158 IMPACT OF MATURED CATTLE OOCYTES AT HIGHER INCUBATION TEMPERATURE ON IN VITRO EMBRYO PRODUCTION

2016 ◽  
Vol 28 (2) ◽  
pp. 209
Author(s):  
M. Nkadimeng ◽  
E. van Marle-Koster ◽  
K. P. M. Lekola ◽  
M. L. Mphaphathi ◽  
M. M. Seshoka ◽  
...  
Keyword(s):  
Incubation Temperature ◽  
Cell Types ◽  
Cell Number ◽  
Cleavage Rate ◽  
Embryo Production ◽  
Developmental Potential ◽  
Cell Numbers ◽  
Significant Difference ◽  
In Vitro Embryo Production

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.

scholarly journals Effect of deslorelin acetate treatment in oocyte recovery and in vitro embryo production in domestic cats

2016 ◽  
Vol 19 (10) ◽  
pp. 1091-1095
Author(s):  
Camila Louise Ackermann ◽  
Eduardo Trevisol ◽  
Leticia Ferrari Crocomo ◽  
Tatiana da Silva Rascado ◽  
Rodrigo Volpato ◽  
...  
Keyword(s):  
Treated Group ◽  
Control Group ◽  
Domestic Cats ◽  
Cleavage Rate ◽  
Embryo Production ◽  
Oocyte Recovery ◽  
Significant Difference ◽  
In Vitro Embryo Production ◽  
Blastocyst Rate

Objectives The present study investigated the effect of contraceptive treatment with deslorelin acetate on in vitro embryo production and oocyte recovery in domestic queens. Methods Twenty-one mature domestic cats were used. Eleven queens (treated group) and one tom were kept in an experimental cattery, and 10 queens were privately owned (control group). When in interestrus or diestrus (day 0) a deslorelin acetate implant (Suprelorin, 4.7 mg/animal) was inserted into the subcutaneous tissue of the interscapular region in all queens in the treated group. After 6 months of treatment, all animals were ovariohysterectomized, and the ovaries were used for in vitro embryo production. Percentage of cleavage was determined 18 h after oocyte insemination and blastocyst formation was assessed on the eighth day of culture. The rate of cumulus-oocyte complexes (COCs) recovery was analyzed by an unpaired t-test. The cleavage and blastocyst rates were expressed as percentages and analyzed by Fisher’s exact test. All analyses were performed using GraphPad Prism v5.0, with P <0.05 set as the level of significance. Results In the treated group, we recovered 8.3 ± 1.15 grade I COCs per queen; the cleavage rate was 60% and the blastocyst rate was 36%. In the control group, we recovered 18.4 ± 3.21 grade I COCs per queen; the cleavage rate was 55.97% and the blastocyst rate was 34%. Forty percent of treated females did not produce any blastocysts. In the treated group, we observed a significant decrease in COC recovery. Although there was no significant difference in cleavage and blastocyst rates between groups, 40% of treated females did not produce any blastocysts. Conclusions Recovery of grade I COCs is negatively affected by deslorelin treatment in domestic cats. Regarding embryo production, new studies are still necessary to evaluate the success of this technique owing to the individual effect caused by deslorelin acetate.

Latrunculin a Enhances the Parthenogenetic Developmental Potentials of Electrically Activated Porcine Oocytes Matured In Vitro

2011 ◽  
Vol 236-238 ◽  
pp. 2548-2553
Author(s):  
Jian Hui Wang ◽  
Dong Min Liu ◽  
Yong Le Liu
Keyword(s):  
Polar Body ◽  
Blastocyst Formation ◽  
Cleavage Rate ◽  
Developmental Potential ◽  
Cell Numbers ◽  
Significant Difference ◽  
Latrunculin A ◽  
The Individual ◽  
20 Nm

The present study was carried out to determine the effect of latrunculin A (Lat-A) and FBS on the developmental potentials of electrically activated porcine oocytes maturedin vitro. Electrically activated MII oocytes were incubated for 2 hr in mPZM-3 supplemented either with 0、20 nM、1 μM Lat-A or 2.2 μg/ml cytochalasin B (CB). They were then removed and placed in mPZM-3 with or without 10% FBS (addition) on Day 4 for further development. The nuclear activation rate was significantly improved when activated oocytes were cultured in mPZM-3 with Lat-A (P<0.05). At higher dosage (1μM) of Lat-A, the extrusion of second polar body was inhibited while the cleavage rate increased significantly (P<0.05). Significant interaction between Lat-A and FBS supplementation on Day 4 was observed duringin vitrodevelopment (P<0.05). The hatched blastocyst rates and cell numbers per blastocyst were significantly enhanced with the supplementation of FBS (P<0.05). The blastocyst formation, hatched blastocyst rates and mean cell numbers per blastocyst of 1 μM Lat-A treatment with FBS supplementation were significantly higher than those of 20 nM Lat-A and CB treatments with FBS supplementation (P<0.05), but the individual effect of FBS supplementation was not observed on blastocyst formation in 20 nM and 1 μM Lat-A treatments. While significant difference was seen in blastocyst formation and cell numbers per blastocyst among all the treatments without FBS supplementation (P<0.05). These results indicate that Lat-A especially at the dosage of 1 μM can significantly improve the developmental potential of electrically activated porcine oocytes, and the FBS supplementation on Day 4 of development have an additional effect on porcine embryo development.

Cleavage Rate of in vitro Matured Oocytes Fertilized with Conventional Semen in Buffaloes

2021 ◽  
Author(s):  
M.H. Pitroda ◽  
K.P. Khillare ◽  
M.B. Amle ◽  
M.D. Meshram ◽  
A.B. Mali ◽  
...  
Keyword(s):  
Fertilization Rate ◽  
Cleavage Rate ◽  
Embryo Production ◽  
Quick Recovery ◽  
Slaughter House ◽  
Maturation Rate ◽  
Aspiration Technique ◽  
Current Scenario ◽  
In Vitro Embryo Production

Background: In vitro embryo production in buffaloes has gained much importance in this current scenario due to ever increasing population and high demand of milk and meat. Slaughter house derived bubaline ovaries are a cheap and abundant source of cumulus oocyte complexes.Methods: Oocytes from the buffalo ovarian follicles were recovered by aspiration technique as it facilitates quick recovery. Total 155 ovaries were used in the present study. Surface follicles were measured using vernier calliper and categorized into three groups viz. less than 3 mm, 3-5 mm and greater than 5 mm based on follicular diameter and oocytes were processed for IVM, IVF and IVC using conventional non sorted semen.Result: Overall percentage of small, medium and large follicles in the ovaries were recorded as 16.29 ± 0.94%, 8.14±0.60%, 5.35 ± 0.76%, respectively. Overall recovery rate of COCs was 38%. The percentage of these oocytes were 16.74% (A), 15.25% (B), 25.26% (C), 18.33% (D) and 29.87% (E) respectively. Maturation rate of oocytes were 81.96 ± 2.70%. Fertilization rate was 74.98 ± 3.87%, Cleavage rate % was 40.84±2.51% and Blastocyst percentage was 21.57±1.75% respectively. Application of in vitro embryo production technique using slaughter house ovaries can salvage the genetic potential of bubaline species.

Abstract 255: A Fibroblast Population Shares A Developmental Origin With Cardiovascular Lineages

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Sara Ranjbarvaziri ◽  
Shah Ali ◽  
Mahmood Talkhabi ◽  
Peng Zhao ◽  
Young-Jae Nam ◽  
...  
Keyword(s):  
Heart Development ◽  
Cardiac Fibroblasts ◽  
Immunohistochemical Analysis ◽  
Cell Types ◽  
Mouse Heart ◽  
Developmental Potential ◽  
Reporter Mice ◽  
Significant Difference ◽  
Definition Of

Rationale: The traditional definition of “cardiovascular” lineages describes the eponymous cell types - cardiomyoctes, endothelial cells, and smooth muscle cells - that arise from a common mesodermal progenitor cell during heart development. Fibroblasts are an abundant mesenchymal population in the mammalian heart which may have multiple, discrete developmental origins. Mesp1 represents the earliest marker of cardiovascular progenitors, contributing to the majority of cardiac lineages. To date no link between Mesp1 and fibroblast generation has been reported. Objective: We hypothesized progenitor cells expressing Mesp1 can also give rise to cardiac fibroblasts during heart development. Methods and Results: We generated Mesp1cre/+;R26RmTmG reporter mice where Cre-mediated recombination results in GFP activation in all Mesp1 expressing cells and their progeny. To explore their developmental potential, we isolated GFP+ cells from E7.5 Mesp1cre/+;R26RmTmG mouse. In vitro culture and transplantation studies into SCID mouse kidney capsule as wells as chick embryos showed fibroblastic adoption. Results showed that at E9.5 Mesp1+ and Mesp1- progenitors contributed to the proepicardium organ and later at E11.5 they formed epicardium. Analysis of adult hearts demonstrated that the majority of cardiac fibroblasts are derived from Mesp1 expressing cells. Immunohistochemical analysis of heart sections demonstrated expression of fibroblast markers (including DDR2, PDGFRα and Col1) in cells derived from both Mesp1+ and Mesp1- progenitors. Additionally, we investigated whether the two distinct fibroblast populations have different potency towards reprogramming to cardiomyocytes. Results showed no significant difference between Mesp1 and non-Mesp1 isolated fibroblasts to convert to cardiomyocyte fate. Conclusions: Our data demonstrates that cardiovascular progenitors expressing Mesp1 contribute to the proepicardium. These cells, as cardiovascular progenitors, also give rise to the highest portion of cardiac fibroblasts in the mouse heart.

Effect of vitrification technique and assisted hatching on rabbit embryo developmental rate

Zygote ◽  
2009 ◽  
Vol 17 (1) ◽  
pp. 57-61 ◽  
Author(s):  
M. Popelková ◽  
Z. Turanová ◽  
L. Koprdová ◽  
A. Ostró ◽  
S. Toporcerová ◽  
...  
Keyword(s):  
Cell Number ◽  
Total Cell ◽  
Control Group ◽  
Assisted Hatching ◽  
Hatching Rate ◽  
Total Cell Number ◽  
Developmental Potential ◽  
Significant Difference ◽  
Rabbit Embryos

SummaryThe aim of the study was to determine the efficiency of two vitrification techniques followed by two assisted hatching (AH) techniques based on post-thaw developmental capacity of precompacted rabbit embryos and their ability to leave the zona pellucida (hatching) during in vitro culture. The total cell number and embryo diameter as additional markers of embryo quality after warming were evaluated. In vivo fertilized, in vitro cultured 8–12-cell rabbit embryos obtained from superovulated rabbit does were cryopreserved by two-step vitrification method using ethylene glycol (EG) as cryoprotectant or by one-step vitrification method with EG and Ficoll (EG+Ficoll). Thawed embryos were subjected to enzymatic or mechanical AH. Vitrified EG group showed significantly lower (P < 0.05) blastocyst rate (22.5%) and hatching rate (15%) than those vitrified with EG + Ficoll (63 and 63% resp.) and that of control (97 and 97% respectively). Significantly lower values of total cell number (P < 0.05) as well as embryo diameter (P < 0.01) in EG group compared with EG + Ficoll and control group were recorded. No significant difference was found in developmental potential of warmed embryos treated by either mechanical or enzymatic AH. The present study demonstrates that the EG + Ficoll vitrification protocol provides superior embryo survival rates over the EG vitrification protocol for 8–12-cell stage precompacted rabbit embryos. No positive effect of either mechanical or enzymatic AH on the post-thaw viability and quality of rabbit embryos in vitro was observed.

scholarly journals 64COMPARISON OF DEVELOPMENTAL POTENTIAL OF IN VIVO AND IN VITRO RECIPIENT OOCYTES AFTER NUCLEAR TRANSFER IN GOAT

2004 ◽  
Vol 16 (2) ◽  
pp. 154
Author(s):  
H.S. Park ◽  
M.Y. Lee ◽  
S.P. Hong ◽  
J.I. Jin ◽  
J.K. Park ◽  
...  
Keyword(s):  
Nuclear Transfer ◽  
Electric Pulse ◽  
Serum Starvation ◽  
Cleavage Rate ◽  
Developmental Potential ◽  
In Vitro Development ◽  
Significant Difference ◽  
Vitro Development

Recent techniques in somatic cell nuclear transfer (SCNT) have been widely used for animal research. In addition, SCNT techniques may allow for the rescue of endangered species. Despite efforts for wildlife preservation, however, some threatened or endangered wild animal species will likely become extinct. As a preliminary experiment of a series in wildlife research, we tried to identify an improved method for the production of more transferable NT embryos in goats. Mature donor animals of Korean native goats (20–25kg) were synchronized with a CIDR (type G; InterAg, New Zealand) vaginal implant for 10 days followed by a total of 8 twice daily injections of 70mg of FSH (Folltropine, London, Ontario, Canada) and 400IU of hCG (Chorulon, Intervet, Moxmeer, The Netherlands). Oocytes were then collected surgically by retograde oviduct flush or direct aspiration from ovarian follicles in vivo at 29–34h after hCG. Oocytes collected from follicles were matured in TCM-199 containing 10% FBS and hormones. Prepared ear skin cells from the goat were cultured in TCM-199 containing 10% FBS at 39°C, 5% CO2 in air, and confluent monolayers were obtained. Oocytes were enucleated and donor cells from serum starvation (0.5%) culture were fused through a single electric pulse (DC 2.36kvcm−1, 17μs), and then activated by a single electric pulse (AC 5vmm−1, 5s+DC 1.56kvcm−1, 30μs) or chemical treatment (5μgmL−1 ionomycin 5min−1, 1.9mM 6-DMAP/4h). Reconstructed oocytes were cultured in M16 medium with 10% goat serum (GS) for 6–7 days. Data were analyzed by chi-square test. In in vitro development, significantly (P&lt;0.05) more oocytes were cleaved (24/30, 80.0%) and developed (7/24, 29.2%) to morula or blastocyst stage, respectively, in NT oocytes activated by Iono + DMAP compared to electric stimulated oocytes (2/21, 40.0%; 0/2, 0%). There was a significant difference in in vitro development of NT embryos by the method of oocyte collection. Cleavage rate was higher (P&lt;0.05) in NT embryos from in vivo oocytes (23/28, 82.1%) than in in vitro matured oocytes (19/35, 54.3%), and further development to morula or blastocyst was also significantly (P&lt;0.05%) higher in NT embryos from in vivo oocytes (7/23, 30.4%) than in NT embryos from in vitro matured oocytes (0/19, 0%). When we compared NT embryos to parthenotes, developmental rate was not significantly different between NT embryos and parthenotes. These results strongly suggest that the in vivo oocytes will have superior developmental potential to oocytes matured in vitro. Table 1 Effect of different oocyte source on in vitro development following caprine SCNT

286 INFLUENCE OF REVERSIBLE MEIOSIS INHIBITION ON SWINE EMBRYOS PRODUCED BY IN VITRO FERTILIZATION AND PATHENOGENETIC ACTIVATION

2006 ◽  
Vol 18 (2) ◽  
pp. 250
Author(s):  
M. G. Marques ◽  
A. B. Nascimento ◽  
V. P. Oliveira ◽  
A. R. S. Coutinho ◽  
M. E. O. A. Assumpção ◽  
...  
Keyword(s):  
Culture Medium ◽  
Cell Number ◽  
Control Group ◽  
Cleavage Rate ◽  
Vitro Fertilization ◽  
Electric Pulses ◽  
Cell Numbers ◽  
Blastocyst Rate ◽  
And Control

The present work evaluated the reversible meiosis inhibition effect on the development of swine embryos produced by in vitro fertilization (IVF) or parthenogenetic activation (PA). The efficiency of PZM3 and NCSU23 embryo culture media was also evaluated. Oocytes from ovaries collected at a slaughterhouse were subjected to IVM in two different groups: CHX (cycloheximide 5 µM for 10 h) and control, both with TCM-199 + 3.05 mM glucose + 0.91 mM sodium pyruvate + 10% porcine follicular fluid (pFF) + 0.57 mM cystein + 10 ng epidermal growth factor (EGF)/mL + 10 IU eCG/mL + 10 IU hCG/mL for the initial 22 h. In the remaining period (20 h for CHX and 22 h for control), medium without hormones was utilized. After IVM, oocytes were denuded and fertilized for 6 h (IFV) or the matured oocytes were submitted to activation by electric pulses (PA) (2 DC of 1.5 kV/cm for 30 µs), incubated for 1 h in culture medium with 10 μM of CHX, and again submitted to the same electric pulses for 60 µs. Embryo development was evaluated by cleavage rate on Day 3 and blastocyst rate and blastocyst cell number on Day 7 of culture. Cleavage and blastocyst rates were analyzed by the equality-of-two-ratios test and cell number by the Kruskal-Wallis and Mann-Whitney tests (P < 0.05). In relation to IVF, the PZM3 medium was more efficient than NCSU23 for cleavage rate in the CHX group (PZM3: 68.4%, NCSU23: 44.4%) and had a better blastocyst rate in the control group (PZM3: 13.4%, NCSU23: 5.6%). With reference to PA, NCSU23 presented better cleavage and blastocyst rates than PZM3 in the CHX group (NCSU23: 89.5%, PZM3: 78.5% and NCSU23: 20.4%, PZM3: 13.0%, respectively). In the control group, only the NCSU23 blastocyst rate was higher than that for PZM3 (NCSU23: 22.5%, PZM3: 10.8%). No culture medium effect on cell number mean of IVF and PA blastocysts was observed. Maturation block improved cleavage rates in IVF groups cultured with PZM3 (68.4% and 50.6%, respectively, for CHX and control) and in PA groups cultured with NCSU23 (89.5% and 80.3%, respectively, for CHX and control), but no improvement of blastocyst rates in both groups (IVF and PA) was verified. Table 1 below shows that maturation block decreased the IVF and increased the PA blastocyst cell numbers. As older oocytes are more effectively activated, oocytes blocked with CHX achieved the maturation stage faster than the control group, therefore resulting in high-quality PA blastocysts. In conclusion, PZM3 was more efficient for IVF embryo production in contrast to NCSU23, whereas NCSU23 can be indicated for PA embryo production. Moreover, maturation blockage with CHX influenced blastocyst cell number, decreasing in IVF embryos and increasing in PA embryos. Table 1. Mean (±SD) of blastocyst cell numbers for IVF or PA groups after in vitro maturation without (control) or with cycloheximide (CHX) and cultured in NCSU23 or PZM3 medium This work was supported by FAPESP 02/10747–1.

18 DEVELOPMENTAL COMPETENCE OF CLONED PORCINE EMBRYOS PRODUCED WITH DIFFERENT CLONING PROCEDURES

2014 ◽  
Vol 26 (1) ◽  
pp. 123
Author(s):  
Y. Liu ◽  
A. Lucas-Hahn ◽  
B. Petersen ◽  
R. Li ◽  
P. Hassel ◽  
...  
Keyword(s):  
In Vitro Culture ◽  
Nuclear Transfer ◽  
Cell Number ◽  
Culture Conditions ◽  
Developmental Competence ◽  
Cleavage Rate ◽  
Cell Numbers ◽  
Blastocyst Rate ◽  
Handmade Cloning

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

206 EFFECT OF FOLLICULAR WAVE SYNCHRONIZATION AND SUPERSTIMULATION ON IN VITRO EMBRYO PRODUCTION

2008 ◽  
Vol 20 (1) ◽  
pp. 182 ◽  
Author(s):  
K. Imai ◽  
Y. Inaba ◽  
H. Yoshioka ◽  
Y. Aikawa ◽  
M. Ohtake ◽  
...  
Keyword(s):  
Formation Rate ◽  
Cumulus Cell ◽  
Oocyte Quality ◽  
Annual Conference ◽  
Cleavage Rate ◽  
Embryo Production ◽  
Follicular Wave ◽  
The Mean ◽  
In Vitro Embryo Production

We previously reported that follicular wave synchronization, by removal of the dominant follicle on Day 5 after ovum pickup (OPU), was effective in increasing oocyte quality in the developing follicles (Imai et al. 2006 32th Annual Conference of the IETS, poster presentation no. 277). The current study was designed to examine the effect of superstimulatory treatment to induce subsequent follicular wave synchronization on embryo production by OPU and IVM-IVF-IVC in Holstein dry cows. Cows were reared under the same feeding and environmental conditions, and 2 OPU sessions were conducted in each cow. In the first session, OPU was performed in 8 cows on arbitrary days of the estrous cycle by 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). Follicles larger than 8 mm in diameter were then aspirated and a CIDR was inserted on Day 5 (the day of first OPU session = Day 0). Cows then received 30 mg of FSH (Antrin-R10; Kawasaki Mitaka Pharmaceutical Co., Tokyo, Japan) twice a day from Days 7 to 10 in decreasing doses (6, 6, 4, 4, 3, 3, 2, 2 mg) by i.m. injection. Cloprostenol (PGF; Clopromate C; Sumitomo Pharmaceuticals Co., Tokyo, Japan; 0.75 mg) was administered in the morning of Day 9 (third day of superstimulation). The second OPU session was performed 48 h after PGF administration (Day 11), and only follicles larger than 5 mm in diameter were aspirated. The CIDR was removed from the cows just before OPU. Collected oocytes were evaluated by their cumulus cell morphology, cytoplasmic color, and density. Grades 1 and 2 COC were matured, fertilized, and cultured as described by Imai et al. [2006 J. Reprod. Dev. 52(Suppl.), S19–S29]. Embryo development was assessed by the cleavage rate on Day 2 and by the blastocyst formation rate on Days 7 to 8 (the day of insemination = Day 0). Data were analyzed by Student's t-test. There were no differences in the mean (� SD) number of aspirated follicles or collected oocytes between the first (32.5 � 6.8 and 26.0 � 12.7, respectively) and second (29.3 � 10.4 and 19.0 � 9.4, respectively) OPU sessions (P > 0.1). The percentage of Grade 1 and 2 oocytes for the second OPU session (90.5 � 13.8%) was significantly higher (P < 0.01) than for the first OPU session (63.1 � 6.3%), and significant differences were found for cleavage (79.4 � 14.1, 61.8 � 25.1, P < 0.01) and blastocyst rates (68.1 � 16.7, 24.2 � 22.3, P < 0.001) between sessions. The mean numbers of blastocysts obtained per session were 4.3 � 2.9 and 12.8 � 8.7 in the first and second sessions, respectively (P < 0.01). These results indicate that superstimulatory treatment and subsequent follicular wave synchronization were effective on in vitro embryo production by increasing the oocyte quality.

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