65 EFFECT OF TRICHOSTATIN A AND 5-AZA-2'-DEOXYCYTIDINE TREATMENT OF DONOR CELLS, FUSED EMBRYOS, OR BOTH ON THE DEVELOPMENTAL COMPETENCE, QUALITY, AND EPIGENETIC STATUS OF CLONED BUFFALO (BUBALUS BUBALIS) EMBRYOS

2016 ◽  
Vol 28 (2) ◽  
pp. 162
Author(s):  
M. Saini ◽  
N. L. Selokar ◽  
H. Agrawal ◽  
S. K. Singla ◽  
M. S. Chauhan ◽  
...  

Somatic cell nuclear transfer (SCNT) is a promising technology in buffalo for multiplication of elite animals, species conservation, and production of transgenic embryos for therapeutic applications. However, the cloning efficiency obtained in this species is very low, which might be due to improper reprogramming of donor cells after SCNT. Treatment of donor cells or fused embryos or both with epigenetic modifiers might be a suitable approach to improve the ability of donor cells to be reprogrammed. The present study was aimed at examining the effects of treatment of donor cells (24 h before SCNT) or fused embryos (10 h post-electrofusion) or both with 50 nM TSA + 7.5 nM 5-aza-dC on the developmental competence, quality, and epigenetic status of buffalo embryos produced by hand-made cloning (HMC) as described earlier (Saini et al. 2014 Reprod. Fertil. Dev. doi: 10.1071/RD14176). The percentage data were analysed using SYSTAT 12.0 (SPSS Inc., Chicago, IL, USA) after arcsine transformation. Differences between means were analysed by one-way ANOVA followed by Fisher’s least significant difference test. The blastocyst rate was significantly higher (P < 0.05) and the apoptotic index was significantly lower (P < 0.05) in embryos produced from donor cells or fused embryos or both treated with TSA + 5-aza-dC than that of controls (Table 1). However, the cleavage rate and the total cell number were not significantly different among all the groups. The global level of H3K18ac, examined by immunofluorescence staining, was higher (P < 0.05) and that of H3K27me3 was lower (P < 0.01) in blastocysts produced from donor cells or fused embryos or both treated with TSA + 5-aza-dC than that of controls. These results show that treatment of donor cells, fused embryos, or both with TSA + 5-aza-dC improves the developmental competence and quality, and alters the epigenetic status of buffalo embryos produced by HMC. However, the effects of treatment with these epigenetic modifiers on the pregnancy rate require further studies. Table 1.Effect of treatment of donor cells, fused embryos, or both with 50 nM TSA + 7.5 nM 5-aza-dC on the developmental competence and level of apoptosis in cloned embryos

2013 ◽  
Vol 25 (1) ◽  
pp. 166
Author(s):  
S.-S. Kwak ◽  
Y. Jeon ◽  
J. D. Yoon ◽  
S.-A. Cheong ◽  
E. Lee ◽  
...  

Previous studies have demonstrated that treatment of cloned embryos with trichostatin A (TSA) or scriptaid, inhibitors of class I and II histone deacetylases (HDAC), significantly enhanced their developmental competence. In the present study, we investigated the effects of sirtinol, an inhibitor of class III HDAC, on the embryonic development of porcine cloned embryos. Data were analyzed with SPSS 17.0 software (SPSS Inc., Chicago, IL, USA) using Duncan’s multiple range test and all experiments were replicated at least 5 times. In experiment 1, 648 parthenotes were divided into 4 groups (0-, 6-, 12-, and 24-h sirtinol treatment after activation) to investigate optimal treatment time using 100 µM sirtinol. The cleavage rate of the 24-h treatment group (81.3%) was significantly (P < 0.05) decreased compared with the 12-h treatment group (88.4%) but there was no difference compared with the control (86.9%) and 6-h treatment groups (86.9%). The parthenotes treated with sirtinol for 12 h after activation had a significantly higher blastocyst formation rate and total cell number in blastocysts (50.5% and 66.9, respectively) than the control (39.4% and 54.1, respectively). In experiment 2, 806 cloned embryos were divided into 5 groups (0, 50, 100, 150, and 200 µM sirtinol treatment for 12 h after activation) to investigate optimal concentration. There was no significant difference in cleavage rate. The rate of blastocyst formation and total cell number in blastocysts were significantly (P < 0.05) improved by treatment with 150 µM sirtinol for 12 h after activation (28.8% and 51.0, respectively) compared with the control (17.5% and 37.1, respectively). The total cell number in blastocysts was also significantly increased in 50 and 200 µM groups (47.9 and 48.4, respectively) compared with the control (37.1). In experiment 3, we examined the effects of 150 µM sirtinol treatment for 12 h after activation with or without 5 nM TSA on in vitro embryonic development after somatic cell nuclear transfer. The rate of blastocyst formation was significantly improved in sirtinol-treated and TSA-treated groups (30.9 and 31.3%, respectively) but not in the sirtinol with TSA group (27.6%) compared with the control (21.7%). The total cell number in blastocysts was significantly increased by treatment with sirtinol and TSA together (73.9) compared with the control (49.0) but there was no difference in only sirtinol- (59.8) or TSA- (59.2) treated groups. There was no significant difference in cleavage rate among groups. Our results suggest that sirtinol improves the embryonic development of porcine cloned embryos and sirtinol with TSA synergistically increases the blastocyst quality. This work was supported by a grant from the Next-Generation BioGreen 21 program (no. PJ008121012011), Rural Development Administration, Republic of Korea.


2012 ◽  
Vol 24 (1) ◽  
pp. 119
Author(s):  
Z. Mei-Ling ◽  
Z. Yun-Hai ◽  
T. Yong ◽  
L. Ya ◽  
C. Hong-Guo ◽  
...  

The objective of present study was to investigate the effects of treatments to donor cells with fresh digestion (FD), cryopreservation/thawing (CT), trichostatin A (TSA) and durations of culture using TSA-CR1aa medium on in vitro development of dairy cow cloned embryos. In addition, some somatic cell cloned embryos were transferred to surrogates in heat to evaluate the in vivo developmental competence. The results (Table 1) showed that pretreatment of donor cells using TSA could significantly increase both cleavage and blastocyst rates of embryos (P < 0.05) compared with FD and CT group, whereas no significant difference was found between FD and CT group. When cloned embryos were subjected to TSA treatment in CR1aa for different times (0, 24, 48 and 60 h), the results showed that the blastocyst rate in the 60-h group was the highest (36.11 ± 1.78%) compared with the other groups (P < 0.05). Whereas the reconstructed embryos derived from donor cells treated with TSA for 24 h were continually cultured in TSA for different times (24, 48 and 60 h), the results showed that the blastocyst rate (37.39 ± 1.78%) in the 60-h group was significantly higher than that of the 24-h (25.48 ± 1.34%) group (P < 0.05). Finally, when the cloned embryos from different groups were respectively transferred to 40 natural oestrus recipients, no significant difference in terms of pregnancy rate among groups was found; however, a viable cloned calf was successfully obtained from TSA-treated donor cells and cloned embryo. Therefore, cloned embryos treated with optimized methods can develop to term. Table 1.Pregnancy results established from embryos of different origins


Zygote ◽  
2011 ◽  
Vol 20 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Ma. Ninia L. Gomez ◽  
Jung Taek Kang ◽  
Ok Jae Koo ◽  
Su Jin Kim ◽  
Dae Kee Kwon ◽  
...  

SummaryThe oocyte is known from recent studies in the mouse, cow, sheep and human to be a central regulator of follicular cell function. However, in the pig, little information is known about the regulation of cumulus expansion by oocyte-secreted factors and oocyte quality. We investigated the possible effects of oocyte-secreted factors during in vitro maturation on cumulus expansion and on porcine oocytes as judged by subsequent embryonic development after parthenogenetic activation. Cumulus–oocyte complexes (COC) from antral follicles of pig ovaries collected from a local abattoir were divided into control and treatment groups and were cultured in tissue culture medium 199 supplemented with follicle-stimulating hormone. Treatment groups consisted of increasing numbers of denuded oocytes (DO) co-cultured with COC (at ratios of COC to DO of 1:1, 1:2, 1:3, 1:4 and 1:5). After incubation for 44 h, cumulus expansion and maturation rates were assessed and oocytes were activated parthenogenetically. Cumulus expansion in the 1 COC:4 DO and 1 COC:5 DO groups was low and altered because full dispersion of the outer layer did not occur. Cell viability was not affected, as measured by the automated cell counter, but scanning electron microscopy revealed only a scanty extracellular matrix. Blastocyst rate was significantly higher in the 1 COC:4 DO (34.4%) and in the 1 COC:5 DO (34.9%) groups (p < 0.05) when compared with other groups. Maturation rate, cleavage rate and total cell number showed no significant difference between control and treatment groups. Amplification by reverse transcription polymerase chain reaction (RT-PCR) showed up-regulation of growth differentiation factor 9 (GDF9) in the cumulus cells in the 1 COC:4 DO group at 44 h. We conclude that denuded porcine oocytes could improve the maturation of COC as evidenced by increased blastocyst development in the 1 COC:4 DO, even though cumulus expansion was poor. This improvement could be a result of the GDF9 up-regulation.


Zygote ◽  
2015 ◽  
Vol 24 (4) ◽  
pp. 549-553 ◽  
Author(s):  
Naresh L. Selokar ◽  
Monika Saini ◽  
Himanshu Agrawal ◽  
Prabhat Palta ◽  
Manmohan S. Chauhan ◽  
...  

SummaryThis study examined the effects of trichostatin A (TSA) treatment of reconstructed buffalo embryos, produced by hand-made cloning using somatic cells isolated from over a decade old frozen–thawed semen, on their in vitro and in vivo developmental competence, quality and epigenetic status. Following treatment of reconstructed embryos with TSA (0, 50 or 75 nM) for 10 h prior to culture, the cleavage (100.0 ± 0, 94.5 ± 2.3 and 96.1 ± 1.2%, respectively) and blastocyst rate (50.6 ± 2.3, 48.4 ± 2.7 and 48.1 ± 2.6%, respectively), total cell number (275 ± 17.4, 289 ± 30.1 and 317 ± 24.2, respectively) and apoptotic index (5.6 ± 0.7, 3.4 ± 0.9 and 4.5 ± 1.4, respectively) were not significantly different among the three groups. However, TSA treatment increased (P < 0.05) the global level of H4K5ac and decreased (P < 0.05) that of H3K27me3 in blastocysts whereas the global level of H3K18ac was not affected significantly. Transfer of embryos treated with 75 nM TSA (n = 10) to recipients resulted in two pregnancies (20%), one out of which was aborted in the second and the other in the third trimester whereas transfer of control embryos (n = 20) or those treated with 50 nM TSA (n = 12) did not result in any pregnancy. In conclusion, these results suggest that TSA treatment of cloned buffalo embryos produced using somatic cells isolated from frozen–thawed semen improved their epigenetic status but not the in vitro developmental potential and offspring rate.


2008 ◽  
Vol 5 (1) ◽  
pp. 55-60
Author(s):  
Liu Ying ◽  
Zhu Shi-En ◽  
Li Rong ◽  
Wang Li-Li ◽  
Wang Hai-Ping ◽  
...  

AbstractThe purpose of this study was to evaluate the effects of donor sex, treatments of cell cycle synchronization and donor nuclei obtained from fresh or frozen–thawed conditions on developmental competence of yak–bovine interspecies nuclear transfer embryos. Bovine (Bos taurus) oocytes were used as recipients and yak (Bos grunniens) ear fibroblast cells were used as donors. Results indicated that the development rate of male blastocysts was higher than that of female (56.6% versus 39.5%, P<0.05), whereas cleavage and total cell number showed no difference between the two groups. No significant difference was observed in the development and quality of blastocysts with donor cells treated by serum starvation or contact inhibition, and there was no significant difference in embryo development with fresh or frozen–thawed donor cells, whereas the cleavage rate in the group of frozen–thawed cells was significantly lower than that of the fresh cell group (54.5% versus 78.2%, P<0.05). The results demonstrated that donor sex could impact the developmental competence of yak–bovine interspecies nuclear transfer embryos, whereas different treatments of cell cycle synchronization and freezing had little influence.


2006 ◽  
Vol 18 (2) ◽  
pp. 246
Author(s):  
K. Imai ◽  
M. Tagawa ◽  
S. Matoba ◽  
M. Narita ◽  
K. Kanayama

The present study was designed to assess the recruitment of follicles after ovum pickup (OPU) and dominant follicle (DF) removal on the follicular wave after OPU in Holstein dry cows. Cows were reared under the same feeding and environmental conditions. In Experiment 1, follicle aspiration (>2 mm in diameter) by OPU using a 7.5-MHz linear transducer with needle (COVA needle; Misawa Medical, Tokyo, Japan) connected to an ultrasound scanner (SSD-1200; ALOKA, Tokyo, Japan) was performed in four cows. Then, ovaries were observed after OPU from Day 1 (Day 0 = the day of OPU) to Day 11 to assess the number of follicles developed. In Experiment 2, two sessions of OPU were performed with a 7 day interval between sessions, with or without dominant follicle removal, to assess the quality of developing follicles and oocytes. In the DF removal group, >8-mm follicles were aspirated at Day 5 after the first OPU session, and the same cows without DF removal were designated as a control (n = 4, crossover trial). Oocytes were evaluated by their cumulus cell morphology, cytoplasmic color, and density. To assess the developmental competence of oocytes, Grades 1 and 2 cumulus-oocyte complexes (COCs) were collected, matured, fertilized, and cultured as described by Imai et al. (2002 J. Vet. Med. Sci. 64(10), 887-891). Embryo development was assessed by the cleavage rate on Day 2 and the blastocyst formation rate on Days 7 to 9 (the day of insemination = Day 0). Data were analyzed by ANOVA or Student t-test. In Experiment 1, a dominant follicle (>8 mm in diameter) was developed during Days 3 to 5 after OPU in each donor. The mean number of developing follicles (>2 mm in diameter) were increased from Day 1 to Day 9 (Day 1: 7.5 � 2.1, Day 3: 19.0 � 1.2, Day 5: 23.3 � 9.0, Day 7: 30.3 � 11.0, Day 9: 42.0 � 15.8 and Day 11: 41.0 � 16.7 (mean � SD), P < 0.05). In Experiment 2, there was no difference in the mean number of developing follicles on the day of OPU and collected oocytes between DF removal and control groups (follicles: 47.8 � 23.0 and 39.3 � 6.2; oocytes: 27.0 � 11.6 and 26.5 � 5.4, respectively). The number of Grades 1 and 2 oocytes for the DF removal group was significantly higher (P < 0.05) than that for the control (83.6 � 1.5 and 63.2 � 14.2, respectively), and no significant difference was found within cleavage (60.0 � 37.2, 53.6 � 23.2) and blastocyst rates (34.1 � 33.9, 34.4 � 16.8). These results indicate that populations of follicles were increased till Day 9 after OPU, and the DF removal was effective at increasing oocyte quality in the developing follicles.


2016 ◽  
Vol 28 (2) ◽  
pp. 209
Author(s):  
M. Nkadimeng ◽  
E. van Marle-Koster ◽  
K. P. M. Lekola ◽  
M. L. Mphaphathi ◽  
M. M. Seshoka ◽  
...  

Heat stress during IVF is associated with reduced fertility in cattle oocytes. It may, however, enhance thermo-tolerance or cause detrimental effects on a variety of cell types or organisms, depending on the duration and intensity of the thermal challenge. The aim of this study was to evaluate the developmental potential of cumulus-oocyte complexes (COC) matured for 18 or 24 h and incubated at 39°C or 41°C. A total of 1000 immature oocytes were collected at slaughter from indigenous South African cow ovaries. The COC were randomly allocated (100/treatment) into 2 maturation times (18 or 24 h) and cultured in M199 + FSH-LH-estradiol medium under oil at 100% humidity and 5% CO2 at 39°C or 41°C. Post maturation, oocytes were subjected to normal subsequent embryo conditions. The Bracket and Oliphant medium was used for IVF. All matured oocytes were fertilised for 6 h with frozen-thawed Nguni bull semen at a concentration of 265 × 106. The presumptive zygotes from each treatment were cultured into SOF-BSA medium under oil and incubated at 39°C for assessment of cleavage rate 48 h post IVF. After Day 7 of culture, blastocyst were stained (Hoechst 33323) for nuclei cell count. Statistical analyses was performed using Genstat® software of SAS (SAS Institute, Cary, NC, USA; P < 0.05). Oocytes that were matured for 18 h in 41°C resulted in more 8-cell embryos (41%) compared with those incubated at 39°C (21.6%). However, no difference was observed for cleavage rate at both maturation times and incubation temperatures (41 or 39°C). There was more morula formation from oocytes matured for 18 h (19.6%) and 24 h (19.0%) at 41°C compared to 39°C (8.4%) group. The results further showed more blastocyst formation during 18 h at 41°C (15.2%) than at 39°C (7.4%) and during 24 h at 41°C (11.2%), 39°C (11.4%). However there was no difference in the nuclei cell number during 18 h at 41°C (45.2), 24 h (45.8), and 18 h at 39°C (43.4) of maturation. Thus, there was a significant difference in the nuclei cell numbers at 24 h on 39°C (n = 133.2) and 41°C (n = 45.8). In conclusion, oocytes that were matured for 18 and 24 h at 41°C or for 18 h at 39°C developed further to blastocyst stage on in vitro embryo production, however, with low nuclei cell numbers due to accelerated maturation temperature or shortened maturation period.


2014 ◽  
Vol 26 (1) ◽  
pp. 123
Author(s):  
Y. Liu ◽  
A. Lucas-Hahn ◽  
B. Petersen ◽  
R. Li ◽  
P. Hassel ◽  
...  

Two nuclear transfer (NT) techniques are routinely used to produce cloned animals, traditional cloning (TC) and handmade cloning (HMC). The TC embryos keep their zona and can be transferred at early stages, whereas HMC embryos are zona-free and must be cultured to the morula/blastocyst stage before transfer. Some studies have shown that in vitro culture reduces embryo development and quality, but it is not known whether embryos produced by TC or HMC differ because of the NT method or the in vitro culture. Therefore, we investigated the developmental competence and histone acetylation (H3K18ac) of porcine NT embryos produced by TC and HMC with (Day 5 and 6) or without (Day 0) in vitro culture. Nuclear transfer experiments were performed on same day (Day 0), using same batch of porcine oocytes and donor cells and same in vitro culture conditions. Cloning procedures were previously described (TC : Cloning Stem Cells 10 : 355; HMC : Zygote 20 : 61). Parthenogenetically activated embryos (PA) were used as control of activation and culture conditions. Embryos from all groups were collected for immunostaining of H3K18ac on Days 0, 5, and 6. The normalized H3K18ac level was calculated as previously described (Epigenetics 6 : 177). Cell numbers per blastocyst in each group were counted on Days 5 and 6. The cleavage rate (Day 2) and blastocyst rates (Days 5 and 6) between groups were analysed by Chi-squared test, whereas cell number per blastocysts and H3K18ac level between groups and days were analysed by ANOVA (SAS version 9.2; SAS Institute Inc., Cary, NC, USA). Cleavage rate of HMC embryos was lower than that of TC embryos, but blastocyst rate and cell number per blastocyst were higher in the HMC group compared with TC (Table 1). Differences of H3K18ac level between HMC, TC, and PA groups were only observed on Day 6 but not on Day 0 or Day 5. Within HMC and TC groups, there was no difference in H3K18ac level between Day 0 and Day 5, but the level was lower on Day 6 compared with Day 5 in the HMC group, whereas the TC group displayed the opposite pattern. In conclusion, NT embryos produced by HMC show higher blastocyst rate and cell number per blastocyst compared with TC embryos. Both in vitro culture and the NT method result in differences of the normalized H3K18ac levels. Further study is needed to investigate putative differences between NT embryos produced by HMC and TC compared to in vivo embryos also after transfer to recipients. Table 1.Cleavage and blastocyst rate, cell numbers, and normalized H3K18ac level for handmade cloning (HMC), traditional cloning (TC), and parthenogenetically activated (PA) embryos1


2019 ◽  
Vol 31 (1) ◽  
pp. 210
Author(s):  
G. Singina ◽  
E. Shedova ◽  
T. Taradajnic ◽  
V. Konnova ◽  
E. Tsyndrina

To date, considerable progress has been achieved in in vitro production (IVP) technologies in cattle; however, developmental potentials of oocytes matured in vitro remain low compared with in vivo-matured oocytes. Thus, a better understanding of different aspects of oocyte maturation may allow us to increase the embryo development rate. Our study was aimed to assess the effects of progesterone (P4) and prolactin (PRL) on the bovine oocyte developmental competence. Bovine cumulus-enclosed oocytes (CEO) were matured using either one-step or two-step maturation conditions. For the one-step protocol, CEO were cultured for 24h in TCM-199 supplemented with 10% fetal calf serum (FCS), 10μg mL−1 porcine FSH, and 10μg mL−1 ovine LH (standard medium). For the two-step procedure, CEO were first cultured for 16h in the standard medium (n=1263) and then transferred to 1 of 3 experimental media and cultured for additional 8h in either absence or presence of either P4 (50 ng mL−1) or bovine PRL (50ng mL−1). The 3 media tested in the two-step maturation were (1) TCM-199 containing 10% FCS (group 1), (2) TCM-199 containing 3mg mL−1 BSA (group 2), or (3) Fert-TALP medium supplemented with 6mg mL−1 BSA (group 3). Fert-TALP was selected because it can potentially be used throughout maturation and fertilization. Following in vitro maturation, all oocytes underwent an IVF/in vitro culture procedure as described previously (Singina et al. 2014 Reprod. Fertil. Devel. 26, 154). The embryo development was evaluated at Days 2 and 7 for cleavage and blastocyst rates. In addition, obtained blastocysts were fixed, and the total cell number and the level of apoptosis were determined using 4′,6-diamidino-2-phenylindole (DAPI) and TUNEL staining. The data from 4 to 5 replicates (113-159 oocytes per treatment) were analysed by ANOVA. For oocytes matured for 24h in the one-step culture, the cleavage rate, blastocyst rate, total cell number, and apoptotic nuclei per blastocyst were 66.1±1.1, 23.7±2.0, 71.4±9.1, and 4.8±1.2%, respectively. For the two-step culture, the cleavage rate did not differ from that of the one-step culture system, ranging from 64.8 to 76.5%. Also, no effects of the two-step systems were observed on total cell number (63.0-78.8) or the proportion of apoptotic nuclei (3.3-5.3%) at the blastocyst stage. The culture of CEO in group 1 (without the supplements) had a reduced blastocyst rate (17.4±0.4%; P&lt;0.05) compared with the standard one-step maturation group, and the addition of P4 (but not PRL) improved the blastocyst yield (P&lt;0.05). Furthermore, when P4 (but not PRL) was added to group 2 and group 3 media, blastocyst rates increased significantly (32.9±3.1 and 32.8±2.7%, respectively) compared with those of the one-step group (P&lt;0.05), but did not differ from those of untreated groups 2 and 3 (26.2±2.7 and 30.0±3.0%, respectively). Our data indicate that P4 supplementation during the terminal phase of two-step IVM can enhance the developmental competence of bovine oocytes and that the nature of this effect depends on the composition of IVM medium, whereas no effect of PRL supplementation was observed. The study was supported by RFBR (No. 17-29-08035).


2006 ◽  
Vol 18 (3) ◽  
pp. 309 ◽  
Author(s):  
Christopher G. Grupen ◽  
Maggie Fung ◽  
David T. Armstrong

Inappropriate coordination of oocyte nuclear and cytoplasmic maturation is thought to contribute to the poor efficiency of embryo production in vitro. With the aim of improving this coordination, the effects of milrinone, an inhibitor of type 3 phosphodiesterases, and butyrolactone-I, a selective inhibitor of cdc2 kinases, on porcine oocyte maturation were investigated. Oocytes recovered from slaughterhouse-derived ovaries of prepubertal animals were treated with the inhibitors for 24 h. At concentrations of 50 and 250 μm, milrinone reversibly inhibited meiotic progression in 57% and 71% of oocytes, respectively. The presence or absence of milrinone in the medium used to wash oocytes for 30 min did not alter the inhibitory effect of the 24 h treatment. At concentrations of 25 and 50 μm, butyrolactone-I inhibited meiotic progression in 61% and 66% of oocytes, respectively, but the effect was not fully reversible in the absence of follicle-stimulating hormone (FSH). The presence of FSH during the butyrolactone-I treatment period increased the ability of oocytes to subsequently complete meiosis at 44 h without changing the inhibitory effect at 24 h. Following in vitro fertilisation at 44 and 50 h, treatment with butyrolactone-I and milrinone, alone or in combination, did not alter embryo cleavage rate, blastocyst formation rate or blastocyst cell number. Despite the different actions of milrinone and butyrolactone-I, the present study demonstrates that these reagents inhibit meiotic progression to a similar extent in the presence of FSH while maintaining developmental competence in porcine oocytes.


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