Effect of exogenous DMNPE-caged ATP on in vitro-matured bovine oocytes prior to parthenogenetic activation, fertilisation and nuclear transfer

2004 ◽  
Vol 16 (8) ◽  
pp. 781 ◽  
Author(s):  
Jun Xue ◽  
Melissa A. Cooney ◽  
Vanessa J. Hall ◽  
Natasha A. Korfiatis ◽  
R. Tayfur Tecirlioglu ◽  
...  

Adenosine triphosphate (ATP) plays an important role during fertilisation of the mammalian oocyte through its ability to alter the frequency and duration of calcium oscillations. It has also been shown that higher ATP levels correlate with increased developmental competence in bovine and human oocytes. During somatic cell nuclear transfer (NT), the incoming nucleus is remodelled extensively, undoubtedly using a variety of ATP-dependent enzymes. The aim of the present study was to determine whether additional exogenous ATP influences activation of parthenogenetic (PA), in vitro-fertilised (IVF) or cloned (NT) in vitro-matured bovine oocytes. Blastocyst development and cell numbers in PA embryos were found to increase in a dose-dependent manner following the photorelease of 0, 50, 100, 500 and 1000 μm DMNPE-caged ATP (adenosine 5′-triphosphate, P3-(1-(4,5-dimethoxy-2-nitrophenyl)ethyl) ester, disodium salt). No cleavage was found following release of 2 and 5 mm DMNPE-caged ATP or with DMNPE-caged ATP (not photoreleased). There were also no differences in blastocyst rates or cell numbers between the control group and groups treated with caged, but not photoreleased, ATP. The addition of exogenous ATP before IVF or to NT couplets did not result in a significant increase in blastocyst development or cell number. Embryo transfer is necessary to determine whether exogenous ATP can positively affect reprogramming, resulting in higher cloned pregnancy rates or live-term births.

2006 ◽  
Vol 18 (2) ◽  
pp. 272
Author(s):  
K. Kananen-Anttila ◽  
M. Eronen ◽  
J. Matilainen ◽  
M. Kallio ◽  
J. Peippo ◽  
...  

We have studied the effect of suppressed IVM on the developmental competence of bovine oocytes, aiming at elucidating the importance of cytoplasmic maturation in fertilization and embryo development. Six replicates of abattoir-derived oocytes were randomly divided into three IVM groups. Control (n = 950): TCM-199 with glutamax-I (Gibco, Grand Island, NY, USA), 0.25 mM Na-pyruvate, 100 IU mL−1 penicillin and 100 μg mL−1 streptomycin, 50 ng mL−1 FSH, and 10% fetal bovine serum (FBS) (Gibco); Serum+FSH-free (n = 944): same as control but without FSH and FBS; α-amanitin (n = 977): same as control but with 10 μg mL−1 α-amanitin. Nuclear maturation of oocytes was studied 24 h after the onset of IVM, the formation of sperm aster structure 10 hours post-insemination (hpi) and the formation of pronuclei 20 hpi. Sperm aster was visualized with β-tubulin antibody (modified from Navara et al. 1999 Dev. Biol. 162, 29–40). Presumptive zygotes were cultured until Day 7 in modified SOFaaci + 4 mg mL−1 fatty acid-free BSA in 5% O2. Cumulus cell expansion was seen only in the control group. The results of nuclear maturation, fertilization, and embryo development are summarized in Table 1. Serum and FSH deprivation did not have a statistically significant effect on the parameters studied (vs. control). α-amanitin exposure during IVM reduced nuclear maturation, fertilization, and Day 3 embryo cleavage vs. control, and resulted in total blockage of Day 7 blastocyst development. The treatment groups had significantly smaller mean diameters of male pronuclei (control: 14 ± 0.6 μ­m; serum+FSH-free: 12 ± 0.5 μ­m, P < 0.05; α-amanitin: 10 ± 0.6 μ­m, P < 0.001) and sperm asters (control: 86 ± 4 μ­m; serum+FSH-free: 82 ± 4 μ­m, P < 0.01; α-amanitin: 49 ± 7 μm, P < 0.001) (nonparametric Kruskall Wallis and Mann-Whitney U tests) vs. control group. Despite reduction in pronucleus and sperm aster diameter, serum and FSH deprivation during IVM did not affect in vitro developmental competence of bovine oocytes, suggesting a need for re-evaluation of the components of IVM. α-Amanitin exposure in IVM disturbed nuclear maturation, fertilization, and embryo development, indicating the essence of early transcription. Table 1. Average percentages ± (n) for nuclear maturation, fertilization (min two pronuclei), embryo cleavage, and blastocyst development


2011 ◽  
Vol 23 (1) ◽  
pp. 134
Author(s):  
I. M. Saadeldin ◽  
B. H. Kim ◽  
B. Roibas da Torre ◽  
O. J. Koo ◽  
G. Jang ◽  
...  

Nuclear transfer (NT) has been used to produce many cloned offspring using several types of cells, including embryonic cells. Even though inner cell mass cells have been used as donor karyoplast for producing cloned animals, there are few studies using trophoblast. In mice, clones were born by nuclear transfer of trophoblasts from the expanded blastocyst into enucleated oocytes as a trial to show the totipotency of both inner cell mass and trophectoderm cells isolated from blastocysts (Tsunoda and Kato 1998 J. Reprod. Fertil. 113, 181–184). However, bovine trophoblast cell (TC) lines have not been used in NT to date. The purpose of this study was to elucidate whether TC as donor cell can be reprogrammed in bovine enucleated oocyte and determine the relative abundance of interferon tau (IFNτ) expression in the resulting cloned preimplantational embryos. Hatched blastocysts produced by IVF were used to isolate TCs on mouse embryonic fibroblasts treated with mitomycin C as feeder cells. TCs and adult fibroblasts (AF, control group for NT) were microinjected to perivitelline space of in vitro mature enucleated oocytes and electrically fused. Reconstructed embryos were chemically activated and cultured in a 2-step chemically defined medium. Levels of IFNτ expression in IVF-, TC-, and AF-derived blastocysts were analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). IVF produced embryos were used as reference to analyze the linear progressive expression of IFNτ through mid-, expanded, and hatching blastocysts. As a result, TCs expressing IFNτ were successfully isolated and cultured on feeder layers. It grew as cell sheets of cuboidal epithelium with high proliferation capacity as a single colony originated from a small clump of cells measured 0.5 cm within 7 days of culture. TCs were reprogrammed in the enucleated oocytes to blastocyst with similar efficiency to AF (14.5% and 15.6%, respectively; P ≤ 0.05). RT-qPCR studies showed that IFNτ expression was higher in TC-derived blastocysts than IVF- and AF-derived blastocysts. Both IVF- and TC-derived blastocysts, showed progressive increase of IFNτ expression through the advancement of blastocyst development when it was compared to AF-derived blastocysts. In conclusion, using TCs expressing IFNτ as donor cell for bovine NT could increase the developmental competence of cloned embryos as indicated by progressive linear increase in IFNτ expression. This study was supported by grants from IPET (#109023-05-1-CG000), NRF (#M10625030005-10N250300510), MKE (#2009-67-10033839, #2009-67-10033805), and BK21 program. Saadeldin I. M. is supported by Islamic Development Bank (IDB) merit scholarship, Jeddah, Saudi Arabia.


2016 ◽  
Vol 28 (2) ◽  
pp. 229
Author(s):  
S. M. B. Ulloa ◽  
J. Heinzmann ◽  
D. Herrmann ◽  
U. Baulain ◽  
K.-G. Hadeler ◽  
...  

High cyclic adenosine monophosphate (cAMP) concentrations are critical for maintaining oocyte meiotic arrest in vivo. For in vitro maturation (IVM), the oocyte is released mechanically from the follicle, which induces a significant drop in intra-oocyte cAMP levels, triggering non-physiological meiotic resumption. It has been proposed that modulation of cAMP before IVM can increase bovine blastocyst rates in vitro. Caffeine is a nonspecific competitive phosphodiesterases (PDE) inhibitor and can inhibit meiotic resumption of oocytes due to maintenance of cAMP levels. It has been reported that gamete treatment with caffeine can increase developmental potential. The current study evaluated the effects of pre-in vitro maturation culture with different concentrations of caffeine on meiotic progress, developmental rates and blastocyst cell numbers. Bovine ovaries were collected from a local abattoir. A total of 6648 cumulus-oocyte complexes were obtained by slicing. Caffeine was used in 5 different concentrations (1, 5, 10, 20, and 30 mM) during slicing, searching, and 2 h pre-IVM culture. A control group, with 2 h pre-IVM without caffeine (0 mM) and a standard control were also included. Oocytes were washed either after standard or pre-IVM treatments and cultured for 24 h in vitro without caffeine. After IVM, oocytes were fertilised in vitro for 19 h, and zygotes were cultured in vitro for 8 days until the blastocyst stage. Subsets of oocytes were fixed in 2% glutaraldehyde at 9, 20, and 24 h after IVM. Hoechst staining was performed to evaluate nuclear status of matured oocytes. Cleavage and blastocyst formation rates were evaluated at Days 3 and 8 after IVF. Expanded blastocysts from all treatments were submitted to differential staining. One-way ANOVA from R software was applied to evaluate differences in cleavage and blastocysts rates and blastocyst cell numbers. Fisher’s exact test complemented by Bonferroni correction was used to determine meiotic progress. Caffeine maintained oocytes in meiotic arrest after 9 h of IVM in a concentration-dependent manner (germinal vesicle: 79.0%, 92.2%, 66.7%, 55.1%, 56.9%, 43.9%, 30.2%, respectively, for 30, 20, 10, 5, 1, 0 mM and standard; P < 0.016). Cleavage rates were similar in all treatments; however 30 mM caffeine decreased blastocyst rates (Table 1; P < 0.05). The number of cells did not differ significantly among in vitro treatments (Table 1; P > 0.05). Developmental competence was not affected by 2 h pre-IVM culture. Caffeine supplementation before IVM delayed resumption of meiosis and affected embryo development. Table 1.In vitro developmental competence of oocytes treated with different caffeine concentrations before IVM


2011 ◽  
Vol 23 (1) ◽  
pp. 200
Author(s):  
B.-C. Yang ◽  
H.-C. Lee ◽  
S. Hwang ◽  
I.-S. Jeon ◽  
D.-K. Lee ◽  
...  

The technique of RNA interference (RNAi) knock-down is a powerful tool for the analysis of gene function in mammalian cells and eggs. Rho GTPase-activating protein 15 (Arhgap15) is closely related to anaemia and immunity, especially as caused by trypanosome. This study was performed to investigate the effect of Arhgap15 gene knock-down on the developmental competence of bovine embryos in vitro. Bovine fibroblast cells were treated with 50 and 100 nM concentrations of Arhgap15 RNAi, respectively. After 24 h of transfection, the control group showed no change in Arhgap15 mRNA level, whereas mRNA expression in the RNAi-treated donor cells was obviously decreased in a dose-dependent manner. These RNAi-treated cells were then transferred into enucleated bovine oocytes to analyse the consequence of RNAi-mediated Arhgap15 gene knock-down. In the control group, cleavage and blastocyst development rates were 75% (102/136) and 14.7% (20/136), whereas those in the knock-down embryos were 81.6% (120/147) and 24.5% (36/147), respectively. The occurrence of cell death by apoptosis was examined in Day 7 blastocysts. Apoptotic cells numbered 12 ± 3.2 in control embryos and 8.9 ± 4.8 in knock-down embryos. Therefore, it can be concluded that RNAi-mediated Arhgap15 gene knock-down in somatic cells did not affect the developmental competence of bovine cloned embryos. This work was supported by grant 120080401034062 from the BioGreen 21 Program, Rural Development Administration, Republic of Korea.


2010 ◽  
Vol 22 (1) ◽  
pp. 183
Author(s):  
T. H. C. De Bem ◽  
P. R. Adona ◽  
R. Rochetti ◽  
F. F. Bressan ◽  
M. S. Miranda ◽  
...  

In vitro embryo production by somatic cell nuclear transfer (SCNT) still presents low efficiency and blastocyst production rates are around 20%. Pre-maturation with cell cycle inhibitors is one alternative that has been studied to improve oocyte competence for use in in vitro production systems. The neurotrophin brain-derived neurotrophic factor (BDNF) has been reported to improve oocyte maturation. The aim of this work was to optimize the in vitro pre-maturation culture of bovine oocytes and its use in SCNT. Oocytes that were submitted to meiosis block before IVM (BL group) were cultured in TCM-199 medium supplemented with 10 ng mL-1 BDNF and 10 μM butyrolactone I for 24 h and then matured in IVM medium (TCM-199, 10% FCS, 0.5 μg mL-1 FSH, 5.0 μg mL-1 LH, 2.0 mM pyruvate, and 50 μg mL-1 gentamicin). Control oocytes (control group) were matured in IVM medium. After 19 h of IVM, oocytes from both groups were denuded with 0.2% hyarulonidase, enucleated, and reconstructed. Reconstructed embryos were chemically activated with ionomycin (5 min) and 6-DMAP (3h) and cultured in vitro in SOF medium for 7 or 8 days. Statistical analyses were performed by using BIOSTATS v.4.0 software. In vitro development variables [1st polar body (PB), fusion, cleavage, and blastocyst rates on Days 7 and 8] and in vivo development rates on Days 35, 60, 90, and 120 of pregnancy were analyzed by chi-square test. Total cell numbers and cells with fragmented DNA were analyzed by ANOVA. A level of 5% significance was considered. Extrusion of 1st PB (BL: n = 693; 69.3% and control: n = 639; 63.5%) and fusion rates (BL: n = 397; 79.2% and control: n = 345; 72.9%) were higher (P < 0.05) in the BL group. There were no differences between treatments for cleavage rates (BL: n = 268; 67.5% and control: n = 228; 66.1%) or blastocyst rates on Day 7 (BL: n = 77; 19.4% and control: n = 69; 20.0%) and Day 8 (BL: n = 81; 20.4% and control: n = 73; 21.2%). Cloned blastocysts from both groups were submitted to TUNEL reaction (Day 8 blastocysts, n = 15 for BL and control groups) for DNA fragmentation analysis or were transferred to synchronized recipients (Day 7 blastocysts, n = 26 and n = 28 for BL and control groups, respectively) for in vivo development analysis. No differences were observed (P > 0.05) between BL and control groups for total cell numbers (n = 127 and n = 138, respectively) and cells with fragmented DNA (0.0209 and 0.0188, respectively). Pregnancy rates at 35 (BL: n = 5; 19.2% and control: n = 9; 32.1%), 60 (BL: n = 3; 11.5 and control: n = 3; 10.7), 90 (BL: n = 3; 11.5 and control; n = 3; 10.7), and 120 days (BL: n = 3; 11.5 and control: n = 3; 10.7) also did not differ (P > 0.05) between treatments. In conclusion, pre-maturation enhanced 1st PB extrusion and fusion rates of oocytes submitted to SCNT, and moreover, it was able to establish pregnancies until 120 days, similarly to the control group. Financial support: FAPESP and CNPQ, Brazil.


Reproduction ◽  
2006 ◽  
Vol 132 (4) ◽  
pp. 549-557 ◽  
Author(s):  
S Ikeda ◽  
K Saeki ◽  
H Imai ◽  
M Yamada

We previously reported that when midkine (MK), a heparin-binding growth differentiation factor was used inin vitromaturation (IVM) culture of bovine cumulus-enclosed oocytes (CEOs), their developmental competence to the blastocyst stage afterin vitrofertilization (IVF) was enhanced and the effect of MK might be mediated by its action upon mural granulosa cells and cumulus cells that closely surround the oocyte. In the present study, when denuded oocytes (DOs) were matured in IVM medium with or without MK (200 ng/ml) in the presence or absence of isolated cumulus cell masses and subjected to IVF, the enhancing effects of MK on the developmental competence of DOs to the blastocyst stage after IVF were exerted only in the presence of cumulus cells. In addition, we prepared the conditioned media of granulosa cells cultured with or without 200 ng MK/ml (CMMK+ or CMMK− respectively) and examined their effects on the IVM of DOs in terms of their developmental competence to the blastocyst stage after IVF. The supplementation of CMMK+ into IVM medium at 40% (v/v) significantly enhanced the blastocyst development compared with the no additive control and the CMMK− supplemented groups. Furthermore, the effects of MK during IVM of bovine CEOs on the cumulus cell apoptosis were investigated. CEOs were cultured up to 24 h in IVM medium without (control) or with 200 ng MK/ml. The genomic DNA was extracted from CEOs at 0, 6, 12, 18 and 24 h of IVM and subjected to ligation-mediated PCR (LM-PCR) to detect the apoptotic internucleosomal DNA fragmentation. DNA fragmentation was scarcely detected at the start of IVM, whereas it increased time-dependently as the IVM culture progressed. The degree of the fragmentation was significantly lower in the MK-treatment group compared with the control group at 18 and 24 h of IVM. The apoptosis-suppressing effect of MK on cumulus cells was further confirmedin situby using TUNEL on CEOs. In conclusion, data from the present study further confirmed that MK enhances the developmental competence of bovine oocytes via cumulus and granulosa cells. It was also demonstrated that MK suppresses the apoptosis that occurs in cumulus cells during the period of IVM of bovine CEOs. The putative soluble factor(s) from cumulus cells was suggested from the experiment using CMMK+ . MK may promote the production of such factors in part by its anti-apoptotic effects on cumulus cells.


2018 ◽  
Vol 30 (10) ◽  
pp. 1342 ◽  
Author(s):  
Zhao-Bo Luo ◽  
Long Jin ◽  
Qing Guo ◽  
Jun-Xia Wang ◽  
Xiao-Xu Xing ◽  
...  

Accumulating evidence suggests that aberrant epigenetic reprogramming and low pluripotency of donor nuclei lead to abnormal development of cloned embryos and underlie the inefficiency of mammalian somatic cell nuclear transfer (SCNT). The present study demonstrates that treatment with the small molecule RepSox alone upregulates the expression of pluripotency-related genes in porcine SCNT embryos. Treatment with the histone deacetylase inhibitor LBH589 significantly increased the blastocyst formation rate, whereas treatment with RepSox did not. Cotreatment with 12.5 μM RepSox and 50 nM LBH589 (RepSox + LBH589) for 24 h significantly increased the blastocyst formation rate compared with that of untreated embryos (26.9% vs 8.5% respectively; P < 0.05). Furthermore, the expression of pluripotency-related genes octamer-binding transcription factor 4 (NANOG) and SRY (sex determining region Y)-box 2 (SOX2) were found to significantly increased in the RepSox + LBH589 compared with control group at both the 4-cell and blastocyst stages. In particular, the expression of NANOG was 135-fold higher at the blastocyst stage in the RepSox + LBH589 group. Moreover, RepSox + LBH589 improved epigenetic reprogramming. In summary, RepSox + LBH589 increases the expression of developmentally important genes, optimises epigenetic reprogramming and improves the in vitro development of porcine SCNT embryos.


2007 ◽  
Vol 19 (1) ◽  
pp. 288
Author(s):  
C. Kubota ◽  
T. Kojima ◽  
T. Nagai ◽  
X. Tian ◽  
X. Yang

The timing of IVM–IVF–IVC is restricted by the onset of oocyte maturation, and sometimes oocytes must be treated at midnight. If we could regulate the timing of IVM of oocytes without decreasing their developmental competence, the IVM–IVF–IVC system could be a more applied technology. The present study was performed to examine the effects of in vitro storage of bovine oocytes in simple media prior to maturation culture to manipulate the start of IVM. Bovine follicular fluid (bFF), Dulbecco&apos;s PBS (PBS), M199 Earle salts (M199), and Earle salts supplemented with 5 mM NaHCO3 (M199A) were used as the fundamental media, after an addition of antibiotics, for in vitro storage of bovine cumulus&ndash;oocyte complexes (COCs) collected from ovaries obtained at the slaughterhouse. The fundamental media except for bFF were supplemented with 10&percnt; fetal bovine serum (FBS) or 1 mg mL&minus;1 polyvinyl alcohol (PVA). COCs were collected from follicles (3&ndash;8 mm in diameter) and washed twice in each medium; then approximately 50 COCs were submerged in 1 mL of each medium in cryotubes (Falcon #2812, 2.5 mL; Becton Dickinson Labware, Lincoln, NJ, USA), which were stored in a container kept at 38.5&deg;C for 22 h under air-closed condition (in vitro storage: IVS). Subsequently, the stored COCs were in vitro-matured (IVM) for 22 h in M199 with 10&percnt; FBS and 20 &micro;g mL&minus;1 estradiol, fertilized (IVF), and cultured in CR1aa (IVC) for examination of their development to the blastocyst stage (Kubota et al. 1998 Mol. Reprod. Dev. 51, 281&ndash;286). Fresh oocytes without IVS were used as controls. The nuclear status of oocytes after IVS&ndash;IVM was compared to that of control oocytes by aceto-orcein stain. Their developmental rates to the blastocyst stage after IVM&ndash;IVF&ndash;IVC were compared between experimental and control groups. The experiment was repeated more than 3 times, and results were statistically analyzed using Student&apos;s t-test. When bFF and PBS supplemented with FBS or PVA were used for IVS, the rates of survived COCs after IVS and the development to the blastocyst stage after IVM&ndash;IVF&ndash;IVC (bFF (n &equals; 87): 0&percnt;, 0&percnt;; PBS/FBS (n &equals; 72): 84&percnt;, 1&percnt;; and PBS/PVA (n &equals; 81): 89&percnt;, 6&percnt;, respectively) were significantly lower than those of the control group (n &equals; 406; 97&percnt; and 29&percnt;, respectively). On the other hand, when M199A supplemented with FBS or PVA was used for IVS, the survival rate after IVS and the developmental rate to the blastocyst stage after IVS&ndash;IVM&ndash;IVF (M199A/FBS (n &equals; 97): 82&percnt;, 28&percnt;; and M199A/PVA (n &equals; 111): 98&percnt;, 31&percnt;, respectively) did not differ from those of the control group. After IVS, cumulus expansion was not seen and most of the oocyte nuclei reached the GVBD stage. These results suggest that the nuclear maturation progress of bovine oocytes can be regulated for at least 22 h in M199A without any deleterious influence on the number of oocytes surviving at an immature state after the storage and their subsequent development to the blastocyst stage after IVM&ndash;IVF&ndash;IVC. The delayed maturation allows a flexible fertilization schedule which is advantageous in research and industrial applications.


2008 ◽  
Vol 20 (1) ◽  
pp. 118
Author(s):  
B. Gajda ◽  
Z. Smorag ◽  
M. Bryla

It is possible to improve the success of cryopreservation of in vitro-produced bovine embryos by modifying the embryos with the metabolic regulator phenazine ethosulfate (PES) (Seidel 2006 Theriogenology 65, 228–235). The PES treatment increased glucose matabolism, tended to increase the pentose phosphate pathway flux of glucose, and clearly reduced accumulation of lipids in cultured bovine embryos (De La Torre-Sanchez et al. 2006 Reprod. Fertil. Dev. 18, 597–607). It is known that porcine embryos have a considerably high content of lipids, and the success rates of their cryopreservation appear to be highly correlated with cytoplasmic lipid content. In our preliminary study, we observed that supplementation of NCSU-23 medium with PES has a positive effect on efficiency of pig blastocysts of good quality (Gajda et al.. 2007 Acta Biochim. Pol. 54(Suppl 1), 52 abst). In the present study, the effects of PES on pig blastocyst development, apoptosis, and survival after vitrification were investigated. In Exp. 1, porcine zygotes obtained from superovulated gilts were cultured in NCSU-23 medium supplemented with 0 (control), 0.025, 0.05, or 0.075 µm PES. The culture was performed at 39�C, with 5% CO2 in air, for 96–120 h. Embryo quality criteria were developmental competence (cleavage, morula stage, and blastocyst stage), cell number per blastocyst, and the degree of apoptosis as assessed by TUNEL staining. In Exp. 2, expanded blastocysts cultured with 0.025 µm PES were vitrified in a ethylene glycol and dimethyl sulfoxide mixture using open pulled straw (OPS) technology (Vajta et al. 1997 Acta Vet. Scand. 38, 349–352). After thawing, the blastocysts were cultured in vitro for re-expansion or transferred to synchronized recipients. Data were analyzed by chi-square test. There was a difference between the 0.025 µm PES-treated and the control group in percentage of cleaved embryos (99.0 and 91.4%, respectively; P < 0.05), between all experimental groups and control in percentage of morula stage (90.7, 87.8, 83.8, and 80.0%, respectively), and between 0.025 and 0.05 µm PES-treated and control in percentage of blastocyst rates (70.0, 75.5, and 65.7%, respectively). The number of cells and percentage of TUNEL-positive nuclei per blastocyst were lower in the PES-treated than in the control group. The survival rate of blastocysts after vitrification and thawing was enhanced in the presence of PES compared to that in the PES-free group (45.2 and 38.9%, respectively; P < 0.05). After transfer of 56 expanded blastocysts cultured with PES and vitrified into 3 recipients, two gilts were confirmed pregnant at 35 days of gestation. In conclusion, a higher blastocyst percentage with a low incidence of apoptosis was obtained in the presence of PES compared to control. These blastocysts also had an increased ability to survive cryopreservation.


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