294 USE OF FORSKOLIN TO PRODUCE IN VITRO BOVINE EMBRYOS UNDER TWO CONCENTRATIONS OF FETAL CALF SERUM

2010 ◽  
Vol 22 (1) ◽  
pp. 303
Author(s):  
D. M. Paschoal ◽  
M. J. Sudano ◽  
L. C. O. Magalhães ◽  
L. F. Crocomo ◽  
F. C. Landim-Alvarenga

The increased storage of lipid granules in in vitro-produced (IVP) bovine embryos seems to be related to the presence and concentration of fetal calf serum (FCS) during culture. The presence of high concentration of lipids on embryos reduces their viability after cryopreservation, which has been one of the main obstacles for the success of vitrification of IVP bovine embryos (Moore et al. 2007 Theriogenology 68, 1316-1325). The present experiment aimed to induce cytoplasmic lipolysis in IVP bovine embryos using forskolin (Sigma-Aldrich, St. Louis, MO, USA), which raises the levels of intracellular cAMP (Seamon et al. 1981 Proc. Natl. Acad. Sci. USA, 78, 3363-3367). Nelore oocytes were matured in TCM-199 + 10% FCS, FSH, and LH in 5% CO2 in air atmosphere, at 38.5°C. After 24 h of maturation, oocytes were fertilized in human tubal fluid (HTF, Irvine, New Zealand) under the same conditions. Presumptive zygotes were cultured in 2 concentrations of FCS: Control 0% (SOFaa + 5 mg mL-1 BSA; basic medium, BM), and Control 2.5% (BM supplemented with 2.5% FCS). On Day 6 of culture embryos were divided into 2 additional treatments: Forskolin 0% (BM + 10 μM forskolin; and Forskolin 2.5% (BM supplemented with 2.5% FCS and 10 μM forskolin). All embryos were cultured in a 5% CO2, 5%O2, and 90% N2 atmosphere at 38.5°C for 7 days, when blastocyst formation rate was evaluated. Embryo viability was also checked by staining the embryos with Hoechst 33342 and propidium iodide. Data were analyzed by ANOVA followed by Tukey’s test, using a 5% significance level. No statistical differences were observed among treatments on cleavage rates, evaluated on Day 3 of culture, or on blastocyst formation rates. Although no statistical differences was observed between treatments on percentage of viable cells, embryos cultured with 0% FCS, independently of the presence of forskolin, presented significantly more damaged cells than embryos cultured with 2.5% FCS (P < 0.05). The results indicate that the presence of FCS is important to reduce degeneration of blastomeres during culture. Moreover, the presence of forskolin on Day 6 of culture did not influence embryo development, indicating that this drug could be a good alternative to reduce embryo lipid content in bovine IVP embryos produced in presence of FCS. Table 1.Effect of fetal calf serum and forskolin on embryo culture Acknowledgments: FAPESP 07/53505-1.


2015 ◽  
Vol 27 (1) ◽  
pp. 208
Author(s):  
S. Matoba ◽  
T. Somfai ◽  
T. Nagai ◽  
M. Geshi

Previously, an early first cleavage and a second cleavage after IVF with a normal cleavage pattern defined by even blastomeres without fragments or protrusions was found to be a potent marker for the selection of embryos with high developmental competence (Sugimura et al. 2012 PLoS ONE 7, e36627). The aim of this study was to investigate the effects of bulls and X-sorting of sperm on the ability of these simple noninvasive markers to predict the potency of bovine IVF embryos to develop to the blastocyst stage in vitro. Immature oocytes were matured in TCM199 supplemented with 0.02 armour unit mL–1 FSH and 5% calf serum at 38.5°C in 5% CO2 and 95% air for 22 to 23 h. After maturation, oocytes were inseminated with either of non-sorted frozen-thawed sperm from 3 bulls (A–C) or X-sorted sperm of bull A. Putative zygotes were cultured (IVC) in CR1aa medium supplemented with 5% calf serum and 0.25 mg mL–1 linoleic acid albumin at 38.5°C in 5% CO2, 5% O2, and 90% N2 for 216 h. Embryo kinetics were observed individually by time-lapse cinematography (CCM-1.3Z; Astec, Fukuoka, Japan; Sugimura et al. 2010 Biol. Reprod. 83, 970–978). First and second cleavage kinetics and pattern were categorized according to Sugimura et al. (2012). For each bull, blastocyst development from embryos possessing the following 3 selection markers was compared: (marker 1) the first cleavage within 28 h after IVF, (marker 2) marker 1 combined with 2 even blastomeres without fragments or protrusions, and (marker 3) marker 2 combined with the second cleavage within 50 h after IVF with ≥6 even blastomeres without fragments or protrusions, respectively. Data were analysed by the Yates' corrected chi-square test. A total of 823 oocytes were used in at least 3 replications. When non-sorted sperm was used for IVF, there was not difference (P > 0.05) in total blastocyst formation rates on Day 8 (Day 0 = IVF) among bulls (ranging between 49.5 and 60.8%); however, blastocyst formation rate of embryos generated from X-sorted sperm of bull A (39.5%) was lower (P < 0.05) compared with other groups despite of similar cleavage rates. Embryos having marker 3 criteria developed to the blastocysts stage at significantly higher rates than those having marker 1 criteria in case of non-sorted sperm of bulls A, B, C, and X-sorted sperm of bull A (75.9, 87.0, 90.0, and 75.0% v. 59.5, 62.2, 63.6, and 46.3%, respectively). In groups produced from non-sorted sperm of bulls A, B, C, and X-sorted sperm of bull A, blastocyst development rates of embryos with marker 2 criteria (73.7, 75.0, 90.0, and 65.8%, respectively) were higher (P < 0.05) than those of embryos having marker 1 criteria but did not differ significantly from those with marker 3 criteria. Our results reveal that a first cleavage within 28 h after IVF to 2 even blastomeres without fragments or protrusions are potent predictive markers of the developmental competence of bovine embryos to the blastocyst stage regardless of bulls and sperm sorting.Research was partly supported by JSPS KAKENHI (26450388).



2010 ◽  
Vol 22 (1) ◽  
pp. 331
Author(s):  
K. Miyata ◽  
H. Koyama ◽  
C. Lessard ◽  
J. Singh ◽  
O. Dochi

Follicular fluid from small and large bovine follicles contains large amounts of progesterone, and during preovulatory period progesterone concen- tration increase markedly by 18 h after LH surge. Furthermore, cumulus cells express membrane progestin receptor beta (Liu et al. 2008 Steroids 73, 1416-1423). For these reasons, we hypothesized that progesterone supports maturation of preovulatory bovine oocytes to MII stage. The object of this study was to investigate the effect of progesterone supplementation of in vitro maturation medium on competence of bovine oocyte to develop into blas- tocysts in vitro. COCs were collected by the aspiration of 2-6 mm follicles from ovaries within 6 h of slaughter. The COCs were divided into 5 groups: (1) a control group, TCM-199 supplemented with 5% calf serum (CS) as IVM medium, and (2 to 5) progesterone (P4) supplementation groups, TCM- 199 supplemented with 5% CS and 1, 3, 5, and 10 μg mL-1 of P4. Groups of 10 COCs were incubated in 50-μL drops of IVM media at 38.5°C under an atmosphere of 5% CO2 in air for 20 h. The matured COCs were inseminated with 3 × 106 sperm mL-1. After 18 h of gamete co-culture, the pre- sumptive zygotes were cultured in CR1aa media supplemented with 5% CS for 9 days at 38.5°C under an atmosphere of 5% CO2, 5%O2, and 90% N2. Embryonic development was evaluated at 48 h after IVF (total cleavage rates) and on Days 7 to 9 (blastocyst rate). Data was analyzedby chi-square test. The results are presented in Table 1. There were no significant differences in the cleavage rates between treatments. However, the blastocyst formation rate of 5 μg mL-1 P4 supplementation group was significantly higher than that of 10 μg mL-1 P4 supplementation group (P < 0.05). In addition, the blastocyst formation rates of 10 μg mL-1 P4 supplementation group was lower than the other groups. These results suggest that progesterone supple- mentation of in vitro, maturation medium affects the competence of the oocytes to develop into blastocysts in vitro, and 5 μg mL-1 P4 supplementation may be effective in increasing embryo production. Furthermore, 10 μg mL-1 P4 supplementation has negative effect on the oocyte competence. Table 1.Effect of progesterone supplementation on development of IVF bovine embryos



2005 ◽  
Vol 17 (8) ◽  
pp. 751 ◽  
Author(s):  
Mona E. Pedersen ◽  
Øzen Banu Øzdas ◽  
Wenche Farstad ◽  
Aage Tverdal ◽  
Ingrid Olsaker

In this study the synthetic oviduct fluid (SOF) system with bovine oviduct epithelial cell (BOEC) co-culture is compared with an SOF system with common protein supplements. One thousand six hundred bovine embryos were cultured in SOF media supplemented with BOEC, fetal calf serum (FCS) and bovine serum albumin (BSA). Eight different culture groups were assigned according to the different supplementation factors. Developmental competence and the expression levels of five genes, namely glucose transporter-1 (Glut-1), heat shock protein 70 (HSP), connexin43 (Cx43), β-actin (ACTB) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), analysed as mRNA by using reverse transcription–polymerase chain reaction, were measured on bovine embryos cultured for 9 days. Gene expression of these in vitro-produced embryos was compared with the gene expression of in vivo-produced embryos. There was no significant difference found in embryo developmental competence between the Day 9 embryos in BOEC co-culture, FCS and BSA supplements in SOF media. However, differences in gene expression were observed. With respect to gene expression in in vivo and in vitro embryos, BOEC co-culture affected the same genes as did supplementation with FCS and BSA. HSP was the only gene that differed significantly between in vitro and in vivo embryos. When the different in vitro groups were compared, a significant difference between the BOEC co-culture and the FCS supplementation groups due to Glut-1 expression was observed.



2017 ◽  
Vol 29 (1) ◽  
pp. 180
Author(s):  
T. Yamanouchi ◽  
S. Sugimura ◽  
H. Matsuda ◽  
M. Ohtake ◽  
Y. Goto ◽  
...  

Bovine oocytes obtained by ovum-pick-up (OPU) following follicle growth treatment (FGT) have improved quality and competence (Imai et al. 2008 Reprod. Fertil. Dev. 20, 182). However, the effect of the presence of FSH or epidermal growth factor (EGF) like peptide during in vitro maturation (IVM) on the developmental competence of FGT oocytes has not been well known. This study was undertaken to examine the developmental competence of FGT oocytes following IVM in the presence of FSH (recombinant human FSH) or EGF-like peptide (amphiregulin; Areg) and IVF. Japanese Black cows (n = 17) were used as donors. Five days after arbitrary OPU (opu group), follicles ≥8 mm in diameter were aspirated again, a controlled internal drug release (CIDR) was inserted into the vagina, and then pFSH was injected twice a day from the evening of Day 6 to the morning of Day 10 with decreasing doses (total of 20 AU; 4, 4, 3, 3, 2, 2, 1, 1 AU/day). On the evening of Day 8, PGF2α (0.5 mg of cloprostenol) was administered. On Day 11, oocytes were aspirated from follicles with ≥5 mm in diameter of the treated donors by OPU (fgt group). The cumulus-oocyte complexes (COC) were cultured in the absence (opu-cont and fgt-cont groups) or presence of 0.1 IU mL−1 FSH (opu-fsh and fgt-fsh groups) or 100 ng mL−1 Areg (opu-areg and fgt-areg groups) in IVM medium (mTCM199 containing 5 mg mL−1 BSA) for 20 to 22 h (1 COC/5 µL, total of 162–171 COC per group), and then co-cultured with 3 × 106 sperm/mL for 6 h. The presumptive zygotes were continued to culture in mCR1aa supplemented with 5% newborn calf serum for 216 h (1 zygote/5 µL) using micro-well culture dishes (Dai-Nippon-Print). When repeating this opu-fgt session in the same cow, an interval at least for 50 days was kept, and the session was performed 28 times. Statistical analysis was carried out by Mann-Whitney’s U-test (between opu and fgt groups) or Steel-Dwass test after Kruskal-Wallis test (among all groups). The number of follicles ≥5 mm increased in the fgt than opu group (17.8 v. 2.9; P < 0.01). The number of COC collected was not different between the opu and fgt groups (23.1 v. 19.6; P > 0.05). The blastocyst formation rate was higher in the fgt than opu group (36.9 v. 23.1%; P < 0.01). Within 6 groups, the blastocyst formation rate was higher in the fgt-fsh (43.3%; P < 0.01) and fgt-areg (39.5%; P < 0.05) groups than the opu-cont (16.3%) group. The rate in the fgt-fsh group was also higher than that in the opu-fsh group (43.3 v. 18.7%; P < 0.01). These results suggested that FGT improved the developmental competence of bovine oocytes, probably through improving the ability of the COC to react against FSH/Areg.



Zygote ◽  
2012 ◽  
Vol 22 (2) ◽  
pp. 146-157 ◽  
Author(s):  
Daniela Martins Paschoal ◽  
Mateus José Sudano ◽  
Midyan Daroz Guastali ◽  
Rosiára Rosária Dias Maziero ◽  
Letícia Ferrari Crocomo ◽  
...  

SummaryThe objective of this study was to assess the viability and cryotolerance of zebu embryos produced in vitro with or without the addition of fetal calf serum (FCS) and forskolin (F). Embryos produced in vivo were used as a control. Presumptive zygotes were cultured in modified synthetic oviductal fluid supplemented with amino acids (SOFaa), bovine serum albumin (BSA) and with (2.5%) or without (0%) FCS. On day 6 of growth, the embryos from each group were divided into treatments with or without 10 μM F to induce embryonic lipolysis, comprising a total of four experimental groups: 2.5% FCS, 0% FCS, 2.5% + F and 0% + F. For vitrification, embryos were exposed to vitrification solution 1 (5 M EG (ethylene glycol)) for 3 min and then transferred to vitrification solution 2 (7 M EG, 0.5 M galactose solution and 18% (w/v) Ficoll 70) before being introduced to liquid nitrogen. The presence of FCS in the culture medium resulted in the production of embryos with a similar rate of damaged cells compared with in vivo-produced embryos. After vitrification, the 2.5% FCS group had a significantly higher rate of damaged cells when compared with the other groups (P < 0.05). The results of this experiment indicated that the omission of FCS and the addition of forskolin do not have deleterious effect on embryo production rates. In addition, embryos produced in the presence of FCS had greater sensitivity to cryopreservation, but this effect was reversed when forskolin was added to the medium, which improved embryo survival without affecting embryo development and quality after vitrification.



2010 ◽  
Vol 58 (4) ◽  
pp. 465-474 ◽  
Author(s):  
Tamás Somfai ◽  
Yasushi Inaba ◽  
Yoshio Aikawa ◽  
Masaki Ohtake ◽  
Shuji Kobayashi ◽  
...  

The aim of the present study was to optimise the culture conditions for the in vitro production of bovine embryos. The development of in vitro fertilised bovine oocytes in CR1aa supplemented with 5% calf serum and IVD101 culture media were compared using traditional microdrops and Well of the Well (WOW) culture systems either under 5% or 20% oxygen tension. After 7 days of culture, a significantly higher blastocyst formation rate was obtained for embryos cultured in CR1aa medium compared to those cultured in IVD101, irrespective of O 2 tensions and culture systems. The blastocyst formation in IVD101 was suppressed under 20% O 2 compared to 5% O 2 . Despite their similar total cell numbers, higher rates of inner cell mass (ICM) cells were observed in blastocysts developed in IVD101 medium than in those developed in CR1aa, irrespective of O 2 tensions. There was no significant difference in blastocyst formation, total, ICM and trophectoderm (TE) cell numbers between embryos obtained by microdrop and WOW culture systems irrespective of the culture media and O 2 tensions used. In conclusion, CR1aa resulted in higher blastocyst formation rates irrespective of O 2 tension, whereas IVD101 supported blastocyst formation only under low O 2 levels but enhanced the proliferation of ICM cells.



2011 ◽  
Vol 23 (1) ◽  
pp. 173
Author(s):  
M. J. Sudano ◽  
D. M. Paschoal ◽  
T. S. Rascado ◽  
L. C. O. Magalhães ◽  
L. F. Crocomo ◽  
...  

Phenazine ethosulfate (PES) is a metabolic regulator that inhibits fatty acid synthesis and favours the pentose-phosphate pathway. Supplementation of fetal calf serum (FCS) during culture has been correlated with the reduction of quality of in vitro produced bovine embryos (IVPE). The aim of the present study was to evaluate embryo development and apoptosis in blastocysts after the supplementation of PES and FCS in culture medium of IVPE. Oocytes (N = 4320) were matured and fertilized in vitro (Day 0). The zygotes (Bos indicus) were cultured in SOFaa medium with 4 concentrations of FCS (0, 2.5, 5, and 10%) and with the use or not of 0.3 μM PES from Day 4 (after 96 h of embryo culture). Embryo development was evaluated after 7 days of culture. Apoptosis in blastocysts (N = 60–80) was accessed through TUNEL reaction. Embryos (Bos indicus) recovered from superstimulated cows were used as in vivo control (n = 15). Data were analysed by ANOVA followed by LSD using PROC GLIMMIX (SAS; SAS Institute Inc., Cary, NC, USA) means ± SEM. Increasing FCS concentration in the culture media did not change cleavage (86.7 ± 1.7, 82.3 ± 1.6, 86.3 ± 1.4, 87.0 ± 1.5, P > 0.05) and augmented blastocyst production (30.5 ± 2.5a, 41.8 ± 2.4b, 40.5 ± 2.6b, 47.2 ± 2.8b, P < 0.05), respectively, for 0, 2.5, 5, and 10%. Additionally, increasing FCS concentration increased apoptosis in blastocysts (13.8 ± 1.2b, 19.1 ± 1.8b, 20.7 ± 1.9bc, 28.4 ± 2.3c, P < 0.05, respectively, for 0, 2.5, 5, and 10%). The addition of PES from Day 4 in the culture medium did not affect (P > 0.05) cleavage (87.0 ± 1.3 and 84.4 ± 1.3), blastocyst production (42.0 ± 2.8 and 43.0 ± 2.0), and apoptosis in blastocysts (20.7 ± 2.0b and 18.9 ± 2.1b), respectively, for control and PES Day 4 groups. Independent of FCS withdrawal or PES addition to culture medium, the in vivo control group presented the lowest apoptosis rate (6.3 ± 1.1a). Therefore, increasing FCS concentration augmented embryo development and reduced blastocyst quality. However, the addition of 2.5% of FCS in the culture medium increased the embryo development without the reduction of blastocyst quality. Moreover, the PES supplementation from Day 4 did not affect embryo development and blastocyst quality. São Paulo Research Foundation – FAPESP.



2011 ◽  
Vol 23 (1) ◽  
pp. 147 ◽  
Author(s):  
D. M. Paschoal ◽  
M. J. Sudano ◽  
T. S. Rascado ◽  
L. C. O. Magalhães ◽  
L. F. Crocomo ◽  
...  

The high concentration of lipids on embryos reduces their viability after cryopreservation. The use of drugs to modify their metabolism has been used to produce embryos with greater resistance to cryopreservation. The present experiment aimed to induce cytoplasmic lipolysis in in vitro produced (IVP) bovine embryos using forskolin (Sigma-Aldrich, St. Louis), which raises the levels of intracellular cAMP. Nelore cow cumulus–oocyte complexes (COC) were matured in TCM 199 and fertilized with frozen Nelore bull semen. Presumptive zygotes were cultured in SOFaa supplemented with BSA in the presence of 2.5% FCS. Embryos were kept in a humidified atmosphere with 5% CO2, 5% O2, and 90% N2 at 38.5°C. On Day 6, embryos were divided into 2 groups: 2.5% FCS (2.5% FCS without forskolin) and 2.5% FCS + F (2.5% FCS plus 10 μM forskolin). Embryo cleavage was recorded on Day 3 (IVF: D0), and blastocyst production on Day 7. Embryo viability was estimated by the index of total number of cells per embryos observed after the staining with propidium iodite and Hoechst 33342. In vitro produced embryos were compared with embryos obtained in vivo from Nelore cows. Embryos were vitrified using the protocol developed by Campos-Chillòn et al. (2006). After thawing, the re-expansion rate and cell number were again estimated (after 12 h). For statistical analysis, percentage cleaved and percentage blastocyst, percentage re-expansion, and total number of cells were transformed using the arcsine transformation (√y/100) and analysed using ANOVA followed by Tukey’s test. The level of significance adopted was 5%. No statistical differences were observed between IVP embryos concerning cleavage (2.5% FCS: 87.48 ± 9.52 and 2.5% FCS + F: 85.13 ± 7.57) and blastocyst formation rates (2.5% FCS: 46.8 ± 13.28 and 2.5% FCS + F: 46.31 ± 11.39). Also, no differences were detected in total number of cells per embryos (2.5% FCS: 162.4 ± 43.3; 2.5% FCS + F: 147.6 ± 35.3 and in vivo: 143.5 ± 11.5) when IVP and in vivo produced embryos were compared. After vitrification the re-expansion rate was similar between IVP and in vivo produced embryos (2.5% FCS: 75.07 ± 9.81; 2.5% FCS + F: 81.09 ± 10.90 and in vivo: 86.40 ± 18.62). But the total cell number of IVP embryos was significantly lower than the in vivo produced embryos [2.5% FCS: 42.6 ± 17.2a (P < 0.001); 2.5% FCS + F: 59.9 ± 46.2a (P < 0.05) and in vivo: 124.2 ± 12.9b]. If one side the viability cell between IVP and in vivo produced embryos is the same, after vitrification in vivo produced embryos showed greater resistance after the vitrification. The addition of forskolin did not interfere in embryo production or quality, but this drug was not efficient in increasing embryo tolerance after vitrification. FAPESP 07/53505-1.



2019 ◽  
Vol 31 (1) ◽  
pp. 163
Author(s):  
Y. Hasiyada ◽  
H. Matsuda ◽  
Y. Aikawa ◽  
M. Ohtake ◽  
T. Yamanouchi

We have reported monozygotic twin calves that can be produced efficiently by blastomere separation of 2-cell stage embryos and by the use of a commercially provided well-of-the-well culture dish (Hashiyada 2017 J. Reprod. Dev.). The present study was conducted to evaluate the effect of a culture supplement, l-ascorbic acid 2-phosphate (AA-2P), a sustained antioxidant substance that reduces reactive oxygen species. Embryos were produced using oocytes from ovaries collected at an abattoir by in vitro maturation, IVF, and in vitro culture (IVC). TCM199 supplemented with 5% calf serum, Brackett-Oliphant solution supplemented with 10mg mL−1 BSA, and CR1aa containing 5% calf serum were used for each culture step. Two-cell stage embryos were obtained 24 to 27h post-insemination (hpi). Zonae pellucidae were removed by exposure to 0.25% pronase. Then, embryos were separated into each blastomere by gentle pipetting in IVC medium. Each blastomere was introduced into a single conical micro-well of 25 wells, each having a diameter and depth of ~287 and 168µm (Dai Nippon Printing, Tokyo, Japan). Culture of blastomeres in wells was performed covered with a droplet of 2.5 µL/well IVC medium supplemented with 0 (n=212), 250 (n=214), 500 (n=206), and 750 µM (n=204) of AA-2P. The blastocyst formation rate at Day 8 after IVF, the quality of blastocysts assessed by morphological observation, and the cell numbers were compared among each concentration of AA-2P. In addition, the developmental speed to the blastocyst stage was analysed using time-lapse cinematography for 0 and 500 µM of AA-2P (n=40, respectively). Statistical analysis was performed using Fisher’s exact test and ANOVA. The blastocyst formation rate (32-40%), the total cell number (108-114), and inner cell mass cell number (26-28) did not differ among groups. The time to reach the 4-cell stage was significantly shorter in media supplemented with 0 µM (43 hpi) than with 500 µM (52 hpi); however, the time to reach the blastocyst stage did not differ (150 and 155 hpi, respectively). Regarding the proportion of quality grade 1 to 3 blastocysts and the developmental speed to the blastocyst stage, high-quality grade 1 embryos were significantly faster than those of middle and low-quality grade 2 and 3 ones in 0 (145 v. 154 hpi; P&lt;0.05) and 500 µM (150v. 158 hpi; P&lt;0.05) supplemented medium. In this experiment, no effect of AA-2P was observed for the culture of isolated blastomeres from 2-cell stage embryos, although it was suggested that blastomeres with high developmental competence reach the blastocyst stage faster, which might reflect the quality of the embryos.



2012 ◽  
Vol 24 (1) ◽  
pp. 194
Author(s):  
S. Miyashita ◽  
Y. Inaba ◽  
T. Somfai ◽  
M. Geshi ◽  
T. Nagai ◽  
...  

The objective of this study was to investigate the effects of the supplementation of a lipid metabolism inducer, L-carnitine (LC) and a membrane stabilizer, linoleic acid albumin (LAA), on the developmental competence and cryosurvival of bovine in vitro-matured/in vitro-fertilized embryos in in vitro culture medium. Cumulus–oocyte complexes collected from the ovaries of slaughtered cattle were matured for 20 h in TCM-199 supplemented with 5% calf serum (CS) and 0.02 AU mL–1 of FSH at 38.5°C in an atmosphere of 5% CO2 in air. After IVF (Day 0), presumptive zygotes were cultured in CRlaa containing 5% CS at 38.5°C in an atmosphere of 5% CO2, 5% O2 and 90% N2 for 9 days. The culture medium was supplemented with 0.6 mg mL–1 of LC (LC group; n = 180) or with 0.25 mg mL–1 of LAA (LAA group; n = 180) or with both LC and LAA (LC + LAA group; n = 180) or without LC and LAA (control; n = 178). The cleavage rates were recorded on Day 2 and the blastocyst formation rates were recorded on Day 7 to 9. Expanded blastocysts harvested on Day 7 and 8 (LAA group: n = 31; LC group: n = 29; LC + LAA group: n = 25; control group: n = 33) were used for freezing in modified PBS supplemented with 1.5 M ethylene glycol, 0.1 M sucrose and 20% CS. After thawing, they were cultured in TCM-199 supplemented with 20% FBS and 0.1 mM β-mercaptoethanol at 38.5°C under 5% CO2 in air for 72 h. The rates of re-expansion, hatching and formation of hatched blastocysts were determined at 24, 48 and 72 h after thawing, respectively. The rates of cleavage and blastocyst formation were expressed as mean ± s.e.m. and analysed by ANOVA. The post-thaw survival rates of frozen embryos were analysed by chi-square test. The cleavage rate in the control group (69.1 ± 2.5%) was significantly lower than that in the LAA (81.8 ± 3.8%) and LC + LAA groups (77.9 ± 1.4%) but did not differ from that in the LC group (73.8 ± 2.4%). The blastocyst formation rate in the control group (21.7 ± 2.8%) was significantly lower (P < 0.05) than those in the LAA and LC + LAA groups (33.5 ± 2.8% and 31.4 ± 2.4%, respectively), but it did not differ significantly from that of the LC group (32.1 ± 3.3%) despite a strong tendency (P = 0.06). There were no significant differences among the control, LC, LAA and the LC + LAA groups in post-thaw re-expansion rates (66.7, 75.9, 67.7 and 76.0%, respectively), hatching rates (48.5, 69.0, 58.1 and 64.0%, respectively) and rates of formation of hatched blastocysts (51.5, 62.1, 61.3 and 64.0%, respectively). These results indicate that the addition of LC and LAA to the medium for in vitro culture of in vitro-matured/in vitro-fertilized bovine embryos improved their ability to develop to the blastocyst stage; however, the effects on the freezing tolerance were not verified.



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