Can Oocyte Selection, Cleavage and Developmental Rates of In vitro Produced Bovine Embryos Assist in the Gender Selection of the Pre-implanted Embryos

The culture of embryos individually in vitro is generally associated with poorer developmental rates. However, the ability to do this successfully would greatly facilitate studies where identification of individual embryos, or the embryos from a particular donor, is necessary. The objective of this study was to examine the effect of culture system on the development of individual IVP bovine embryos. Presumptive zygotes (n = 1301, 6 replicates), produced by IVM/IVF, were used. The aim of Experiment 1 was to compare development of bovine embryos in SOF or CR1aa supplemented with 5% FCS. Zygotes were cultured in droplets under oil as follows: (i) 20/25 μL, (ii) 20/100 μL or (iii) 20/100 μL individually in the Well of the Well (WOW) system (Vajta et al. 2000 Mol. Reprod. Dev. 55, 254–264). Twenty WOW were prepared in a 100 μL droplet of medium under oil using a sterile rod. The aim of Experiment 2 was to compare development of embryos cultured in groups but individually identifiable on the cell adhesive Cell-Tak (Stokes et al. 2005 Dev. Biol. 284, 62–71) or in the WOW system. Zygotes were cultured as follows: (i) 20/20 μL, (ii) 20/20 μL with Cell-Tak, (iii) 20/100 μL with Cell-Tak or (iv) 20/100 μL in WOW. A drop of Cell-Tak (1 μL/20 μL medium) was placed on the base of the dish, dried for 20 min, washed with sterile water and dried completely. Once dried, the area was covered with 10 μL of FCS-free medium and groups of 20 zygotes were placed on the Cell-Tak in a 5 × 4 grid formation a maximum of 160 μm apart. Then, an additional 10 μL or 90 μL medium supplemented with FCS was added to give a final volume of 20 or 100 μL. Cleavage and blastocyst rates were assessed on Day 2 and Days 7–9, respectively. Data (means ± SE) were analyzed by one way ANOVA. In Experiment 1, there were no differences between SOF and CR1aa with respect to culture of embryos individually in WOW (P > 0.05); therefore, SOF was used as the basal medium for Experiment 2. There were no differences (P > 0.05) between the cleavage and blastocyst rate among drop sizes and individual culture systems; individual culture, irrespective of the system used (Cell-Tak or WOW), resulted in the similar developmental rates to the control. In conclusion, individual embryo culture offers the opportunity to study embryo development in a more powerful manner. Furthermore, the use of the cell adhesive Cell-Tak may be more practical because it removes the potential variability associated with well dimensions in the WOW system and may improve any potential paracrine effects during embryo culture. Further studies are required to establish the viability of such embryos after transfer. Table 1.Effect of individual culture system on development of IVP bovine embryos Supported by Science Foundation Ireland.

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109 INTRAFOLLICULAR GLUCOSE CONCENTRATION HAS AN INFLUENCE ON THE SEX OF BOVINE BLASTOCYSTS PRODUCED IN VITRO

Reproduction Fertility and Development ◽

10.1071/rdv23n1ab109 ◽

2011 ◽

Vol 23 (1) ◽

pp. 160

Author(s):

E. Abele ◽

H. Stinshoff ◽

A. Hanstedt ◽

S. Wilkening ◽

S. Meinecke-Tillmann ◽

...

Keyword(s):

Sex Ratio ◽

Follicular Fluid ◽

Glucose Concentration ◽

Blastocyst Stage ◽

Total Cell ◽

Bovine Embryos ◽

Developmental Rates ◽

Group 2 ◽

Group 1

Several factors have been shown to alter the sex ratio of bovine embryos generated in vitro, i.e. the maturity of the oocyte at the time of insemination, the duration of sperm-oocyte co-incubation and the culture conditions after in vitro fertilization. It has been shown that the presence of glucose during in vitro culture reduced the development of female embryos to the blastocyst stage compared with controls cultured in the absence of glucose. The sex ratio of bovine embryos has also been linked with changes in the composition of the follicular fluid in which the oocyte undergoes growth and maturation, i.e. the intrafollicular testosterone concentration. However, no information is available regarding the effect of intrafollicular glucose concentration on the sex ratio of embryos after in vitro production (IVP). The purpose of this study was to determine whether different glucose concentrations in the follicular fluid at the time of cumulus–oocyte complex (COC) collection have an effect on the sex ratio of the resulting blastocysts after IVP. Ovaries from a local abattoir were transported to the laboratory within 2 h of slaughter. Follicles (3–8 mm) were individually dissected and the glucose concentration of each follicle was measured using a blood glucose monitoring system (Freestyle Freedom Lite, Abbott, Germany). Based on a glucose concentration, COC [low glucose: <1.1 mM (group 1) and high glucose: >1.1 mM (group 2)] were pooled in groups and used for blastocyst production employing standard protocols for IVP. Developmental rates were recorded at Day 3 (cleavage) and Day 7/8 (blastocyst stage). Total cell number of blastocysts was determined after Hoechst staining. Sex of the embryos was analysed via PCR using bovine X- and Y-chromosome specific primers. Developmental rates for COC stemming from follicles with different glucose concentrations did not show significant differences (P > 0.05) compared to each other [Cleavage rate: group 1: 81.8 ± 4.7% (93/117); group 2: 79.3 ± 4.9% (94/123); blastocyst rate: group 1: 35.6 ± 5.2% (38/117); group 2: 31.6 ± 5.2% (38/123)]. Total cell numbers were similar in embryos of both groups [Group 1: 117.7 ± 8.1 (n = 18); group 2: 117.2 ± 6.4 (n = 18)]. The overall sex ratio significantly differed (P < 0.05) from 1:1 in favour of females in both groups [Group 1: 85 v. 15% (n = 20); group 2: 63.6 v. 36.4% (n = 22)]. No significant difference (P > 0.05) in the overall sex ratio was detected in blastocysts produced under standard IVP conditions employed in the laboratory [without measurement of follicular glucose concentration, 55.0 v. 45.0%, (n = 20)]. In conclusion, under the conditions used in the present study, the intrafollicular glucose concentration from which the immature COC was collected affects the sex of the resulting embryo after IVP, favouring females. Further studies are needed to confirm these findings in living cows using the ovum pickup technique.

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98 EXPERIMENTAL TRANSFER OF BOVINE IVF-DERIVED 32-CELL STAGE EMBRYOS INTO THE UTERUS: ENVIRONMENTAL EFFECTS ON DEVELOPMENTAL CHARACTERISTICS

Reproduction Fertility and Development ◽

10.1071/rdv28n2ab98 ◽

2016 ◽

Vol 28 (2) ◽

pp. 179

Author(s):

M. Hoelker ◽

D. Salilew-Wondim ◽

F. Rings ◽

D. Tesfaye ◽

K. Schellander

Keyword(s):

Culture Media ◽

Uterine Cavity ◽

Blastocyst Stage ◽

Considerable Proportion ◽

Bovine Embryo ◽

Bovine Embryos ◽

Cell Stage ◽

Developmental Rates ◽

Uterine Environment

Usually, in vitro-produced bovine embryos are cultured in vitro in static culture systems for 7 to 9 days in media composed according the oviducal fluid although it is well accepted that around Day 4.5–5 the bovine embryo enters the uterine cavity, providing environmental conditions different from the oviduct. Therefore, one has to raise the question whether changing culture media properties after Day 5 of culture could have beneficial effects on early development of bovine embryos. To answer that question, we transferred bovine IVF derived 32-cell stage embryos into the uterine cavity of synchronized recipients. All embryos had been matured and fertilized under routine standard conditions and were cultured in synthetic oviducal fluid supplemented with essential and nonessential amino acids (SOFaa) supplemented with either 0.3% fatty acid free bovine serum albumin (BSAfaf/Uterus) or 10% serum (serum/uterus) at 38.5°C, 5% O2, and 5% CO2 in humidified air prior transfer into the uterine environment, allowing further development to the blastocyst stage within the physiological environment prior recollection at Day 7 by routine uterine flushing followed by comparison with statically in vitro-developed embryos cultured in media supplemented with serum (serum/serum group) or BSAfaf (BSAfaf/BSAfaf group). All in all, a total of 1031 in vitro-derived 32-cell stage embryos were transferred to 21 synchronized Simmental recipient heifers. Of these, a total of 680 embryos (66%) could be recollected at Day 7. Embryos of the serum/serum group reached a higher blastocyst rate compared with embryos of the BSAfaf/BSAfaf group (68% v. 41%; P < 0.05, ANOVA, Tukey test), whereas the developmental rate to the blastocyst stage did not differ after 9 days of in vitro culture, indicating higher developmental kinetics of bovine 32-cell stage embryos when culture media is supplemented with serum. Moreover, embryos of the serum/uterus group reached significantly lower developmental rates to the blastocyst stage until Day 7 compared with embryos of the serum/serum group (12.9% v. 68.4%). Likewise, embryos in the BSAfaf/uterus group reached significantly lower developmental rates to the blastocyst stage until Day 7 compared with embryos in the BSAfaf/BSAfaf group (16.0% v. 40.1%). When allowed to develop for additional 48h in vitro, developmental rates to the blastocyst stage at Day 9 were still higher in BSAfaf/BSAfaf treatment compared with the BSAfaf/uterus treatment (91.4% v. 74.4%) and the serum/serum treatment compared with the serum/uterus treatment (92.5% v. 56.0%). Taken together, the results of our study demonstrate that uterine transfer of bovine 32-cell stage embryos results in reduction of developmental kinetics as well as lower developmental rates compared with embryos statically cultured in vitro. That might indicate, that a considerable proportion of bovine 32-cell stage embryos might not be able to adapt to the uterine environment.

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Selection of viable in vitro-fertilized bovine embryos using time-lapse monitoring in microwell culture dishes

Journal of Reproduction and Development ◽

10.1262/jrd.2017-041 ◽

2017 ◽

Vol 63 (4) ◽

pp. 353-357 ◽

Cited By ~ 14

Author(s):

Satoshi SUGIMURA ◽

Tomonori AKAI ◽

Kei IMAI

Keyword(s):

Time Lapse ◽

Bovine Embryos ◽

Selection Of

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Production of sexed bovine embryos in vitro can be improved by selection of sperm treatment and co‐culture system

Reproduction in Domestic Animals ◽

10.1111/rda.13926 ◽

2021 ◽

Author(s):

Ivona Travnickova ◽

Pavlina Hulinska ◽

Svatava Kubickova ◽

Katerina Hanzalova ◽

Bartozs Kempisty ◽

...

Keyword(s):

Culture System ◽

Bovine Embryos ◽

Selection Of

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142 IN VITRO DEVELOPMENT OF BOVINE EMBRYOS CULTURED IN KSOM, CR1AA, OR KSOM/CR1aa

Reproduction Fertility and Development ◽

10.1071/rdv17n2ab142 ◽

2005 ◽

Vol 17 (2) ◽

pp. 221 ◽

Cited By ~ 1

Author(s):

M.R.B. Mello ◽

C.E. Ferguson ◽

A.S. Lima ◽

M.B. Wheeler

Keyword(s):

Embryo Culture ◽

Cumulus Cells ◽

Bovine Embryos ◽

In Vitro Production ◽

Cell Stage ◽

In Vitro Development ◽

Significant Difference ◽

Developmental Rates ◽

Vitro Development

In vitro embryo culture is an important step of in vitro production of bovine embryos. It has been shown that IVF-derived bovine embryos cultured in KSOM or CR1aa have high development rates. In our laboratory, we have observed that 8-cell embryos are morphologically superior when embryos are cultured in KSOM whereas blastocysts are morphologically superior when embryos are cultured in CR1aa. Based on these observations, we hypothesized that development of IVF-derived bovine embryos can be improved by sequential use of these media (KSOM and CR1aa). The aim of this experiment was to compare the in vitro development of bovine embryos cultured in KSOM, CR1aa or KSOM/CR1aa supplemented with BSA at Day 0 and BSA and FBS at Day 3. In order to accomplish the sequential culture, fertilized oocytes where cultured in KSOM to the 8-cell stage and then transferred to CR1aa for further development. Oocytes were purchased from Bomed (Madison, WI, USA), and after 22 hours of maturation were fertilized with frozen-thawed semen for 5 hours at 39°C in 5% CO2. After fertilization, the presumptive zygotes were denuded from cumulus cells by votexing and were randomly allotted to one of 3 treatments: (1) cultured only in KSOM (n = 110), (2) cultured only in CR1aa (n = 102), and (3) cultured in KSOM in the first 3 days and then in CR1aa from Day 3 to Day 9 (n = 110). The embryo culture was carried out in 50-μL droplets of medium that were placed in an airtight modular incubator filled with 5% CO2, 5% O2 and 90% N2. The embryos were evaluated on Days 6 to 9 post insemination. All embryo developmental rates were calculated from presumptive zygotes. The Day 6 morula rates were 52%, 40%, and 47% for KSOM, CR1aa, and KSOM/CR1aa, respectively. The Day 7 blastocyst rates for KSOM (40%), CR1aa (25%), and KSOM/CR1aa (30%) were not significantly different; however, Day 9 hatched blastocyst rates were significantly higher (P < 0.05) for KSOM (22%) compared to CR1aa (9%) but not different from KSOM/CR1aa (14%). Regarding embryo quality, Day 7 transferable embryos rates (Grade 1 and Grade 2) were 35%, 25%, and 30%, respectively for KSOM, CR1aa, and KSOM/CR1aa; however, no significant difference was observed. These results indicate that IVF-derived bovine embryos can develop in KSOM, CR1aa, or KSOM/CR1aa with no significant difference among morula, blastocyst and hatched blastocyst rates. However, the combination of KSOM and CR1aa during in vitro culture did not decrease the morula and blastocyst rates.

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121 DEVELOPMENT OF IN VITRO-PRODUCED BOVINE EMBRYOS CULTURED IN SEQUENTIAL OR CONTINUOUS MEDIA

Reproduction Fertility and Development ◽

10.1071/rdv20n1ab121 ◽

2008 ◽

Vol 20 (1) ◽

pp. 141

Author(s):

L. S. Amorim ◽

D. J. Walker ◽

G. E. Seidel Jr

Keyword(s):

Culture Media ◽

Cumulus Cells ◽

Similar Efficacy ◽

Defined Medium ◽

Bovine Embryos ◽

Cleavage Rate ◽

Cell Stage ◽

Developmental Rates ◽

Effects Of Media

Slaughtered bovine females have different characteristics including age, nutritional status, breed, and management system, all of which may affect the results obtained in in vitro embryo production. Another key consideration is that early embryos move from the oviduct to a slightly different environment in the uterus, which has led to development of sequential embryo culture media (e.g. Lane M et al. 2003 Theriogenology 60, 407–419). However, the benefits and importance of using sequential media are not fully known. Therefore, the aim of the present study was to compare developmental rates of oocytes obtained from slaughterhouse-derived ovaries from cows or heifers after culture in sequential media (CDM-1, CDM-2) or in a continuous medium (C-CDM). The experiment was a 3 × 2 × 2 factorial design [bulls (A, B, or C), source (cows or heifers), and medium (sequential or continuous)]. Cumulus–oocyte complexes were aspirated, within 5 h of slaughter, from 3- to 8-mm ovarian follicles of cows (1482 oocytes) and fattened heifers usually fed melengesterol acetate (2818 oocytes). Embryos were produced in vitro as described by De La Torre-Sanchez et al. 2006 Reprod. Fertil. Devel. 18, 585–596, with slight modifications. Presumptive zygotes were vortexed to remove cumulus cells and cultured for 2.5 d in C-CDM (CDM supplemented with 5.0 mm L-lactate, essential and nonessential amino acids, and 0.5% FAF-BSA, or in CDM-1 (De La Torre-Sanchez et al. 2006 Reprod. Fertil. Devel. 18, 585–596) at 39°C in a humidified incubator under 5% CO2, 5% O2, and 90% N2. Cleavage was assessed after 2.5 d; 2- to 6-cell embryos were considered as cleaved, but were not cultured further. Embryos at the 7- to 8-cell stage were cultured for an additional 4.5 d in fresh C-CDM or CDM-2. The percentage blastocysts per oocyte was assessed after 7 and 8 days of culture. Data were arcsin-transformed and evaluated by ANOVA. There was a significant interaction between bull and ovary source for both 8-cell embryos and cleavage rate (P < 0.05); however, this interaction was no longer significant for blastocysts. No other interactions were significant nor a source of ovaries. Culturing embryos in CDM-C refreshed after cleavage evaluation (continuous) or culturing embryos in CDM-1 early and CDM-2 after cleavage evaluation (sequential) resulted in similar cleavage and blastocyst rates (Table 1). We conclude that bovine embryos can be produced using a single chemically defined medium (+BSA) with similar efficacy as a system using 2 sequential media. Table 1. Effects of media on embryonic development (mean ± SE)

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