oxidative stress. Nanoparticles are often used to defend against free radicals and oxidative stress generated through the entire process of cryopreservation. Recently, artificial or natural nanovesicles including liposomes and exosomes, respectively, have shown regenerative capabilities to repair damaged sperm during the freeze-thaw process. Exosomes possess a potential pleiotropic effect because they contain antioxidants, lipids, and other bioactive molecules regulating and repairing spermatozoa. In this review, we highlight the current strategies of using nanoparticles and nanovesicles (liposomes and exosomes) to combat the cryoinjuries associated with semen cryopreservation.

Extenders for alpaca epididymal spermatozoa: Comparison of INRA96 and andromed

Artificial insemination would be a useful technique for alpaca breeders to use as an aid to breeding to increase fleece quality. The technique, however, is not well developed in alpacas, partly because of the viscous nature of their seminal plasma. Castration conducted for husbandry purposes can provide a source of epididymal spermatozoa to test semen extenders or handling regimens, thus circumventing the problem of the viscous ejaculate. In this experiment, two semen extenders (Andromed and INRA96) developed for other species (bovine and equine, respectively) were tested with alpaca spermatozoa derived from the cauda epididymis. Sperm total motility (mean ± SEM A: 29.1 ± 4.8 % compared with I: 35.4 ± 4.8 %; NS), membrane integrity (A: 58 ± 9% compared with I: 56 ± 9%; NS) and acrosome integrity (A: 65 ± 7% compared with I: 54 ± 7%; NS) were not different between the two extenders. Progressive motility with use of INRA96 was greater after incubating for 30 min than after incubating for 10 min (35 ± 4% vs. 12 ± 4%, respectively; P = 0.03). In conclusion, viable epididymal spermatozoa could be extracted from the castrated organs after overnight transport. There were no differences in sperm quality between the two extenders; therefore, it appears that either extender could be used for alpaca spermatozoa. These results could help in the development of a technique for artificial insemination in alpacas.

Preservation of the spermatozoa of the dromedary camel (Camelus dromedarius) by chilling and freezing: The effects of cooling time, extender composition and catalase supplementation

This study sought to determine the characteristics of dromedary camel sperm following 24 h chilling and cryopreservation, testing two different buffers and cryoprotectants and the presence of catalase (500 IU/mL). Ejaculates were liquefied in Tris-Citric acid-Fructose buffer, and centrifuged through a colloid. For Experiment 1 (n = 5) sperm were cooled 24 h in Green Buffer or INRA-96® containing 0 or 3% glycerol or ethylene glycol. Experiment 2 (n = 5) used the same six treatments to evaluate sperm cryopreserved after 24 h cooling. A test of fertility was run (n = 12 recipients) with split ejaculates of fresh semen cooled 24 h in Green Buffer with and without glycerol. Experiment 3 (n = 7) cryopreserved sperm cooled 2 and 24 h in Green Buffer without cryoprotectant and with and without catalase. Sperm parameters measured before and after treatments included motility, viability and acrosome integrity. Experiment 1 showed no reduction in all sperm parameters after 24 h and no differences between buffers or presence or not of either cryoprotectant. Experiment 2 showed Green Buffer to be better than INRA for supporting sperm frozen after 24 h cooling while, for both buffers, there were few differences in sperm parameters if cryoprotectant was present or absent. Pregnancies were confirmed in 4/6 animals (67%) while no recipients receiving sperm chilled with glycerol were pregnant. In Experiment 3, catalase-supplemented sperm had maintained better motility 2 h post thaw; there were no differences between 2 or 24 h cooled sperm parameters for presence or absence of catalase. There was neither advantage nor disadvantage to coooling sperm 24 h prior to cryopreservation. We concluded that dromedary sperm can be chilled (24 h) and then either inseminated or cryopreserved. While glycerol presence in Green Buffer during chilling did not interfere with cryosurvival it may be toxic to the fertility of fresh chilled sperm. Catalase supplementation during cooling helps maintain sperm motility post thaw.

Saadeldin I, Ba-Awadh H, G. Al-Mutary M, F. Moumen A, N. Alowaimer A, Abdalla H. Efficiency of Commercial Egg Yolk-Free and Egg Yolk-Supplemented Tris-Based Extenders for Dromedary Camel Semen Cryopreservation

Simple Summary

This study compared the efficiency of commercial egg yolk-free (AndroMed, OPTIXcell) and egg yolk-supplemented (Triladyl, Steridyl) Tris-based extenders for semen cryopreservation in dromedary camels. The camel-specific extender SHOTOR was used for reference. SHOTOR, Triladyl, Steridyl, AndroMed, and OPTIXcell can all be used for camel semen cryopreservation; however, SHOTOR and Triladyl provide the best post-thawing sperm quality.

Abstract

This study compared the efficiency of commercial egg yolk-free (AndroMed, OPTIXcell) and egg yolk-supplemented (Triladyl, Steridyl) Tris-based extenders for semen cryopreservation in seven adult dromedary camels. The camel-specific extender SHOTOR was used as control. The collected semen samples were evaluated and diluted with SHOTOR, Triladyl, Steridyl, AndroMed, or OPTIXcell. The diluted semen was gradually cooled and equilibrated for two hours before liquid nitrogen freezing. Semen was evaluated prior to freezing and after freeze-thawing cycles for motility, kinetics, vitality, abnormality, plasma membrane integrity, and DNA fragmentation using computer-assisted sperm analysis. In pre-freezing evaluation, progressive sperm motility was higher in SHOTOR-diluted samples (21.54 ± 1.83) than in samples diluted with Steridyl, OPTIXcell, or AndroMed (15.76 ± 1.80, 17.43 ± 1.10, and 13.27 ± 1.07, respectively). Moreover, Triladyl and SHOTOR resulted in significantly (p < 0.05) better sperm vitality and DNA integrity than all other diluents, but Triladyl resulted in a significantly (p < 0.05) better plasma membrane integrity (87.77 ± 0.31) than SHOTOR (85.48 ± 0.58). In the post-thawing evaluation, Triladyl led to significantly (p < 0.05) higher sperm motility (38.63 ± 0.81%; p < 0.05) when compared to SHOTOR, Steridyl or AndroMed (35.09 ± 1.341%, 34.4 ± 0.84%, and 31.99 ± 1.48%, respectively), with OPTIXcell being the least efficient (28.39 ± 0.86%). Progressive sperm motility was the highest when using Triladyl. Post-thawing curvilinear, straight line and average path sperm velocities were highest with Triladyl and lowest with AndroMed. Triladyl led to the highest linearity coefficient and straightness sperm coefficient, while SHOTOR to the highest DNA and plasma membrane integrity. OPTIXcell and AndroMed resulted in poor post-thawing sperm vitality, while Steridyl was less efficient than Triladyl. The highest rate of sperm abnormalities was recorded with OPTIXcell and the lowest with SHOTOR or Triladyl. In conclusion, SHOTOR, Triladyl, Steridyl, AndroMed, and OPTIXcell can all be used for camel semen cryopreservation; however, SHOTOR and Triladyl provided the best post-thawing sperm quality. Based on our findings, Triladyl is the best commercially available extender for dromedary camel semen cryopreservation to date.