Birth of piglets from in vitro-produced, zona-intact porcine embryos vitrified in a closed system

The Open Cryotop System Is Effective for the Simultaneous Vitrification of a Large Number of Porcine Embryos at Different Developmental Stages

The Superfine Open Pulled Straw (SOPS) system is the most commonly used method for vitrification of pig embryos. However, this system only allows the vitrification of four to seven embryos per straw. In this study, we investigated the effectiveness of the open (OC) and closed (CC) Cryotop^® systems to simultaneously vitrify a larger number of porcine embryos. Morulae, early blastocysts and full blastocysts were vitrified with the open Cryotop^® (n = 250; 20 embryos per device) system, the closed Cryotop^® (n = 158; 20 embryos per device) system and the traditional superfine open pulled straw (SOPS; n = 241; 4–7 embryos per straw) method. Fresh embryos from each developmental stage constituted the control group (n = 132). Data expressed as percentages were compared with the Fisher's exact test. The Kruskal-Wallis test was used to analyze the effect of the different vitrification systems on the embryo quality parameters and two-by-two comparisons were accomplished with the Mann-Whitney U test. Differences were considered statistically significant when p < 0.05. Vitrified and control embryos were incubated for 24 h and examined for viability and quality. At the warming step, the embryo recovery rate for the CC system was 51%, while all embryos were recovered when using OC and SOPS. There were no differences between the vitrification and control groups in the postwarming viability of full blastocysts. In contrast, morulae and early blastocysts that were vitrified-warmed with the SOPS system had lower viability (p < 0.01) compared to those from the OC, CC and control groups. The embryonic viability was similar between the OC and control groups, regardless of the developmental stage considered. Moreover, the embryos from the OC group had comparable total cell number and cells from the inner cell mass and apoptotic index than the controls. In conclusion, the OC system is suitable for the simultaneous vitrification of 20 porcine embryos at different developmental stages and provides comparable viability and quality results to fresh embryos subjected to 24 h of in vitro culture.

Successful vitrification of early-stage porcine cloned embryos

The objective of this study was to investigate the survival and development of porcine cloned embryos vitrified by Cryotop carrier at the zygote, 2- and 4-cell stages. The quality of resultant blastocysts was evaluated according to their total cell number, apoptotic cell rate, reactive oxygen species (ROS) production, glutathione (GSH) content and mRNA expression levels of genes related to embryonic development. The survival rates of zygotes, 2- and 4-cell embryos after vitrification did not differ from those of their fresh counterparts. Vitrification still resulted in significantly decreased blastocyst formation rates of these early-stage embryos. Moreover, the total cells, apoptotic rate, ROS and GSH levels in resultant blastocysts were unaffected by vitrification. The mRNA expression levels of PCNA, CPT1, POU5F1 and DNMT3B in the blastocysts derived from vitrified early-stage embryos were significantly higher than those in the fresh blastocysts, but there was no change in expression of CDX2 and DNMT3A genes. In conclusion, our data demonstrate that the early-stage porcine cloned embryos including zygotes, 2- and 4-cells can be successfully vitrified, with respectable blastocyst yield and quality.

Non-surgical transfer of vitrified porcine embryos using a catheter designed for a proximal site of the uterus

This study aimed to compare the efficiency of non‐surgical embryo transfer (ET) using a newly developed catheter, which enables transferring embryos into a proximal site of the uterus (mostly uterine body), and surgical ET of vitrified porcine embryos. In Experiment 1, the catheter was inserted into 12 gilts, with each half of the group allocated to skilled or novice operators. The time required for insertion into the uterus did not differ between skilled and novice operators (4 min 9 s and 4 min 6 s, respectively). In Experiment 2, 12 gilts were used as recipients for non‐surgical and surgical ET with vitrified embryos (n = 6, each). There was no significant difference in the rate of piglet production based on the number of transferred embryos between surgical and non‐surgical ET (25.8% vs. 15.4%, p = .098). The results suggest that non‐surgical ET catheter allowed for easy insertion and transfer of embryos without special training. Although the catheter is effective for deposition of embryos into the proximal site of uterus, the efficiency of piglet production is not enhanced compared with surgical ET. The ET method using this catheter, being labor‐saving and less‐invasive, may contribute to the improvement of ET in pigs.

Embryo collection from pigs post-pseudopregnancy induced by estradiol dipropionate

We aimed to define whether embryo collection carried out after pseudopregnancy was of similar outcome and quality as after artificial abortion. To induce pseudopregnancy, 30 gilts or sows were given 20 mg intramuscular estradiol dipropionate (EDP) 10-11 days after the onset of estrus. Ten additional pigs were inseminated artificially at natural estrus as a control group. Prostaglandin F_2α (PGF_2α ) was administered twice with a 24 hr interval beginning 15, 20, or 25 days after EDP-treatment (n = 10 per group) or between 23 and 39 days after artificial insemination in control pigs. Following this, all pigs were given 1,000 IU equine chorionic gonadotropin and 500 IU human chorionic gonadotropin (hCG) and then inseminated. Embryos were recovered 6 or 7 days after hCG treatment and outcome was recorded. There was no significant difference in the number of normal embryos collected from the pigs with PGF_2α initiated at different time points or from the control group. Embryonic developmental stages 7 days after hCG treatment also did not differ among groups. These results indicate that the use of EDP to induce pseudopregnancy, followed by PGF_2α administration to synchronize estrus for subsequent embryo harvest, is a suitable alternative to the artificial abortion method.

Effect of Knockout Serum Replacement During Postwarming Recovery Culture on the Development and Quality of Vitrified Parthenogenetic Porcine Blastocysts

The postwarming recovery culture, as one of the steps in cryopreservation process, is directly correlated with the survival and quality of embryos. Generally, recovery medium includes undefined serum or serum components that may cause the instability of results and other problems. The objective of this study was to evaluate the effect of knockout serum replacement (KSR) as a substitute for serum during recovery culture on the development and quality of vitrified parthenogenetic porcine blastocysts. Fetal bovine serum (FBS) was used as a positive control. The expanded blastocysts on day 5 were vitrified by the Cryotop method, and recovered with 10% (v/v) KSR or 10% (v/v) FBS for 48 hours after warming. Survival and hatching rates of vitrified blastocysts were significantly increased by KSR or FBS supplementation. The vitrified blastocysts recovered in KSR or FBS exhibited significantly decreased percentages of membrane damage and apoptosis, and increased total cells. Addition of KSR or FBS during recovery culture significantly reduced reactive oxygen species levels, and improved mitochondrial activity and adenosine triphosphates content in the vitrified blastocysts. Vitrification did not affect the gene expression of PCNA, CDX2, and CPT1, but significantly increased mRNA levels of POU5F1 and uPA. KSR added to the recovery medium significantly upregulated mRNA levels of PCNA and CPT1, and downregulated POU5F1 mRNA levels. The expression levels of PCNA, CDX2, CPT1, and uPA in vitrified blastocysts were significantly upregulated by addition of FBS to recovery medium. Moreover, the BAX: BCL2L1 ratio was similar between fresh and vitrified blastocysts, and KSR or FBS supplementation had no effect on the value. In conclusion, our data showed that KSR supplementation during recovery culture can improve the development and quality of vitrified parthenogenetic porcine blastocysts. These findings provide a useful reference that KSR could be used to replace FBS as a defined serum supplement for recovery culture of vitrified blastocysts.

Effect of different penetrating and non-penetrating cryoprotectants and media temperature on the cryosurvival of vitrified in vitro produced porcine blastocysts

The aim of this study was to determine the most efficient vitrification protocol for the cryopreservation of day 7 in vitro produced (IVP) porcine blastocysts. The post-warm survival rate of blastocysts vitrified in control (17% dimethyl sulfoxide + 17% ethylene glycol [EG] + 0.4 mol/L sucrose) and commercial media did not differ, nor did the post-warm survival rate of blastocysts vitrified in medium containing 1,2-propandiol in place of EG. However, vitrifying embryos in EG alone decreased the cryosurvival rate (55.6% and 33.6%, respectively, p < .05). Furthermore, the post-warm survival rates of blastocysts vitrified with either trehalose or sucrose as the non-penetrating cryoprotectant did not differ. There was also no significant difference in post-warm survival of blastocysts vitrified in control (38°C) media and room temperature (22°C) media with extended equilibration times, although when blastocysts were vitrified using control media at room temperature, the post-warm survival rate increased (56.8%, 57.3%, 72.5%, respectively, p < .05). The findings show that most cryoprotectant combinations examined proved equally effective at supporting the post-warm survival of IVP porcine blastocysts. The improved post-warm survival rate of blastocysts vitrified using media held at room temperature suggests that the cryoprotectant toxicity exerted in 22°C media was reduced.

Cryotolerance of porcine in vitro-produced blastocysts relies on blastocyst stage and length of in vitro culture prior to vitrification

The aim of our study was to assess whether the cryotolerance of in vitro-produced embryos could be influenced by the length of in vitro culture and size of blastocoel cavity before vitrification, using the pig as a model. For this purpose we analysed the cryoresistance and apoptosis rate of blastocysts at different stages of development as derived on Day 5 and 6 of in vitro culture. Blastocysts were subsequently vitrified, warmed and cultured for 24 h. Re-expansion rates were recorded at 3 and 24 h and total cell number and apoptotic cells were determined at 24 h. Day-6 blastocysts showed the highest rates of survival after warming, which indicates higher quality compared with Day-5 blastocysts. Higher re-expansion rates were observed for expanded blastocysts and those in the process of hatching when compared with early blastocysts. Total cell number and apoptotic cells were affected by blastocyst stage, vitrification–warming procedures and length of in vitro culture, as expanding and hatching–hatched blastocysts from Day 6 presented higher percentages of apoptotic cells than fresh blastocysts and blastocysts vitrified at Day 5. Our findings suggest that the cryotop vitrification method is useful for the cryopreservation of porcine blastocysts presenting a high degree of expansion, particularly when vitrification is performed after 6 days of in vitro culture. Furthermore, these results show that faster embryo development underlies higher blastocyst cryotolerance and provide evidence that blastocoel cavity expansion before vitrification is a reliable index of in vitro-produced embryo quality and developmental potential.

A comparison of different vitrification devices and the effect of blastocoele collapse on the cryosurvival of in vitro produced porcine embryos

The aim of this study was to determine the optimum conditions for vitrifying in vitro produced day 7 porcine embryos using different vitrification devices and blastocoele collapse methods. Firstly embryos were collapsed by micro-pipetting, needle puncture and sucrose with and without conducting vitrification. In the next experiment, non-collapsed embryos were vitrified in an open device using either superfine open-pulled straws (SOPS) or the CryoLoop^TM system, or vitrified in a closed device using either the CryoTip^TM or Cryo Bio^TM’s high security vitrification system (HSV). The post-thaw survival of embryos vitrified in the open devices did not differ significantly (SOPS: 37.3%; CryoLoop^TM: 37.3%) nor did the post-thaw survival of embryos vitrified in the closed devices (CryoTip™: 38.5%; HSV: 42.5%). The re-expansion rate of embryos that were collapsed via micro-pipetting (76.0%) did not differ from those that were punctured (75.0%) or collapsed via sucrose (79.6%) when vitrification was not performed. However, embryos collapsed via sucrose solutions (24.5%) and needle puncture (16.0%) prior to vitrification were significantly less likely to survive vitrification than the control (non-collapsed) embryos (53.6%, P < 0.05). The findings show that both open and closed vitrification devices were equally effective for the vitrification of porcine blastocysts. Collapsing blastocysts prior to vitrification did not improve survival, which is inconsistent with the findings of studies in other species. This may be due to the extremely sensitive nature of porcine embryos, and/or the invasiveness of the collapsing procedures.

Cryopreservation of In Vitro-Produced Early-Stage Porcine Embryos in a Closed System

Cryostorage of porcine embryos in a closed pathogen-free system is essential for the maintenance and safeguard of swine models. Previously, we reported a protocol for the successful cryopreservation of porcine embryos at the blastocyst stage in 0.25 mL ministraws. In this experiment, we aimed at developing a protocol to apply the same concept for the cryopreservation of early-stage porcine embryos. Porcine embryos from day 2 through day 4 were delipidated by using a modified two-step centrifugation method and were then cryopreserved in sealed 0.25 mL straws by using a slow cooling method. Control groups included open pulled straw (OPS) vitrified embryos after delipidation and noncryopreserved embryos without delipidation. There were no significant differences in cryosurvival between embryos frozen in 0.25 mL straws and OPS vitrified embryos across all the stages (two cell to morula) examined (p>0.05). Similarly, in all groups examined, the blastocyst rates were not different between the two cryopreserved groups. However, the blastocyst rates from the cryopreserved groups were significantly lower than the noncryopreserved controls (p<0.05). This experiment demonstrated that early-stage porcine embryos can survive cryopreservation in a closed system by using a slow cooling method at a comparable rate to those vitrified by using an ultrarapid cooling method (p>0.05). However, the developmental competence was significantly reduced after cryopreservation compared to noncryopreserved embryos. Further research is needed to optimize the protocol to improve the developmental potential of cryopreserved early-stage porcine embryos in sealed straws.

Vitrification in human and domestic animal embryology: work in progress

According to the analysis of papers published in major international journals, rapidly increasing application of vitrification is one of the greatest achievements in domestic animal and especially human embryology during the first decade of our century. This review highlights factors supporting or hampering this progress, summarises results achieved with vitrification and outlines future tasks to fully exploit the benefits of this amazing approach that has changed or will change many aspects of laboratory (and also clinical) embryology. Supporting factors include the simplicity, cost efficiency and convincing success of vitrification compared with other approaches in all species and developmental stages in mammalian embryology, while causes that slow down the progress are mostly of human origin: inadequate tools and solutions, superficial teaching, improper application and unjustified concerns resulting in legal restrictions. Elimination of these hindrances seems to be a slower process and more demanding task than meeting the biological challenge. A key element of future progress will be to pass the pioneer age, establish a consensus regarding biosafety requirements, outline the indispensable features of a standard approach and design fully-automated vitrification machines executing all phases of the procedure, including equilibration, cooling, warming and dilution steps.

Successful production of piglets derived from expanded blastocysts vitrified using a micro volume air cooling method without direct exposure to liquid nitrogen

This study was conducted to clarify the feasibility of newly developed vitrification techniques for porcine embryos using the micro volume air cooling (MVAC) method without direct contact with liquid nitrogen (LN₂). Expanded blastocysts were vitrified in a solution containing 6 M ethylene glycol, 0.6 M trehalose and 2% (wt/vol) polyethylene glycol in 10% HEPES-buffered PZM-5. The blastocysts were collected from gilts and vitrified using the new device (MVAC) or a Cryotop (CT). Blastocysts were stored in LN₂ for at least 1 month. After warming, cryoprotective agents were removed using a single step. Survival of the embryos was assessed by in vitro culture (Experiment 1) and by embryo transfer to recipients (Experiment 2). In Experiment 1, the embryos vitrified by the MVAC or CT and fresh embryos without vitrification (Control) were used. The survival rates of embryos in the MVAC, CT and Control groups were 88.9% (32/36), 91.7% (33/36) and 100% (34/34), respectively, after 48 h culture, and the hatching rates of embryos after 48 h incubation were 69.4% (25/36), 63.9% (23/36) and 94.1% (32/34), respectively. In Experiment 2, 64 vitrified embryos were transferred to 5 recipient gilts, and 8 healthy piglets were produced from 3 recipients in the MVAC group. Similarly, 66 vitrified embryos were transferred to 5 recipient gilts, and 9 healthy piglets were produced from 2 recipients in the CT group. These results indicated that porcine expanded blastocysts can be cryopreserved using the MVAC method without potential pathogen contamination from LN₂.

High-throughput cryopreservation of in vivo-derived swine embryos

Cryopreservation of swine embryos is inefficient. Our goal was to develop a non-invasive method for “relatively” high-throughput cryopreservation of in vivo-produced swine embryos. Since removal of the lipid droplets within early swine embryos improves cryosurvival we wanted to apply a technique of high osmolality treatment followed by centrifugation that was first developed for in vitro-produced swine embryos to in vivo-produced swine embryos. The first aim was to determine how sensitive the in vivo-produced zygote and 2-cell stage embryo was to various high osmolality conditions for a short duration. Culture for 6, 12 or 18 min at 300, 400 or 500 milliosmoles (mOsm) had no detectable affect on the resulting blastocyst stage embryos (number of inner cell mass nuclei, trophectoderm nuclei, total number of nuclei, ratio of the trophectoderm to inner cell mass nuclei or percent blastocyst). However there was an effect of gilt on each of these parameters. For the second aim we focused on 300 mOsm for 6 min, 400 mOsm for 12 min, 500 mOsm for 12 min, and 500 mOsm for 18 min. The embryos were centrifuged for the duration of high osmolality treatment, then cultured to the blastocyst stage and vitrified. After vitrification and thawing the 500 mOsm for 18 min had the highest percent re-expansion with no difference in the total number of nuclei. While requiring a different base culture medium than in vitro-produced embryos, in vivo-derived embryos also survive cryopreservation without damage to their zona pellucida.

Vitrification procedure decreases inositol 1,4,5-trisphophate receptor expression, resulting in low fertility of pig oocytes

Although cryopreservation of mammalian oocytes is an important technology, it is well known that unfertilized oocytes, especially in pigs, are highly sensitive to low temperature and that cryopreserved oocytes show low fertility and developmental ability. The aim of the present study was to clarify why porcine in vitro matured (IVM) oocytes at the metaphase II (MII) stage showed low fertility and developmental ability after vitrification. In vitro matured cumulus oocyte complexes (COCs) were vitrified with Cryotop and then evaluated for fertility through in vitro fertilization (IVF). Although sperm-penetrated oocytes were observed to some extent (30-40%), the rate of pronuclear formation was low (9%) and none of them progressed to the two-cell stage. The results suggest that activation ability of cryopreserved oocytes was decreased by vitrification. We examined the localization and expression level of the type 1 inositol 1,4,5 trisphosphate receptor (IP3 R1), the channel responsible for Ca(2+) release during IVF in porcine oocytes. Localization of IP3 R1 close to the plasma membrane and total expression level of IP3 R1 protein were both decreased by vitrification. In conclusion, our present study indicates that vitrified-warmed porcine COCs showed a high survival rate but low fertility after IVF. This low fertility seems to be due to the decrease in IP3 R1 by the vitrification procedure.

Effects of lipid polarisation on survival of in vivo-derived porcine zygotes vitrified by the superfine open pulled-straw method

This study aimed to evaluate the post-warming in vitro viability of intact porcine zygotes vitrified using the superfine open pulled-straw (SOPS) method and to investigate whether cryotolerance is increased by lipid polarisation before vitrification. In vivo-derived zygotes (n = 317) were either untreated before SOPS vitrification or subjected to one of the following pre-treatments: (1) centrifugation (20 min, 15 000g) or (2) equilibration in high-osmolality medium (6 min, 400 mOsm kg–1) followed by centrifugation. Vitrified–warmed and non-vitrified fresh zygotes were cultured in vitro for 120 h. There were no differences in the blastocyst formation rates between the vitrification groups (from 35.4 ± 5.3% to 48.2 ± 5.6%), but fresh zygotes exhibited higher (P < 0.001) blastocyst formation rates (87.5 ± 5.3%) than did vitrified–warmed zygotes. The total blastocyst cell number was similar among all groups (from 34.9 ± 2.8 to 44.1 ± 2.8). In conclusion, SOPS vitrification is a promising method for the cryopreservation of untreated in vivo-derived porcine zygotes. Neither lipid polarisation by centrifugation nor exposure to a high-osmolality medium followed by centrifugation affected the post-warming in vitro viability of zygotes. Our study also demonstrated that the donor is an important factor in determining the success of vitrification for in vivo-derived porcine zygotes.

Genome resource banking of biomedically important laboratory animals

Genome resource banking is the systematic collection, storage, and redistribution of biomaterials in an organized, logistical, and secure manner. Genome cryobanks usually contain biomaterials and associated genomic information essential for progression of biomedicine, human health, and research. In that regard, appropriate genome cryobanks could provide essential biomaterials for both current and future research projects in the form of various cell types and tissues, including sperm, oocytes, embryos, embryonic or adult stem cells, induced pluripotent stem cells, and gonadal tissues. In addition to cryobanked germplasm, cryobanking of DNA, serum, blood products, and tissues from scientifically, economically, and ecologically important species has become a common practice. For revitalization of the whole organism, cryopreserved germplasm in conjunction with assisted reproductive technologies, offer a powerful approach for research model management, as well as assisting in animal production for agriculture, conservation, and human reproductive medicine. Recently, many developed and developing countries have allocated substantial resources to establish genome resources banks which are responsible for safeguarding scientifically, economically, and ecologically important wild type, mutant, and transgenic plants, fish, and local livestock breeds, as well as wildlife species. This review is dedicated to the memory of Dr. John K. Critser, who has made profound contributions to the science of cryobiology and establishment of genome research and resources centers for mice, rats, and swine. Emphasis will be given to application of genome resource banks to species with substantial contributions to the advancement of biomedicine and human health.

Non-surgical deep intrauterine transfer of superfine open pulled straw (SOPS)-vitrified porcine embryos: evaluation of critical steps of the procedure

Previous trials achieved extremely poor results when using the one-step warming method in a syringe in combination with non-surgical deep intrauterine transfer (NET) of superfine open pulled straw (SOPS)-vitrified embryos. This study aimed to assess the effect of the warming procedure on the in vitro and in vivo development of SOPS-vitrified embryos. The effect of the passage of the vitrified-warmed (VW) embryos through the NET catheter was also evaluated. Groups of 4 to 6 morulae and blastocysts, collected from weaned sows, were SOPS-vitrified in 1 μL of vitrification medium, warmed by the one-step warming method in a dish or in a 1-mL syringe and cultured in vitro for 48 h to evaluate the embryo survival (ES) and hatching rates (HR). Warming in syringe had a deleterious effect (P < 0.05) on the in vitro ES (60.5 ± 10.4%) and HR (39.6 ± 9.5%) of VW embryos in comparison with embryos warmed in a dish (85.4 ± 10.6% and 69.0 ± 8.4%, respectively). This decreased embryonic development was due to the increased time required between the removal of the straws from the liquid nitrogen and the contact of the embryos with the warming medium when the warming was performed in a syringe in comparison with that for the warming in a dish. After verifying that the passage of VW embryos through the NET catheter does not have a damaging effect on their further in vitro development, the negative effect of warming in a syringe was also confirmed after NET. Fifteen fresh and SOPS-vitrified embryos warmed in a syringe or in a dish were transferred to each recipient (n = 28) and recovered 24 h later to assess their developmental progression. All embryos from the syringe group were found to have degenerated at recovery. The in vivo ES and HR from the dish group (80.4 ± 3.4% and 14.2 ± 7.2%, respectively) were lower (P < 0.05) than those from the fresh group (94.0 ± 4.1% and 36.8 ± 7.8%, respectively). Combining the warming in a dish and the NET procedure, 35 VW embryos were transferred to each of 10 gilts. Five recipients farrowed an average of 10.4 ± 0.9 piglets. In conclusion, the method of one-step warming in a syringe has a negative effect on the in vitro and in vivo viability of SOPS-vitrified porcine embryos. In addition, NET of SOPS-vitrified embryos warmed by the one-step method in a dish showed promising reproductive performance of recipients. However, despite the great potential of this technology, further developments are required for large-scale commercial applications.

Emerging applications of sperm, embryo and somatic cell cryopreservation in maintenance, relocation and rederivation of swine genetics

Advances in porcine assisted reproductive technology (ART) make it possible to use cryopreserved sperm, embryos and somatic cells in the maintenance, relocation and regeneration of swine genetics. In this review, development of key application-limiting technology is discussed in each cell type, focusing on the efficiencies, ease of storage and transportation, and minimization of pathogen transmission. Methods to regenerate swine genetics and/or models using frozen sperm, embryos and somatic cells in combination with other porcine ARTs, such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and somatic cell nuclear transplantation (SCNT), are also discussed. The applications of these ARTs utilizing cryopreserved cells will greatly increase the efficiency as well as biosecurity for maintenance, relocation and rederivation of swine genetics/models.

Advances on in vitro production and cryopreservation of porcine embryos

There have been intensive attempts to establish reliable in vitro production (IVP) and cryopreservation methods of embryos in pigs. Although a great deal of progress has been made, current IVP systems and cryopreservation still suffer from insufficient cytoplasmic abilities of in vitro matured oocytes, polyspermic fertilization, poor quality of in vitro produced embryos and low efficiency of embryo cryopreservation. Compared to other mammalian species, pig oocytes and embryos are characterized by large amounts of lipid content stored mainly in the form of lipid droplets in the cytoplasm. This fact has a negative influence on biotechnological applications on porcine oocytes and embryos. In this review, we will discuss recent studies about methods and techniques for modifying porcine embryo IVP system and embryo cryopreservation that produces high quality of pig blastocysts using in vitro maturation, in vitro fertilization, in vitro culture, microsurgical manipulation, addition of protein, the use of cytoskeleton stabilizing agents and various physical methods. The presented methods and techniques make it possible to modify the characteristics of oocytes and embryos and thus may become major tools in mammalian gamete and embryo agricultural or biotechnological applications in the future.