Pregnancy resulting from cattle oocytes matured and fertilized in vitro

Oocytes, embryos and pluripotent stem cells from a biomedical perspective

The veterinary and animal science professions are rapidly developing and their inherent and historical connection to agriculture is challenged by more biomedical and medical directions of research. While some consider this development as a risk of losing identity, it may also be seen as an opportunity for developing further and more sophisticated competences that may ultimately feed back to veterinary and animal science in a synergistic way. The present review describes how agriculture-related studies on bovine in vitro embryo production through studies of putative bovine and porcine embryonic stem cells led the way to more sophisticated studies of human induced pluripotent stem cells (iPSCs) using e.g. gene editing for modeling of neurodegeneration in man. However, instead of being a blind diversion from veterinary and animal science into medicine, these advanced studies of human iPSC-derived neurons build a set of competences that allowed us, in a more competent way, to focus on novel aspects of more veterinary and agricultural relevance in the form of porcine and canine iPSCs. These types of animal stem cells are of biomedical importance for modeling of iPSC-based therapy in man, but in particular the canine iPSCs are also important for understanding and modeling canine diseases, as e.g. canine cognitive dysfunction, for the benefit and therapy of dogs.

In vitro fertilization and development of bovine oocytes recovered from the ovaries of individual donors: A comparison between the cutting and aspiration method

Bovine oocytes were recovered from ovaries by either the cutting or the aspiration method, after which the oocytes were fertilized and cultured in vitro to investigate their developmental ability. In the cutting method, the surface and the interior of ovaries were cut with a set of 10 razors stacked at 2-mm intervals in modified TCM-199 medium supplemented with 5% fetal bovine serum; the liberated oocytes were then collected. In the aspiration method all visible follicles (2 to 5 mm in diameter) at the ovarian surface were aspirated with a syringe and an 18-gauge needle. Significantly more oocytes were recovered by the cutting than the aspiration method (mean: 63.3 vs 22.1), and the proportion of Rank A oocytes was also higher for the cutting method (84.6 vs 41.3%). Although no significant differences were observed between the 2 methods in the proportion of fertilized oocytes developing to the blastocyst stage in culture, the average number of blastocysts obtained by the cutting method was about 3.6-fold higher than by aspiration. The blastocysts were transferred nonsurgically to 37 (cutting method) and 36 (aspiration method) recipients, and 22 (59.0%) and 19 (52.8%), respectively, became pregnant.

Dynamic changes of estradiol and progesterone concentrations during in vitro oocyte maturation in cattle

Two culture techniques, an open system using 1.0-ml medium and a covered system using 50-mul droplets of medium covered by paraffin oil, used for in vitro bovine follicular oocyte maturation were compared. Estradiol-17beta (E2) was added to Ham's F-10 medium together with other supplementations. In the absence of oocytes, E2 concentration remained unchanged in the 1.0-ml open system, but it decreased gradually in the 50-mul covered system. In the presence of oocytes, E2 increased significantly in the 1.0-ml open system, but this increase could not be detected in the 50-mul covered system. Progesterone (P4) concentration increased in both systems, but it was much higher in the 1.0-ml culture than in the 50-mul culture. The two culture systems allowed an identical nuclear oocyte maturation rate of 88.6 vs 87.0%, a sperm penetration rate of 54.3 vs 59.6%, and a polyspermy rate of 6.8 vs 11.6% for 1.0-ml and 50-mul systems, respectively. The cleavage rate, however, differed significantly (78.3 vs 41.7% for 1.0-ml and 50-mul systems, respectively). It is concluded that diffusion of steroids into the paraffin oil occurs and may affect the cleavage rate but not the maturation or penetration rate.

Influence of the semen deposition site on the calves' sex ratio in Simmental dairy cattle

It has been suggested that the time of insemination has effect on the calves' sex ratio because of the differences in timing of capacitation, motility and survival time of the X and Y spermatozoa in the female reproductive tract. We have conducted a field trial to study the effects of different semen deposition sites on the sex ratio and fertility in cattle. Two groups of 450 cows were inseminated via artificial insemination: group A was inseminated into the uterine body and group B was inseminated deep into the uterine horn ipsilateral to the ovary with dominant follicle. After applying several exclusion criteria, a total of 607 pregnant cows were considered for data analysis (group A = 318 and group B = 289 cows). The conception rate was 7% higher (p < 0.05) in the group A, with 23% more of the male calf pregnancies (p < 0.001). At the same time, 18% more of the female calves were calved in the group B (p < 0.005). The difference in male calves between the two groups was 21% and in female calves was 20% (p < 0.001). We conclude that semen deposition site plays a significant role in differences in gender ratio observed after calving. Intracornual semen deposition resulted in a higher ratio of female calves, whereas uterine body deposition site resulted in higher male calves ratio, probably contributing physiologically to the differences in motility, capacitation time, the lifespan of X vs Y spermatozoa and to the pronounced shift of X spermatozoa in the female genital tract.

Early morphological events of in vitro fertilized bovine oocytes with frozen-thawed spermatozoa

Bovine follicular oocytes were matured and inseminated in vitro with spermatozoa capacitated in vitro. The first evidence of sperm penetration was observed at 3 h after insemination. The penetration rate increased until 5 h, and reached a maximum rate (92%) at 5 h. Decondensation of the sperm head and pronuclear formation were observed 4 h and 7 h after insemination, respectively. Female chromatins of all penetrated oocytes were activated at 3 h, and female pronuclei were formed at 7 h after insemination. Percentages of oocytes with male and female pronuclei at 9 h were 88 and 94%. Polyspermy (4, 7, 19 and 29% at 4, 5, 7 and 9 h after insemination, respectively) and abnormal development of male pronuclei (6 and 7% at 7 and 9 h after insemination, respectively) were also seen.

Potential use of ovum pick-up for embryo production and breeding in cattle

The efficacy of transvaginal ultrasound-guided puncturing of ovarian follicles for collecting immature oocytes in cattle was studied. Three experiments were conducted to examine the effects of puncturing on follicle recruitment and on the number of oocytes collected. Puncture sessions were executed twice weekly at regular intervals of 3 and 4 d respectively. The oocytes were matured, fertilized and allowed to develop in vitro and the number of transferable embryos was recorded. The health of the cows was checked daily. In Experiment 1, dairy cows (n=10) were punctured over a period of 5 mo, and the collected oocytes were fertilized with the semen of 1 bull. In Experiment 2, oocytes were collected from one 12 year old high pedigree dairy cow and an one month pregnant cow were punctured. The oocytes of the old cow were fertilized with semen of 8 different bulls. In Experiment 3, beef cows (n=6) were punctured over a 2 mo period and the semen of 2 different bulls of the same breed was used to fertilize the oocytes from 3 of these cows. In Experiment 1, 14.5 +/- 0.4 (mean +/- SEM) follicles were punctured per session, and 8.0 +/- 0.3 (mean +/- SEM) oocytes were recovered. A mean of 16% of the oocytes developed into transferable embryos with a pregnancy rate of 40%. The results did not differ between the months of the experiments, indicating that the transvaginal puncturing method can be used successfully over a 5 mo period. No detrimental effects were observed after clinical and post mortem examinations, nor did breed, age or reproductive status appear to affect the results. However, large differences were observed between individual cows and between cow/bull combinations.

Term development of caprine embryos derived from immature oocytes in vitro

Ovaries were surgically removed from female goats (Toggenburg, Nubian and Saanen breeds). Oocytes were collected by follicular aspiration or after ovaries were minced, then matured in mTCM-199 with 100 microg LH+0.5 microg FSH+1.0 microg estradiol 17-beta/ml for 27 h prior to in vitro fertilization (17). Although more oocytes were made available by mincing than by aspiration, higher proportions of aspirated oocytes were fertilized and developed to morulae. Proportions that fertilized and reached morulae were 82/102 (80.4%) and 50/102 (49.0%) versus 77/126 (61.1%) and 27/126 (21.4%) for oocytes obtained by aspiration and after ovarian mincing, respectively (P<0.05). Proportions of inseminated ova undergoing cleavage and continuing development to the morula stage differed significantly (P<0.05) among 5 co-culture treatment groups, with higher proportions of cleavage (23/27, 85.2%) and morulae (14/27, 51.9%) obtained by co-culture on caprine cumulus cells (cCC). Some oocytes reached the blastocyst stage (4/54, 7.4%)following oocyte collection by aspiration and culture on caprine oviduct epithelial cells (cOEC). After 4- and 8-cell stage embryos obtained by aspiration and culture on cCC were transferred pregnancy resulted. Twin male kids (developed from different embryos) were born on August 6, 1993, and have developed into normal bucks. Conditions reported here provided an adequate environment for support of oocyte maturation, fertilization and early embryonic development in vitro (IVMFC) with normal development after embryo transfer.

Effect of oviductal epithelial cells on fertilization of pig oocytes in vitro

The incidence of polyspermy is reduced by co-culture of pig oocytes with oviductal cells. It is not known whether the effect is due to soluble factors secreted into the medium. Oviductal epithelial cell monolayers and cell-conditioned media were prepared and their effects on fertilization of pig oocytes were examined. In vitro matured pig oocytes were inseminated with ejaculated boar spermatozoa at a concentration of 1x10(5) or 1x10(6) cells/ml and co-cultured in one of 5 culture systems: an oviductal epithelial cell monolayer, a fibroblast monolayer, an oviductal epithelial cell-conditioned medium, or a fibroblast-conditioned medium, and medium alone (modified-TCM199). In all 5 systems, the majority (range 85 to 100%) of the oocytes were penetrated by sperm. When oocytes were inseminated with spermatozoa at a concentration of 1x10(5) cells/ml, the percentages of monospermic oocytes were significantly higher in the oocytes co-cultured with oviductal epithelial cells and fibroblasts than that of the oocytes cultured without these cells. In contrast, when oocytes were inseminated with spermatozoa at a concentration of 1x10(6) cells/ml, the percentages of monospermic oocytes were significantly higher in the oocytes co-cultured with epithelial cells than those cultured with the fibroblasts and in the control medium. The suppressive effect on polyspermy was observed in the oviductal epithelial cells-conditioned medium when oocytes were inseminated with spermatozoa at both concentrations of 1x10(5) and 1x10(6) cells/ml. The effect was absent in the fibroblasts-conditioned medium. Moreover, the effect of the epithelial cells was maintained during the culture period, whereas the proportion of monospermic oocytes co-cultured with fibroblasts showed a gradual decrease, reaching 0% after 16 h. These results suggest that a soluble factor(s) derived from the oviductal epithelial cells decreased the number of spermatozoa penetrating the oocytes without suppressing the high rate of fertilization.

Successful pig embryonic development in vitro outside a CO2 gas-regulated incubator: effects of pH and osmolality

We investigated the effects of HEPES in the medium (to maintain pH) and paraffin oil covering the medium (to maintain osmolality) on the developmental ability of porcine embryos produced in vitro using tightly closed glass tubes in the absence of a CO2 gas-regulated incubator. Putative porcine zygotes obtained by in vitro fertilization (IVF) of in vitro-matured (IVM) oocytes (day of IVF=Day 0) were cultured in 5% CO2 gas-equilibrated NCSU-37 media containing pyruvate and lactate during Days 0-2, and glucose during Days 2-6, in open glass tubes in a CO2 incubator or tightly closed glass tubes without a CO2 incubator at 38.5 degrees C. The following four media were used: (1) medium covered with paraffin oil and supplemented with HEPES; (2) medium covered with paraffin oil but with no HEPES supplementation; (3) medium not covered with paraffin oil but supplemented with HEPES; (4) medium not covered with paraffin oil and with no HEPES supplementation. As a control group, zygotes were cultured in medium with neither paraffin oil coverage nor HEPES supplementation using a four-well dish in a CO2 gas-regulated incubator. After culture, the osmolality in each of the four closed conditions was maintained at approximately 285-286 mOsm, lower (P<0.05) than that in the control (291 mOsm). In the two HEPES-supplemented media groups in the closed-tube system, the pH was maintained at 7.5-7.7, and the blastocyst development rates (15.5% in non-oil covered and 18.5% in oil covered group) did not differ significantly from that of the control (20.2%), although the mean cell numbers in the blastocysts in the two closed-tube condition groups (28.2 and 33.0) were lower (P<0.05) than in the control (43.5). In contrast, the pH was higher in the two groups without HEPES supplementation (approximately 8.0) than the control (7.4; P<0.05), and the blastocyst development rates (10.9% in non-oil covered and 7.5% in oil covered group) or total cell numbers in the blastocyst (24.8 and 28.7) in the two non-HEPES groups were drastically decreased (P<0.05) compared to those in the control (20.2% and 43.5). These results suggested that maintenance of pH is important for successful in vitro porcine embryo culture under closed-air conditions, whereas the range of osmolality that suits embryo development is not limited to a small range. Furthermore, blastocyst production was possible in a glass tube without a CO2 incubator, although blastocyst quality was lower compared to those produced in an incubator.

Intrafallopian transfer of gametes and early stage embryos for in vivo culture in cattle

It may be possible to avoid inadequate in vitro culture conditions by incubating gametes or embryos in the oviducts for a short time. Ideally, an optimized procedure should be devised, combining in vitro and in vivo systems, in order to achieve synchronization in cattle. We transferred gametes as well as embryos in various stages of development and placed them into the oviducts. Embryos were recovered on Day 7 by flushing of oviducts and uterine horns. Blastocyst rates were determined on Day 7 and on Day 8. Experimental designs included transfer of in vitro matured cumulus oocyte complexes into previously inseminated heifers (COCs group), transfer of in vitro matured COCs simultaneously with capacitated spermatozoa (GIFTs group), transfer of four to eight cell stage embryos developed in vitro after IVM/IVF (Cleaved Stages group) and a group of solely in vitro produced embryos (IVP control group). Our results indicate that in vivo culture of IVM/IVF embryos in the homologous bovine oviduct has a positive influence on subsequent pre-implantation development. In addition, we have evidence that in vitro maturation and in vivo fertilization cannot be synchronized.

In vivo culture of IVM/IVF embryos in bovine oviducts by transvaginal endoscopy

This study was conducted to establish a new approach for in vivo culture of in vitro produced embryos in the bovine oviduct by transvaginal endoscopy. Embryos were in vitro matured, fertilized and cultured for 1-4 days and assigned to groups consisting of 10-30 embryos. Embryos were transferred unilaterally into oviducts of 24 heifers by the means of transvaginal endoscopy. After 3-6 days of in vivo incubation embryos were re-collected. Experiment I aimed to evaluate the capability of embryos to migrate to the uterus. The uterine horns of four animals were flushed first, followed by a combined flushing of both oviducts and uterine horns resulting in collection rates of 31 and 34%, respectively. In experiment II, the transfer of embryos into the oviduct close to ovulation (day 1-2--experiment IIA) or at a more advanced cyclic stage (day 3--experiment IIB) succeeded in the collection of 46 and 34% of the transferred complexes, of which 13 and 37% showed the blastocyst stage. This is the first report of successful recovery of transferable blastocysts by transvaginal endoscopy after tubal in vivo culture in the homologous species of originally in vitro produced embryos.

Effects of aromatic cationic molecules on bovine viral diarrhea virus and embryonic development

Bovine viral diarrhea virus (BVDV) has been shown to replicate in embryo culture systems and remain associated with bovine embryos developing in vitro. In this study, novel antiviral agents were evaluated for capability to inhibit replication of BVDV without affecting embryonic development. Serial concentrations of 2-[5(6)-{2-imidazolinyl}-2-benzimidazolyl]-5-(4-aminophenyl)furan (DB456) or 2-(4-[2-imidazolinyl]phenyl)-5-(4-methoxyphenyl)furan (DB606) were prepared in IVC medium. Then, bovine uterine tubal epithelial cells (UTC) were placed in IVC media with varying concentrations of DB456 or DB606. Within 1h, a genotype I or II strain of BVDV was added to the cultures. Cultures were maintained for 7 days. Infectious virus was quantitated in IVC media collected on days 3 and 7 and in UTC lysates harvested on day 7. The effective antiviral concentrations of DB606 were much lower than effective antiviral concentrations of DB456. In subsequent experiments, IVF presumptive zygotes were cultured in IVC medium with or without DB456 or DB606 at multiple concentrations for 7 days to evaluate effect of the compound on conceptus development. On day 7, stage of embryonic development was observed, and blastocysts were harvested and stained using Hoechst 33342 to enumerate embryonic cells. While DB456 inhibited blastocyst development, DB606 at 20 times the effective antiviral concentration did not hinder blastocyst development or reduce the mean number of cells per blastocyst. These preliminary results indicated that bovine embryo cultures might be safely supplemented with effective concentrations of an antiviral agent.

Relationship between oxygen consumption and sex of bovine in vitro fertilized embryos

The present study was conducted to examine the relationship between the oxygen consumption rate and sex ratio of bovine in vitro fertilized embryos on each day of blastocyst formation. The quality of blastocysts collected on day 7, 8, and 9 after in vitro fertilization (IVF) were categorized as ranks A and B (excellent and good, respectively) based on microscopic observation of the morphology. The oxygen consumption rate and sex of individual blastocysts were evaluated using two novel techniques: scanning electrochemical microscopy (SECM) and loop-mediated isothermal amplification (LAMP), respectively. The oxygen consumption rates of embryos of rank A were significantly higher (p < 0.05) than those of rank B, irrespective of the day of blastocyst appearance after IVF. Neither did the proportion of male embryos of ranks A and B differ significantly from each other at any of the days examined, nor from the average proportion (53%). The oxygen consumption rate of embryos of rank B collected on day 8 was significantly higher (p < 0.05) in female embryos than in male embryos collected on the same day. However, there were no apparent differences of oxygen consumption rates at each day of blastocyst appearance between male and female embryos of rank A. These results indicate that the oxygen consumption rate of individual embryos reflects their quality but does not correlate with the sex ratio of embryos of excellent quality.

Effects of Retinol on the in vitro Development of Bos Indicus Embryos to Blastocysts in Two Different Culture Systems

The objective of this study was to evaluate the effect of retinol on the in vitro development of early embryos of cultured Bos indicus (Expt 1) to the blastocyst stage in medium simplex of optimization (KSOM) or sintetic fluid of oviduct (SOF) or co-cultured (Expt 2) with an oviduct cell monolayer (OCM) in KSOM or SOF. A total of 3149 cumulus-oocyte complexes obtained by aspirating follicles (2-5 mm diameter) from ovaries of slaughtered animals were selected for IVM and incubated in TCM 199 supplemented with 25 mM HEPES at 39 degrees C in air with 5% CO(2) and maximum humidity for 24 h. In vitro fertilization (IVF) was performed in modified defined medium (mDM) medium. Eighteen hours after IVF, cumulus cells were removed and presumptive zygotes were randomly allocated to the experimental groups. Zygotes cultured (Expt 1) in KSOM + retinol, KSOM, SOF + retinol and SOF were incubated in maximum humidity at 39 degrees C, 5% CO(2), 5% O(2) and 90% N(2). Zygotes co-cultured (Expt 2) in KSOM + retinol + OCM, KSOM + OCM, SOF + retinol + OCM and SOF + OCM were incubated at 39 degrees C, 5% CO(2). In both experiments media were partially changed 48 h after IVF and unfertilized ova were removed. Afterwards embryos were kept in culture or co-culture for further 9 days. In Expt 1, blastocyst rates (day 7) were 14.6% (KSOM + retinol), 15.8% (KSOM), 16.4% (SOF + retinol) and 15.9% (SOF). In Expt 2, the blastocyst rates (day 7) were 25.4% (KSOM + retinol + OCM) 14.2% (KSOM + OCM), 24.3% (SOF + retinol + OCM) and 15.9% (SOF + OCM). The same influence profile of retinol was observed in the formation of the expanded (day 9) and hatched (day 11) blastocysts. The results obtained in Expt 2 demonstrated that the addition of 0.28 microg/ml retinol to the embryo culture media used in this study had a significant (p < 0.05) positive effect on bovine early embryonic development, under the conditions tested, and can be used to enhance in vitro embryo production.

Post-warming hatching and birth of live calves following transfer of in vitro-derived vitrified water buffalo (Bubalus bubalis) embryos

Viability of in vitro-derived vitrified-warmed preimplantation stage buffalo embryos were assessed in vitro and in vivo. Oocytes were collected from ovaries of slaughtered riverine buffaloes, matured and fertilized in vitro with frozen semen from riverine buffalo bull and cultured on cumulus cell monolayers. Resultant preimplantation stage embryos were cryopreserved by vitrification with ethylene glycol, ficoll and sucrose. Seventy-one frozen embryos were warmed in 0.5M sucrose and were further cultured in vitro for 72 h to assess hatching rate. On the other hand, 95 embryos were transferred non-surgically to riverine buffalo recipients to assess development competence in vivo through detection of pregnancy and birth of live calves. Hatching rate of 83.10% (59/71) was noted among embryos cultured in vitro. Pregnancy rate was 16.36% (9/55) while calving rate was 10.91% (6/55) after transfer of in vitro-derived vitrified-warmed embryos to recipient animals. Six healthy and normal calves with average birth weight of 38.75+/-3.55 kg were born from the transferred embryos. These results indicate the viability of vitrified in vitro-derived buffalo embryos and the potential application of in vitro embryo production and vitrification techniques for production and transport of buffalo embryos from germplasm-rich sources to guarantee genetic improvement in many parts of the world.

Commercialization of animal biotechnology

Commercialization of animal biotechnology is a wide-ranging topic for discussion. In this paper, we will attempt to review embryo transfer (ET) and related technologies that relate to food-producing mammals. A brief review of the history of advances in biotechnology will provide a glimpse to present and future applications. Commercialization of animal biotechnology is presently taking two pathways. The first application involves the use of animals for biomedical purposes. Very few companies have developed all of the core competencies and intellectual properties to complete the bridge from lab bench to product. The second pathway of application is for the production of animals used for food. Artificial insemination (AI), embryo transfer, in vitro fertilization (IVF), cloning, transgenics, and genomics all are components of the toolbox for present and future applications. Individually, these are powerful tools capable of providing significant improvements in productivity. Combinations of these technologies coupled with information systems and data analysis, will provide even more significant change in the next decade. Any strategies for the commercial application of animal biotechnology must include a careful review of regulatory and social concerns. Careful review of industry infrastructure is also important. Our colleagues in plant biotechnology have helped highlight some of these pitfalls and provide us with a retrospective review. In summary, today we have core competencies that provide a wealth of opportunities for the members of this society, commercial companies, producers, and the general population. Successful commercialization will benefit all of the above stakeholders.

Correlation between the cell number and diameter in bovine embryos produced in vitro

This study was designed to examine the effects of age and developmental stage of in vitro-produced bovine embryos on the cell number of the embryos and to investigate the correlation between the cell number and diameter in the embryos. The diameter and cell number in blastocysts and expanded blastocysts collected on days 7-9 after in vitro fertilization (IVF) were examined. Although the diameters of the blastocysts collected on days 7 and 8 after IVF were smaller than those of the expanded blastocysts collected on day 9, the cell number in both types of embryos was similar. The cell numbers of the blastocysts and expanded blastocysts decreased with increasing embryo age. There were positive correlations between the cell number and diameter in bovine embryos at each stage collected on each day after IVF. However, the value of the correlation coefficient in the day-9 expanded blastocyst group tended to be higher than that in the other groups. These results indicate that the cell number of in vitro-produced embryos is affected by the embryonic stage and age. The diameter of the embryo may be potentially used for the viability testing of the expanded blastocysts collected on day 9 after IVF.

Transgenic production from in vivo-derived embryos: effect on calf birth weight and sex ratio

We examined transgenic-cattle production by DNA microinjection into 1-, 2-, and 4-cell embryos, analyzing the impact on calf size and subsequent viability. Embryos were either collected at an abattoir by flushing oviducts from superovulated and artificially inseminated cows (in vivo-derived) or obtained by in vitro maturation and in vitro fertilization of oocytes aspirated from excised ovaries (in vitro-derived). A human serum albumin (hSA) milk-expression DNA construct was microinjected, either in one of the visible pronuclei of in vitro- and in vivo-derived 1-cell embryos or in the nuclei of two blastomeres of 2- and 4-cell in vivo-derived embryos. Microinjection-induced mortality (lysis and developmental block) was equivalent ( approximately 40%) for all microinjected embryos. Embryos were co-cultured with BRL cells in B-2 medium containing 10% fetal calf serum (FSC). Overall, embryo development to morulae/blastocysts was significantly greater for in vivo-derived ova (15.5%) than for in vitro-derived oocytes (9.3%). All morulae and blastocysts were transferred to synchronized recipient females on Days 6-8 post-fertilization. A total of 189 calves were delivered. Birth weights were significantly greater for calves generated from in vitro-derived oocytes compared with those generated from in vivo-derived oocytes. One transgenic bull calf was obtained from the microinjection of a 2-cell embryo. Fluorescence in situ hybridization (FISH) analysis of lymphocytes detected one transgenic integration site in all cells. Transmission frequency of the hSA transgene in embryos obtained through IVM/IVF/IVC utilizing the semen of the transgenic calf confirmed that it was not mosaic.

Dynamic changes in plasma concentrations of gonadotropins, inhibin, estradiol-17beta and progesterone in cows with ultrasound-guided follicular aspiration

To elucidate the effects of ultrasound-guided transvaginal follicular aspiration, plasma concentrations of FSH, LH, inhibin, estradiol-17beta and progesterone, and folliculogenesis were examined in Holstein cows. Four clinically healthy cows with regular estrous cycles were scanned by ultrasound per rectum once a week for 9 weeks before the commencement of follicular aspiration. All visible follicles were divided into 3 categories based on their sizes (2 < or = small < 5 mm; 5 < or = medium < 10 mm, large > or = 10 mm). The follicular aspiration was started at random during the estrous cycle and conducted under epidural anesthesia induced with 5 ml of 2% lidocaine once a week for 6 weeks. The average number of total visible follicles > or = 2 mm in diameter at 7 days after aspiration (21.7 +/- 7.4, n = 24) was similar to that before starting aspiration (26.7 +/- 10.5, n = 36). Plasma inhibin and estradiol-17beta declined and fell to a trough on 1.5 days and returned to pre-aspiration values by 5 days after aspiration. Plasma concentrations of FSH increased and reached peak levels between 1 and 1.5 days after aspirations. Plasma concentrations of LH also increased and reached peak levels between 0.5 and 1.5 days after aspirations. Both plasma FSH and LH had returned to pre-aspiration levels by 5 days after aspirations. Plasma concentrations of progesterone did not change with the follicular aspiration. These results demonstrate that follicular aspiration decreases plasma concentrations of inhibin and estradiol-17beta, which in turn leads to a rise in plasma concentrations of FSH and LH. It is suggested that marked increases in plasma concentrations of FSH and LH after the aspiration stimulate the development and maturation of a new cohort of follicles within one week in cows.

Plasma oestrone and oestradiol concentrations throughout gestation in cattle: relationship to stage of gestation and fetal number

The objectives of the study were to characterise the peripheral plasma oestrone (E1) and oestradiol-17beta (E2) concentrations throughout gestation in the cow and to correlate this with the stage of gestation and fetal number. Cows (n = 10) were equally divided into two groups after non-surgical embryo transfer of in-vitro matured and in-vitro fertilised (IVM - IVF) embryos; Group 1 received a single embryo, Group 2 received twin embryos. Blood was collected about every third day from day 0 (day 0 was defined as first day of standing oestrus), then daily for the last 10 days of gestation and sampling was stopped one day post partum. Plasma E1 concentration exceeded that of E2 throughout gestation in both groups of cows. The time trend concentrations of plasma E1 were significantly affected by the stage of gestation (P < 0.01) and fetal number (P < 0.01) in the last two trimesters of gestation. The time trend concentrations of plasma E2 were significantly affected by the stage of gestation (P<0.01) but not foetal number (P = 0.09). In both groups there was marked preparturient increase in E1 and E2 concentrations. Plasma E2 profile between days 10 prepartum to parturition paralleled E1 in cows carrying a single foetus but was disparate during the same period in the twin-bearing cows. To conclude, our results indicate that although plasma E1 concentration was greater than E2 throughout gestation, both were related to the stage of gestation and that fetal number was correlated with circulating E1 levels in the last two trimesters of gestation.

Peritoneal fluid from rabbits or goats as media for in vitro maturation, fertilization and initial culture of caprine oocytes

The efficacy of peritoneal fluid from rabbit and goat for in vitro maturation, fertilization and initial culture of embryos from caprine oocytes was evaluated. Peritoneal fluid was collected from adult female goats (n = 9) or rabbits (n = 9). Good quality oocytes were subjected to in vitro maturation and fertilization in three different media viz. Tissue Culture Medium (TCM-199), goat Peritoneal Fluid (gPF) and rabbit Peritoneal fluid (rPF). Maturation rates were 74.7+/-2.07% and 63.6+/-5.28% in TCM-199, gPF 65.8+/-2.54% and 55.6+/-3.79%, and rPF 57.7+/-1.78% and 44.6+/-3.01% when evaluated on the basis of cumulus cell expansion and the achievement of metaphase-II stage, respectively. However, no significant differences were observed in respect of maturation rate between the control and gPF and between gPF and rPF groups. Freshly ejaculated buck semen was treated with heparin (10 microg/ml) and after 45 min incubation with heparin, 8.0% sperm were live and acrosome reacted. The proportions of fertilized oocytes based on male and female pronuclei formation or on cleavage development were 50.5+/-5.03, 42.3+/-3.15 and 34.2+/-1.98%; 31.0+/-2.80, 27.9+/-2.12 and 21.8+/-1.69% for TCM, gPF and rPF, respectively. It was concluded that peritoneal fluids either from goats or rabbits could be used as an alternative medium to TCM-199. However, further research is required to confirm its efficacy for embryo development up to the blastocyst stage.

In vitro fertilization and in vitro culture of bovine embryos in the presence of noncytopathic bovine viral diarrhea virus

In vitro embryo production has been used extensively in research and is now offered as a commercial service, yet the hazards of introducing specific infectious agents into in vitro embryo production systems have not been completely defined. The introduction of noncytopathic bovine viral diarrhea virus (BVDV) is a special concern. One objective of this study was to determine if noncytopathic BVDV-infected uterine tubal cells in IVF and IVC systems affected the rate of cleavage and development. An additional objective was to determine if either degenerated ova or embryos produced in the presence of the infected cells had virus associated with them after washing. Follicular oocytes (n = 645) collected from slaughterhouse ovaries were matured and fertilized in vitro, and presumptive zygotes were cultured for 7 d. Primary cultures of uterine tubal cells for use during IVF and IVC were divided into 2 groups. One-half of the cultures was infected with noncytopathic BVDV while the other half was not exposed to the virus. Approximately equal groups of mature oocytes were inseminated, and the presumptive zygotes were cultured with infected or noninfected uterine tubal cells. After 7 d in IVC, zona pellucida-intact (ZP-I) morulae and blastocysts and degenerated ova were washed and assayed for the presence of infectious virus. Infections of uterine tubal cells were not apparent and did not reduce rates of cleavage and development (P > 0.05; Chi-square test for heterogeneity). After washing, BVDV was isolated at a significantly higher rate from groups of virus-exposed degenerated ova (79%) than from individual virus-exposed morulae and blastocysts (37%; P = 0.0002; Mantel-Haenszel summary, Chi-square).

Comparison of various maturation treatments on in vitro maturation of goat oocytes and their early embryonic development and cell numbers

In the present study, comparison of 2 different culture media (Ham's F-12 and M-199) for supporting in vitro maturation of goat oocytes, and their subsequent embryonic development was evaluated in the presence or absence of sera (estrous goat serum, EGS and fetal calf serum, FCS) and hormones (FSH, 0.5 ug/ml, LH, 5 ug/ml and estradiol, 1 ug/ml). Neither medium (Ham's F-12 or M-199) when supplemented with EGS and hormones showed any notable changes in the maturation rate nor in cleavage and blastocyst development. The mean cell number for blastocysts was also significantly low (P < 0.05). However, Ham's F-12 medium supplemented with FCS and hormones showed a considerable increase in the maturation rate, but subsequent embryonic development was not appreciably increased. However, maturation, cleavage and blastocyst development rates of oocytes matured in M-199 medium in combination with 10% FCS and hormones were significantly higher (P < 0.05). Mean cell number per blastocyst was also significantly increased in this latter treatment compared with that of the other groups (P < 0.05). The results thus indicated that both the culture medium and serum have a marked effect on maturation and subsequent embryonic development. Further, the results also showed that the combination of M-199 with FSH, LH and E2 supplemented with 10% FCS was the most efficacious medium for in vitro maturation and subsequent embryonic development of the media, sera and hormone combinations studied.

Effects of media, serum, oviductal cells, and hormones during maturation on bovine embryo development in vitro

Our objective was to optimize in vitro maturation conditions of bovine oocytes as assessed by embryo development. In Experiment 1, cumulus-oocyte complexes were matured in either M-199 or RPMI-1640. Each medium was supplemented with an antibiotic-antimycotic solution (1%) and estrous cow serum (20%). Cumulus cell expansion after 24 h was greatest for cumulus-oocyte complexes matured in RPMI-1640. Morulae development on d 7 was greater (21.1%) for oocytes matured in M-199 than for oocytes that matured in RPMI-1640 (9.6%). In Experiment 2, cumulus-oocyte complexes were matured in M-199 supplemented with antibiotic-antimycotic solution (1%). Main effects were serum type (20%; estrous cow serum vs. superstimulated estrous cow serum) and coculture (with or without bovine oviductal epithelial cells). The percentage of oocytes developing into blastocysts (d 9) was higher for oocytes matured in estrous cow serum regardless of coculture. In Experiment 3, effects of estradiol-17 beta (0, 1, and 2 micrograms/ml) and equine LH (0, 10, 20, and 30 micrograms/ml) on cumulus cell expansion and development after fertilization were determined. Cumulus cell expansion and blastocyst development decreased with estradiol-17 beta in the maturation medium, but LH in the medium enhanced expansion of cumulus cells and blastocyst development.

The effects of follicular fluid on in vitro maturation, oocyte fertilization and the development of bovine embryos

We determined the effects of follicular fluid in the maturation medium on bovine oocyte maturation, fertilization and subsequent development, as well as on the number of cells in blastocysts following culture. Fluid and oocytes from bovine follicles less than 5 mm in diameter were collected from the ovaries of slaughtered cows. For the maturation medium, follicular fluid at concentrations of 10, 30 or 60% (v/v) was added to Medium 199 with Earle's salts supplemented with 0.1 microg/ml estradiol-17 beta (E(2), Experiment 1) or 0.1 microg/ml E2 and 100 IU/ml hCG (Experiment 2). The control medium contained polyvinylpyrrolidone (PVP; 3 mg/ml) instead of follicular fluid. After maturation for 24 h, oocytes were fertilized in vitro with bull frozen-thawed spermatozoa and cultured on a monolayer of granulosa cells for 9 d. There were no differences in maturation or fertilization rates of oocytes. In Experiment 1, maturation medium containing 10% follicular fluid did not affect the developmental rate of the oocytes to > 2-cell, 8 to 16-cell, blastocyst and hatched blastocyst stage embryos, respectively; whereas 60% decreased embryonic development (P < 0.05) compared with the control. Blastocysts and hatched blastocysts developed from fertilized oocytes which had been matured in medium containing 10 and 30% follicular fluid/E(2) had more cells than the controls (P < 0.01). In Experiment 2, maturation medium containing 10 or 30% follicular fluid did not affect the development fertilized oocytes to the blastocyst stage compared with the control, but decreased at 60% (P < 0.01). There were no differences in the number of cells from Day 9 blastocysts and hatched blastocysts from fertilized oocytes matured in maturation medium containing follicular fluid and E(2) + hCG. The results of these experiments suggest that the addition of bovine follicular fluid to the maturation medium enhances the cell numbers in blastocysts from bovine follicular oocytes matured in vitro.

Differential cleavage and developmental rates and their correlation with cell numbers and sex ratios in buffalo embryos generated in vitro

In vitro matured and fertilized buffalo oocytes were co-cultured with buffalo oviductal epithelial cells (BOEC) in CRlaa medium. Cleaved embryos were separated according to the time of completion of first cleavage (i.e., before 30 h and after 30 h post insemination) and cultured for 5 to 10 d and allowed to develop to the blastocyst stage. Zygotes cleaving before 30 h were termed fast-cleaving while those cleaving after 30 h were termed slow-cleaving. The results indicated that fast-cleaving embryos are more likely to develop into blastocysts (25%) than slow-cleaving embryos (7.8%). The quality and viability of fast-cleaving and fast-developing blastocysts was found to be better than that of slow-cleaving, slow-developing blastocysts as judged by cell numbers (67.7 +/- 3.7 vs 35.2 +/- 2.1). However, the mitotic index was not different between the 2 groups. The sex of fast-developing and slow-developing blastocysts was determined via the polymerase chain reaction (PCR) to correlate the rate of embryonic development with the sex ratio of the embryos. Embryos produced by Bull 293 and Bull M-82, irrespective of their being fast or slow-developing, gave rise to more females and males, respectively. From these results, we suggest that there may be a sire effect on sex ratio of in vitro produced buffalo embryos.

Effect of fetal mass, number and stage of gestation on pregnancy-specific protein B concentrations in the bovine

In this study we characterized the peripheral plasma pregnancy-specific protein-B (PSPB) profile throughout gestation and examined the effect of stage of gestation, fetal mass and number on this profile in Holstein cows after non surgical embryo transfer. Cows (n = 12) were divided into 2 groups: Group 1 = single embryo recipient cows (n = 5), Group 2 = twin-embryo recipient cows (n = 7). Blood was collected approximately every third day from Day 0 (Day 0 = first day of standing estrus), then daily for the last 10 d of gestation, and sampling was stopped 1 d post partum. Two twin-embryo recipient cows had abnormal pregnancies; therefore, their data were excluded from the group. The time trend concentrations of plasma PSPB were significantly affected by the stage of gestation (P < 0.001) and fetal number (P < 0.001). In both groups PSPB increased gradually, with the mean levels being significantly higher (P < 0.01) in the twin-bearing group from Day 50 onwards (0.7 +/- 0.2 vs 9.2 +/- 4.5 ng/ml, singleton and twin-bearing cows, respectively) except for Day 10 pre-partum. By mid-gestation (Day 140), mean PSPB levels increased in the singleton (P < 0.001) cows by thirty-fold (21.2 +/- 3.2 ng/ml) as opposed to a ten-fold (98.4 +/- 13.2 ng/ml) increase in the twin-bearing (P < 0.001) group. The mean PSPB concentrations between Days 30 to 20 prepartum dramatically increased by about 700 to 200% in singleton (128.8 +/- 46.3 to 745.6 +/- 66.7 ng/ml) and twin-bearing cows (375.6 +/- 130.4 to 861.5 +/- 127.9 ng/ml), respectively. The PSPB levels between Day 10 prepartum to parturition were significantly higher (P < 0.001) in the twin-bearing group than in the singleton group (745.6 +/- 66.7 to 1627.4 +/- 238.9 ng/ml vs 861.5 +/- 127.9 to 3103.0 +/- 643.0 ng/ml in singleton and twin-bearing groups, respectively). Calf birthweight was correlated (P < 0.01) to peripheral PSPB concentration in singleton cows; however, this relationship decreased with the subsequent increase in fetal number. Cows giving birth prematurely to stillborn calves or to a schistosomus reflexus calf exhibited abnormal PSPB profiles. These results indicate that peripheral PSPB levels are correlated to the stage of gestation and fetal number. In addition, the peripheral pattern of PSPB is a valuable guage for predicting fetoplacental viability.

Factors affecting bovine embryo development in synthetic oviduct fluid following oocyte maturation and fertilization in vitro

Employing a total of 3465 bovine oocytes this study was aimed at improving the efficiency of bovine embryo production under defined and undefined conditions. Following in vitro maturation (IVM) and in vitro fertilization (IVF), oocytes were allocated to various culture treatments using synthetic oviduct fluid (SOF). In our 3 experiments we showed that: 1) the addition of fetal calf serum (FCS 10% v/v) to SOF droplets after 20 to 24 h significantly improved blastocyst yields on Day 6 (21 vs 12%; P < 0.01), but not at later stages and resulted in significantly higher Day-8 blastocyst cell numbers (148 +/- 61 vs 92 +/- 35; P < 0.05); 2) the removal of bovine serum albumin (BSA) from the standard SOF medium resulted in significantly reduced blastocyst yields on Days 6, 7 and 8, respectively (17 vs 8%; 28 vs 18%; 31 vs 21%; P < 0.05); 3) the presence or absence of cumulus cells surrounding the presumptive zygote in culture in SOF had no effect on cleavage rate, percentage of 5-8 cell embryos or blastocyst yields (Day 6,7 or 8); 4) the culture of presumptive zygotes in SOF in an atmosphere of 5% CO2 in air (20% O2) resulted in significantly reduced development compared with culture in 5% CO2, 5% O2, 90% N2 in terms of blastocyst yield on Days 6, 7 and 8 and on Day 8 hatching rate, respectively (5 vs 22%; 9 vs 33%; 13 vs 48%; 50 vs 8%; P < 0.001) and 5) embryo density (1 embryo per 1 or 3 microl SOF) or replacing the culture medium every 48 h had no effect when SOF was supplemented with serum; however, under serum-free conditions, changing of the media resulted in a slightly improved Day-6 blastocyst yield such that renewal of serum-free medium mimicked the effect of serum addition.

Culture of bovine embryos to the blastocyst stage using Buffalo rat liver (BRL) cells

A comparison was made between the development of in vitro matured and fertilized bovine oocytes in co-culture with bovine oviduct epithelial (BOE) cells or with Buffalo rat liver (BRL) cells. Both cell types supported development from the 1-cell to the blastocyst stage with equal efficiencies (4.4% for BRL cells, 4.0% for BOE cells). Medium conditioned by either cell type supported development to the blastocyst stage as efficiently as co-cultures (6.4 and 7.3% blastocysts for BOE and BRL conditioned medium, respectively). A higher percentage of blastocyst development was found when embryos were cultured closely apposed in small drops of BRL-conditioned medium compared with larger volumes (20.5 versus 7.0%). The ability of BRL-conditioned medium to support embryonic development was dependent on the duration of the conditioning period (optimum 24 to 48 h), and was not lost when the medium was stored at -20 degrees C for extended periods. The effects were independent of the conditions used to promote maturation in vitro and the procedure for fertilization. With 2 different methods to produce embryos in culture, both the BRL cell co-culture and BRL-conditioned medium in microdrops supported embryo development to the blastocyst stage. The use of the BRL cell line reduces the variability associated with primary BOE cell cultures.

Oocyte morphology in dominant and subordinate follicles

The structure of oocytes aspirated from the dominant and its subordinate follicles was investigated from the achievement of follicular dominance to ovulation. Ovulation was induced in 18 heifers and 5 cows by injection of cloprostenol at days 8-14 (day 0 = day of ovulation), and follicular development was monitored by ultrasonography. The animals were slaughtered at days 3-11, but animals slaughtered on days 8-11 were given a second injection of cloprostenol at day 7 to allow ovulation of the dominant follicle of the first follicular wave. Oocytes were aspirated from the dominant (largest) and two largest subordinate follicles and processed for transmission electron microscopy, whereas the follicular fluids were analyzed for concentrations of estradiol-17 beta (E2) and progesterone (P4). Dominant follicular growth was associated with increase in the concentration of E2 and P4 in the follicular fluid, which was E2-dominated. From days 3-7, the dominant oocytes had pronounced junctional contacts with the cumulus cells and a nonundulating nuclear envelope but showed an increase in the number of lipid droplets and a decrease in the size of Golgi complexes, the size of cortical granule clusters, and the number of microvilli stacks. After cloprostenol injection on day 7, but before the anticipated LH surge, the dominant oocytes showed a reduced oocyte-cumulus contact, vacuolization of the nucleolus, undulation of the nuclear envelope, and dispersal of the mitochondrial clusters. The morphological alterations occurring in the dominant oocytes before the anticipated LH surge are suggested to be a prerequisite for the oocyte to achieve the competence to undergo final maturation. Subordinate follicles ceased growing at about days 3-4 and their follicular fluid had low E2:P4 ratio or was P4-dominated. Subordinate oocytes displayed degenerative features in their cumulus investment and nuclear activation and maturation especially after day 5. The structural changes associated with oocyte degeneration showed similarities with the processes seen before and during final maturation of the dominant oocytes.

Birth of double-muscled Belgian Blue calves after transfer of in vitro produced embryos into dairy cattle

The possible application of the bovine in vitro fertilization technique for economical beef production was evaluated by transferring in vitro produced Belgian Blue embryos to synchronized dairy cows and heifers. In total, 4167 oocytes, collected in the slaughterhouse from double-muscled Belgian Blue cows, were matured in vitro. Frozen-thawed semen from 3 Belgian Blue bulls was used for in vitro fertilization. Zygotes were cultured in B(2) + 10% estrous cow serum together with oviductal cells at 39 degrees C in 5% CO(2) in air. After 7 days, 576 (13.8%) transferable embryos were obtained. One hundred and eighteen of the most advanced embryos were selected for fresh transfer into 90 recipients. Some of the remaining embryos were frozen using conventional methods. After fresh transfer, 50 recipients (55.6%) had elevated progesterone at day 23. Thirty cows (33.3%) calved after a mean gestation length of 282.8+/-6.0 days and produced 25 single births and 5 twins. The sex ratio was 71.4%. The mean birth weight was 45.1+/-8.3 kg. Three calves were of the conventional type instead of double-muscled and 2 calves died of congenital malformations. After transfer of in vitro produced frozen-thawed Belgian Blue embryos into 27 recipients (1 embryo/recipient), 2 bull calves (7.4%) were born. Bovine embryo production by in vitro techniques could form a low-cost supply of beef calves. However, to render it commercially attractive, selection of sires and dams has to be performed with great care.

Noncytopathic bovine viral diarrhea virus in a system for in vitro production of bovine embryos

Techniques for in vitro production of bovine embryos have evolved to the extent that applications for the commercial production of calves have been proposed. However, little is known about the epidemiological implications of the procedures. One concern is the introduction of noncytopathic bovine viral diarrhea virus (BVDV). In this study, follicular oocytes (n=247) collected from 10 cows were matured and fertilized in vitro and presumptive zygotes were cultured for 7 d. Primary cultures of bovine oviductal epithelial cells for use during in vitro fertilization and culture were divided into 2 groups. Treated oviductal cells were infected with BVDV while control cells were not exposed to the virus. Two approximately equal groups of mature oocytes from each cow were inseminated, and the presumptive zygotes were cultured with infected or noninfected oviductal cells. After 7 d in culture, zona pellucida-intact morulae/blastocysts and degenerated ova were washed, sonicated and assayed for the presence of virus. The rates of cleavage and development were also compared by Chi-square analysis. After washing, virus was not isolated from morulae and blastocysts but was isolated from some groups of degenerated ova. Infections of oviductal cells were inapparent and did not significantly (P>0.05) affect rates of cleavage or development.

Relationships between the completion of first cleavage and the chromosomal complement, sex, and developmental rates of bovine embryos generated in vitro

One thousand eighty-four two-cell bovine embryos produced from 1,574 oocytes matured and fertilized in vitro were cultured as groups separated according to the time when they completed their first cleavage (24, 30, 40, 48, or 62 hr postinsemination; hpi). At 5 days after insemination, the proportions of each group that had progressed to the eight-cell stage or beyond were determined and the 350 that had done so were fixed and examined cytogenetically for cell number, chromosomal abnormalities, and sex. Embryos in the "early" cleaving (24 and 30 hpi) and "late" cleaving (40-62 hpi) groups were compared. Early cleaving embryos were more likely to have developed to the eight-cell stage or beyond (52.2% vs. 20%), contained more cells (22 vs. 17), and were more likely to be male (3.6:1 vs. 0.93:1). It is suggested that these phenotypic differences between the sexes begin before the embryonic genome is generally thought to become activated and are due either to differential processing of X- and Y-bearing sperm within the zygote or to very early differential expression of genes derived from X- and Y-bearing sperm.

Microinjection of bovine embryos with a foreign gene and its detection at the blastocyst stage

This study was designed to measure the survival and development of pronuclear stage bovine zygotes after microinjection with DNA and either culture in vitro or incubation in the sheep oviduct and to determine the percentage of embryos that retain exogenous DNA at the blastocyst stage. In vitro matured and fertilized oocytes were examined for pronuclear development 18 to 20 h after coincubation with sperm. An ovine somatotropin gene construct was microinjected into ova with visible pronuclei. Microinjected ova and unmanipulated ova from the same in vitro derived pool were cocultured with oviductal epithelial cells or incubated in the sheep oviduct and cocultured, respectively, for 7 d. Blastocysts were subjected to polymerase chain reaction analysis for detection of exogenous DNA. The percentage of cleaved embryos that formed blastocysts was similar for microinjected and unmanipulated cultured ova. The percentage of blastocysts recovered from the sheep oviduct that hatched was higher than for blastocysts that developed in coculture. Fourteen of 26 (54%) blastocysts that developed from microinjected ova were positive for the exogenous DNA by polymerase chain reaction. The implications are discussed for polymerase chain reaction detection of the exogenous gene construct in a relatively high proportion of microinjected blastocysts.

Effects of different protein supplements in fertilization medium on in vitro penetration of cumulus-intact and cumulus-free bovine oocytes matured in culture

Bovine oocytes matured in culture were inseminated with frozen-thawed spermatozoa in BO medium containing 5 mM-caffeine, 10 mug/ml of heparin and different protein supplements at various concentrations. When cumulus-enclosed oocytes were inseminated, no significant differences were observed in the penetration rates (89 to 100%) between media with and without protein supplements and among the different concentrations of each protein supplement, except for 20% calf serum (CS), in which the penetration rate decreased drastically (43%). Notably higher incidences of polyspermy were obtained in medium with FCS (75 to 86%) than with either no supplement (25%) or with BSA (20 to 24%) and CS (13 to 49%). On the other hand, there was almost no penetration of cumulus-free oocytes in the nonsupplemented control medium. Concentration-dependent increases in penetration and polyspermy occurred with BSA, FCS and CS supplementation. A high concentration (5%) of FCS yielded a high incidence (97%) of polyspermy. A decrease in the penetration of cumulus-enclosed oocytes was observed when spermatozoa were capacitated with a high concentration (20%) of CS; difficulty of sperm penetration of cumulus-free oocytes occurred when the capacitation medium lacked protein supplementation; and an increased rate of polyspermy was observed following supplementation with FCS in both cumulus-enclosed and cumulus-free oocytes after insemination with spermatozoa from 5 different bulls.

In vitro maturation and fertilization of buffalo oocytes (): Effects of media, hormones and sera

Media (TCM-199 and Ham's F-10); sera (fetal calf serum, FCS, and buffalo estrous serum, BES); and hormones (FSH, 0.5 ug/ml, LH, 5 ug/ml and estradiol 1 ug/ml) were tested to determine the efficiency of in vitro maturation and fertilization of buffalo follicular oocytes. Immature good quality cumulus-oocyte complexes (COCs) were randomly assigned to 1 of 4 experiments. Each experiment consisted of 6 treatment groups. Oocytes cultured for 24 hours in medium (TCM-199 or Ham's F-10) containing 10% FCS or BES had a significantly higher maturation rate than those in medium alone (P < 0.05). However, the maturation rate was higher in medium supplemented with 10% FCS than with 10% BES. Addition of hormones alone or in combination with sera further improved the maturation rate, but no significant difference was observed in the maturation rate among the 3 hormone-treated groups. Immature oocytes matured in the various cultures were fertilized with frozen-thawed buffalo spermatozoa. Our findings show that hormone and/or serum supplementation of TCM-199 did not improve the fertilization rate. Supplementation of Ham's F-10 with LH alone or in combination with LH + FSH + E(2) and with FCS significantly improved the fertilization rate of oocytes while medium with FSH, E(2) or no hormones did not (P < 0.05); same media supplemented with BES resulted in lower fertilization rates both in the presence or absence of hormones. The results indicate that the culture medium has a marked effect on the fertilization rate of buffalo oocytes. Ham's F-10 + LH + FSH + E(2) supplemented with FCS was the most efficacious culture system of those studied for the in vitro maturation of buffalo oocytes.

Use of in vitro fertilization for production of calves from involuntary cull cows

PURPOSE

The main purpose of the study was to assess the feasibility of a combined system for in vitro maturation of oocytes, in vitro fertilization, and in vitro culture of embryos for production of calves from cows that have to be removed prematurely from production units.

RESULTS

Eighteen cows that were to be culled from experimental dairy production units were ovariectomized. An average of 45.7 oocytes per cow was collected from the ovaries. After in vitro maturation and fertilization of the oocytes, an average of 40.8 presumptive zygotes was placed into in vitro culture, with an average of 16.1 cleaving by day 2 and an average of 5.7 developing to morulae/blastocysts by day 6 or 7. A greater mean quantity of oocytes was collected from cows that were ovariectomized between day 5 and day 13 of the estrous cycle than from those that were ovariectomized between day 0 and day 3 of the estrous cycle. Correspondingly larger mean numbers of cleaved zygotes and morulae/blastocysts were produced from the cows that were ovariectomized between day 5 and day 13 of the cycle. Transferable embryos were produced from 17 of the 18 cows. Eighteen embryos from six oocyte donor cows were transferred to recipients. Six of the eighteen recipients were confirmed to be pregnant after 40 days. Three of the pregnant recipients delivered live calves at term. Two others remain pregnant but have not reached term. The sixth recipient aborted at approximately 120 days of gestation.

CONCLUSIONS

Results from the preliminary study indicate that this system can be used for production of calves from cull cows. Although transferable embryos were produced from all except one cow, there was a high degree of variability among cows in total number of oocytes recovered and embryos produced. More donors need to be evaluated to determine the effects of age, breed, reason for culling, and source of semen.

Developmental ability of enucleated bovine oocytes matured in vitro after fusion with single blastomeres of eight-cell embryos matured and fertilized in vitro

Single blastomeres from eight-cell stage bovine embryos matured and fertilized in vitro were electrically fused with enucleated oocytes matured in vitro. In experiment 1, The percentage of these reconstituted embryos developed to the two- to eight-cell stage 48 hr after electrofusion was increased when both the eight-cell embryos and the enucleated oocytes were derived from oocytes cultured with granulosa cells (14% vs. 38%). In experiment 2, the relationship between activation of oocytes and developmental ability of reconstituted embryos was examined. Although both ethanol and electrical stimulation efficiently induced parthenogenetic activation of oocytes matured in vitro for 26-28 hr (ethanol, 89%; electrical stimulation, 73%), the ratio of the second polar body extrusion differed (80% vs. 22%). Ethanol-treated enucleated oocytes, however, were not significantly different from the early cleavage of the reconstituted embryos 48 hr after electrofusion (nontreated, 38%; treated, 43%). In experiment 3, reconstituted embryos at the two- to eight-cell stage 48 hr after the electrofusion were cocultured with granulosa cells for 6-7 days. Of 69 embryos, one developed to a morula and three developed to blastocysts.

Effect of epidermal growth factor (EGF) and defined simple media on in vitro bovine oocyte maturation and early embryonic development

The purpose of this study is to evaluate the effect of EGF and defined simple media on in vitro bovine oocyte maturation and early embryonic development. Bovine follicular oocytes were matured in vitro and co-cultured with frozen-thawed bull sperm, which was capacitated with Hepes buffered saline (HBS) solution. After incubation of oocyte-sperm complexes for 4 days, the cleavage rate was evaluated. The results obtained were as follows: 1) When bovine oocytes were matured and embryos were developed in Park-Lin medium 1 (PL(1)) containing fetal calf serum (FCS) or EGF + bovine serum albumin (BSA), the latter treatment was more effective in inducing embryonic cleavage (18%) than FCS alone (10%). 2) When bovine oocytes were matured in Park-Lin medium 2 (PL(2)) without EGF and the subsequent embryos were developed in PL(2) medium with EGF, the cleavage rate was 22.6%. 3) When bovine oocytes were matured in PL(2) medium with EGF and then the embryos were developed in PL(2) medium with EGF, the cleavage rate was 35.8%. 4) When bovine oocytes were matured in Park-Lin medium 3 (PL(3)) without EGF and then the embryos were developed in PL(3) medium, the cleavage rate was 50%. 5) When bovine oocytes and resulting embryos were matured in PL(3) medium with EGF, the cleavage rate was 53%. 6) The parthenogenesis rate induced by PL(3) medium in our current study was comparable to the findings reported by other laboratories. These results suggest that EGF stimulates in vitro bovine oocyte maturation and subsequently affects embryonic development. It is suggested that PL(3) medium is a better defined simple medium than the other media currently used by other laboratories for in vitro bovine oocyte maturation.