296 INFLUENCE OF SHORT-TERM HEAT STRESS ON THE BLASTOCYST RATE OF BOVINE EMBRYOS (INDICUS VS. TAURUS) FROM OOCYTES OBTAINED BY OVUM PICKUP

2006 ◽  
Vol 18 (2) ◽  
pp. 255
Author(s):  
E. Sartorelli e Sartorelli ◽  
A. C. Z. Barcelos ◽  
R. A. Satrapa ◽  
D. F. Martins ◽  
M. F. G. Nogueira ◽  
...  
Keyword(s):  
Heat Stress ◽  
High Temperatures ◽  
Bos Indicus ◽  
Bovine Embryos ◽  
Short Term ◽  
Cleavage Rate ◽  
Blastocyst Rate ◽  
The Difference ◽  
Resistance To Heat

There is evidence that the deleterious effects of heat stress (HS) on fertility are less pronounced in Bos indicus than in B. taurus breeds, due primarily to differences in their thermoregulatory capacity. In the present work, the resistance to heat stress of Nelore embryos (B. indicus) was compared to either a breed not adapted (Angus; B. taurus) or adapted to high temperatures (Bonsmara; 5/8 B. indicus × 3/8 B. taurus). In Experiments (Exp.) 1 (Nelore vs. Angus) and 2 (Nelore vs. Bonsmara), oocytes obtained by ovum pickup OPU (during autumn) were matured (TCM-199), fertilized, and cultured (SOFaaci) in vitro. Ninety-six hours post-insemination (hpi), embryos with more than 16 cells were randomly allocated in two main groups: Group Control (embryos were maintained at 39°C all of the time) and Group HS (embryos were maintained at 41°C during 12 h and afterwards returned to 39°C). Blastocyst rates were determined on the 7th day of culture. In Exp. 1, 294 oocytes from Nelore and 144 from Angus cows had a cleavage rate of 67.9 and 59.4%, respectively. Ninety-six-hpi embryos (>16 cells) were distributed in four groups: Nelore Control (n = 97), Nelore HS (n = 95), Angus Control (n = 34) and Angus HS (n = 25). The blastocyst rates were 39/97 (40.2%), 23/95 (24.2%), 19/34 (55.9%), and e 8/25 (32.0%), respectively. The difference in rate of blatocyst formation caused by heat stress on Nelore (16.0%) and Angus (23.9%) was not significantly different (P < 0.05), and suggests, from oocytes obtained by OPU, that Nelore embryos may be more tolerant to HS than Angus embryos. However, it is necessary to increase the number of blastocysts per group in order to better characterize the effects of heat stress on these embryos. In Exp. 2, 294 oocytes from Nelore and 101 from Bonsmara cows had a cleavage rate of 41.2 and 51.2%, respectively. Ninety-six-hpi embryos (>16 cells) were distributed in four groups: Nelore Control (n = 44), Nelore HS (n = 49), Bonsmara Control (n = 22), and Bonsmara HS (n = 22). The blastocyst rates were 35/44 (79.5%), 30/49 (61.2%), 10/22 (45.5%), and 6/22 (27.3%), respectively. In spite of the fact that Bonsmara embryos had a lower blastocyst rate as compared to Nelore, the decline on blastocyst rate caused by HS was very similar in Nelore (18.3%) and Bonsmara embryos (18.2%). Additional OPU are underway to test the hypothesis that thermotolerance of Nelore embryos is similar to that in embryos from a breed adapted to high temperatures (Bonsmara), and superior to embryos from a non adapted breed (Angus). E. S. S., R. A. S., and M. F. G. N. were supported by a fellowship from FAPESP, and A. C. Z. B. by a fellowship from CAPES of Brazil.

209 EFFECT OF HEAT STRESS ON DEVELOPMENT OF IN VITRO-FERTILIZED AND PARTHENOGENETIC BOVINE EMBRYOS

2011 ◽  
Vol 23 (1) ◽  
pp. 203
Author(s):  
F. Paludo ◽  
M. M. Pereira ◽  
C. C. R. Quintao ◽  
L. T. Iguma ◽  
M. M. Gioso ◽  
...  
Keyword(s):  
Heat Stress ◽  
Bos Taurus ◽  
Apoptotic Cell ◽  
Chemical Activation ◽  
Bos Indicus ◽  
Bovine Embryos ◽  
Cell Numbers ◽  
Bovine Reproduction ◽  
Blastocyst Rate

Heat stress has been a challenge for bovine reproduction in tropical and subtropical environments. Although the role of the oocyte in thermotolerance has been studied, little attention has been paid to the contributions of sperm to embryo resistance to heat shock. The current study aimed to evaluate the development of fertilized and nonfertilized (parthenogenetic) bovine embryos undergoing heat stress during the pre-implantation stage. Cumulus–oocyte complexes obtained from ovaries collected from Bos indicus × Bos taurus crossbred cows at slaughter were in vitro matured with TCM-199 supplemented with 20 μg mL–1 of FSH, under 5% CO2 at 38.5°C for 24 h. Afterward, oocytes were randomly allocated into 2 groups: 1) IVF and 2) PART (chemical activation for parthenogenesis induction). In vitro-fertilized oocytes were cultured with 2.0 × 106 Holstein sperm mL–1 in Fert-TALP medium supplemented with heparin, for 20 h. For chemical activation, oocytes were activated with calcium ionomycin for 4 min, followed by 6-DMAP for 4 h, both in CR2aa medium supplemented with 0.1% BSA. Presumptive IVF (n = 1 262) or PART (n = 1 206) zygotes were denuded by vortexing and cultured in CR2aa medium with 2.5% of FCS under 5% CO2, 5% O2, and 90% N2 at 38.5°C. At 44 h post-insemination or chemical activation, embryos were exposed to 38.5 or 41°C for 12 h in an atmosphere of 5% CO2, 5% O2, and 90% N2. After that, embryos were cultured at 38.5°C under 5% CO2, 5% O2, and 90% N2 until Day 8 post-insemination. Blastocyst rates were evaluated at Day 7 and Day 8 post-insemination and were calculated based on the total number of presumptive zygotes. Blastocysts at 192 h post-insemination or activation were fixed and permeabilized for TUNEL assay (DeadEndTM Florimetric TUNEL System, Promega, Madison, WI) according to the manufacturer’s instructions. The effect of heat stress was compared within groups (IVF or PART) and the data were analysed by ANOVA. As expected, heat stress reduced the blastocyst rate of IVF embryos at Day 7 (24.3 ± 2.0% and 17.4 ± 2.2% for nonstressed and stressed IVF embryos; P < 0.05) and at Day 8 (32.4 ± 1.9% and 23.0 ± 2.1% for nonstressed and stressed IVF embryos; P < 0.01). However, the effect of heat stress on blastocyst rate of PART embryos was observed only at Day 8 post-insemination (30.0 ± 1.7% and 22.6 ± 2.0% for nonstressed and stressed PART embryos; P < 0.05), with no difference in blastocyst rate at Day 7 (21.6 ± 1.5% and 18.2 ± 1.8% for nonstressed and stressed PART embryos; P > 0.05). There was no difference in total cell numbers between nonstressed and stressed IVF or PART embryos. Apoptosis cell numbers and the apoptotic cell index were higher (P < 0.05) for stressed IVF (18.45 ± 1.24 and 0.16 ± 0.00) and PART (16.40 ± 5.20 and 0.17 ± 0.00) embryos than for nonstressed IVF (13.70 ± 0.75 and 0.13 ± 0.00) and PART (14.15 ± 0.86 and 0.13 ± 0.00) embryos. In conclusion, heat stress can induce apoptosis in both IVF and PART embryos, but its effect on pre-implantation development may occur at earlier stages in IVF embryos when compared with PART embryos. Financial support from Fapemig and CNPq.

134 Effects of Gas Tension During Culture upon Development of Bovine Embryos from Beef (Nellore) and Dairy (Girolando) Breeds

2018 ◽  
Vol 30 (1) ◽  
pp. 207
Author(s):  
J. G. V. Grázia ◽  
L. G. Lacerda ◽  
L. G. B. Siqueira ◽  
C. A. G. Pellegrino ◽  
L. S. Grapiuna ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Initial Period ◽  
Bos Indicus ◽  
Southeastern Brazil ◽  
Bovine Embryos ◽  
Low Oxygen ◽  
Cleavage Rate ◽  
High O2

Culture of bovine embryos is a critical step during in vitro embryo production (IVEP) and, as such, has been the focus of numerous studies on cattle IVEP. Improvements of culture conditions to mimic the in vivo maternal microenvironment involves studying the optimal gas tension for pre-implantation embryonic development. In the commercial conditions, there is great variability in results, in part because of the difference between breeds and donors. The objective of this study was to evaluate the effects of culture in high or low oxygen tension upon the development of embryos from a crossbred dairy breed (Girolando F1; Gir × Holstein) and a beef Bos indicus breed, Nellore. We collected data from an IVEP commercial operation located in a tropical area of southeastern Brazil (Minas Gerais State) from February to May 2017. The study was designed in a 2 × 2 factorial arrangement of treatments: 2 O2 tensions during culture (5%, low O2 v. 20%, high O2) and 2 breeds (Nellore, beef v. Girolando F1, dairy). Thus, the following 4 groups were studied: Nellore-high O2 (n = 86 donors), Nellore-low O2 (n = 107 donors), Girolando F1-high O2 (n = 114 donors), and Girolando F1-low O2 (n = 110 donors). Outcome variables were the number of cleaved embryos 72 h post-insemination (hpi), cleavage rate relative to the total number cumulus–oocyte complexes (COC) put in culture, number and percentage of blastocysts 192 hpi relative to the structures kept in culture. Variables that were not normally distributed were transformed using the formula log(y + 0.05). Data were analysed using the GLM procedure of SAS (SAS Institute Inc., Cary, NC, USA) for the main effects of gas tension (low v. high O2) and breed (Girolando F1 v. Nelore). Results are shown as mean ± SEM. Gas tension affected the number of cleaved embryos (10.52 ± 0.92 v. 8.33 ± 0.72 for high and low O2, respectively; P < 0.01) and cleavage rates (40.58 ± 2.49 v. 44.41 ± 2.88 for high and low O2; P < 0.01 in Nellore), but did not affect these variables in Girolando F1 donors (13.23 ± 1.33 v. 10.76 ± 0.76 cleaved embryos, for high and low O2; P = 0.63; 58.01 ± 2.00 v. 60.19 ± 1.97 cleavage rate, for high and low O2; P = 0.80). Nonetheless, the number and percentage of blastocysts were not affected by gas tension in either breed. Results for Nellore were 4.99 ± 0.56 v. 3.51 ± 0.38 blastocysts in high and low O2, respectively (P = 0.051) and 41.92 ± 3.91% v. 39.81 ± 3.77% blastocysts, in high and low O2 (P = 0.11). For Girolando F1, numbers of blastocysts were 5.84 ± 0.66 v. 4.24 ± 0.39 in high and low O2 (P = 0.19) and percentage of blastocysts 49.14 ± 2.97% v. 49.11 ± 3.40% in high and low O2 (P = 0.46). These results suggest that oxygen tension during culture affects IVEP differently depending on breed. The initial period of culture, recognised as critical in IVEP, seemed more sensitive to high O2 tension, particularly in Nellore.

171 EFFECT OF LONG-TERM TRANSPORTATION OF OVARIES ON THE DEVELOPMENT OF IN VITRO-PRODUCED BOVINE EMBRYOS

2006 ◽  
Vol 18 (2) ◽  
pp. 193
Author(s):  
M. Nakatate ◽  
K. Tsuchiya ◽  
I. Adachi ◽  
K. Takahashi ◽  
A. Aisan ◽  
...  
Keyword(s):  
Bovine Embryos ◽  
Cleavage Rate ◽  
Chi Square ◽  
Vitro Fertilization ◽  
Thermos Flask ◽  
Blastocyst Rate ◽  
Functional Peptides ◽  
Number Of Cells

The transportation of bovine ovaries would allow the shipment of oocytes for research purposes after the slaughter of valuable cows. The objective of this study was to investigate the effect of long-term transportation of ovaries on the development of in vitro-produced bovine embryos. After collection of the ovaries from a slaughterhouse, they were placed inside a thermos flask and transported to the laboratory. The thermos flask was covered with a freezer pack in a foam polystyrene box. The transportation time was 17–18 h, and the temperature of the thermos flask changed from 20°C to 28°C (average 23.8°C) during the transportation. Cumulus–oocyte complexes (COCs) were collected by the aspiration of follicles with a diameter of 2–6 mm. The COCs were matured for 20 h in IVMD101 (RIFP: Research Institute for the Functional Peptides, Yamagata, Japan) containing DM199 supplemented with 5.56 mM glucose, 0.91 mM pyruvate, 5 mM taurine, 5 mM selenium, 5 mM HEPES, and 10 µg/mL gentamicin at 38.5°C under an atmosphere of 5% CO2 in air (Hoshi 2003 Theriogenology 59, 675–685). The matured COCs were inseminated with 5 × 106 sperm/mL in IVF100 (RIFP) medium comprising a modified BO medium supplemented with 1.25 mM sodium pyruvate, 0.5 mM cysteine, 5 mg/mL BSA, 7.5 µg/mL sodium heparin, 5 mM caffeine, and 10 µg/mL gentamicin. After 6 h of gamete co-culture, the presumed zygotes were cultured in IVD101 (RIFP) medium comprising DM199, 2.48 mM lactate, 0.27 mM pyruvate, and 2.22 mM of glucose for 9 days at 38.5°C under an atmosphere of 5% CO2, 5% O2, and 90% N2 in air. As controls, bovine ovaries were transported to the laboratory within 1–1.5 h. Embryo development was evaluated based on the cleavage rate, blastocyst rate, and total number of cells on Days 7–9 after in vitro fertilization. The experiment was replicated five times, and data were analyzed by chi-square test and ANOVA. Results are presented in Table 1. There were no differences in the cleavage rate between the treatments. The blastocyst rate and the number of cells in the blastocyst after long-term transportation of ovaries were significantly lower than those in the controls. These results suggest that the long-term transportation of bovine ovaries does not affect on the cleavage; however, the blastocyst rate and the quality of blastocysts may be affected. Therefore, additional experiments are required to determine suitable conditions for long-term transportation of bovine ovaries. Table 1. Effect of long-term transportation of ovaries on the development of bovine IVM/IVF embryos

175 EFFECT OF HEAT STRESS ON GENE EXPRESSION OF IN VITRO-PRODUCED BOVINE EMBRYOS (BOS TAURUS VS. BOS INDICUS)

2012 ◽  
Vol 24 (1) ◽  
pp. 199
Author(s):  
C. F. Silva ◽  
A. C. S. Castilho ◽  
R. A. Satrapa ◽  
R. Z. Puelker ◽  
E. M. Razza ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heat Stress ◽  
Mrna Expression ◽  
Reverse Transcription ◽  
Target Genes ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Mrna Levels ◽  
Bovine Embryos

Heat stress (HS) reduces the production of bovine embryos, especially taurine embryos, which are not adapted to heat. However, little is known about the competence of embryos produced under HS in breeds adapted or not adapted to heat. The aim of this study was to compare the gene expression of PLAC8, HSF1, COX2 and CDX2, related to competence and implantation, in bovine in vitro-produced embryos (Bos taurus vs Bos indicus), submitted or not submitted to HS. Oocytes from Nelore (zebu) and Jersey (taurine) cows were aspirated by ovum pickup, in vitro-matured in TCM-199 medium with bicarbonate containing 10% FCS, 2 μg mL–1 of pyruvate, 75 μg mL–1 of gentamicin, 20 μg mL–1 of FSH and 10 IU mL–1 of LH for 22 h at 38.5°C in 5% CO2 in air. Matured oocytes were fertilized with semen from Nelore (n = 6) and Jersey (n = 6) bulls, respectively, at 38.5°C in 5% CO2 in air. The fertilization medium was TALP-IVF supplemented with 6 mg mL–1 of fatty acid-free BSA, 2 μL mL–1 of pyruvate, 75 μg mL–1 of gentamicin, 11 μg mL–1 of heparin and 44 μL mL–1 of penicillamine, hypotaurine and epinephrine. The day of fertilization was considered Day 0. Twelve hours post-insemination, presumptive zygotes were denuded and randomly divided into 2 groups, nonstressed or stressed and both were in vitro cultured at 38.5°C in 90% N2, 5% CO2 and 5% O2 in SOFaaci medium supplemented with 5% FCS, 5% BSA and 0,2% sodium pyruvate. In the stressed group, 96-h post-insemination embryos were subjected to HS of 41°C for 6 consecutive hours and then returned to 38.5°C. On Day 7, pools with 5 blastocysts [Nelore (n = 9); Nelore HS (n = 7); Jersey (n = 5); Jersey HS (n = 5)] were subjected to RNA extraction (RNeasy, Qiagen Inc., Valencia, CA, USA). The expression of target genes was analysed by real-time reverse transcription PCR with oligo-dT in reverse transcription and bovine specific-primers in PCR. The expression of cyclophilin A was used as an internal control. The mean mRNA levels of target genes among groups were compared by parametric ANOVA, followed by orthogonal contrast. Heat stress reduced (P < 0.05) mRNA expression of CDX2 and PLAC8 in both breeds; additionally, the expression of these genes was higher in the zebu breed when compared with the taurine breed. Messenger RNA expression of COX2 did not differ between groups, under HS or not, in both the Jersey and Nelore breeds. Moreover, HS reduced the mRNA expression of HSF1 (P < 0.05) in Nelore groups, but not in Jersey groups. The highest levels of PLAC8 and CDX2 in nonstressed Nelore embryos indicate better competence and a higher capacity of implantation of these embryos when compared with Jersey and HS embryos in both breeds. Moreover, low HSF1 levels in stressed Nelore embryos indicate the thermotolerance ability of this breed. In conclusion, the data indicate that HS alters the pattern of gene expression in Nelore and Jersey in vitro-produced bovine embryos. This research was supported by FAPESP.

Efficiency of different incubation systems for the in vitro production of bovine embryos

Zygote ◽  
2018 ◽  
Vol 26 (4) ◽  
pp. 314-318 ◽  
Author(s):  
Camila M. Cavalcanti ◽  
Iana S. Campelo ◽  
Mirelly M.A.S. Silva ◽  
João V.S. Albuquerque ◽  
Luciana M. Melo ◽  
...  
Keyword(s):  
Oxygen Species ◽  
Bovine Embryos ◽  
In Vitro Production ◽  
Cleavage Rate ◽  
Significant Difference ◽  
Maturation Rate ◽  
Blastocyst Rate ◽  
Vitro Production ◽  
Bovine Oocytes

SummaryThis study aimed to compare the efficiency of different incubation systems for in vitro embryo production in bovine. Oocytes/embryos were cultured in three incubators: conventional – CONV, mini bench – MINI and portable – PORT. After in vitro maturation (IVM), oocytes were verified for maturation rate. The remaining structures were submitted to in vitro fertilization and culture to verify cleavage (day 2) and blastocyst (day 7) rates. Reactive oxygen species (ROS) were evaluated in post-IVM oocytes and embryos (days 2 and 7) using arbitrary fluorescence units (AFUs). No significant difference (P>0.05) was observed for maturation rate. The CONV system (74.0%) produced the highest cleavage rate (P<0.05) when compared with PORT (59.5%), but similar (P>0.05) to MINI (65.0%). The same pattern and differences were observed for blastocyst rate: CONV (33.3%), MINI (32.3%) and PORT (21.9%). ROS levels were not different (P>0.05) in post-IVM oocytes: CONV (35.6±4.5), MINI (29.4±4.0) and PORT (35.6±4.5). For day-2 embryos, ROS levels were higher (P<0.05) in MINI (44.2±3.1) in comparison with CONV (27.7±3.7) and PORT (33.3±3.2). No significant difference (P>0.05) was observed in blastocysts. In conclusion, although it produced high ROS levels at day 2 of culture, the MINI system was as efficient as the CONV system for blastocyst production. This option may be an interesting and economical for the in vitro embryo industry.

PSV-5 Relationship between sire conception rate, sperm motility, sperm SERPINA5 relative concentration, and in vitro produced embryos in dairy bulls

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 310-310
Author(s):  
Saulo Menegatti Zoca ◽  
Julie Walker ◽  
Taylor Andrews ◽  
Adalaide C Kline ◽  
Jerica J Rich ◽  
...  
Keyword(s):  
Embryo Development ◽  
Sperm Motility ◽  
Relative Concentration ◽  
Early Embryo ◽  
Conception Rate ◽  
Cleavage Rate ◽  
Blastocyst Rate ◽  
Positive Correlations ◽  
Sire Conception Rate

Abstract Sire conception rate (SCR) is a field measure of fertility among bulls, but it can be influenced by several factors (Sperm transport, sperm-egg binding, early embryo development, etc). The objective of this study was to evaluate the relationship between SCR, sperm motility, SERPINA5 concentrations, and in vitro embryo development. Measurements were performed in 19 bulls with SCR values ranging from -7.7 to 4.45. For each bull, an aliquot of frozen-thawed semen was used for analyses of total (TMOT) and progressive (PROG) motility. Remaining semen was fixed with 2% formaldehyde, and concentration of SERPINA5 was determined by immunolocalization (antibody SERPINA5/Dylight405; PA5-79976-Invitrogen / ab201798-Abcam). Mean fluorescence intensity was determined in ~200 sperm heads/bull. Approximately 149 oocytes/bull were fertilized in vitro for embryo development analysis (cleavage and blastocyst rates). Statistical procedures were performed in SAS (9.4) using the procedures CORR for correlations (SCR, TMOT, PROG, SERPINA5, cleavage and blastocyst) and GLIMMIX for comparison of “field-fertility” (SCR divided in HIGH or LOW) and “field-embryo-fertility” (LOW-SCR sires were divided based on blastocyst rate (HIGH or LOW) resulting in two classifications; LOW-HIGH≥31% and LOW-LOW≤26%, respectively). There were positive correlations (P &lt; 0.05) between cleavage-blastocyst (r=0.50), SERPINA5-cleavage (r=0.48), and TMOT-PROG (r=0.76). Sire SCR was not associated with SERPINA5, TMOT, PROG, cleavage and blastocyst rate (P &gt; 0.52). Among LOW-SCR sires, LOW-LOW sires (-4.83±0.60) tended to have a better SCR score than LOW-HIGH (-6.18±0.42) sires (P = 0.08), but there were no differences (P &gt; 0.43) between LOW-HIGH, LOW-LOW, and HIGH sires for SERPINA5, TMOT, PROG, and cleavage. In conclusion, some LOW SCR sires have good embryo development indicating a different mechanism for their low SCR; however, these differences in SCR could not be explained by TMOT, PROG, SERPINA5, cleavage and blastocyst. There were, however, positive correlations between cleavage-blastocyst rate, and SERPINA5-cleavage rate.

scholarly journals Improvement of quality of oocytes collected in the autumn by enhanced removal of impaired follicles from previously heat-stressed cows

Reproduction ◽  
2001 ◽  
pp. 737-744 ◽  
Author(s):  
Z Roth ◽  
A Arav ◽  
A Bor ◽  
Y Zeron ◽  
R Braw-Tal ◽  
...  
Keyword(s):  
Heat Stress ◽  
Embryo Development ◽  
Treated Group ◽  
Oocyte Quality ◽  
Control Group ◽  
Delayed Effect ◽  
Cleavage Rate ◽  
Lactating Cows ◽  
Summer Heat

The fertility of dairy cows decreases during the summer and remains low during the cooler autumn although the animals are no longer under heat stress. The aim of this study was to characterize a delayed effect of summer heat stress on oocyte quality in the autumn and to improve oocyte quality by enhanced removal of follicles damaged during the previous summer. Lactating cows (n = 16) were subjected to heat stress during the summer. In autumn, ovarian follicles (3-7 mm in diameter) were aspirated by an ultrasound-guided procedure during four consecutive oestrous cycles. Follicles were aspirated from control cows on day 4 and from treated cows on days 4, 7, 11 and 15 of each oestrous cycle. All cows received PGF(2alpha) and GnRH injections on days 19 and 21, respectively, and maintained cyclicity, as indicated by plasma progesterone concentrations. On day 4 of each cycle, the oocytes recovered were examined morphologically, matured and activated in vitro, and cultured for 8 days. In cycle 1 (early October) both groups showed low percentages of grade 1 oocytes, cleavage, four- and eight-cell embryos, morulae and parthenogenetic blastocysts. Subsequently, the number of grade 1 oocytes increased earlier (cycle 2) in treated than in control cows (cycle 3; P < 0.05). The cleavage rate in the control group remained relatively low throughout (32-58%), whereas in the treated group it increased from 40% (cycle 1) to 75% (cycles 3 and 4; P < 0.05). The number at each stage of embryo development increased slightly but remained low throughout in the control group, whereas in the treated group significant (P < 0.05) increases of all stages were observed in cycles 3 and 4. The results show a delayed effect of summer heat stress on oocyte quality and embryo development in the autumn. Enhanced removal of the impaired cohort of follicles led to earlier emergence of healthy follicles and high quality oocytes in the autumn.

scholarly journals In vivo culture of bovine embryos and quality assessment of in vivo vs. in vitro produced embryos

2012 ◽  
Vol 50 (No. 4) ◽  
pp. 149-158 ◽  
Author(s):  
V. Havlicek ◽  
M. Lopatarova ◽  
S. Cech ◽  
R. Dolezel ◽  
T. Huber ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Recovery Rate ◽  
Bovine Embryos ◽  
In Vivo Culture ◽  
Blastocyst Rate ◽  
Culture Procedure ◽  
Recovery Methods

Routine access to the bovine oviduct for in vivo culture accomplishes various demands on embryo production for scientific as well as commercial purposes. The experiments conducted in the present study focused on the efficiency of recovery methods after temporary in vivo culture of bovine embryos in oviducts of the homologous species using transvaginal endoscopy (Experiment I) and on the quality assessment of recovered blastocysts (Experiment II). In Experiment I in vitro matured oocytes were fertilized, cultured for 1 to 3 days and transferred unilaterally into the ipsilateral oviducts of 54 heifers by the means of transvaginal endoscopy. After 4 to 6 days of in vivo culture embryos were re-collected either by non-surgical flushing of uterine horns (U-group) or by combined flushing of the oviducts and uterine horns (OU-group). In total the recovery rate was 38.4% (780/2029). After flushing at day seven, 106 blastocysts (blastocyst rate: 13.6% ) were found. The additional 24 h of in vitro culture (day eight) resulted in 153 blastocysts (blastocyst rate: 19.6% ). The recovery rate in the OU-group was twice as efficient as in the U-group (390/1358 vs. 390/671, P &lt; 0.01). The recovery rates among the different stages of transferred embryos did not differ significantly; likewise cross-effects among the stages and the recovery methods were non-significant. The recovery methods (P &lt; 0.001) and the interaction between the recovery methods and the stages of transferred embryos (P &lt; 0.01) had an influence on blastocyst yields on day seven (U-group 37/1358 vs. OU-group 69/671) and day eight (U-group 48/1358 vs. OU-group 105/671). In Experiment II embryo quality was assessed by the survival rate of blastocysts after freezing in ethylene glycol. Day seven embryos were produced in vitro (in vitro group D7) or by IVM/IVF followed by a combined culture procedure (2 to 3 days in vitro prior to 4&nbsp;to 5 days in vivo) (in vivo group D7) or after superovulation and collection at day seven (superovulation group). Embryos from in vitro group D7 re-expanded only for 6 h after thawing, embryos from in vivo group D7 and superovulation group were alive for 24 h and 72 h of culture, respectively. Only embryos derived by superovulation showed hatching activity. Blastocysts from the in vitro group D7 and the in vivo group D7 that were held in culture medium for additional 24 h (day eight) showed an analogous post-thawing culture behaviour. In conclusion, the results of the present study demonstrated that some embryos transferred for in vivo culture remain in the oviduct even at day seven. Hence, combined flushing of oviducts and uterine horns after in vivo culture in the bovine oviduct is necessary for effective embryo re-collection. The quality of recovered embryos after temporary in vivo culture assessed by cryotolerance was in-between those produced in vitro or recovered after superovulation.

scholarly journals Developmental competence and oxidative state of mouse zygotes heat-stressed maternally or in vitro

Reproduction ◽  
2002 ◽  
pp. 683-689 ◽  
Author(s):  
M Ozawa ◽  
M Hirabayashi ◽  
Y Kanai
Keyword(s):  
Hydrogen Peroxide ◽  
Heat Stress ◽  
Mouse Embryos ◽  
Developmental Competence ◽  
Preimplantation Embryos ◽  
Physiological Changes ◽  
Cleavage Rate ◽  
Maternal Environment ◽  
Stressed Group

Mammalian preimplantation embryos are sensitive to maternal and direct heat stress. However, the mechanisms by which heat stress affects early embryonic development in vivo or in vitro are unknown. This study examined whether heat-stress-induced loss of developmental competence in mouse embryos was mediated by physiological changes in the maternal environment or by high temperatures alone. After fertilization, zygotes at the same stage were heat-stressed at 39.5 degrees C for 12 h either maternally (measured by maternal rectal temperature) or directly in culture. Zygotes in each group were cultured at 37.5 degrees C for a further 84 h to assess their developmental ability. Neither type of heat stress affected the first cleavage rate. However, the proportion of embryos that developed to morulae or blastocysts was significantly lower in the maternally heat-stressed group, but not in the directly heat-stressed group. Moreover, maternal heat stress significantly reduced intracellular glutathione concentrations and enhanced hydrogen peroxide concentrations in both zygotes and two-cell embryos that were recovered immediately after heat stress or 12 h later, respectively. In contrast, direct heat stress had little effect on concentrations of glutathione or hydrogen peroxide in cultured early embryos. These results demonstrate that maternal heat stress at the zygote stage reduces the developmental ability of mouse embryos via physiological changes in the maternal environment that lead to an increase in intracellular oxidative stress on the embryo.

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