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 ◽  
...  

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.

2014 ◽  
Vol 26 (1) ◽  
pp. 123
Author(s):  
Y. Liu ◽  
A. Lucas-Hahn ◽  
B. Petersen ◽  
R. Li ◽  
P. Hassel ◽  
...  

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


2007 ◽  
Vol 19 (1) ◽  
pp. 147
Author(s):  
H. T. Lee ◽  
J. M. Jang ◽  
S. H. Lee ◽  
M. K. Gupta

In vitro production of cloned porcine embryos by somatic cell nuclear transfer (SCNT) has become routine in several laboratories but the efficiency and quality of the resultant blastocysts remains sub-optimal. Cloned porcine blastocysts show low cell number, high fragmentation rate, and apoptosis which results in lower pregnancy rates upon embryo transfer. Earlier we reported that supplementation of culture media with amino acids benefit pre-implantation embryo development of in vivo- as well as in vitro-fertilized porcine embryos (Koo et al. 1997 Theriogenology 48, 791–802). This study evaluated how exogenous amino acids could affect pre-implantation development and quality of cloned or parthenogenetic porcine embryos. The effects of commercially available amino acids, referred to as Eagle&apos;s non-essential amino acids (NEAA), added or not added (control) to NCSU23 medium containing fatty acid-free BSA were studied. Oocytes recovered from abattoir-derived prepubertal porcine ovaries were matured in vitro and parthenogenetically activated (PA) or nuclear-transferred with fetal fibroblasts (SCNT), as described earlier (Uhm et al. 2000 Mol. Reprod. Dev. 57, 331–337). At 168 h post-activation, blastocysts were harvested for assessment of embryo quality by TUNEL labeling, Hoechst 33342 staining, and gene expression analysis. Results showed that, in the PA group, the cleavage rate was not affected by the supplementation of NEAA. However, the blastocyst rate was significantly improved when NEAA was present in the medium compared to that of the control group (38.9 &plusmn; 0.3 vs. 27.5 &plusmn; 0.3&percnt;, respectively) throughout the culture period. The supplementation during the pre-compaction period alone gave better results than during the post-compaction period alone (59.5 &plusmn; 0.9 vs. 33.4 &plusmn; 0.3&percnt;, respectively). In the SCNT group, however, both cleavage (73.6 &plusmn; 0.2 vs. 64.2 &plusmn; 0.4&percnt;) and blastocyst rate (18.7 &plusmn; 0.2 vs. 13.8 &plusmn; 0.3&percnt;) were improved by NEAA supplementation. Furthermore, these blastocysts had higher hatching ability (30.0 &plusmn; 1.8 vs. 14.6 &plusmn; 4.9&percnt;) than those of control group (P &lt; 0.05). Supplementation of NEAA also increased the mean nuclei number of PA-derived (76.1 &plusmn; 4.9 vs. 66.5 &plusmn; 3.3) as well as SCNT-derived (43.1 &plusmn; 2.6 vs. 31.8 &plusmn; 1.9) blastocysts and reduced the time during which blastocysts formed. TUNEL assay revealed that incidence of nuclear fragmentation and apotosis was reduced by NEAA. Real-time qRT-PCR for Bax and Bcl-XL transcripts revealed that the relative abundance of Bax was reduced while that of Bcl-XL was increased. These effects were more pronounced when NEAA was present during the pre-compaction period alone. Thus, our data suggest that NEAA improves the yield and quality of cloned porcine embryos by enhancing blastocyst expansion and positively modulating the total cell number and apoptosis. These data may have implications for understanding the nutritional needs of cloned porcine embryos produced in vitro and for optimizing the composition of culture media to support their development. This work was supported by the Research Project on the Production of Bio-Organs (No. 200503030201), Ministry of Agriculture and Forestry, Republic of Korea.


2018 ◽  
Vol 30 (1) ◽  
pp. 175
Author(s):  
G. A. Kim ◽  
J.-X. Jin ◽  
S. Lee ◽  
A. Taweechaipaisankul ◽  
B. C. Lee

Melatonin and its metabolites are powerful antioxidants and free radical scavengers. Because porcine embryos are vulnerable to oxidative stress in vitro, the addition of various protective chemicals to the culture medium, including melatonin, has been explored. The aim of this study was to investigate the effect of melatonin on in vitro developmental competence of porcine parthenogenetically activated (PA) embryos. Immature cumulus–oocyte complexes (COC) were collected and cultured in medium comprising TCM-199 supplemented with 10 ng mL−1 epidermal growth factor, 0.57 mM cysteine, 0.91 mM sodium pyruvate, 5 μL mL−1 insulin, transferrin selenium solution 100×, 10% porcine follicular fluid, 10 IU mL−1 eCG, and 10 IU mL−1 hCG for 44 h. Then, COC were denuded and PA with electrical stimulation, and PA embryos were cultured in porcine zygote medium 5 (PZM-5) supplemented with melatonin at increased concentrations (10−9, 10−7, 10−5 M) at 39°C in a humidified atmosphere of 5% O2, 5% CO2, and 90% N2 for 7 days. Subsequent embryo development, including cleavage rate, blastocyst rate, and blastocyst cell numbers, was compared between groups (mean no. of embryos; control, 27.14; 10−9 M, 28.86; 10−7 M, 27.71; 10−5 M, 26.43). The experiments were repeated 7 times for each treatment group. Statistical analyses of all data were performed using one-way ANOVA with Dunn’s multiple comparison test. Results are expressed as the mean ± SEM and all differences were considered significant at P < 0.05. No apparent effect on cleavage rate of melatonin treatment of various concentrations was noted. Blastocyst cell number did not show any significant difference between groups. However, the potential of PA oocytes to develop into blastocysts was significantly higher in the group supplemented with 10−9 M melatonin compared with the control group (35.44 ± 3.84 v. 24.71 ± 1.59) and other melatonin treated groups (10−5 M, 21.35 ± 2.82; 10−7 M, 24.01 ± 2.31; P < 0.05). These indicated that treatment with 10−9 M melatonin in embryo culture might reduce the oxidative stress properly compared with other concentrations, which results in improvement of blastocyst rate formation. In conclusion, treatment with 10−9 M melatonin positively promoted the blastocyst formation rate of porcine PA embryos with no beneficial effects on their blastocyst cell numbers or cleavage rate. This study was supported by the National Research Foundation (#2015R1C1A2A01054373; 2016M3A9B6903410), Research Institute for Veterinary Science and the BK21 PLUS Program.


Zygote ◽  
2016 ◽  
Vol 24 (6) ◽  
pp. 890-899 ◽  
Author(s):  
A.L.S. Guimarães ◽  
S.A. Pereira ◽  
M. N. Diógenes ◽  
M.A.N. Dode

SummaryThe aim of this study was to evaluate the effect of adding a combination of insulin, transferrin and selenium (ITS) and l-ascorbic acid (AA) during in vitro maturation (IVM) and in vitro culture (IVC) on in vitro embryo production. To verify the effect of the supplements, cleavage and blastocyst rates, embryo size and total cell number were performed. Embryonic development data, embryo size categorization and kinetics of maturation were analyzed by chi-squared test, while the total cell number was analyzed by a Kruskal–Wallis test (P < 0.05). When ITS was present during IVM, IVC or the entire culture, all treatments had a cleavage and blastocyst rates and embryo quality, similar to those of the control group (P < 0.05). Supplementation of IVM medium with ITS and AA for 12 h or 24 h showed that the last 12 h increased embryo production (51.6%; n = 220) on D7 compared with the control (39.5%; n = 213). However, no improvement was observed in blastocyst rate when less competent oocytes, obtained from 1–3 mm follicles, were exposed to ITS + AA for the last 12 h of IVM, with a blastocyst rate of 14.9% (n = 47) compared with 61.0% (n = 141) in the control group. The results suggest that the addition of ITS alone did not affect embryo production; however, when combined with AA in the last 12 h of maturation, there was improvement in the quantity and quality of embryos produced. Furthermore, the use of ITS and AA during IVM did not improve the competence of oocytes obtained from small follicles.


2019 ◽  
Author(s):  
Mahboobeh Rasoulzadeh Bidgoli ◽  
robab latifnejad roudsari ◽  
ali montazeri

Abstract Background: Infertility is an emotional tension which influences the whole aspects of relationships in infertile couples. A main objective of infertility treatments is elevation of pregnancy rate. The present study aimed to examine the effect of collaborative counseling on pregnancy rate in infertile women, undergoing in vitro fertilization in Mashhad, Iran. Methods: In this clinical trial, 60 women with primary infertility were selected from an infertility research center and were randomly allocated into intervention (n=29) and control (n=31) groups. The intervention group received individual counseling, based on the collaborative reproductive healthcare model with collaboration of a midwife, a gynecologist and a clinical psychologist in five sessions during a two-month period. The control group received routine care. Positive pregnancy test was considered as a criterion of treatment success at the end of the study. Data were analyzed using statistical tests including independent samples t-test. Results: There was no significant difference in pregnancy rate between intervention and control groups (P = 0.298). Also, there were no significant differences in follicle and embryo numbers between two groups. However, a significant difference was observed between two groups in terms of oocyte numbers where the intervention group had more oocyte (P = 0.014). Conclusion: Overall the findings indicated that the collaborative infertility counseling did not improve treatment success in infertile women undergoing in vitro fertilization


2017 ◽  
Vol 20 (1) ◽  
pp. 19-24 ◽  
Author(s):  
S. Prochowska ◽  
W. Niżański

Abstract The aim of this study was to provide a comparative analysis of in vitro fertilizing potential of frozen-thawed urethral and epididymal feline spermatozoa. Both types of semen were collected from 7 cats and cryopreserved in liquid nitrogen. To perform in vitro fertilization, both urethral and epididymal samples from the same individual were thawed and spermatozoa were co-incubated with in vitro matured cat oocytes. Obtained embryos were cultured in vitro for 7 days in a commercial medium. Cleavage rate, morula rate and blastocyst rate were calculated. Experiment was run in 10 replicates. The examined parameters showed no significant differences between urethral and epididymal spermatozoa (p>0.05). Cleavage rate and embryo’s development were highly variable between replicates, even for the different sperm samples collected from one individual. There was no significant correlation between fertilizing capacity of two types of spermatozoa collected from the same male. In this study we confirmed that cryopreserved urethral spermatozoa have equally good fertilizing potential as epididymal ones, and both can be successfully used for in vitro fertilization in cats with the use of commercial medium.


2006 ◽  
Vol 18 (2) ◽  
pp. 264
Author(s):  
J. Hyslop ◽  
Z. Machaty

Apoptosis or programmed cell death is a process during which cells die in a controlled fashion in response to a variety of stimuli. Apoptosis has been demonstrated to occur during pre-implantation development both in vivo and in vitro and it is believed to contribute to early embryonic loss. It is also believed that parthenogenetic embryos generally have a lower developmental potential compared to those derived from fertilization. In the present study we investigated the rate of apoptosis in parthenogenetic pig embryos produced by activating oocytes through various methods. Pig oocytes were collected from slaughterhouse ovaries and matured in vitro. Parthenogenetic development was induced by three different methods. In Group 1, oocytes were activated by two consecutive electrical pulses. In Group 2, oocytes were electroporated and then incubated for 4 h in 5 mM butyrolactone I, a specific inhibitor of cyclin dependent kinases. In Group 3, electroporated oocytes were incubated for 5 h in cycloheximide, a protein synthesis inhibitor. Activated oocytes were cultured for 7 days in NCSU-23 medium. At the end of the culture period the embryos were fixed in 4% paraformaldehyde and permeabilized in 0.1% Triton X-100 with sodium citrate. They were then incubated in a TUNEL reaction medium that specifically identifies apoptotic nuclei by labeling fragmented DNA with a fluorochrome. Blastocysts produced by in vitro fertilization and DNase I-treated embryos were used as controls. The proportions of apoptotic cells were compared using ANOVA. Forty-three blastocysts were analyzed for apoptotic activity in the electroporation group. These embryos had a blastocyst rate of 33.6 ± 8.7%, total cell number of 31.9 ± 13.2, and an average of 2.7 ± 2.2 apoptotic cells per embryo; the rate of apoptosis was 9.1 ± 7.1%. Twenty-eight blastocysts were used for the TUNEL reaction in the group where activation was induced with the combined treatment of electroporation and butyrolactone (Group 2). On average, the blastocyst rate was 54.5 ± 6.4% and blastocysts contained 27.4 ± 9.6 cells of which 2.8 ± 3.9 were apoptotic; the percentage of apoptosis for this group was 10.0 ± 12.1%. In the cycloheximide treated group (Group 3), the onset of apoptosis was investigated using 29 blastocysts. The blastocyst rate was 38.2 ± 15.9% with an average total cell number of 27.2 ± 11.4%. The TUNEL assay revealed that the mean number of apoptotic cells per embryo in these blastocysts was 2.1 ± 1.5, representing 9.0 ± 7.6% apoptotic cells. The blastocysts (n = 14) produced by in vitro fertilization had a blastocyst rate of 18.0 ± 5.1% and 29.9 ± 12.0 cells; 9.2 ± 8.1% of these cells (2.6 ± 2.2 cells per embryo) showed signs of apoptosis. All nuclei in the DNase I-treated embryos showed positive signals following the TUNEL reaction. The results confirm previous findings that apoptosis occurs in blastocyst stage embryos. There was no difference in the percentage of apoptotic cells between embryos whose development was triggered by different oocyte activation methods; the rate of apoptosis in parthenogenetic blastocysts was similar to that in blastocysts produced by in vitro fertilization.


2008 ◽  
Vol 20 (1) ◽  
pp. 118
Author(s):  
B. Gajda ◽  
Z. Smorag ◽  
M. Bryla

It is possible to improve the success of cryopreservation of in vitro-produced bovine embryos by modifying the embryos with the metabolic regulator phenazine ethosulfate (PES) (Seidel 2006 Theriogenology 65, 228–235). The PES treatment increased glucose matabolism, tended to increase the pentose phosphate pathway flux of glucose, and clearly reduced accumulation of lipids in cultured bovine embryos (De La Torre-Sanchez et al. 2006 Reprod. Fertil. Dev. 18, 597–607). It is known that porcine embryos have a considerably high content of lipids, and the success rates of their cryopreservation appear to be highly correlated with cytoplasmic lipid content. In our preliminary study, we observed that supplementation of NCSU-23 medium with PES has a positive effect on efficiency of pig blastocysts of good quality (Gajda et al.. 2007 Acta Biochim. Pol. 54(Suppl 1), 52 abst). In the present study, the effects of PES on pig blastocyst development, apoptosis, and survival after vitrification were investigated. In Exp. 1, porcine zygotes obtained from superovulated gilts were cultured in NCSU-23 medium supplemented with 0 (control), 0.025, 0.05, or 0.075 µm PES. The culture was performed at 39�C, with 5% CO2 in air, for 96–120 h. Embryo quality criteria were developmental competence (cleavage, morula stage, and blastocyst stage), cell number per blastocyst, and the degree of apoptosis as assessed by TUNEL staining. In Exp. 2, expanded blastocysts cultured with 0.025 µm PES were vitrified in a ethylene glycol and dimethyl sulfoxide mixture using open pulled straw (OPS) technology (Vajta et al. 1997 Acta Vet. Scand. 38, 349–352). After thawing, the blastocysts were cultured in vitro for re-expansion or transferred to synchronized recipients. Data were analyzed by chi-square test. There was a difference between the 0.025 µm PES-treated and the control group in percentage of cleaved embryos (99.0 and 91.4%, respectively; P < 0.05), between all experimental groups and control in percentage of morula stage (90.7, 87.8, 83.8, and 80.0%, respectively), and between 0.025 and 0.05 µm PES-treated and control in percentage of blastocyst rates (70.0, 75.5, and 65.7%, respectively). The number of cells and percentage of TUNEL-positive nuclei per blastocyst were lower in the PES-treated than in the control group. The survival rate of blastocysts after vitrification and thawing was enhanced in the presence of PES compared to that in the PES-free group (45.2 and 38.9%, respectively; P < 0.05). After transfer of 56 expanded blastocysts cultured with PES and vitrified into 3 recipients, two gilts were confirmed pregnant at 35 days of gestation. In conclusion, a higher blastocyst percentage with a low incidence of apoptosis was obtained in the presence of PES compared to control. These blastocysts also had an increased ability to survive cryopreservation.


2016 ◽  
Vol 28 (2) ◽  
pp. 209
Author(s):  
M. Nkadimeng ◽  
E. van Marle-Koster ◽  
K. P. M. Lekola ◽  
M. L. Mphaphathi ◽  
M. M. Seshoka ◽  
...  

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.


2002 ◽  
Vol 14 (5) ◽  
pp. 291 ◽  
Author(s):  
N. W. Kurniani Karja ◽  
Takeshige Otoi ◽  
Masako Murakami ◽  
Minori Yuge ◽  
Mokhamad Fahrudin ◽  
...  

The effects of protein supplementation in culture medium on development to the hatching and hatched blastocyst stages of cat in vitro-fertilized embryos were investigated. In the first experiment, presumptive zygotes derived from in vitro maturation and in vitro fertilization (IVF) were cultured in modified Earle's balanced salt solution (MK-1) supplemented with 0.4% bovine serum albumin (BSA) or 5% fetal bovine serum (FBS) for 9 days. There were no significant differences between the BSA and FBS groups with respect to the proportion of cleavage and development to the morula and blastocyst stages of zygotes. However, the presence of FBS in the medium enhanced development to the hatching blastocyst stage of zygotes compared with the BSA group (31.4% v. 7.8%). Moreover, 2.9% of zygotes cultured with FBS developed to the hatched blastocyst stage. The mean cell number of blastocysts derived from zygotes cultured with FBS was significantly higher (P&lt;0.01) than that from zygotes cultured with BSA (136.6 v.101.5). In the second experiment, embryos at the morula or blastocyst stage, which were produced by culturing in MK-1 supplemented with 0.4% BSA after IVF, were subsequently cultured in MK-1 with 0.4% BSA or 5% FBS. Significantly more morulae developed to the blastocyst (P&lt;0.05) and hatching blastocyst stages (P&lt;0.01) in the FBS group than in the BSA group (71.5% and 53.6% v. 44.9% and 6.0%, respectively). Although none of the morulae cultured with BSA developed to the hatched blastocyst stage, 11.5% of morulae cultured with FBS developed to the hatched blastocyst stage. Moreover, the proportion of development to the hatching blastocyst stage of blastocysts was significantly higher (P&lt;0.01) in the FBS group than in the BSA group (68.7% v. 9.8%). None of the blastocysts cultured with BSA developed to the hatched blastocyst stage, whereas 7.3% of blastocysts cultured with FBS developed to the hatched blastocyst stage. The results of the present study indicate that supplementation with FBS at different stages of early embryo development promotes development to the hatching and hatched blastocyst stages of cat IVF embryos.


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