scholarly journals 301 EFFECT OF ENERGY SUBSTRATES ON METABOLISM, NUCLEAR MATURATION, AND DEVELOPMENT OF GILT AND SOW OOCYTES DURING IN VITRO MATURATION

2005 ◽  
Vol 17 (2) ◽  
pp. 301 ◽  
Author(s):  
L. Tubman ◽  
A. Peter ◽  
R. Krisher

Metabolic mechanisms control both nuclear and cytoplasmic maturation in oocytes. Elevated glucose metabolism is typically associated with improved developmental competence. The objective of this study was to compare nuclear maturation, oocyte metabolism, and subsequent embryonic development following the use of different energy substrates during in vitro maturation (IVM) and to determine the specific role of each substrate. Cumulus-oocyte complexes (20–50/treatment (Trt)/replicate) were placed into maturation medium for 42 h in 7% CO2 in air at 38°C. Maturation treatments included a negative control (NC; 0.01 mM pyruvate and 6 mM lactate), addition of 1:100 dilution of fatty acids (FA; Gibco, Grand Island, NY, USA), 1 × NEAA/0.5 × EAA/1 mM glutamine (AA), or 2 mM glucose (GLU) individually; and a positive control (PC; addition of all three substrates). For each of six replicates, metabolism of 10 denuded oocytes/treatment was measured in hanging drops containing labeled glucose (0.0125 mM 5-3H glucose, glycolysis; 0.482 mM 1-14C glucose, pentose phosphate pathway, PPP). Oocytes were then fixed and stained for determination of meiotic stage. Remaining oocytes were fertilized and cultured in vitro. Cleavage and blastocyst development were recorded at 30–40 and 144 h post-insemination, respectively. The Purdue Porcine Media system was used throughout (PPM; Herrick et al. 2003 Reprod. Fertil. Dev. 15, 249–254). All data were subjected to analysis of variance. Oocyte metabolism and embryonic development are presented In Table 1. Except for FA, energy substrate influenced the percentage of oocytes reaching metaphase II (NC, 1.37 ± 0.01; FA, 1.35 ± 0.01; AA, 33.33 ± 0.06; GLU, 25.81 ± 0.06; PC, 54.29 ± 0.06) but age of oocyte donor did not. Blastocyst metabolism and cell number were not affected by treatment. In general, sows were more responsive to treatment effects. These data demonstrate that exogenous fatty acids do not play a role in porcine oocyte maturation. Amino acids appear to promote meiosis and glycolysis, but do not support oocyte developmental potential. Elevated metabolism in this treatment may be due to a recovery effect when glucose-starved oocytes were placed into glucose containing metabolism medium. Glucose appears to be important for meiosis and cytoplasmic maturation leading to developmental competence with minimal effect on oocyte metabolism. The success of the positive control suggests that a combination of glucose and amino acids is beneficial to maturation and embryonic development of porcine oocytes. Table 1. Metabolism and development of oocytes after IVM

Zygote ◽  
2020 ◽  
pp. 1-6
Author(s):  
Ji-Eun Park ◽  
Sang-Hee Lee ◽  
Yong Hwangbo ◽  
Choon-Keun Park

Summary The aim of the present study was to investigate the effects of porcine follicular fluid (pFF) from large-sized (LFF; >8 mm in diameter) and medium-sized (MFF; 3–6 mm in diameter) follicles on the maturation and developmental competence of porcine oocytes. Cumulus–oocyte complexes (COCs) were collected from follicles 3–6 mm in diameter. The collected COCs were incubated for 22 h with LFF or MFF (in vitro maturation (IVM)-I stage) and were incubated subsequently for 22 h with LFF or MFF (IVM-II stage). Cumulus expansion was confirmed after the IVM-I stage and nuclear maturation was evaluated after the IVM-II stage. Intracellular glutathione (GSH) and reactive oxygen species (ROS) levels were measured and embryonic development was evaluated. Relative cumulus expansion and GSH levels were higher in the LFF group compared with in the MFF group after the IVM-I stage (P < 0.05). After the IVM-II stage, the numbers of oocytes in metaphase-II were increased in the LFF group and GSH content was higher in all of the LFF treatment groups compared with in the MFF treatment groups during both IVM stages (P < 0.05). ROS levels were reduced by LFF treatment regardless of IVM stage (P < 0.05). Blastocyst formation and the total numbers of cells in blastocysts were increased in all LFF treatment groups compared with the control group (P < 0.05). These results suggested that pFF from large follicles at the IVM stage could improve nucleic and cytoplasmic maturation status and further embryonic development through reducing ROS levels and enhancing responsiveness to gonadotropins.


2015 ◽  
Vol 27 (1) ◽  
pp. 240
Author(s):  
J. D. Yoon ◽  
E. Lee ◽  
S.-H. Hyun

Growth differentiation factor 8 (GDF8) is a member of the transforming growth factor-β that has been identified as a strong physiological regulator. The purpose of this study was to investigate the effects of GDF8 on in vitro porcine oocytes maturation and subsequent embryonic development after pathenogenetic activation (PA) and in vitro fertilization (IVF). We investigated nuclear maturation, intracellular glutathione (GSH), reactive oxygen species (ROS) levels, sperm penetration (SP) analysis, and subsequent embryonic development after PA and IVF. Each concentration (0, 1, 10, and 100 ng mL–1) of GDF8 was added in maturation medium during process of in vitro maturation. Data were analysed by ANOVA followed by Duncan using SPSS (Statistical Package for Social Science) mean ± s.e.m. After 44 h of IVM, no significant difference was observed on nuclear maturation from the different concentration (0, 1, 10, and 100 ng mL–1) of GDF8 treatment groups (85.5, 85.9, 89.4, and 87.6%, respectively) compared with the control (P > 0.05). The 10- and 100-ng mL–1 GDF8-treated groups showed a significant (P < 0.05) decrease in intracellular ROS levels compared with other groups. The embryonic developmental competence after PA was affected with GDF8 treatment during IVM. The 10- and 100-ng mL–1 treatment groups showed significantly (P < 0.05) higher cleavage rates (67.5 and 69.1%, respectively) compared with control group (53.7%). The 10- and 100-ng mL–1 treatment groups also showed significantly (P < 0.05) higher blastocyst formation rates (50.5 and 52.7%, respectively) compared with other groups (34.5 and 35.8%). The IVF embryonic developmental competence also was affected with GDF8 treatment during IVM. The 10-ng mL–1 treatment group showed a significantly (P < 0.05) higher blastocyst formation rates and total cell number compared with control (21.5 and 131.3 v. 15.0 and 92.6%, respectively). Also, in the sperm penetration assessment, the 10- and 100-ng mL–1 treatment groups showed higher mono spermy ratio and fertilization efficiency (32.7 and 27.1, 32.0 and 26.5 v. 22.6 and 19.7%, respectively) than control, which was significant (P < 0.05). In conclusion, the treatment with 10 ng mL–1 of GDF8 during IVM improved the PA and IVF porcine embryo developmental competence by decreasing the intracellular ROS levels.This work was supported, in part, by a grant from the Next-Generation BioGreen 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2013R1A2A2A04008751), Republic of Korea.


2014 ◽  
Vol 26 (1) ◽  
pp. 191
Author(s):  
Y. Jeon ◽  
J. D. Yoon ◽  
L. Cai ◽  
S. U. Hwang ◽  
E. Kim ◽  
...  

Zinc (Zn) is one of the abundant transition metals in biology and is an essential component of most cells. However, there are few reports about the effect of Zn in porcine oocytes. The objective was to investigate the effects of supplementary Zn during in vitro maturation (IVM) of porcine oocytes. We investigated nuclear maturation, intracellular glutathione (GSH) levels, reactive oxygen species (ROS) levels, and subsequent embryonic development after IVF. Before the experiment, Zn concentrations in IVM medium and body fluids were measured using inductively coupled plasma spectrophotometer (sensitivity: 1 μM) and treatment concentrations were determined. Zinc concentration was 12.6 μM in porcine plasma and 12.9 μM in porcine follicular fluid. We confirmed that Zn was not detected in IVM medium. A total of 541 cumulus–oocyte complexes (COC) were used for the evaluation of nuclear maturation. The COC were matured in TCM-199 medium supplemented with various concentrations of Zn (0, 6, 12, 18, and 24 μM). After 44 h of IVM, no significant difference was observed in all groups (metaphase II rate: 85.7, 88.7, 90.4, 90.3, and 87.2%, respectively). A total of 100 matured oocytes were examined for the effects of different Zn concentrations (0, 6, 12, 18, and 24 μM) on porcine oocyte intracellular GSH and ROS levels, which were measured through fluorescent staining and image analysis program. The groups of 12, 18, and 24 μM showed a significant (P < 0.05) increase in intracellular GSH levels (1.45, 1.67, and 1.78, respectively) compared with the control and 6 μM group (1.00 and 1.08, respectively). The intracellular ROS level of oocytes matured with 12, 18, and 24 μM (0.82, 0.68, and 0.55) were significantly (P < 0.05) decreased compared with the control and 6 μM groups (1.00 and 1.03, respectively). Finally, the developmental competence of oocytes matured with different concentrations of Zn (0, 6, 12, 18, and 24 μM) was evaluated after IVF. There were no significantly different in cleavage rates. However, cleavage patterns and blastocyst (BL) formation were different. Fragmented embryo ratio of the 12 μM group (14.9%) was significantly lower than that of the other groups (control, 6, 18, and 24 μM: 26.4, 17.8, 18.4, and 18.0%, respectively). Oocytes treated with 12 μM Zn during IVM had a significantly higher BL formation rate (28.2%) after IVF compared with the control (19.8%). In conclusion, these results indicate that Zn treatment as body fluid concentration during IVM improved the developmental potential of IVF in porcine embryos by increasing the intracellular GSH concentration and decreasing the ROS level. This work was supported, in part, by a grant from the Next-Generation Bio Green 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.


2014 ◽  
Vol 26 (1) ◽  
pp. 190
Author(s):  
E. Kim ◽  
Y. Jeon ◽  
J. D. Yoon ◽  
L. Cai ◽  
S. U. Hwang ◽  
...  

The objective was to investigate the effects of zinc (Zn) insufficiency during in vitro maturation (IVM) of porcine oocytes. Zinc insufficiency was induced by treatment of Zn chelator, N,N,N′,N′-tetrakis-(2-pyridylmethyl)-ethylendiamine (TPEN). In experiment 1, we investigated the effect of duration of Zn insufficiency in IVM on oocytes maturation and subsequent embryonic development after parthenogenetic activation (PA). First, 10 μM TPEN was added to the IVM medium for 0, 7, 15, or 22 h. After TPEN treatment, 10 μM Zn were supplemented on IVM medium except in the 0 h group. Reductions in the nuclear maturation rates were dependent on TPEN duration. The 0-h-treated oocytes showed 83.9 ± 3.9% metaphase II (MII) rate; the 7-h-treated oocytes had significantly lower MII rate (44.8 ± 3.0%) than 0-h-treated oocytes. The majority of 15- and 22-h-treated oocytes were arrested at metaphase I (MI rate: 98.0 ± 1.0 and 97.2 ± 1.7%, MII rate: 0 and 0%, respectively). Embryonic developmental competence was similar to maturation results. Reduction in cleavage and blastocyst (BL) rates were also dependent on duration of TPEN treatment (cleavage rate: 65.3 ± 1.4, 42.6 ± 4.8, 2.6 ± 0.1, and 3.0 ± 1.6%; BL formation rate: 29.3 ± 2.8, 9.2 ± 1.5, 0, and 0% for 0, 7, 15, and 22 h). Total cell number of BL was also significantly different. Total cell number of BL in the 0-h-treated group (51.4 ± 4.5) was significantly higher than that in the 7-h-treated group (23.2 ± 1.6). In experiment 2, to confirm that the Zn insufficiency caused oocyte immaturities and loss of developmental competence in TPEN-treated oocytes, we investigated nuclear maturation and subsequent embryonic development following 3 groups: (1) non treatment (control); (2) 10 μM TPEN treatment during 22 h of IVM; (3) 10 μM TPEN + 10 μM Zn treatment during 22 h of IVM. Only TPEN-treated oocytes and TPEN+Zn-treated oocytes showed contrasting results. Oocyte maturation rates and subsequent embryonic development competence in TPEN with Zn-treated oocytes were similar to control (MII rate: 93.0 ± 1.2 and 92.7 ± 1.8%, BL formation rate: 42.0 ± 6.7 and 40.0 ± 7.5% for TPEN+Zn-treated oocytes and control). These results were significantly different compared with only TPEN-treated oocytes’ results (MII rate: 0.61 ± 0.61%, BL formation rate: 0%). In conclusion, Zn is an essential element for successful oocyte maturation and embryo development in porcine. Zinc insufficiency caused meiotic block and had lasting effects on early embryo development. This work was supported, in part, by a grant from the Next-Generation BioGreen 21 Program (No. PJ00956901), Rural Development Administration, and the National Research Foundation of Korea Grant funded by the Korean Government (NRF-2012R1A1A4A01004885, NRF-2013R1A2A2A04008751), Republic of Korea.


2020 ◽  
Vol 6 (3) ◽  
pp. 110-120
Author(s):  
Christie L Sun ◽  
Sally L Catt ◽  
Kiri Beilby ◽  
Mulyoto Pangestu

In vitro maturation (IVM) is a promising assisted reproductive technology (ART) for human infertility treatment. However, when cumulus oocyte complexes (COCs) are removed from their follicular environment when manipulated in vitro, it can lead to a decrease of intra-oocyte cyclic adenosine 3’, 5’-monophosphare (cAMP) causing spontaneous nuclear maturation and an asynchrony with the oocytes’ cytoplasmic maturation, resulting in poor embryo developmental outcomes. Nuclear and cytoplasmic synchrony is important during oocyte maturation within antral follicles.It is maintained partially by the actions of c-type natriuretic peptide (CNP) binding with natriuretic peptide receptor 2 (NPR2), supporting high cAMP levels thus holding the oocyte in meiotic arrest. Addition of CNP to pre-IVM media has the capacity of maintaining cAMP levels and thus improve synchrony. Moreover, in women with advanced maternal age, successful IVM of aging oocytes faces significant challenges due to the morphological and cellular changes.  Inhibiting initiation of nuclear maturation by cAMP modulator, CNP during pre-IVM period and thus improve oocyte developmental competence regardless of oocyte age.


2010 ◽  
Vol 22 (1) ◽  
pp. 324 ◽  
Author(s):  
M. De los Reyes ◽  
D. Luna ◽  
J. Palomino

Low development of IVM canine oocytes could be in part attributed to an impaired cytoplasmic maturation. In mammalian oocytes, migration and the redistribution of cortical granules (CGs) around the periphery of the oocyte contribute to the inhibition of polyspermy and it is an important criterion to evaluate cytoplasmic maturation. The state of nuclear maturation and the distribution of CGs were evaluated in canine oocytes cultured for different periods in order to compare the synchrony of nuclear and cytoplasmic maturation during in vitro maturation. Bitch ovaries at different stages of the estrous cycle were obtained following ovariectomy. COCs with compact cumulus cells showing a homogeneous cytoplasm were selected for experiments. Thirty-six COCs were processed at immature stage, placed in PBS medium until evaluation. A total of 275 COCs were matured in vitro for 48, 72, and 96 h in TCM-199 with Earle’s salt supplemented with 25 mM Hepes, 10% FCS, 0.25 mM pyruvate, 10 IU mL-1 of hCG, 300 IU mL-1 penicillin, and 20 mg mL-1 streptomycin, at 38.5°C and 5% CO2. At each culture period, the oocytes were stained with Lens culinaris agglutinin (LCA), labeled with fluorescein isothiocyanate, and the CGs distributions were examined under a fluorescent microscope. The nuclear status of the denuded oocytes was determined by DAPI staining under a fluorescence microscope. For each treatment, at least four replicates were performed and the data was analyzed by ANOVA using Tukey’s test to determine the differences P < 0.05. Three types of CGs distribution were distinguished during canine oocyte maturation: (1) homogeneous distribution throughout the cytoplasm including the cortex; (2) heterogeneous (clusters) within the cytoplasm and (3) densely distributed beneath the oolemma. Nuclear stages were classified as immature or germinal vesicle (GV) stage; resumption of meiosis or germinal vesicle break down (GVBD); metaphase I to telophase I (MI toTel I); and mature or second metaphase (MII). The distribution patterns of GCs were different (P < 0.05) among oocytes cultured for different periods and the nuclear maturation status also differed between oocytes cultured for different intervals (P < 0.05). Most (>84%) of the immature oocytes at GV showed a uniform distribution of CGs throughout the cytoplasm. At 48 h of culture, CGs distribution was mainly Type 2 (25%) and 3 (61%) and the oocytes were at GVBD (33%) and MI-Tel I (33%) stages. Most nuclei of the type 3 oocytes were in the MI (40%) and MII (11%) stages, corresponding to those oocytes matured for 72 (88%) or 96 h (71%). These results indicate that canine oocytes migrate to the cortex during IVM and this process is not finished before 72 h of culture. In addition, although the re-distribution of the CGs occurred in parallel with nuclear maturation, the oocytes cannot always proceed to the MII stage; however, in such oocytes the CGs are distributed beneath the oolemma. Supported by Grant FONDECYT 1080618.


2014 ◽  
Vol 26 (1) ◽  
pp. 200 ◽  
Author(s):  
C. de Frutos ◽  
R. Vicente-Perez ◽  
P. J. Ross

In vitro maturation (IVM) of oocytes in domestic animals is a widespread practice of research and commercial relevance. Gonadotropic hormones are typically supplemented to the IVM medium to stimulate resumption of meiosis, progression to metaphase II (MII), and oocyte developmental competence. The common use of pituitary-derived products presents 2 problems: contamination from other pituitary hormones and inconsistences from batch-to-batch variation. Recombinant hormones can help circumvent these issues and identify specific gonadotropin requirements for in vitro maturation. The aim of the present study was to determine the effect of supplementing recombinant bovine LH and/or FSH (AspenBio) to the maturation of ovine oocytes in terms of cumulus expansion and progression to the MII stage. Abattoir-derived sheep cumulus–oocyte complexes (COC) were obtained from 1- to 5-mm-diameter antral follicles by ovary slicing. Oocytes with a homogeneous cytoplasm surrounded by at least 3 layers of cumulus cells were selected and cultured in serum-free IVM medium (Cotterill et al. 2012 Reproduction 144, 195–207) at 38.5°C and 5% CO2. The COC obtained from 8 replicates were allocated into 4 experimental groups: (1) no hormones; (2) 1.5 μg mL–1 recombinant bovine LH (rbLH); (3) 1.5 μg mL–1 recombinant bovine FSH (rbFSH); and (4) rbLH and rbFSH. The expansion of cumulus cells was recorded in each group after 24 h of IVM and COC classified as (1) very poor or no cumulus expansion (grade 1); (2) limited cumulus expansion (grade 2); and (3) full cumulus expansion (grade 3). Nuclear maturation in the 4 treatments was evaluated by assessing progression to the MII stage via DNA staining with Hoechst 33342 and fluorescence imaging. The effect of treatment on the observed proportion of MII oocytes was evaluated using a mixed logit model including treatment and replicate as fixed and random effects, respectively. Culture in IVM medium in the absence of gonadotropins or in the presence of rbLH resulted in poor cumulus expansion (grade 1). The supplementation of IVM medium with rbFSH (with or without rbLH) yielded a high degree of cumulus expansion (grades 2–3). Likewise, addition of rbFSH enhanced progression of oocytes to the MII stage, whereas use of rbLH, although it had an effect on progression to MII, did not augment the effect of rbFSH (Table 1). These results indicate that rbFSH is necessary and sufficient to induce sheep oocyte maturation in a high proportion of oocytes. Table 1.Cumulus expansion and oocyte nuclear stage after IVM


2016 ◽  
Vol 28 (2) ◽  
pp. 235
Author(s):  
J. D. Yoon ◽  
E. Lee ◽  
S.-H. Hyun

Growth differentiation factor-8 (GDF8) is a member of the transforming growth factor-β that has been identified as a strong physiological regulator. SB-431542 (SB) is a specific inhibitor of transforming growth factor-β superfamily type I activin receptor-like kinase (ALK) receptors such as ALK4, ALK5, and ALK7. The purpose of this study is investigation of the effects of GDF8 and SB on porcine oocytes during in vitro maturation and subsequent embryonic development. We first performed ELISA to detect GDF8 concentrations in follicular fluid for each size of follicle; sizes were as follows: small (<3 mm), medium (>3 mm and <6 mm), and large (>6 mm) follicle. After detection of the GDF8 concentration in follicular fluid, we investigated the effect of GDF8 and SB treatment during in vitro maturation (IVM) on nuclear maturation, intracellular glutathione (GSH), and reactive oxygen species (ROS) levels, and embryonic development after IVF and parthenogenetic activation (PA). Data were analysed by ANOVA followed by Duncan using SPSS (Statistical Package for Social Science, IBM, New York, NY, USA) mean ± SEM. The ELISA result showed different concentrations of GDF8 for each grade of follicular fluid: small, 0.479 ng mL–1; medium, 0.668 ng mL–1; and large, 1.318 ng mL–1. During the IVM process, 1.318 ng mL–1 of GDF8 and 5 ng mL–1 of SB were added to the maturation medium as control, SB, SB+GDF8, and GDF8 treatment groups. After 44 h of IVM, GDF8 group (90.4%) showed a significantly higher nuclear maturation rate than control and SB+GDF8 groups (85.4 and 81.7%). The SB group (78.9%) showed significantly reduced nuclear maturation rate compared with control (P < 0.05). The GDF8 treatment group showed a significant decreased intracellular ROS and increased GSH levels compared with other groups (P < 0.05). The SB+GBF8 treatment group showed a significantly better cytoplasmic maturation than the SB treatment group. In the PA embryonic development analysis, the GDF8 treatment group showed a significantly higher blastocyst formation rate compared with other groups (47.9, 37.2, 46.4, and 58.7% respectively; P < 0.05). In the IVF embryonic development analysis, the GDF8 treatment groups showed significantly higher blastocyst formation rate compared with the SB group (28.2 and 42.2%, respectively; P < 0.05). In conclusion, treatment with GDF8 during porcine oocyte IVM improved the embryonic developmental competence via increased cytoplasmic maturation and led to better oocyte maturation from the ALK receptor inhibition by SB.


2016 ◽  
Vol 28 (2) ◽  
pp. 234
Author(s):  
P. Ferré ◽  
T. T. M. Bui ◽  
M. T. Tran ◽  
T. Wakai ◽  
H. Funahashi

The interruption of communication between oocyte and cumulus cells (CC) can trigger meiotic resumption and exogenous additives, such as follicular fluid (FF) and growth differentiation factor-9 (GDF9), can improve oocyte quality and the developmental competence. This study was undertaken to examine if the absence and presence of FF from medium follicles (MF; 3–6 mm in diameter) or recombinant human GDF9 (Biovision, Milpitas, CA, USA) during the first or/and second half of in vitro maturation (IVM) had any effects on IVM of oocytes from small follicles (SF; 0.5–2 mm in diameter) or MF when the oocytes were denuded at 20 h after the start of IVM. Cumulus-oocyte complexes (COC) were aspirated from SF or MF of slaughtered prepubertal gilt ovaries. Groups of ~30 COC were cultured in a 300-μL drop of porcine oocyte medium containing 50 µM β-mercaptoethanol (mPOM) with or without 10% (v/v) FF and/or 100 ng mL–1 GDF9 at 39°C and 5% CO2 in air. During the first 20 h after the start of IVM, the medium was supplemented with 1 mM dibutyryl c-AMP, 10 IU mL–1 eCG and 10 IU mL–1 hCG. After the first period of IVM, the CC surrounding the oocytes were removed and the denuded oocytes continued culture for IVM with or without FF or/and GDF9 in the absence of dibutyryl c-AMP and gonadotropins in the same medium for another 24 h. At the end of IVM, meiotic progression of the oocytes was examined by DAPI staining. Statistical analyses from at least 4 replicates data were performed by a 2-way ANOVA and a Tukey’s multiple comparisons test. Removal of CC 20 h after the start of IVM significantly improved the incidence of mature oocytes derived from SF (59.2–64.1% v. 41.6–43.1% in controls, P < 0.05) but not from MF (73.1–78.5% v. 70.6–71.8% in controls), whereas regardless of supplementation with FF or GDF9, the maturation rates were always significantly higher in the denuded oocytes from MF (72.4–83.6%) than SF (57.8–66.2%; P < 0.05). Despite of the origin of COC (SF or MF), maturation rates of oocytes denuded 20 h after the start of IVM were not affected by supplementation with FF or GDF9 during the first and/or second half of IVM (P > 0.05). In summary, CC removal from COC 20 h after the start of IVM promotes nuclear maturation of oocytes from SF. Exogenous additives such as GDF9 and follicular fluid from MF do not seem to affect the promotion of nuclear maturation in our experimental conditions.


Sign in / Sign up

Export Citation Format

Share Document