Sucrose increases the quality and fertilizing ability of cryopreserved chicken sperms in contrast to raffinose

Engineered extracellular vesicles: a breakthrough approach to overcoming sperm cryopreservation challenges

Freezing sperm for artificial insemination (AI) has been common for decades, but this method causes damage to sperm, which affects its viability and fertility. Various strategies have been used to treat sperm cryopreservation complications, but their results are still not satisfactory. The latest approach in this field is using extracellular vesicles (EVs). The role of EVs in reproduction, such as spermatogenesis, sperm capacitation, and fertility has been proven. EVs can deliver proteins, lipids, nucleic acids, and other molecules to the sperm for repair. The EVs carry proteins, lipids, nucleic acids, and other molecules, which could be involved in sperm quality, functionality or fertility. The application of EV derived from animal and human cell sources for cryoinjury treatment indicates the improvement of sperm quality after freeze-thawing. In addition, different EV engineering methods regarding various EV cargos could be more influential for cryopreserved sperm treatment because they could provide EV customized content for delivering to cryoinjured sperm, according to their unique needs to enhance viability and fertility. In this review, first, we reminded the sperm cryopreservation complications, and next explained the conventional and modern strategies for overcoming them. Then, we have pointed out the role of EV in sperm development and the following mentioned the study results of using EV from different cell sources in sperm cryoinjuries repair. Also, we suggested several predisposing molecules (including microRNAs and proteins) for EV engineering to treat sperm cryopreservation complications by indirect engineering procedure, including genetic manipulation and incubation with therapeutic molecules, and direct engineering procedure, including electroporation, sonication, incubation, saponin permeabilization, extrusion, CaCl2-heat shock, and freeze/thawing. Finally, we discussed the limitations of EV application and ethical considerations in this context. In the meantime, despite these limitations, we pointed out the promising potential of the EV engineering strategies to reduce infertility rates by helping to overcome sperm cryopreservation challenges.

Developing Efficient Methods of Sperm Cryopreservation for Three Fish Species (Cyprinus carpio L., Schizothorax prenanti, Glyptosternum maculatum)

Sperm cryopreservation is helpful for maintaining the genetic diversity of fish species. This study was aimed at developing efficient methods to cryopreserve the sperm of three fish species, including koi carp (Cyprinus carpio L.), Ya fish (Schizothorax prenanti), and Glyptosternum maculatum. Firstly, based on the analysis of sperm viability, the cryomedium, dilution ratio, volume, and cooling procedure were assessed and optimized in koi carp. The results showed that the highest sperm viability was up to 63.23 ± 1.36% after a 14-day cryopreservation using the optimal method, briefly, sperm frozen with a volume of 50 μL (Vol.sperm:Vol.cryomedium = 1:9) of cryomedium containing 10% DMSO and 3% sucrose in D17 through ultrarapid cooling. Secondly, both the mitochondrial membrane potential and the DNA fragmentation index of sperm were examined and found to be significantly damaged after the cryopreservation. Intriguingly, the fertilization rate of sperm after 14-day cryopreservation is up to 63.03 ± 1.36% and the elongation of cryopreservation time (210 days) just slightly affected the fertilization rate (55.09 ± 4.70%) in koi carp. Thirdly, the optimal cryopreservation method was applied to cryopreserve Glyptosternum maculatum sperm; the cell viability was 45.39 ± 4.70%. And then this method, after a minor modification (3% sucrose of cryomedium replaced with 3% SMP) was adopted to cryopreserve Ya fish sperm, the cell viability was up to 70.45 ± 2.23%. Lastly, the ultrastructure and morphology of sperm was observed by SEM, and it was found that the cryopreservation prominently caused sperm head swelling and tail shortening in three fish species. In conclusion, this study established effective methods for cryopreserving sperm in three fish species and elaborated the injuries on sperm caused by cryopreservation. And the findings facilitate developing more protocols with practical value to cryopreserve sperm in different fish species.

Preserving Life: How Retinoic Acid (RA) Enhances Cell Viability and Reduces Apoptosis in Cryopreserved Blastocyst Cells of Pudong Chickens

The preservation of chicken embryonic cells is essential for protecting avian genetic resources and enhancing breeding programs. This study investigates the effects of retinoic acid (RA) on the viability, functionality, and adhesion of thawed chicken blastoderm cells (BCs) following cryopreservation. After thawing and culturing the cells for 24 h, RA treatment resulted in significantly higher cell viability and adhesion rates compared to the control group, with the 2.0 μM RA group demonstrating the best outcomes. After 48 and 72 h of culture, similar trends were observed, with the 2.0 μM RA group consistently maintaining the highest cell viability and adhesion rates. Furthermore, immunofluorescence TUNEL assays revealed that RA significantly reduced both early and late apoptosis rates, particularly at a concentration of 2.0 μM, which exhibited a strong protective effect. Flow cytometry analysis indicated that RA treatment enhanced the mitochondrial membrane potential (MMP), reflecting improved cellular health. Analysis of the apoptosis-related genes BAX, BCL-2, and Caspase-3 revealed that moderate RA concentrations promoted the expression of anti-apoptotic factors while also upregulating pro-apoptotic factors, with the 2.0 μM RA group exhibiting the highest expression levels. Cell cycle analysis showed that RA significantly influenced the distribution of BCs across different phases, with the 4.0 μM RA group exhibiting the highest proportion of cells in the G1/G0 phase, suggesting an enhanced tolerance to cryopreservation stress. Conversely, the S phase cell population was notably reduced at higher RA concentrations, indicating potential inhibition of cell proliferation. These results suggest that RA not only significantly enhances the survival rates and mitochondrial function of BCs, but also regulates the cell cycle, providing better conditions for BC cryopreservation. Overall, the addition of RA represents a valuable strategy for optimizing cryopreservation techniques in chicken embryonic cells, with implications for avian genetic resource conservation and breeding strategies.

Successful Cryoprotectant-Free Vitrification of Honey Bee (Apis mellifera) Drone Sperm With Royal Jelly Supplemented Extender

In trying to protect honey bee species and maintain genetic diversity, employing effective approaches for drone sperm conservation is crucial. Based on literature, drone sperm cryopreservation extenders and methods have not been fully optimized. Our research aim was to enhance drone bee sperm preservation by incorporating royal jelly (RJ) in the extender of the cryoprotectant-free vitrification method. Drone sperm was collected from adult drone bees (36 days old) using the manual inversion method. Different concentrations of RJ (0%, 0.5%, 1%, 2.5% and 5%) were added to the extender. Diluted sperm were cryopreserved using a cryoprotectant-free vitrification technique where 10 µL aliquots of the diluted sperm were directly dropped into the liquid nitrogen and then stored. Data were analysed based on a completely randomized design with ten replications. Sperm quality parameters, including motility, viability and DNA damage, were evaluated in vitro. Queens were artificially inseminated to measure the ability of motile sperm to reach the spermathecae. The results showed that 1% and 2.5% of RJ supplementation significantly enhanced sperm motility and viability and reduced DNA fragmentation compared to control and higher RJ concentrations. Specifically, the 1% RJ group resulted in the highest sperm viability, while both the 1% and 2.5% groups maintained lower DNA fragmentation rates. Queens inseminated with sperm treated with 1% and 2.5% RJ showed a notably higher number of motile sperm in their spermathecae. In conclusion, supplementation of 1% RJ to the cryoprotectant-free vitrification media may improve drone sperm quality parameters post-warming. Our findings provide valuable insights into optimizing drone bee sperm preservation, contributing to the conservation of these vital pollinators.

Probing the impact of commercial cryoprotectants and freezing technique on the motility of human spermatozoa cryopreserved onto extremely water-repellent soot-coated surfaces

The cryopreservation of human spermatozoa is an integral part of cryobiology, aiming to support the in-vitro fertilization. The latter relies on the availability of as much as possible reproductively active spermatozoa, whose number after thawing decreases due to the accompanied freezing injury and the cytotoxicity of cryoprotectants. An innovative option to circumvent these obstacles is to make the freezing interface non-wettable, by coating it with rapeseed oil soot possessing intrinsic cryoprotective properties, delaying the ice formation and possibly providing identical rates of intracellular dehydration and extracellular crystallization. It may mean that this technique can reduce or avoid the need of harmful cryoprotective agents, but to reach such a developmental stage, the synergistic effect of certified cryoprotectants and cooling velocities on the efficiency of soot-mediated sperm cryopreservation must be clarified. With the intention to address this research gap, we reveal that the slow freezing/thawing of distinct mixtures of three cryoprotectants (SpermFreeze™, CryoSperm™ and DMSO) and the human semen of nine patients equalizes the percent of survived spermatozoa, but declines their curvilinear velocity. At instant freezing (∼7-20 s) and slow thawing, via specially-designed soot fabric-coated sheet metal cryoboxes, the inclusion of 10 % DMSO is noxious, but the post-thaw motility reaches 74-100 % independently of the cryoprotective solutes. These surprising findings are ascribed to the formation of a quasivitrified semen, whose complete freezing ensures a fraction of extracellular ice matching that from the equilibrium phase diagram, eluding the osmotic shocks and paving the path for future replacement of the classic vitrification.

Cryopreservation Strategies for Poultry Semen: A Comprehensive Review of Techniques and Applications

Poultry semen preservation is crucial for sustaining genetic diversity, improving production efficiency, and facilitating various breeding initiatives. This review underscores the importance and challenges associated with different preservation techniques. We investigate effective techniques for semen collection and evaluation, focusing on vital parameters such as volume, concentration, motility, and morphology. Preservation strategies are categorized into short-term approaches, such as dilution with extenders, and mid-to-long-term strategies, like freezing and the use of cryoprotectants. Additionally, we explore several factors affecting semen quality, including male age and genetics, seasonal impacts, and stress during handling. Assessing the quality of preserved semen is critical, particularly regarding post-thaw motility. The applications of these preservation techniques in artificial insemination, genetic enhancement, the conservation of endangered breeds, and biobanking are highlighted. This review identifies critical research opportunities, including the development of improved cryoprotectants, refining freezing protocols, comprehending the mechanisms of semen damage, and innovating novel preservation technologies. Addressing these challenges will enhance poultry semen preservation and contribute to sustainable poultry farming.

Sperm fitness assessment in poultry: Brief review of in vitro methods

In the poultry industry, every chick or poult produced has high economic value; therefore, selection of male breeders capable of transmitting desirable traits to their offspring has an important role in fertility and hatching success. Following either natural mating or artificial insemination, sperm must go through a sequence of steps to fertilize the egg: 1. Go from the site of deposition (vagina) to the Sperm Storage Tubules (SST); 2. Enter and stay inside the SST; 3. Reacquire motility; and 4. Bind to and penetrate the egg. To perform these tasks successfully, sperm must be alive, motile, and have structural integrity (membrane, glycocalyx, acrosome, and DNA). To evaluate sperm fitness, several in vitro tests can be performed; however, it is often necessary to combine several assays to have a more reliable fertility estimation, as each procedure evaluates specific and distinct sperm features. In this article, we briefly review in vitro tests that can be used to evaluate poultry sperm, associating them with each step for fertilization. The sperm-egg interaction assay using the inner perivitelline layer of chicken eggs is highlighted, since it is a single test that evaluates multiple sperm characteristics and is highly correlated with fertility.

Optimization of Cholesterol-Loaded Cyclodextrin Combined with Soybean Lecithin as a Cryoprotectant for Rooster Sperm

There are many applications of soybean lecithin (SL) and cholesterol-loaded cyclodextrin (CLC) in sperm freezing processes. To the best of our knowledge, there have been few cases of the combined use of SL and CLC in freezing rooster semen. We investigated the effects of CLC, SL, and their combination on rooster sperm cryodamage. Three experiments were conducted: experiment 1, SL (0.5%, 1%, 1.5%, 2.0%); experiment 2, CLC (1.25 mg, 2.5 mg, 5 mg, 10 mg, 15 mg); and experiment 3, CLC + SL (2.5 mg + 0.25%, 2.5 mg + 0.5%, 2.5 mg + 1%, 2.5 mg + 1.5%). Semen samples were cryopreserved using a programmed cryostat, followed by the determination of post-thaw sperm quality, antioxidant indices, and hatching. The results showed that the combination of 2.5 mg CLC + 0.5% SL had the most significant synergistic effect on cryodamage, and the viability (56.69%), motility (54.35%), mitochondrial activity (54.23%), plasma membrane integrity (53.52%), acrosome integrity (54.71%), and antioxidant activity (MDA concentration: 5.65 nmol/mL; SOD activity: 152.73 U/mL) were significantly greater than those of the other combinations (p < 0.05). Nevertheless, the combined CLC and SL addition group did not substantially increase the fertilization and hatching rates of frozen semen compared with the addition of 2.5 mg CLC. In conclusion, the addition of 2.5 mg CLC and 2.5 mg CLC + 0.5% SL enhanced the quality and fertility of frozen rooster sperm.

Impacts of adding sucrose or trehalose to extenders with different glycerol concentrations on freezablility and fertility of buffalo bull semen

This experiment was conducted to determine the most suitable glycerol concentration (3 or 6%) and/or non-penetrating cryoprotectants (trehalose and sucrose) for the cryopreservation of buffalo semen, with the aim of enhancing the cryopreservation protocol. Semen of Egyptian buffalo were pooled and diluted with eight Tris extenders supplemented with either 6% glycerol (control group, GL6), 3% (low level, GL3), sucrose (SU, 50 mM), trehalose (TR, 50 mM), 6% glycerol together with 50 mM of sucrose (GL6SU) or 50 mM of trehalose (GL6TR), and 3% of glycerol together with 50 mM of sucrose (GL3SU) or 50 mM of trehalose (GL3TR), then frozen following the standard protocol. Findings indicated that GL3 extender resulted in the highest values of progressive motility, sperm kinematics, sperm membrane integrity, and viability of post-thawed semen (37 °C for 30 s). On the contrary, the Tris extender enriched only with SU and TR groups had the lowest values of sperm quality compared to the other groups (p < 0.05). All GL supplemented groups showed higher intact acrosome levels and lower detached acrosome and dead sperm with intact acrosome compared to those with TR and SU alone (p < 0.05). A significant increase in viable sperm was observed in the GL3, GL6, and GL3SU groups compared to the other groups (p < 0.05). The Tris extender supplemented with low glycerol (3%) significantly reduced the levels of MDA. In the in vivo fertility trial, it was shown that the pregnancy rate was higher in the GL6SU group (72%) than in the GL3SU group (68%; p > 0.05). Collectively, these results suggest that there is potential in using low glycerol (3%) as a cryoprotective agent in the medium for buffalo sperm cryopreservation without significant adverse effects compared to the addition of 6% glycerol. This study supported the sustainability of materials used in assisted reproductive technology by reducing the glycerol content in the freezing medium. Further research is needed to confirm this hypothesis.

Supplementing semen extenders with a combination of phosphorus and vitamin B12 Improves post-thawed cryopreserved rooster semen quality

Semen cryopreservation is an important technique for preserving the genetic material of numerous species. However, frozen semen is highly susceptible to sperm DNA damage and reduced motility, resulting in decreased fertility. The standard method for cryopreservation and several approaches have not been elucidated. This study aimed to determine the effects of supplementing rooster semen extender with a combination of phosphorus and vitamin B12 on cryopreserved semen quality. Semen was collected weekly via dorso-abdominal massage from 57 Burmese × Vietnam-crossbred Thai native roosters aged 1-3 years. In total, 139 semen samples were collected, pooled, and diluted to 200 million sperm per dose. The pooled sample was divided into six experimental groups: a control group (0.00%) diluted with modified Beltville Poultry Semen Extender (BPSE) and five treatment groups diluted with modified BPSE supplemented with phosphorus and vitamin B12 at concentrations 0.02, 0.04, 0.06, 0.08, and 0.10%, respectively. The semen samples were frozen and evaluated at 0, 15, and 30 min after thawing. Sperm kinematic parameters were determined using a computer-assisted sperm analysis system. Sperm quality was evaluated by measuring sperm viability, mitochondrial activity, acrosome integrity, and plasma membrane integrity. Statistical analyses were performed using a general linear mixed model (MIXED) in SAS. Factors in the statistical model were experimental groups, time after thawing, and interaction between experimental groups and time after thawing. Total and progressive motilities were greater in semen supplemented with 0.04% phosphorus and vitamin B12 compared with those in the control (p < 0.05). At 15 min post-thawing, VCL, VAP, and HPA in the 0.04% phosphorus and vitamin B12 supplementation group was greater than that in the control (p < 0.05). Phosphorus and vitamin B12 supplementation did not affect sperm kinematics at 0 and 30 min after thawing (p > 0.05). All the sperm parameters that were tested for the 0.04% phosphorus and vitamin B12 supplementation group in modified BPSE were the highest at all the timepoints after thawing. Thus, supplementing frozen semen extender with 0.04% phosphorus and vitamin B12 increased sperm motility, sperm kinematic parameters, and sperm quality.

A simple and fast alternative method to remove glycerol from chicken semen after cryopreservation

A concentration of 11% of glycerol is the standard one for sperm cryopreservation in chickens, however, the presence of just 2% glycerol already causes severe fertility reduction, suggesting the necessity of removing glycerol before artificial insemination (AI). The major approach developed for this purpose is serial dilution followed by centrifugation (SDC), which demands special equipment (such as a refrigerate room) to maintain post-thaw semen at 4 °C, besides being time consuming. Therefore, we attempted to develop a simple method to remove glycerol from chicken frozen-thawed semen based on a colloidal gel, Percoll, which is ordinarily used to select motile and viable sperm in mammals as well as in fresh chicken semen. In this study, we used a Percoll based glycerol removal solution (GRS) containing sucrose to avoid frozen-thawed sperm suffering from osmotic stress. Subsequently, several conditions including GRS compositions (GRS A, B, C and D) and centrifugation temperatures (4 and 20 °C) were compared by their influence on sperm in vitro parameters. Afterwards, GRS A and D were selected for fertility evaluation, compared to conventional SDC method. Our results showed that the fertility with GRS A at both 4 and 20 °C were higher than GRS D (p < 0.05) and similar or even superior to the fertility obtained with SDC method. Altogether, our novel GRS protocol is a valuable method for chicken sperm cryobanking policy, supported by its notable results of fertility as well as saving 44% of time, with a simple equipment at flexible operation temperatures of 4 or 20 °C.

Effects of glucose and trehalose on tris-citric acid-egg yolk-fructose diluents for semen cryopreservation in goat

Objectives

This study aimed to examine the impacts of the wide range of concentrations of glucose and trehalose on the tris-citric acid-egg yolk-fructose (TCEF) extenders for cryopreservation of goat semen.

Materials and Methods

The sperm sample was pooled, washed, and diluted in control (TCEF without glucose and trehalose), TCEF + glucose (75, 150, 450, and 900 mm), and TCEF + trehalose (75, 150, 450, and 900 mm). After equilibrations, the semen straws were frozen under LN2 in the LN2 tank. After LN2 storage, the straws were thawed at 37°C for 30 seconds. The sperm parameters of all study groups were checked after equilibration and freezing.

Results

After equilibration, the progressive motility (PM), total motility (TM), and viability of sperm in G-75, G-150, G-450, T-75, T-150, and T-450 were not significantly different (p < 0.05) from those in control. After cryopreservation and thawing, the PM, TM, and plasma membrane integrity (PMI) of T-150 were significantly higher (p < 0.05) than in control, G-75, G-900, T-75, and T-900. The viability of sperm in T-150 was substantially higher (p < 0.05) than in the control, whereas there was no significant difference among the control, G-75, G-900, T-75, and T-900. However, the acrosome integrity (AI) of sperm in G-900 was significantly decreased (p < 0.05) compared to the control, G-75, G-150, G-450, T-75, T-150, and T-450.

Conclusion

According to the findings, the supplementation of 150 mm trehalose in the TCEF diluent was more efficient for sperm cryopreservation in the buck as reflected by PM, TM, viability, PMI, and AI.

Kinetic vitrification: concepts and perspectives in animal sperm cryopreservation

Sperm cryopreservation is an important tool for genetic diversity management programs and the conservation of endangered breeds and species. The most widely used method of sperm conservation is slow freezing, however, during the process, sperm cells suffer from cryoinjury, which reduces their viability and fertility rates. One of the alternatives to slow freezing is vitrification, that consist on rapid freezing, in which viable cells undergo glass-like solidification. This technology requires large concentrations of permeable cryoprotectants (P- CPA's) which increase the viscosity of the medium to prevent intracellular ice formation during cooling and warming, obtaining successful results in vitrification of oocytes and embryos. Unfortunately, this technology failed when applied to vitrification of sperm due to its higher sensitivity to increasing concentrations of P-CPAs. Alternatively, a technique termed 'kinetic sperm vitrification' has been used and consists in a technique of permeant cryoprotectant-free cryopreservation by direct plunging of a sperm suspension into liquid nitrogen. Some of the advantages of kinetic vitrification are the speed of execution and no rate-controlled equipment required. This technique has been used successfully and with better results for motility in human (50-70% motility recovery), dog (42%), fish (82%) and donkey (21.7%). However, more studies are required to improve sperm viability after devitrification, especially when it comes to motility recovery. The objective of this review is to present the principles of kinetic vitrification, the main findings in the literature, and the perspectives for the utilization of this technique as a cryopreservation method.

New approaches for long-term conservation of rooster spermatozoa

In contrast to the livestock industry, sperm cryopreservation has not yet been successfully established in the poultry industry. This is because poultry sperm cells have a unique shape and membrane fluidity, differing from those of livestock sperm. The objective of this review is to discuss the cellular and molecular characteristics of rooster spermatozoa as a cause for their generally low freezability. Furthermore, here, we discuss novel developments in the field of semen extenders, cryoprotectants, and freezing processes, all with the purpose of increasing the potential of rooster sperm cryopreservation. Currently, it is very important to improve cryopreservation of rooster sperm on a global scale for the protection of gene resources due to the incidence of epidemics such as avian influenza.

Cryopreservation of Semen in Domestic Animals: A Review of Current Challenges, Applications, and Prospective Strategies

Cryopreservation is a way to preserve germplasm with applications in agriculture, biotechnology, and conservation of endangered animals. Cryopreservation has been available for over a century, yet, using current methods, only around 50% of spermatozoa retain their viability after cryopreservation. This loss is associated with damage to different sperm components including the plasma membrane, nucleus, mitochondria, proteins, mRNAs, and microRNAs. To mitigate this damage, conventional strategies use chemical additives that include classical cryoprotectants such as glycerol, as well as antioxidants, fatty acids, sugars, amino acids, and membrane stabilizers. However, clearly current protocols do not prevent all damage. This may be due to the imperfect function of antioxidants and the probable conversion of media components to more toxic forms during cryopreservation.

Advances in storage of poultry semen

Semen cryopreservation is a key biotechnological strategy used to preserve and protect genetic resources, which are subject to increasingly serious reductions in some species, and to protect animal biodiversity. Assisted reproductive techniques, however, are still not utilized to the same extent in avian species to the extent that occurs in mammals. The reasons for this situation are described in this review. The content of this paper is focused on current poultry preservation systems, published since 2010, and new strategies that are very promising for preserving avian genetic resources. Two major types of storage technologies which are utilized for avian sperm preservation, liquid storage and cryopreservation, are emphasized. The issues on which there is a focus includes supplementation of avian extenders with various compounds prior to the preservation period, use of cryoprotectants and fertility results when there were in vitro sperm evaluations. Results from recent studies indicate there are opportunities to improve the quality of bird semen after preservation. It is obvious that cryo-diluent composition may be the most important factor for development of efficacious cryopreservation methods for avian semen.

Poultry genetic heritage cryopreservation and reconstruction: advancement and future challenges

Poultry genetics resources, including commercial selected lines, indigenous breeds, and experimental lines, are now being irreversibly lost at an alarming rate due to multiple reasons, which further threats the future livelihood and academic purpose. Collections of germplasm may reduce the risk of catastrophic loss of genetic diversity by guaranteeing that a pool of genetic variability is available to ensure the reintroduction and replenishment of the genetic stocks. The setting up of biobanks for poultry is challenging because the high sensitiveness of spermatozoa to freezing–thawing process, inability to cryopreserve the egg or embryo, coupled with the females being heterogametic sex. The progress in cryobiology and biotechnologies have made possible the extension of the range of germplasm for poultry species available in cryobanks, including semen, primordial germ cells, somatic cells and gonads. In this review, we introduce the state-of-the-art technologies for avian genetic resource conservation and breed reconstruction, and discuss the potential challenges for future study and further extending of these technologies to ongoing and future conservation efforts.

Effect of Betaine and Raffinose in Cryopreservation Medium on Fertility in Kadaknath Chicken

BACKGROUND: Kadaknath is an important indigenous chicken with black pigmentation and cryopreserved semen reputably had low fertility. OBJECTIVE: The aim of this study was to evaluate the effects of betaine and raffinose in semen extenders on post thaw semen parameters and fertility. MATERIALS AND METHODS: Semen was cryopreserved in 4% dimethyl sulfoxide (DMSO) with betaine supplemented at 0.1, 0.2 and 0.4 M or raffinose supplemented at 1, 5 and 10 mM. Post thaw semen parameters and fertility were evaluated. RESULTS: Betaine at higher concentrations significantly (p < 0.05) inhibited the post thaw sperm motility, live sperm and MTT dye reduction and a declining trend in the fertility with increasing betaine. Inclusion of raffinose had no effect on the post thaw in vitro semen parameters, however, the fertility was significantly (p < 0.05) higher in the 10 mM raffinose supplemented group. CONCLUSION: Betaine has negative effect on post thaw semen parameters and raffinose at 10 mM concentration improves the fertility from cryopreserved semen.

Animal board invited review: Germplasm technologies for use with poultry

Over the last century, several reproductive biotechnologies beyond the artificial incubation of eggs were developed to improve poultry breeding stocks and conserve their genetic diversity. These include artificial insemination (AI), semen storage, diploid primordial germ cell (PGC) methodologies, and gonad tissue storage and transplantation. Currently, AI is widely used for selection purposes in the poultry industry, in the breeding of turkeys and guinea fowl, and to solve fertility problems in duck interspecies crosses for the production of mule ducklings. The decline in some wild game species has also raised interest in reproductive technologies as a means of increasing the production of fertile eggs, and ultimately the number of birds that can be raised. AI requires viable sperm to be preserved in vitro for either short (fresh) or longer periods (chilling or freezing). Since spermatozoa are the most easily accessed sex cells, they are the cell type most commonly preserved by genetic resource banks. However, the cryopreservation of sperm only preserves half of the genome, and it cannot preserve the W chromosome. For avian species, the problem of preserving oocytes and zygotes may be solved via the cryopreservation and transplantation of PGCs and gonad tissue. The present review describes all these procedures and discusses how combining these different technologies allows poultry populations to be conserved and even rapidly reconstituted.

Beneficial Influence of Soybean Lecithin Nanoparticles on Rooster Frozen-Thawed Semen Quality and Fertility

Simple Summary

Soy lecithin (SL) can be used in to prevent spermatozoa cryodamage during cryopreservation by mitigating the efflux of cholesterol or phospholipids, thus reducing the formation of intracellular ice crystals. SL nanoparticles (nano-SL) have a smaller particle size and higher solubilizing capacity as compared with those that have not undergone nanotreatment. Thus, they allow for a better interaction or coating of sperm, decreasing cold shock injury during freezing–thawing processes. The objective of this study was to determine the optimal concentration of nano-SL. In order to achieve this, we assessed the quality of frozen–thawed semen in vitro and in vivo. We found that a nano-SL dosage of 1.0% in the semen extender had an affirmative influence on post-thawing quality in roosters, improving various parameters related to sperm motion, protecting the membrane and acrosome integrities, increasing mitochondrial activity and antioxidant capacity, and reducing the oxidative stress caused by the cryopreservation process. Moreover, enrichment of 1.0% nano-SL in the semen extender improved the fertilizing capacity of rooster sperm after artificial insemination.

Abstract

The present study aimed to investigate the impact of different concentrations (0%, 0.5%, 1.0%, 1.5%, and 2.0%) of nano-soybean lecithin (SL) in the extender on sperm quality, sperm motion characteristics, and fertility outcomes of post-thawed rooster semen. Adult Ross broiler breeder roosters (n = 20) were subjected to semen collections twice a week for three weeks. At each collection, semen samples were pooled and allocated into five treatments corresponding to different nano-SL concentrations (control, SL0.5, SL1.0, SL1.5, and SL2.0). Sperm parameters, including motility (collected using a computer-assisted sperm analysis system), plasma membrane and acrosome integrities, and mitochondrial activity were assessed. Sperm malondialdehyde (MDA) and antioxidant activities (total antioxidant capacity (TAC); superoxide dismutase (SOD); glutathione peroxidase (GPx)) were evaluated. The fertility and hatchability obtained with frozen–thawed rooster semen supplemented with the optimum nano-SL concentration were assessed after artificial insemination. The results showed that the addition of 1% nano-SL into the extender led to a higher semen motility in roosters, improved plasma membrane and acrosome integrities, and higher mitochondrial activity of post-thawed rooster semen in comparison to controls (p < 0.05). The MDA levels in the SL0.5 and SL1.0 groups were lower than the other groups (p < 0.05). TAC activities in SL0.5, SL1.0, and SL1.5 groups were significantly higher than those in the other groups (p < 0.05). It was observed that the concentration of SOD was higher in the SL1.0 group than in the other groups (p < 0.05). The activity of GPx was not influenced in any of the cases (p > 0.05). Moreover, the percentages of fertility and hatchability in the SL1.0 group were higher (56.36% and 58.06%) than those in the control group (42.72% and 40.43%). In summary, the addition of nano-SL to the extenders enhanced the post-thawed semen quality and fertility of roosters by reducing the level of oxidative stress. The optimum nano-SL concentration was 1.0%. These results may be beneficial for improving the efficacy of semen cryopreservation procedures in poultry breeding.

Effects of Saccharides Supplementation in the Extender of Cryopreserved Rooster (Gallus domesticus) Semen on the Fertility of Frozen/Thawed Spermatozoa

The aim of this study was to create balanced media for the cryopreservation of rooster semen in pellets to maintain the functional state of the sperm after thawing. Fructose was replaced by trehalose in experimental media in proportions of 10% (LCM-T10) and 20% (LCM-T20), while LCM was used as a control. After artificial insemination of the hens, the eggs were incubated (n = 400). To determine the functional safety of spermatozoa in the genital tract of hens after 5, 10, and 15 days from the last insemination, we used a method for assessing the interaction of sperm with the perivitelline membrane. Significantly higher rates of egg fertilization (82-86%) were obtained when using LCM-T10 and LCM-T20 compared to control (79%, p < 0.05). Egg fertility on the 5th day from the last insemination with the LCM-T20 diluent reached 100% versus 86% in the control; on the 10th day, the fertility rates were 55% versus 20%, respectively. The best results for fertility duration were obtained by freezing spermatozoa with LCM-T20 medium. The numbers of interaction points of spermatozoa with the perivitelline membrane were as follows: on the 5th day from the last insemination with LCM-T20-461.5 ± 11.5 holes/cm² (LCM-control-13.7 ± 2.7 holes/cm²), p < 0.01; on the 10th day with LCM-T20-319.3 ± 12.9 holes/cm² (LCM-control-14.9 ± 3.5 holes/cm²); and on the 15th day with LCM-T20-345.2 ± 11.1 holes/cm² (LCM-control-0 holes/cm²). In conclusion, the use of trehalose in LCM diluent medium can increase the fertility of frozen/thawed sperm and the duration of their fertility in the genital tract of hens.

Effect of supplementation of valine to chicken extender on sperm cryoresistance and post-thaw fertilization capacity

Recent reports showed a positive correlation between frozen-thawed rooster sperm DNA integrity and the concentrations of valine in seminal plasma. The present study evaluated the effect of supplementing valine to semen extender for freezing sperm of 2 endangered local Spanish chicken breeds with different sperm cryoresistance: Red Villafranquina (VF) showing low sperm DNA integrity after cryopreservation and Quail Castellana that shows higher DNA integrity. One pool of semen per breed was obtained twice a week for 10 wk (n = 40, 20 per breed). Each pool was divided into 2 fractions. One of these fractions was frozen in presence of valine as additive in the extender (concentration 10 mmol), whereas the other was used as control. The evaluation of the samples before and after freezing-thawing included motility (CASA-Mot system), viability (propidium iodide and SYBR-14), DNA integrity (terminal deoxynucleotidyl transferase dUTP nick end labeling), and fertility rate (percentage of eggs with blastoderm development after artificial insemination). Supplementation of valine increased several motility variables of fresh semen. In VF breed, valine increased percentage of progressive motile sperm (P = 0.025), curvilinear velocity (P = 0.033), straight-line velocity (P = 0.040), and average path velocity (P = 0.033), whereas progressive motile sperm (P = 0.019), curvilinear velocity (P = 0.006), straight-line velocity (P = 0.003) and average path velocity (P = 0.004) were improved in the Quail Castellana breed. Valine addition increased the DNA integrity of cryopreserved semen (decreased post-thaw DNA fragmentation) in both breeds, with a significant effect (P = 0.002) in VF (36.3% VF-control vs 31%VF-valine). As expected, Quail Castellana cryopreserved sperm control showed higher fertility rate (34.4% ± 12.1) than VF cryopreserved sperm control (16.1% + 6.2). Supplementing valine to the freezing extender doubled (P = 0.026) the fertility rate of VF (32.6% ± 12.2) compared with the control (16.1% + 6.2). In conclusion, supplementation of valine to chicken freezing extenders shows a positive effect on DNA fragmentation and fertilizing ability of frozen-thawed sperm, with a better response in a breed considered as the lowest freezer in our conservatory.

Oxidative and nitrosative stress in frozen-thawed pig spermatozoa. II: Effect of the addition of saccharides to freezing medium on sperm function

Saccharides have bioprotective properties, with a high capacity to preserve biological proteins and membranes during sperm cryopreservation. The aim of this study was to evaluate how replacing the lactose of cryopreservation media by sucrose (SUC) or trehalose (TRE) at concentrations of 0.2 M (SUC-1 and TRE-1) and 0.25 M (SUC-2 and TRE-2) affects frozen/thawed pig spermatozoa. The media used were composed of medium A (saccharide/egg yolk) and B (saccharide/egg yolk/glycerol), their osmolality being determined prior to freezing. Cell viability, membrane lipid disorder, acrosome integrity, mitochondrial membrane potential (MMP), lipid peroxidation, thiol group oxidation, total reactive oxygen species (ROS), peroxynitrite and superoxide anion (O₂^●-) were determined through flow cytometry; total motility (TM), progressive motility (PM) and kinetic parameters motility were determined immediately after thawing (T0) and again 30 (T30) and 60 (T60) minutes later. The SUC-2 and TRE-2 groups maintained viability significantly and presented fewer lipid membrane disorders, respectively, both with a significant increase in MMP. The production of O₂^●- and peroxynitrite was lower in the TRE-2 groups compared to the control (P < 0.05). Total motility at T0 was greater in the TRE-2 group (P < 0.05). Sperm kinetics was not affected by the treatment. The use of saccharides SUC and TRE at a concentration of 0.25 M improves sperm quality, so that both non-penetrating cryoprotectants can be utilized in pig sperm freezing media.

Insights into Species Preservation: Cryobanking of Rabbit Somatic and Pluripotent Stem Cells

Induced pluripotent stem cells (iPSCs) are obtained by genetically reprogramming adult somatic cells via the overexpression of specific pluripotent genes. The resulting cells possess the same differentiation properties as blastocyst-stage embryonic stem cells (ESCs) and can be used to produce new individuals by embryonic complementation, nuclear transfer cloning, or in vitro fertilization after differentiation into male or female gametes. Therefore, iPSCs are highly valuable for preserving biodiversity and, together with somatic cells, can enlarge the pool of reproductive samples for cryobanking. In this study, we subjected rabbit iPSCs (rbiPSCs) and rabbit ear tissues to several cryopreservation conditions with the aim of defining safe and non-toxic slow-freezing protocols. We compared a commercial synthetic medium (STEM ALPHA.CRYO3) with a biological medium based on fetal bovine serum (FBS) together with low (0-5%) and high (10%) concentrations of dimethyl sulfoxide (DMSO). Our data demonstrated the efficacy of a CRYO3-based medium containing 4% DMSO for the cryopreservation of skin tissues and rbiPSCs. Specifically, this medium provided similar or even better biological results than the commonly used freezing medium composed of FBS and 10% DMSO. The results of this study therefore represent an encouraging first step towards the use of iPSCs for species preservation.

Validation of the Turkey Semen Cryopreservation by Evaluating the Effect of Two Diluents and the Inseminating Doses

Simple Summary

Achieving an effective freezing protocol, that is able to preserve the fertilizing ability of turkey semen, is a key aim for the establishment of the first national semen cryobank of autochthonous chicken and turkey breeds within our national project (Tutela della biodiversità nelle razze avicole italiane—TuBAvI). In this regard, we have performed different studies in order to define the best conditions for cryopreservation of turkey semen; namely, we identified an effective freezing protocol which is based on the use of dimethylsulfoxide as a permeant cryoprotectant (CPA) combined with Ficoll as a non-permeant CPA. Here, our purpose was to test this protocol in vivo, by evaluating the effect of two extenders and three inseminating doses. The good fertility and hatching rates achieved here are promising for future studies, in which our cryopreservation protocol will be tested on Italian autochthonous turkey breeds and also to the advantages offered by the extensive use of frozen semen in the turkey breeding industry.

Abstract

This study was designed to test the fertilizing ability of cryopreserved turkey semen, and here, two experiments were performed: an in vitro analysis to assess the effects of Tselutin and Lake diluents and an in vivo test to determine the fertility and hatching rates by also studying the feat of three insemination doses (250, 400 and 600 × 10⁶ sperm/hen). Pooled semen samples were diluted with Tselutin or Lake extender which contained 20% of dimethylsulfoxide and 1 mM of Ficoll at final sperm concentration of 3 × 10⁹ sperm/mL. Thereafter, semen was packaged into straws and frozen on liquid nitrogen. The post-thaw sperm quality was evaluated considering motility (computer-aided sperm analysis—CASA system) and membrane integrity (flow cytometry). Significantly higher values of progressive motility and some kinetic parameters in semen frozen with Lake were found. When we compared the extenders in vivo, no significant effects were detected, whilst sperm concentration significantly affected both fertility and hatching rates, with the best results obtained with the sperm concentration of 400 × 10⁶ sperm/hen. From the results obtained, it emerged that the extender type only affected sperm motility characteristics, not the fertilizing ability of frozen-thawed semen, while inseminating dose markedly affected fertility and hatching rates.

Comparative transcriptome analysis digs out genes related to antifreeze between fresh and frozen-thawed rooster sperm

The objective of this study was to investigate differences in mRNA expression between fresh and frozen–thawed sperm in roosters. In trial 1, gene expression profiles were measured using microarray with Affymetrix GeneChip Chicken Genome Arrays. The results showed that 2,115 genes were differentially expressed between the 2 groups. Among these genes, 2,086 were significantly downregulated and 29 were significantly upregulated in the frozen–thawed sperm group. Gene Ontology (GO) analysis showed that more than 1,000 differentially expressed genes (DEG) of all significantly regulated genes were involved in GO terms including biological processes, molecular function, and cellular component. Kyoto Encyclopedia of Genes and Genomes analysis showed that DEG were significantly (P < 0.05) enriched on ribosome, oxidative phosphorylation, proteasome, cell cycle, oocyte meiosis, and spliceosome pathways. In trial 2, ejaculated semen was collected from 18 roosters and divided into 5 recombinant HSP90 protein–supplemented groups (0.01, 0.1, 0.5, 1, or 2 μg/mL) and one control group with no recombinant HSP90 protein supplementation to evaluate the effect of recombinant HSP90 protein in the extender on post-thaw quality of rooster semen. The results showed that post-thaw sperm viability and motility was significantly improved (P < 0.05) in the extender containing 0.5 and 1 μg/mL of recombinant HSP90 protein compared with the control. Our preliminary results will provide a valuable basis for understanding the potential molecular mechanisms of cryodamage in frozen–thawed sperm and theoretical guidance to improve the fertility of frozen–thawed chicken sperm.

Finding an Effective Freezing Protocol for Turkey Semen: Benefits of Ficoll as Non-Permeant Cryoprotectant and 1:4 as Dilution Rate

Simple Summary

The most adopted biotechnology for the conservation of genetic resources in avian species is semen cryopreservation. Therefore, the identification of a reference cryopreservation procedure represents a key point for ensuring the long-term conservation of genetic diversity in birds, through the implementation of a semen cryobank. In this study, our goal was to discover an effective freezing protocol for Meleagris gallopavo in order to realize the first Italian semen cryobank of autochthonous chicken and turkey breeds within our project (TuBAvI). For this purpose, we investigated the effects of three non-permeant cryoprotectants (sucrose, trehalose, and Ficoll) and two dilution rates (1:2 and 1:4) on the in vitro cryosurvivability of turkey spermatozoa. After thawing, the best semen quality was found in semen frozen in the presence of Ficoll and diluted at a final rate of 1:4. This paper provides encouraging results, however further studies are programmed to standardize the semen cryopreservation protocol.

Abstract

The present study aimed to find an effective cryopreservation protocol for turkey semen through the combined use of dimethylsulfoxide (DMSO) and three non-permeant cryoprotectants (NP-CPAs), sucrose, trehalose, and Ficoll 70. In addition, the action of two dilution rates (1:2 and 1:4) were also investigated. Semen was processed according to two final dilution rates and the following treatments: Tselutin extender (TE)/DMSO (control), TE/DMSO + sucrose or trehalose 50, 100, 200, or 400 mM, and TE/DMSO + Ficoll 0.5, 0.75, 1, or 1.5 mM. In total 26 different combinations treatments were achieved. The diluted semen was filled up into straws and frozen on liquid nitrogen vapor. The post-thawing sperm quality was assessed by analyzing motility, membrane integrity, osmotic resistance, and DNA integrity. The results obtained revealed a significant effect of NP-CPA concentration on total and progressive motility, on most of the kinetic parameters, on membrane integrity and DNA integrity, while the post-thaw quality was less affected by dilution rate. The highest post-thaw quality for all sperm quality parameters assessed except curvilinear velocity (VCL) and DNA integrity were found in semen frozen with 1 mM Ficoll/1:4 (p < 0.05). Our findings provide an important contribution for the identification of a reference procedure for turkey semen cryopreservation, in order to create the first national avian semen cryobank.

Different concentrations of cysteamine, ergothioneine, and serine modulate quality and fertilizing ability of cryopreserved chicken sperm

The aim of this study was to evaluate the effects of freezing diluents supplemented in three potential amines/amino acids, namely, antioxidant cysteamine (2-aminoethanethiol [AET]), ergothioneine (ERG), and serine (SER), in optimization of chicken sperm cryopreservation. The semen of 36 Pradu Hang Dum males, selected based on their motility vigor score, was frozen by a simple freezing method using nitrogen vapors and dimethylformamide (DMF). In a first experiment, a wide range of AET, ERG, and SER doses were tested. Semen quality was evaluated after incubation at 5°C or after cryopreservation in straws in the Blumberger Hahnen Sperma Verdünner (BHSV) diluent + DMF (6% v/v) with or without AET, ERG, or SER. The best targeted doses of AET, ERG, or SER were then selected for experiment 2 that was focused on cryopreserved semen. Frozen-thawed sperm quality was evaluated by different in vitro tests and by evaluation of fertility. Objective motility parameters were evaluated by computer-assisted sperm analysis. Membrane integrity, acrosome integrity, and mitochondria function were evaluated using appropriate dyes and flow cytometry. Lipid peroxide production was assessed by the thiobarbituric acid test (malondialdehyde production). Fertility obtained with frozen-thawed semen supplemented or not in AET, ERG, or SER was evaluated after artificial insemination of laying hens. ERG and AET decreased sperm lipid peroxidation and decreased fertility, even at low doses. The presence of 4 mmol of SER significantly decreased lipid peroxidation, increased the frozen-thawed sperm quality, and increased fertility after sperm cryopreservation (90% vs. control 84%, P < 0.05). In a third experiment, the use of 1 mmol of sucrose (the best result of our previous study) added to 4 mmol of SER-supplemented extender was tested. This addition allowed to the highest levels of fertility (93%). In conclusion, the addition of 4 mmol of SER in semen cryopreservation diluents decreases peroxidation and improves the efficiency of the process.