scholarly journals 240 GESTATION LENGTH AND BIRTH WEIGHT OF IN VITRO PRODUCED EMBRYOS FROM ZEBU DAIRY CATTLE

2005 ◽  
Vol 17 (2) ◽  
pp. 270 ◽  
Author(s):  
L.S.A. Camargo ◽  
J.H.M. Viana ◽  
A.A. Ramos ◽  
W.F. de Sa ◽  
A.M. Ferreira ◽  
...  

Gir cattle are a popular zebu dairy breed in tropical and subtropical regions because of their tolerance of heat stress and resistance to tick-borne disease. The use of in vitro embryo production (IVP) technology may help accelerate genetic improvement of this breed. However, in general, IVP systems have been implicated in the production of large offspring and a greater proportion of male calves. Natural breeding results in newborn Gir calves weighing around 25 kg despite the fact that dams may weigh over 500 kg. It is unknown whether in vitro-produced Gir embryos also result in large offspring. The aim of this work was to evaluate the effect of in vitro embryo production on gestation length, birth weight, and sex ratio in Gir cattle. COCs were harvested by oocyte pickup from mature non-lactating Gir cows and in vitro-matured in TCM 199 medium (Gibco, Sao Paulo, Brazil) with 10% inactivated estrous cow serum for 24 h under 5% CO2 at 38.5°C in air. Gir spermatozoa were obtained through the swim-up method and co-incubated with oocytes in Fert-TALP media (Parrish JJ et al. 1988 Biol. Reprod. 38, 1171–1180) with 10 μg/mL heparin (Sigma, Sao Paulo, Brazil) and 6 mg/mL fatty acid-free bovine albumin (Sigma) for 18 h in 5% CO2 at 38.5°C in air. Presumptive zygotes were co-cultured with their own cumulus cells in CR2aa medium (Wilkinson RF et al. 1996 Theriogenology 45, 41–49) with 10% fetal calf serum in humid atmosphere of 5% CO2 at 38.5°C in air. Fresh Day 7 blastocysts were transferred to synchronized B. indicus × B. taurus crossbred recipients. Data of gestation length, birth weight, and gender ratio from 26 IVP calves (IVP group) were recorded and compared to data obtained from Gir calves produced by artificial insemination or natural mating (n = 24; control group) using ANOVA or chi-square analysis. There was no difference (P > 0.05) in gestation length between pregnancies of the IVP and control groups (mean ± SEM, 285.4 ± 1.5 vs. 284.4 ± 1.1 days, respectively). IVP and control calves showed similar (P > 0.05) weight at calving (29.6 ± 0.9 vs. 26.9 ± 1.2 kg for IVP and control male calves, and 27.0 ± 2.5 vs. 25.2 ± 0.5 kg for IVP and control female calves, respectively). The percentage of male calves was greater (P < 0.05) in the IVP group than in the control group (76.9% vs. 43.4%, respectively). IVP calves did not show abnormalities associated with Large Offspring Syndrome, such as breathing difficulty and perinatal death. These data suggest that in vitro production may affect the development of Gir embryos, biasing the sex ratio in a manner similar to previously reported for in vitro-produced embryos from Bos taurus breeds. This work was supported by FAPEMIG and CNPq.

2008 ◽  
Vol 20 (1) ◽  
pp. 185
Author(s):  
E. Mullaart ◽  
B. Landman ◽  
J. S. Merton

Animals derived by ovum pickup-in vitro production (OPU-IVP) have a higher birth weight compared with animals derived by AI (Wagtendonk et al. 2000 Theriogenology 53, 575–597). It has been suggested that this higher birth weight is the result of epigenetic changes such as aberrant methylation and gene expression pattern, which are caused by the presence of serum in the culture medium (Wrenzycki et al. 2004 Anim. Reprod. Sci. 82–83, 593–603). The present study aimed to investigate whether the higher birth weight, possibly caused by epigenetic changes, is a permanent characteristic that is transmitted to the offspring. We therefore monitored the birth weight of calves born after insemination of OPU-IVP-derived animals. Ovum pickup-IVP was performed according to routine procedures. Immature COC were recovered by OPU. The COC were matured in vitro in TCM-199 supplemented with fetal calf serum (FCS)/LH/FSH. Subsequently, matured oocytes were fertilized with frozen–thawed gradient-separated semen and further cultured for 7 days in TCM-199/10% FCS on a BRL monolayer (CoCul group) or in SOFaaBSA (SOF group). First-generation OPU-IVP animals were produced from oocytes collected by OPU of AI-derived animals. The second generation was produced by inseminating OPU-IVP animals. Calves generated by inseminating AI animals were used as a control group. Birth weights of control AI, first-generation, and second-generation calves were analyzed by using restricted maximum likelihood (Genstat 9.1). Model Birth Weight: *Fixed: Parity Recipient + Sex + Gestation Length + Year + Embryo Type (AI, first, or second generation) + Culture System (CoCul or SOF). *Random: Sire + Barn. The results (Table 1) clearly show that the first-generation (OPU-IVP) calves had, on average, a 3.4-kg greater birth weight than the AI calves. The second-generation calves, however, had approximately the same birth weight as the calves in the AI control group. Our results indicated that the high birth weight of OPU-IVP-derived calves is not a permanent characteristic that is transmitted to their offspring. Previous studies have demonstrated that the fertility of OPU-IVP-derived animals is in the normal range (Wagtendonk et al. 2000 Theriogenology 53, 575–597). Table 1. Birth weight (least squares means ± SE) of AI calves (control), first generation OPU-IVP-derived calves, and second generation AI derived calves from OPU-IVP mothers


2011 ◽  
Vol 23 (1) ◽  
pp. 255 ◽  
Author(s):  
A. C. Oliveira ◽  
M. C. C. Mattos ◽  
M. R. Bastos ◽  
J. R. S. Gonçalves ◽  
L. H. Lunardi ◽  
...  

The objective of this study was to evaluate the use of pLH in replacement of eCG on the last day of P-36 superstimulatory treatment in Nellore donors. Recent studies demonstrated improvement in embryo production when the last 2 doses of FSH were replaced by eCG. However, consecutive use of eCG in bovine superstimulatory protocols may induce antibody against eCG, decreasing embryo production. Twenty-five Nellore cows were randomly allocated in 4 groups: P-36 (control), P-36/eCG, P-36/LH2, and P-36/LH4. All animals underwent 4 treatments in a cross-over design. Donors received an intravaginal device containing 1.0 g of progesterone (IVD, Primer®, Tecnopec, Sao Paulo, Brazil) and oestradiol benzoate (2.0 mg, IM; Estrogin®, Farmavet, Sao Paulo, Brazil) at a random stage of the oestrous cycle (D0). Cows from the control group were superestimulated with decreasing doses of pFSH (133 mg, IM; Folltropin-V®, Bioniche, Ontario, Canada; D5-8). In the P-36/eCG group, the last 2 doses of pFSH were replaced by 2 doses of eCG (200 IU each dose, IM; Folligon®, Intervet, Boxmeer, the Netherlands). In the P-36/LH2 and P-36/LH4 groups, the last 2 doses of pFSH were replaced by 2 doses of 1 and 2 mg of pLH, respectively (IM; Lutropin®, Bioniche). All animals were treated with prostaglandin F2α (150 μg d-cloprostenol, IM; Prolise®, Tecnopec) on D7, and the IVD was removed 36 h after. Ovulation was induced with 12.5 mg of pLH (IM) on D9, and all animals received fixed-time artificial insemination 12 and 24 h after pLH. Embryo flushing was performed on D16. Data were analysed by ANOVA (Proc Mixed, SAS). There was a significant difference in the number of corpus luteum in the eCG group (19.2 ± 2.4) when compared with the LH2 (12.7 ± 2.0) and LH4 groups (12.3 ± 1.5; P < 0.05). In addition, there was a tendency of lower ovulation rate in the LH2 group as compared with the eCG group (50.6 and 67.8%, respectively; P = 0.06). However, there was no difference in viable embryo yield among groups P-36 (3.3 ± 0.7), P-36/eCG (4.5 ± 0.5), P-36/LH2 (3.7 ± 0.8), and P-36/LH4 (4.2 ± 1.0); P > 0.05. In conclusion, eCG can be replaced by pLH (4.0 mg), in the last day of P-36 protocol, without affecting the production of viable embryos in Nellore cows. The authors acknowledge FAPESP (Sao Paulo, Brazil) for funding and fellowships for A. C. S. Oliveira, M. C. C. Mattos, and M. R. Bastos.


2019 ◽  
Vol 31 (1) ◽  
pp. 192
Author(s):  
M. L. Zwiefelhofer ◽  
E. M. Zwiefelhofer ◽  
S. X. Yang ◽  
S. Maeda ◽  
J. Singh ◽  
...  

The study was done to determine whether minimal handling protocols for ovarian synchronization and ovarian superstimulation may be used to increase in vitro embryo production in bison. Ultrasound-guided cumulus-oocyte complex (COC) collection was done in a group of bison (n=23; random start) during the anovulatory season to synchronize new follicular wave emergence. The COC were classified morphologically (compact-good and -regular, expanded, denuded, degenerate) but not processed further. At the time of COC collection (Day 0), bison were assigned randomly to 3 groups and given 5mL of saline IM (non-superstimulated controls; n=11), 10 Armour units of pFSH (Antrin R10, Kyoritsu Seiyaku Corp., Tokyo, Japan) in 5mL of saline IM once per day from Day 0 to 2 (regular FSH; n=5), or 30 armour units of a sustained-release form of pFSH (Antrin R10Al, Kyoritsu Seiyaku Corp.) in 5mL of saline SC on Day 0 (long-acting FSH; n=7). On Day 4, a second COC collection was performed. Only compact COC were processed. The COC were matured in vitro for 25 to 28h at 38.8°C, fertilized (2×106 sperm mL−1) and co-incubated at 38.8°C in 5% CO2 for 18h. Presumptive zygotes were denuded and cultured at 38.8°C in 5% O2, 5% CO2 and 90% N2. Nominal data were compared by t-test and analysis of variance. Binomial data were compared among groups by chi-squared. There was no difference between the first (random) COC collection (n=23) and second collection (n=11 non-superstimulated controls) in the total number of follicles detected, but the distribution among size categories (3-4, 4-8, and &gt;8mm) differed, i.e. fewer in the 3 to 4mm category at the time of the second COC collection (12.2±1.0v. 8.1±1.4; P&lt;0.05). In the nonstimulated control group, there were no differences between the first and second COC collections in the number of follicles aspirated (12.7±1.0v. 10.4±1.5), number of COC collected (7.7±0.9v. 5.3±1.3), or in the categorical distribution of COC. At the second COC collection, the number of follicles in the &gt;8mm category was greater in the regular FSH group than in the control or long-acting FSH groups (2.8±0.5v. 1.1±0.3, and 1.9±0.4, respectively; P&lt;0.05), but no differences were detected in the number of follicles aspirated, COC collected, or in the categorical distribution of COC. The cleavage rate (of total oocytes submitted to in vitro maturation), recorded 2 days after IVF, was higher in the control group than in either the regular FSH or long-acting FSH groups [25/35 (71.4%), 7/28 (25.0%), 8/35 (22.8%); P&lt;0.0001]. The freezable embryo production rate, recorded 7 days after IVF, was greater in the control group than in the regular FSH or long-acting FSH groups [19/35 (54.3%), 5/28 (17.9%), 5/35 (14.3%); P&lt;0.01]. In conclusion, minimal-handling interventions used in the present study to increase embryo production in bison were not effective, likely as a result of the timing, frequency, and duration of superstimulation. A random start resulted in greater COC collection than collection 4 days after ovarian synchronization, and embryo production rates were greater in non-superstimulated bison. This work was supported by Parks Canada and Saskatchewan ADF. Antrin products donated by Kyoritsu Seiyaku Corp., Japan.


2016 ◽  
Vol 19 (10) ◽  
pp. 1091-1095
Author(s):  
Camila Louise Ackermann ◽  
Eduardo Trevisol ◽  
Leticia Ferrari Crocomo ◽  
Tatiana da Silva Rascado ◽  
Rodrigo Volpato ◽  
...  

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


2016 ◽  
Vol 28 (2) ◽  
pp. 248 ◽  
Author(s):  
L. Ferré ◽  
Y. Bogliotti ◽  
J. Chitwood ◽  
M. Kjelland ◽  
P. Ross

Transvaginal ultrasound needle-guided ovum pick-up (OPU) and in vitro embryo production (IVP) offer a reliable alternative to conventional embryo transfer to produce offspring. The success of OPU/IVP greatly depends on the number and quality of retrieved oocytes. The aim of this study was to compare OPU/IVP performance from stimulated Holstein cows. Holstein (Bos taurus) >8-year-old pluriparous open dry cows (n = 28) were used for OPU as oocyte donors. Follicular waves in all groups were synchronized by gonadotropin-releasing hormone (GnRH), prostaglandin F2α (PGF), and CIDR administrated on Day 0, followed by stimulation treatments 48 h later. No pre-synch was used. Total hormone dosage were administrated as follows: Group 1: pFSH = 180 mg (Folltropin, Bioniche, Belleville, ON, Canada; n = 7), Group 2: pFSH/LH = 500 IU (Pluset, Calier, Barcelona, Spain; n = 7), Group 3: eCG = 1500 IU (eCG, Biogénesis-Bagó, Buenos Aires, Argentina; n = 7) and Group 4: Control (n = 7), no stimulation. All injections were performed intramuscularly (i.m.) twice a day, during three days. OPU was performed 48 (Group 1) or 24 h (Group 2 and 3) after the last injection. The control group received saline solution i.m. Follicles were classified according to diameter in 4 categories: small (2–5 mm); medium (6–9 mm); large (10–14 mm) and extra large (>15 mm). A Mindray DP-30 Vet (Mindray Medical, Shenzhen, China) was equipped with a micro-convex transducer 5.0- to 8.5-MHz probe along with a disposable 21G needle. The OPU flow rate was 15 mL min–1. Retrieved oocytes were classified according to IETS guidelines as viable (grade 1 + 2) and non-viable (grade 3 + 4). The IVP protocol was according to that in Reprod. Fertil. Devel. (2004, 16, 253). Fertilization (Day 0) was carried out using female sex-sorted semen selected with a discontinuous density gradient (PureSperm, Nidacon, Mölndal, Sweden) and diluted to 1 × 106 sperm mL–1. ANOVA was used for comparisons of mean values and a chi-squared test was used for proportions. Results are presented in the Table 1. In conclusion, pFSH stimulation before ovum pick-up in Holstein cows increased the number of collected and viable oocytes, cleavage, embryo development, and hatching rates in comparison to other follicle stimulation hormones and non-stimulation. A cost-benefit analysis of these methods could be valuable in order to inform whether or not a stimulation protocol is necessary for a commercial IVP operation. Table 1.Numbers of follicles, collected and viable oocytes, cleavage rate, blastocysts and hatching rate


2019 ◽  
Vol 16 (2) ◽  
pp. 83-87
Author(s):  
A. A. OLOYE ◽  
N. OBI

Fifteen plurigravida rabbits weighing between 2.0 and 2.6 kg were used for the study of gestational characteristics after pre-copulatory oral administration of aqueous leaf extract of Spondias mombin. The fifteen does were divided into three groups of five does per group. Four untreated reproductively proven bucks kept separately in different cages were used for copulation. Dosages administered were 400mg/kg and 800mg/kg for groups A and B respectively while distilled water was served to control group C. Mating, pregnancy diagnosis using ultrasound and determination of birth parameters were conducted subsequently at the end of extract treatment. Average litter size,birth weight and gestation length observed in all dosage groups had statistically similar values (p≥0.05).However, it is worth noting the relatively higher values of average litter size in 800mg/kg dosage group and control (5.60±0.40) compared to 400mg/kg group (5.40±0.75) and the highest birth weight value recorded for 800mg/kg (46.63±3.55) compared to 400mg\kg group (45.30±3.22) and control (42.38±3.74). It was concluded that pre-copulatory administration of aqueous leaf extract of Spondias mombin at dosages as high as 800mg/kg to rabbit does not have deleterious effect on its prolificacy and does have pro-fertility tendencies.        


2014 ◽  
Vol 94 (1) ◽  
pp. 35-42 ◽  
Author(s):  
L. L. Vianna ◽  
J. Pradieé ◽  
E. C. S. Santos ◽  
A. O. Gonçalves ◽  
L. F. M. Pfeifer ◽  
...  

Vianna, L. L., Pradieé, J., Santos, E. C. S., Gonçalves, A. O., Pfeifer, L. F. M., Rheingantz, M. G. T., Dode, M. A. N., Vieira, A. D., Lima, V. F. H., Correa, M. N. and Pegoraro, L. M. C. 2014. Isolate® and Optiprep® minigradients as alternatives for sperm selection in bovine in vitro embryo production. Can. J. Anim. Sci. 94: 35–42. The objective of this study was to evaluate alternatives in small volumes to conventional gradient of Percoll® on semen quality, in vitro embryo production, sex ratio and embryo survival after vitrification. Thawed semen was randomly allocated to one of four density gradient selection methods: (1) conventional Percoll® (P), (2) MiniPercoll (MP), (3) MiniIsolate (MI), and (4) MiniOptiprep (MO). Sperm kinetics and quality were evaluated. Use of P, MP and MI gradients did not affect sperm motility (P>0.05). However, there was a decrease in total and progressive sperm motility in MO (70.8 and 51.3% vs. 87.3 and 69.5% for P; 87.3 and 73% for MP; 92.3 and 78.8% for MI; P<0.05). The MO had lower membrane integrity compared with P, MP and MI (39.7 vs. 70.5, 72.3, 63.8%, respectively, P<0.05). The percentage of blastocysts produced was higher in MI than in MP and MO (21.1 vs. 16.1 and 16.9%, P<0.05) and similar to P (18.4%; P>0.05). Sex ratio and embryo survival after vitrification were similar among groups (P>0.05). Semen selected by Isolate and Optiprep gradient, at the concentrations and small volumes used, demonstrated similar characteristics and in vitro embryo production to conventional Percoll® gradient.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francisco A. García-Vázquez ◽  
Carla Moros-Nicolás ◽  
Rebeca López-Úbeda ◽  
Ernesto Rodríguez-Tobón ◽  
Ascensión Guillén-Martínez ◽  
...  

AbstractRecent evidence supports involvement of the acute phase protein haptoglobin in numerous events during mammalian reproduction. The present study represents an in-depth investigation of haptoglobin expression and secretion in the porcine oviduct and uterus, and assesses its effect on porcine in vitro embryo production. A systematic study was made of sows in different oestrous stages: late follicular, early luteal and late luteal stages. Relative haptoglobin mRNA abundance was quantified by RT-qPCR. In addition, expression of the protein was analysed by immunohistochemistry and the results were complemented by Western-blot and proteomic analyses of the oviductal and uterine fluids. In vitro porcine fertilization and embryo culture were carried out in the presence of haptoglobin. The results indicate that haptoglobin mRNA expression in the porcine oviduct and uterus is most abundant during the late luteal stage of the oestrous cycle. By means of Western blot and proteomic analyses haptoglobin presence was demonstrated in the oviduct epithelium and in the oviductal and uterine fluids in different stages of the oestrous cycle. The addition of haptoglobin during gamete co-incubation had no effect on sperm penetration, monospermy or efficiency rates; however, compared with the control group, blastocyst development was significantly improved when haptoglobin was present (haptoglobin: 64.50% vs. control: 37.83%; p < 0.05). In conclusion, the presence of haptoglobin in the oviduct and uterus of sows at different stages of the oestrous cycle suggests that it plays an important role in the reproduction process. The addition of haptoglobin during in vitro embryo production improved the blastocyst rates.


2015 ◽  
Vol 27 (8) ◽  
pp. 1249 ◽  
Author(s):  
G. Gamarra ◽  
C. Ponsart ◽  
S. Lacaze ◽  
B. Le Guienne ◽  
P. Humblot ◽  
...  

Rapid genetic improvement in cattle requires the production of high numbers of embryos of excellent quality. Increasing circulating insulin and/or glucose concentrations improves ovarian follicular growth, which may improve the response to superovulation. The measurement of anti-Müllerian hormone (AMH) can help predict an animal’s response to superovulation treatment. The aim of the present study was to investigate whether increasing circulating insulin concentrations, through propylene glycol (PG) drenches, could improve in vitro embryo production in oestrus-synchronised superovulated heifers with different AMH profiles. Holstein heifers were grouped according to pre-experimental AMH concentrations as low (L) or high (H). The PG drench increased circulating insulin and glucose concentrations and reduced β-hydroxybutyrate and urea concentrations compared with the control group. AMH was a good predictor of follicle and oocyte numbers at ovum pick-up (OPU), and of oocyte and embryo quality (AMH H > AMH L). PG in the AMH H group increased the number of follicles and blastocyst quality above that in the control group, but did not improve these parameters in the AMH L group. These results indicate that short-term oral PG supplementation modifies an animal’s metabolic milieu and is effective in improving in vitro embryo production, after superovulation–OPU, more markedly in heifers with high rather than low AMH concentrations.


2011 ◽  
Vol 23 (1) ◽  
pp. 201 ◽  
Author(s):  
F. Asghari ◽  
M. Shahidi ◽  
Y. Chashnidel ◽  
H. Deldar ◽  
Z. Ansari-Pirsaraei ◽  
...  

A large proportion of ovine oocytes fail to develop into viable embryos following maturation, fertilization, and culture in vitro. Accurate, fast, and noninvasive predictors of ovine oocyte quality are therefore in urgent need for oocyte selection before in vitro maturation (IVM). Recent studies have shown that oocyte competence can be predicted through the presence of the glucose-6-phosphate dehydrogenase (G6PD) enzyme, as indicated by brilliant cresyl blue (BCB), a dye that can be degraded by G6PD. Thus, oocytes that have completed their growth phase show decreased G6PD activity and exhibit cytoplasm with a blue colouration (BCB+), whereas growing oocytes are expected to have a high level of G6PD, which results in colourless cytoplasm (BCB–). The brilliant cresyl blue staining test, as a noninvasive intrinsic criterion, has been successfully used to identify the more competent oocytes in various species. Therefore, this study aimed to investigate whether BCB staining, as an indicator of G6PD activity, can be used to select developmentally competent ovine oocytes before IVM and thereby increase the efficiency of in vitro embryo production. Ovine ovaries were obtained from a local slaughterhouse and transported to the laboratory, where cumulus–oocyte complexes (COC) were recovered by slicing the ovaries. Only oocytes with one or more complete layers of unexpanded cumulus cells and a homogeneous cytoplasm were used. The COC were exposed to 26 mM BCB diluted in modified Dulbecco’s PBS for 90 min at 39°C in humidified air. After BCB exposure, the COC were examined under a stereomicroscope and divided into 2 groups: BCB+ (blue cytoplasm, low G6PD activity) and BCB– (colourless cytoplasm, high G6PD activity). Cumulus–oocyte complexes in the control group were incubated for IVM directly after selection, without exposure to BCB dye. After IVM, oocytes were subjected to IVF followed by embryo culture for 7 days (5% CO2, 39°C, humidified air). Results were analysed by a chi-square test, and P < 0.05 was considered statistically significant. The proportion of oocytes that cleaved by Day 2 after insemination was significantly (P < 0.05) higher for the control and BCB+ groups [67.3% (68/101) and 71.7% (81/113), respectively] than for the BCB– group [50.5% (46/91)]. Significant differences among groups were also observed on Day 7 after fertilization, when the embryos reached the blastocyst stage of development. The BCB+ group yielded a significantly (P < 0.05) higher proportion of blastocysts [34.5% (39/113)] than both the control [20.8% (21/101)] and BCB– [4.3% (4/93)] groups. In addition, the blastocyst rate of development in the control group was significantly (P < 0.05) higher than that for the BCB– group. In conclusion, results of this study show that selection of ovine oocytes based on G6PD activity through the BCB test can be used as an efficient predictor of in vitro embryonic developmental competence. This positive predictive parameter of oocyte quality may also be useful in increasing the efficiency of blastocyst production during in vitro embryo production procedures in the ovine.


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