In Vitro Embryo Production Embryos Research Articles

Effects of mycobacterium cell wall fraction on embryo development following in vitro embryo production and pregnancy rates following embryo transfer in virgin dairy heifers

An experiment was conducted to determine whether administration of mycobacterium cell wall fraction (MCWF; Amplimune, NovaVive) could enhance embryo developmental competence following in vitro embryo production (IVP) and pregnancy establishment after embryo transfer (ET). Nulliparous, Holstein heifers (n = 40; age 8–15 months) were submitted to two rounds of ovum pick-up (OPU) and IVP in a crossover design. Thirty-six h after follicle wave synchronization, treatments (saline or MCWF, 5 mL, im) were administered in conjunction with a single dose of follicle stimulating hormone (175 IU) and OPU was performed 48–52 h later. Recovered cumulus-oocyte complexes were used for IVP to assess embryo development. For ET, nulliparous, Holstein heifers (n = 225; age 12–18 months) were used as recipients. At 12–24 h after detection of spontaneous estrus, recipients were randomly treated with either saline or MCWF (5 mL, im). The effect of MCWF on pregnancy per ET (P/ET) was assessed in a 2 × 2 factorial design with recipients treated with or without MCWF receiving a fresh IVP embryo from a donor treated with or without MCWF at day 7 or 8 after detected estrus. Blood samples were collected from a subset of donors (n = 8) and recipients (n = 26 to 33 per treatment) prior to treatment and at 6 and 24 h post-treatment to determine serum concentration of interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and interferon-γ. Blood samples were also collected from a group of recipients (n = 31 to 39 per treatment) to assess serum concentration of progesterone at days 4, 7, and 16 post-treatment. Pregnancy status was determined at days 40 and 100 of gestation. Donor treatment with MCWF tended (P < 0.07) to increase the proportion of oocytes that developed into transferable embryos, but there was no effect of MCWF on other parameters of embryo development. The P/ET at days 40 and 100 of gestation and pregnancy loss were not affected by donor treatment or recipient treatment with MCWF and there was no interaction. Serum concentration of proinflammatory cytokines among donors and recipients and serum concentration of progesterone among recipients were not increased by treatment with MCWF. Results of the present study indicate that treatment of donors with MCWF has minimal impact on subsequent embryo development following IVP. Moreover, regardless of whether donors or recipients were treated with MCWF, there was no effect on P/ET following transfer of IVP embryos.

Transmission of Mycoplasma bovis infection in bovine in vitro embryo production

Mycoplasma bovis (M. bovis) causes several costly diseases in cattle and has a negative effect on cattle welfare. There is no effective commercial vaccine, and antimicrobial resistance is common. Maintaining a closed herd is the best method to minimize the risk of introduction of M. bovis. Assisted reproduction is crucial in a closed herd to make genetic improvements. M. bovis has been found in commercial semen, and contaminated semen has been the source of disease in naïve dairy herds. The objective of this study was to evaluate M. bovis transmission in bovine in vitro embryo production (IVP) using several possible exposure routes. We used a wild-type M. bovis strain isolated from semen at a final concentration of 106 CFU/mL to infect cumulus–oocyte complexes, spermatozoa, and 5-day-old embryos. We also used naturally contaminated semen in fertilization. Blastocysts were collected on day 7–8 and zona pellucida (ZP)-intact embryos were either washed 12 times, including trypsin washes as recommended by the International Embryo Technology Society (IETS), or left unwashed. Washed and unwashed embryos, follicular fluids, maturation medium, cumulus cells, fertilization medium, and G1 and G2 culture media, as well as all wash media were analyzed using enrichment culture followed by real-time PCR detection of M. bovis. Altogether, 76 pools containing 363 unwashed embryos and 52 pools containing 261 IETS washed embryos were analyzed after oocytes, spermatozoa, or 5-day-old embryos were infected with M. bovis or naturally contaminated semen was used in fertilization. We could not detect M. bovis in any of the embryo pools. M. bovis was not found in any of 12 wash media from different exposure experiments. M. bovis did not affect the blastocyst rate, except when using experimentally infected semen. Contrary to an earlier study, which used a cell co-culture system, we could not demonstrate M. bovis in embryo wash media or tight adherence of M. bovis to ZP-intact embryos. Naturally infected semen did not transmit M. bovis to embryos. We conclude that by using our IVP system, the risk of M. bovis transmission via IVP embryos to recipient cows is very low.

Lipid profile of bovine grade-1 blastocysts produced either in vivo or in vitro before and after slow freezing process

Currently, in vitro embryo production (IVP) is successfully commercially applied in cattle. However, the high sensitivity of embryos to cryopreservation in comparison to in vivo (IVD) embryos slows the dissemination of this biotechnology. Reduced cryotolerance is frequently associated with lipid accumulation in the cytoplasm mainly due to in vitro culture conditions. The objective of this study was to evaluate the lipid composition of biopsied and sexed embryos, produced either in vivo or in vitro from the same Holstein heifers before and after a slow freezing protocol. Lipid extracts were analysed by liquid chromatography-high resolution mass spectrometry, which enabled the detection of 496 features. Our results highlighted a lipid enrichment of IVP embryos in triglycerides and oxidised glycerophospholipids and a reduced abundance in glycerophospholipids. The slow freezing process affected the lipid profiles of IVP and IVD embryos similarly. Lysophosphatidylcholine content was reduced when embryos were frozen/thawed. In conclusion, the embryonic lipid profile is impacted by IVP and slow freezing protocols but not by sex. Lysophosphatidylcholine seemed highly sensitive to cryopreservation and might contribute to explain the lower quality of frozen embryos. Further studies are required to improve embryo freezability by modulating the lipidome.

24 Lipid composition of fresh or frozen sexed bovine blastocysts produced invivo or invitro

Currently, invitro embryo production (IVP) is successfully applied commercially in cattle. However, the high sensitivity of embryos to cryopreservation compared with invivo-derived (IVD) embryos still impairs the dissemination of this biotechnology. Reduced cryotolerance is frequently associated with lipid accumulation in the cytoplasm mainly due to invitro culture conditions. The objective of this study was to evaluate the lipid content of fresh and frozen sexed bovine grade 1 IVP or IVD embryos. The same 8 Holstein heifers were used in a Latin square design for both IVP and IVD embryo production. Zygotes were cultured in synthetic oviductal fluid (SOF) supplemented with 1% oestrus cow serum. The same bull was used for IVP and IVD. All expanded Day 7 blastocysts (n=40 IVP and 40 IVD) were biopsied and sexed. Half of the embryos (n=20 in each group) was slow frozen (1.5M ethylene glycol, 0.1m sucrose) and thawed before lipid extraction. Remaining embryos underwent lipid extraction in the fresh state. Briefly, the liposoluble fraction of the embryos was extracted according to the Bligh and Dyer method using chloroform and methanol. Liquid chromatography–high-resolution mass spectrometry (LC-HRMS) analysis was performed and operated in positive ionization mode. Lipids with variance intensities greater than 30% in quality control samples were removed as well as those identified as background noise. Partial least square discriminant analysis (PLS-DA) was used to show the relationship between variance in the data and difference among embryo origin (IVP vs. IVD), state before extraction (fresh vs. frozen), and sex of the embryos (male vs. female). The differentially lipid species groups were identified using Wilcoxon test, and considered significantly different when P&amp;lt;0.05. LC-HRMS analysis allowed us to identify 75 lipids. PLS-DA showed that embryo origin (IVP vs. IVD) and state before extraction (fresh vs. frozen) can be determined by LC-HRMS profiles by group in PLS-DA plot, despite slight overlaps. Sex of the embryos did not allow us to differentiate the lipid profile. However, 15 lipids varied significantly between male and female IVD, predominantly triglycerides (TG), whereas no lipid varied between the sexes in the IVP homologues. Moreover, 26 lipids varied significantly between IVP and IVD fresh embryos with enrichment of IVP embryos in TG, phosphatidyl choline, cholesteryl ester, and less diglyceride and lysophospholipid (LP) compared with IVD embryos. The comparison of the lipid profiles before and after freezing for IVP embryos showed that only 7 lipids varied significantly between fresh and frozen states with a decrease in LP for the frozen embryos. For the invivo counterparts, 13 lipids varied significantly, including the same LP as those identified for IVP embryos in the same way. Our results showed that the embryonic lipid profile is mainly affected by IVP and slow freezing protocols and, to a lesser extent, by sex. Further studies are needed to improve IVP protocols and optimize the cryotolerance of IVP embryos in cattle.

Evolution of knowledge on ovarian physiology and its contribution to the widespread application of reproductive biotechnologies in South American cattle.

As our understanding of ovarian function in cattle has improved, our ability to control it has also increased. Luteal function in cattle has been studied in detail, and prostaglandin F2α has been used for several years for the elective induction of luteal regression. More recently, follicle wave dynamics has been studied and protocols designed to induce follicular wave emergence and ovulation have reduced, and even eliminated, the need for estrus detection. The addition of progestin-releasing devices, estradiol, GnRH and equine chorionic gonadotropin (eCG) have provided opportunities for fixed-time AI (FTAI) and possibilities for increased pregnancy rates. In embryo transfer programs, these same treatments have eliminated the need for estrus detection, permitting fixed-time embryo transfer and the initiation of superstimulatory treatments without regard to day of the estrous cycle. Collectively, new treatment protocols have facilitated the application of assisted reproductive technologies, and this is especially true in South America. Over the last 20 years, the use of AI in South America has increased, due largely to the use of FTAI. There has been more than a 10-fold increase in the use of FTAI in Brazil with more than 11 million treatments in 2016, representing 85% of all AI. Similar trends are occurring in Argentina and Uruguay. Production of in vivo-derived (IVD) embryos has remained relatively stable over the years, but in vitro embryo production (IVP) has increased dramatically over the past 10 to 15 years, especially in Brazil where more than 300,000 IVP embryos were produced in 2010. World-wide, more than 666,000 bovine IVP embryos were produced in 2016, of which more than 57% were produced in South America. The use of assisted reproductive technologies has facilitated the dissemination of improved genetics and increased reproductive performance; other South American countries are now following suit.

100 FACTORS AFFECTING PREGNANCY RATES IN THE TRANSFER OF IN VITRO-PRODUCED JAPANESE BLACK CATTLE EMBRYOS

Despite the rapid expansion of in vitro embryo production (IVP) technology for genetic improvement in the cattle industry in the last decades, pregnancy rates by the transfer of IVP embryos are still lower than those derived from in vivo-produced embryos. The objective of this study was to analyse factors affecting pregnancy rates after the transfer of IVP Japanese Black cattle embryos under farm conditions. Holstein heifers (n = 4,475) and cows (n = 8,541) were selected as recipients. Most cows (80%) were managed in tie-stall barns and most heifers (80%) were managed in pens. Embryo transfers were performed for 9 years, from 2004 to 2012. The embryos were produced from oocytes derived from a local abattoir and semen from 14 proven bulls by the Livestock Improvement Association of Japan (Hamano and Kuwayama 1993 Theriogelogy 39, 703–712). The fresh IVP embryos (quality; IETS code 1) that reached the blastocyst stage after 7 to 8 days (insemination = Day 0) were transported by an airplane (2 h) and subsequently by a car (1.5 h). Embryos were non-surgically transferred to each recipient on Day 7 to 9 of their natural oestrous cycle on farms. Pregnancy was diagnosed on Day 40 to 60 after oestrus. Pregnancy results were statistically analysed using the GLM procedures of SAS. The following variables were included in the model: recipient parity (0, 1, 2, or 3), day (7, 8, or 9) of the oestrous cycle at the time of embryo transfer, oestrus behaviour (increased activity observed by farmers), presence of mucus at oestrus, presence of blood after oestrus, and year (1, 2, 3, 4, 5, 6, 7, 8, or 9) and season (April–June as spring, July–September as summer, October–December as fall, or January–March as winter) of embryo transfer. The Bonferroni correction was used to counteract the problem of multiple comparisons. Heifers had significantly higher pregnancy rates than cows (51.0% v. 37.9%, respectively; P &lt; 0.01), and first parity cows had higher pregnancy rates than third parity cows (42.9% v. 35.7%, respectively; P &lt; 0.01). Pregnancy rates were significantly higher in recipients that received an embryo transfer on Day 8 of their oestrous cycle, than on Day 7 (46.6% v. 42.4%, respectively; P &lt; 0.01). Recipients without oestrus behaviour had higher pregnancy rates than those with oestrus behaviour (46.3% v. 43.4%, respectively; P &lt; 0.01). The presence of mucus and/or blood after oestrus and the season of transfer were not found to significantly affect pregnancy rates. The results of this study indicated that performing IVP embryo transfers on Day 8 of a recipient’s oestrous cycle will improve the pregnancy rate, season does not have an effect on pregnancy rate, and the detection of oestrus by monitoring increased activity is not always reliable and instead should be determined by multiple symptoms on farm conditions.

193 IMPROVED POST-THAW SURVIVAL OF BOVINE EMBRYOS PRODUCED IN SERUM-FREE IN VITRO PRODUCTION SYSTEM

Over a few decades the bovine in vitro embryo production (IVP) systems have been improving rapidly. Still, the goal to produce the same quality embryos in vitro as in vivo has not yet been reached. The FCS is usually added to media during IVP to provide growth factors and energy sources. Currently, serum-free culture systems are often preferred due to the lower risk of contamination and prevention of the development of large offspring syndrome. The aim of this study was to establish whether complete elimination of FCS from the bovine IVP system has an effect on blastocyst rates, embryo quality, and embryo survival rates after slow freezing. We replaced our conventional in vitro maturation (IVM) medium [tissue culture medium-199, 10% (v/v) FCS, 10 µg mL–1 epidermal growth factor (EGF), 1500 U mL–1 serum gonadotropin and chorionic gonadotropin (PG600), Na-pyruvate 0.5 mM, gentamycin sulfate 50 µg mL–1 and l-glutamine 1 mM] with SOF (SOFaaci) supplemented with 0.4% fatty acid-free BSA fraction V, 10 µg mL–1 EGF, and 1500 U mL–1 PG600. Matured cumulus-oocyte complexes (COC) from both experimental groups (total of 1145 from serum-free IVP and 687 from our conventional IVP system) were used for in vitro fertilisation and culture. Blastocyst rates were similar in the serum-free and our usual IVP protocol, 18 and 22%, respectively. Seventy-seven Grade 1 (according to IETS) Day 7 blastocysts from the serum-free IVP system and 80 Grade 1 Day 7 blastocysts from our conventional IVP system were frozen in 1.5 M ethylene glycol and 0.1 M sucrose containing cryopreservation medium. The post-thaw survival rates after 24 h of culture and evaluated as percentages of re-expanded embryos were 63.6% for the serum-free IVP and 46.3% for the conventional IVP system (P &lt; 0.05, Z Test for 2 population proportions). These results indicate that it is possible to have a completely serum-free bovine IVP system and based on the slow freezing and thawing results the quality of serum-free IVP embryos might be better than of the embryos matured in our conventional maturation media. However, more experiments and increased sample sizes are needed to confirm the results. This study was supported by Project 3.2.0701.12–0036 of Archimedes Foundation, AP 2.4 of CCRMB, and institutional research funding (IUT 08–01) of the Estonian Ministry of Education and Research.

Efficacy of a single intramuscular injection of porcine FSH in hyaluronan prior to ovum pick-up in Holstein cattle

Plasma FSH profiles, in vitro embryo production (IVP) after ovum pickup (OPU), and establishment of pregnancy with IVP embryos were compared in untreated Holstein oocyte donors and those superstimulated with multiple injections or a single intramuscular (IM) injection of porcine FSH (pFSH) in hyaluronan (HA). Plasma FSH profiles were determined in 23 heifers randomly allocated to one of four groups. Controls received no treatment, whereas the F200 group received 200 mg of pFSH in four doses, 12 hours apart. The F200HA and F300HA groups received 200- or 300-mg pFSH in 5 mL or 7.5 mL, respectively of a 0.5% HA solution by a single IM injection. Plasma FSH levels were determined before the first pFSH treatment and every 6 hours over 96 hours. All data were analyzed by orthogonal contrasts. Circulating FSH area under curve (AUC) in pFSH-treated animals was greater than that in the control group (P = 0.02). Although the AUC did not differ among FSH-treated groups (P = 0.56), the total period with elevated plasma FSH was greater in the F200 group than in the HA groups (P < 0.0001). However, the F300HA group had a greater AUC than the F200HA group (P = 0.006), with a similar total period with elevated plasma FSH (P = 0.17). The IVP was performed in 90 nonlactating Holstein cows randomly allocated to one of the four treatment groups as in the first experiment. A greater proportion of medium-sized (6–10 mm) follicles was observed in cows receiving pFSH, regardless of the treatment group (P < 0.0001). Also, numbers of follicles (P = 0.01), cumulus–oocyte complexes (COCs) retrieved (P = 0.01) and matured (P = 0.02), cleavage rates (P = 0.002), and blastocysts produced per OPU session (P = 0.06) were greater in cows receiving pFSH, regardless of the treatment group. Cows in the F200HA group had a greater recovery rate (P = 0.009), number of COCs cultured (P = 0.04), and blastocysts produced per OPU session (P = 0.06) than cows in the F300HA group. Similar pregnancy rates were observed 50 to 60 days after transferring IVP embryos from donors in the different treatment groups (P > 0.05). In conclusion, a single IM injection of pFSH combined in 0.5% HA resulted in similar plasma FSH profiles as twice-daily pFSH treatments. Treatment of nonlactating donors with pFSH, with or without HA, resulted in increased IVP over untreated controls. A single dose of 200 mg of pFSH in 0.5% HA resulted in greater IVP than 300-mg pFSH in HA. Finally, pregnancy rates with IVP embryos were similar, regardless donor treatment.

Maternal age and in vitro culture affect mitochondrial number and function in equine oocytes and embryos.

Advanced maternal age and in vitro embryo production (IVP) predispose to pregnancy loss in horses. We investigated whether mare age and IVP were associated with alterations in mitochondrial (mt) DNA copy number or function that could compromise oocyte and embryo development. Effects of mare age (<12 vs ≥12 years) on mtDNA copy number, ATP content and expression of genes involved in mitochondrial replication (mitochondrial transcription factor (TFAM), mtDNA polymerase γ subunit B (mtPOLB) and mitochondrial single-stranded DNA-binding protein (SSB)), energy production (ATP synthase-coupling factor 6, mitochondrial-like (ATP-synth_F6)) and oxygen free radical scavenging (glutathione peroxidase 3 (GPX3)) were investigated in oocytes before and after in vitro maturation (IVM), and in early embryos. Expression of TFAM, mtPOLB and ATP-synth-F6 declined after IVM (P<0.05). However, maternal age did not affect oocyte ATP content or expression of genes involved in mitochondrial replication or function. Day 7 embryos from mares ≥12 years had fewer mtDNA copies (P=0.01) and lower mtDNA:total DNA ratios (P<0.01) than embryos from younger mares, indicating an effect not simply due to lower cell number. Day 8 IVP embryos had similar mtDNA copy numbers to Day 7 in vivo embryos, but higher mtPOLB (P=0.013) and a tendency to reduced GPX3 expression (P=0.09). The lower mtDNA number in embryos from older mares may compromise development, but could be an effect rather than cause of developmental retardation. The general down-regulation of genes involved in mitochondrial replication and function after IVM may compromise resulting embryos.

Differences in amniotic amino acid concentrations between pregnancies obtained with transfer of vitrified thawed in vitro–produced embryos and with natural mating in sheep

In vitro embryo production (IVP) and cryopreservation are associated with a high incidence of pregnancy complications and fetal abnormalities that may be linked with alterations of placental development. The amniotic fluid is partly derived from the transport of water and solutes across the placenta and provides the fetus with amino acids (AAs), which are the building blocks for biomolecules involved in physiological growth and development. To better understand the anomalies associated with IVP pregnancies, the present study was conducted to test the hypothesis that amniotic concentrations of AAs differ in pregnancies derived from vitrified/thawed (V/T) IVP embryos compared with gestations obtained with natural mating (NM) in sheep. Amniotic fluid was sampled in ewes that were pregnant after transfer of V/T IVP embryos and that had conceived with NM between Days 60 and 65 (V/T, n = 6; NM, n = 11) and between Days 80 and 85 (V/T, n = 5; NM, n = 14) of gestation via ultrasound-guided amniocentesis. Concentrations of 16 AAs in the amniotic fluid were measured using high-performance liquid chromatography. From Days 60 to 65 of gestation, concentrations of cystine, phenylalanine, and isoleucine were lower in V/T compared with NM ewes. From Days 80 to 85 of pregnancy, the mean concentrations of cystine and lysine were lower in the V/T versus NM groups. The total AA concentration per ewe was similar between the groups from Days 60 to 65 and 80 to 85 of gestation and decreased by 55% from Days 60 to 65 and 80 to 85 of gestation in all ewes. The most abundant AA from Days 60 to 65 of gestation was alanine in both groups, whereas from Days 80 to 85, the most abundant AAs were alanine in NM and glycine in V/T ewes; cystine was the less abundant detectable AA in all ewes at both stages of gestation. Results report that V/T IVP embryos have decreased concentrations of individual AAs in the amniotic fluid during the second trimester of gestation possibly because of an impaired placental vasculogenesis or because of a reduced placental transport. These novel findings are relevant to unravel the mechanisms responsible for the issues of pregnancies achieved with the transfer of IVP and cryopreserved embryos.

143 COMPARISON OF COMMERCIAL IN VITRO EMBRYO PRODUCTION AND PREGNANCY RATES OF BRAHMAN DONORS IN PANAMA VERSUS DOMINICAN REPUBLIC

It has been previously demonstrated (IETS 2011) that Panama is applying the biotechnology of in vitro embryo production (IVP) to their bovine reproduction management systems. The present work demonstrates the ability to apply the IVP technology across 2 distant country borders. Herein, we demonstrate that a country (Dominican Republic; DR) that does not have a bovine IVP laboratory can take advantage of fresh bovine IVP embryos for transfer using distant IVP facilities in another country (Panama; ~1500 km away). The objective of this study was to demonstrate that a model system for large-scale commercial in vitro bovine embryo production for beef and dairy producers, that do not have IVP technology in their home country, could be developed producing comparable results. As the same laboratory provides IVP services to the both countries, a special sanitary protocol was developed in order to legalize the exchange of biological materials (oocytes or embryos). The data obtained in DR was compared to Panamanian client data because identical conditions were utilised for IVP. Cattle production systems were similar, as Brahman (a Zebu type of cattle) is the most popular breed in both countries. Oocytes were collected from 10 different herds in Panama and 4 different herds in DR. The oocytes were transported in an oocyte transporter in both instances. However, oocytes from DR were transported in InVitro Brasil™ maturation medium from 12 to 18 h and in Panama from 6 to 12 h before they were placed in a standard CO2 incubator. In both cases, the oocytes were matured for 24 h before fertilization with conventionally frozen Brahman semen in InVitro Brasil™ fertilization medium, followed by culture for up to 7 days in InVitro Brasil™ embryo culture medium. The embryos were transferred on Day 7, either in Panama or DR. They were transported by car in Panama and via airplane back to DR. A comparison of oocyte number and quality, cleavage, embryo production, and pregnancy rate, was made using the same in vitro production system for Brahman donors from September 2012 until May 2013. The difference between sites in the relative number of viable oocytes, relative number of cleaved oocytes among viable oocytes, relative number of embryos produced among cleaved oocytes, and relative number of embryos produced among viable oocytes was tested using Fisher's exact test. Pregnancy rate was analysed with chi-squared. We realise these results represent field data; however, we believe the present work is a significant step in demonstrating the potential for wide commercial-scale dissemination of IVP technology between distant countries. The number of embryos produced in Panama was slightly, but significantly, higher than those produced in DR; this is likely due to the larger number of donors and oocytes from the Panamanian herds. However, the pregnancy rate was higher in DR, likely due to the health status of DR recipients. These data illustrate that IVP using Brahman donors could be used as a tool to improve and spread superior genetics. Furthermore, this technique can serve as a model for other Central American and Caribbean countries under similar management systems. Table 1.Panama and the Dominican Republic in vitro Brahman embryo production and pregnancy (September 2012 through May 2013)

230 OVUM PICKUP - IN VITRO PRODUCTION EFFICIENCY FOR CONSERVATION OF THE FLAMENGA CATTLE BREED

The introduction of more specialised and productive dairy breeds into commercial herds in recent decades has caused a gradual loss of interest in dual-purpose cattle breeds, such as the Flamenga. Because of its importance to biodiversity, the high risk of loss of this small Brazilian herd, located in one geographic region in Southern Brazil, justifies the need for and efforts in genetic conservation of the Flamenga breed. The ovum pickup (OPU) procedure is a potential tool for such conservation purposes. Thus, the aim of this study was to evaluate the oocyte and embryo yield potential of the Flamenga breed, as compared with Holstein control counterparts, after in vivo oocyte retrieval followed by in vitro embryo production (IVP). Four Flamenga and 4 Holstein multiparous milking cows from the same herd were subjected to weekly ultrasound-guided OPU sections for 10 consecutive weeks. The number of visible follicles per ovary per female was recorded before the aspiration of ≥3-mm follicles. Retrieved cumulus–oocyte complexes (COC) were morphologically graded according to the method of (Leibfried and First 1979 J. Anim. Sci. 48, 76–86), and viable COC (Grades I, II, and III) from both breeds and from slaughterhouse ovaries (IVP controls) were used for the IVP of embryos, based on our established procedures (Vieira et al. 2002 Cryobiology 45, 91–94). Frozen semen from the same Flamenga breed bull was used in all groups. Quantitative (visible and aspirated follicles, collected COC), and qualitative (COC recovery efficiency, cleavage and blastocyst rates) data were compared between breeds and IVP controls (when pertinent) by Student’s t-test and chi-square test, respectively, for P &lt; 0.05. Results are presented in Table 1. The pools of visible and aspirated follicles were similar between breeds. However, the COC recovery efficiency was higher for Flamenga than for Holstein females. In vitro embryo development was also different between breeds, with cleavage rate being significantly lower for Holsteins than for Flamenga and IVP controls. Blastocyst rates also differed between treatments. Nonetheless, development to the blastocyst stage, when based on cleavage, was similar between Flamenga and Holstein embryos, but with both breeds being lower than the IVP controls. Oocyte quality was likely the cause of such differences in embryo developmental potential between groups, with Flamenga females yielding more oocytes and IVP embryos than Holstein cows. In summary, the use of OPU-IVP procedures was demonstrated to be suitable for the preservation of the Flamenga breed in Southern Brazil. Table 1.Follicular pool and oocyte and embryo yield between Flamenga and Holstein cows following ovum pickup–in vitro production (IVP) procedures This study was supported by CAPES and CNPq/Brazil.

96 RECOVERY RATES OF BOVINE IVP EMBRYOS CRYOPRESERVED BY SLOW FREEZING AND VITRIFICATION (OPS AND SSV) METHODS

In current commercial bovine in vitro embryo production (IVP) systems, the majority of costs are related to acquisition and preparation of recipient cows, which must be proportional to the produced embryos. Nevertheless, most of the time this relation is not obtained, and one option is the cryopreservation of extra embryos. Unfortunately, there is a large difference in the pregnancy rates of fresh and cryopreserved IVP embryos or the rates of recovery of frozen-thawed embryos according to the technique used for cryopreservation. The aim of this work was to compare recovery taxes (re-expansion and eclosion) of bovine IVP embryos produced following conventional systems, without any specific media or supply for cryopreservation, simulating one condition of extra produced embryos. The COC obtained from abattoir ovaries were matured (TCM-199, supplemented with FCS, LH, FSH, E2, pyruvate, and antibiotic) for 24 h and fertilized (Fert-TALP supplemented with BSA, PHE, and heparin) for 18 to 22 h (Day 0) in vitro. At Day 1, presumptive zygotes were transferred to development media (SOFaa supplemented with BSA and FCS), and at Day 7, grade I embryos were submitted to 3 different cryopreservation methods: slow freezing (ethylene glycol 1.5 M from 6°C to -35°C, 1°C min-1) and vitrification (DMSO, ethylene glycol, and sucrose) by OPS or SSV After the cryopreservation process, all embryos were specifically thawed according to their method and re-cultured in SOFaa for 48 h when the re-expansion and eclosion taxes were evaluated (number of viable embryos after the cryopreservation process). According to results, the taxes of viable embryos cryopreserved by vitrification methods were better than slow freezing, except expanded blastocysts cryopreserved by slow freezing, disproving literature data that show more ability for ice crystal formation in this embryo stage than others due to liquid storage. When the total of embryos is considered in the different methods (n = 1464), the vitrification method was superior to the others, but when new methodologies could be applied aimed at less lipid storage in structures (oocytes and embryos) by gas atmosphere control or total-defined cultured media, better rates can most likely be obtained with the OPS method as SSV or slow freezing. Table 1.Viable embryo rates after different cryopreservation methods WTA-Watanabe Applied Technology.

Effect of cytoplasmic lipid content on in vitro developmental efficiency of bovine IVP embryos

The objective was to evaluate the effect of cytoplasmic lipid content on the embryonic developmental efficiency of bovine in vitro embryo production (IVP) embryos. Ovaries from Korean native cows (Bos taurus coreanae) were collected from a local abattoir, and cumulus-oocyte complexes (COCs) were recovered from follicles 2 to 8 mm in diameter. The oocytes were divided into three groups, dependent on their cytoplasm color: pale color (PC), brown color (BC), and dark color (DC). The COCs were fertilized using frozen-thawed semen from a single Hanwoo bull. Based on measurement of the cytoplasmic color intensity of oocytes after 22 h of in vitro maturation (IVM), the DC group had lower (P < 0.05) color intensity than that in the BC and PC groups (56.3 ± 2.7, 93.3 ± 5.1, and 123.9 ± 12.0, respectively). Based on MitoTracker Green FM staining, the number of mitochondria in the DC (170.1 ± 31.2) group was significantly higher than that in the BC (137.5 ± 30.8) and PC (105.5 ± 25.3) groups. The cleavage rate in the DC (81.5%) group was also higher than that in the PC (50.4%) group (P < 0.05), as was the development rate to blastocyst stage (18.9% vs. 9.8%). Finally, cell numbers of blastocysts in the DC (150.8 ± 28.0) group were higher (P < 0.05) than that in the BC (107.6 ± 17.8) and PC (80.5 ± 12.3) groups. In conclusion, cytoplasm color was a useful selection parameter for abattoir-derived oocytes destined for IVP.

246 IN VITRO PRODUCTION OF SPRINGBOK (ANTIDORCAS MARSUPIALIS) EMBRYOS

The objective of this experiment was to develop in vitro embryo production (IVP) technologies in springbok (Antidorcas marsupialis), a southern African antelope. Springbok, a fairly common species on game farms in parts of South Africa, may be used as a model species for gamete rescue and IVP techniques to be applied to the conservation of other threatened antelope species. Springbok belong to the family bovidae, subfamily antilopinae, tribe antilopini, which comprises about twenty species in genera Gazella, Antilope, Procapra, Antidorcas, Litocranius, and Ammodorcas. In this tribe alone, there are 4 species or subspecies that are critically endangered, 3 that are endangered, and 10 that are considered vulnerable, demonstrating the need for antelope conservation efforts. In addition, our studies contributed to the South African biological resource bank, so that banked springbok semen and embryos might be used in the future for managed genetic contribution to isolated captive or wild populations via assisted reproductive technologies. Oocytes were recovered (3 replicates) from ovaries obtained at supervised culls for management purposes in South Africa, and cultured in defined Gmat or undefined TCM-199 with FCS maturation medium for 28-30 h (Brad et al. 2004 Reprod. Fertil. Dev. 16, 223). Oocytes were fertilized with frozen-thawed springbok epididymal spermatozoa in modified SOF fertilization medium with caffeine (Herrick et al. 2004 Biol. Reprod. 71, 948–958). Eighteen hours after insemination, a randomly selected subset of the zygotes were fixed to determine fertilization success. The remaining zygotes were cultured in G1/G2 media. On Day 7 of culture, embryos were analyzed for development to the morula or blastocyst stage. A total of 259 selected oocytes were collected from 50 females (5.2 selected oocytes/female on average). There was no difference in the percentage of oocytes normally fertilized (2 pronuclei, PN) between oocytes matured in Gmat (n= 43; 12%) and those matured in TCM-199 (n= 42; 10%). There were significantly (P &amp;lt; 0.05) more oocytes penetrated (e2 PN) when matured in TCM (50%) compared to Gmat (23%). There were no differences in embryonic cleavage or morula/blastocyst development (of total oocytes inseminated) between treatments (Gmat,n= 89, 54%, 9.0%; TCM-199, n= 85, 68%, 9.4%, respectively). In both treatments, the average blastocyst grade was 2.125 using the standard bovine grading system (Curtis, Cattle Embryo Transfer Procedure, 1991). In conclusion, in vitro oocyte maturation, fertilization, and embryo culture to the blastocyst stage is possible in springbok. Importantly, blastocysts can be produced in vitro under semi-defined conditions, demonstrating that oocyte maturation without serum does support developmental competence. This is important for the potential international movement of IVP embryos to be used for genetic management in the conservation of antelope species.