Modified dietary fiber from cassava pulp affects the cecal microbial population, short-chain fatty acid, and ammonia production in broiler chickens

The objective of this study was to investigate the effects of modified dietary fiber from cassava pulp (M-DFCP) supplementation in broiler diets on cecal microbial populations, short-chain fatty acids (SCFAs), ammonia production, and immune responses. A total of 336, one-day-old male broiler chicks (Ross 308) were distributed over 4 dietary treatments in 7 replicate pens (n = 12 chicks) using a completely randomized design. Chicks were fed the control diet and 3 levels of M-DFCP (0.5, 1.0, and 1.5%) for an experimental duration of 42 d. The M-DFCP contained total dietary fiber (TDF), soluble dietary fiber (SDF), insoluble dietary fiber (IDF), cello-oligosaccharides (COS), and xylo-oligosaccharides (XOS) of approximately 280.70, 22.20, 258.50, 23.93, and 157.55 g/kg, respectively. The 1.0 and 1.5% M-DFCP supplementation diets showed positive effects on stimulating the growth of Lactobacillus spp. and Bifidobacterium spp., enhancing SCFAs (acetic, propionic, butyric acid, and branched SCFAs) and lactic acid concentrations during growing periods. Broilers fed 1.0 and 1.5% M-DFCP also exhibited a significant increase in caecal Lactobacillus spp. and lactic acid concentrations during the finisher period as well. In addition, M-DFCP also reduced cecal digesta and excreta ammonia production in broilers over both periods (0-21 and 22-42 d of age). However, M-DFCP did not exhibit any effect on total serum immunoglobulin (Ig) or lysozyme activity. In conclusion, this study shows that M-DFCP can be used as a dietary fiber source in broiler diets, with a recommended level of approximately 1.0%.

Unveiling how vitrification affects the porcine blastocyst: clues from a transcriptomic study

Background

Currently, there is a high demand for efficient pig embryo cryopreservation procedures in the porcine industry as well as for genetic diversity preservation and research purposes. To date, vitrification (VIT) is the most efficient method for pig embryo cryopreservation. Despite a high number of embryos survives in vitro after vitrification/warming procedures, the in vivo embryo survival rates after embryo transfer are variable among laboratories. So far, most studies have focused on cryoprotective agents and devices, while the VIT effects on porcine embryonic gene expression remained unclear. The few studies performed were based on vitrified/warmed embryos that were cultured in vitro (IVC) to allow them to re–expand. Thus, the specific alterations of VIT, IVC, and the cumulative effect of both remained unknown. To unveil the VIT-specific embryonic alterations, gene expression in VIT versus (vs.) IVC embryos was analyzed. Additionally, changes derived from both VIT and IVC vs. control embryos (CO) were analyzed to confirm the VIT embryonic alterations. Three groups of in vivo embryos at the blastocyst stage were analyzed by RNA–sequencing: (1) VIT embryos (vitrified/warmed and cultured in vitro), (2) IVC embryos and (3) CO embryos.

Results

RNA–sequencing revealed three clearly different mRNA profiles for VIT, IVC and CO embryos. Comparative analysis of mRNA profiles between VIT and IVC identified 321, differentially expressed genes (DEG) (FDR < 0.006). In VIT vs. CO and IVC vs. CO, 1901 and 1519 DEG were found, respectively, with an overlap of 1045 genes. VIT-specific functional alterations were associated to response to osmotic stress, response to hormones, and developmental growth. While alterations in response to hypoxia and mitophagy were related to the sum of VIT and IVC effects.

Conclusions

Our findings revealed new insights into the VIT procedure-specific alterations of embryonic gene expression by first comparing differences in VIT vs. IVC embryos and second by an integrative transcriptome analysis including in vivo control embryos. The identified VIT alterations might reflect the transcriptional signature of the embryo cryodamage but also the embryo healing process overcoming the VIT impacts. Selected validated genes were pointed as potential biomarkers that may help to improve vitrification.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00672-1.

Oviduct fluid during IVF moderately modulates polyspermy in in vitro-produced goat embryos during the non-breeding season

The present study determined i) the presence of proteins (oviduct-specific glycoprotein, OVGP1; heat shock protein-70A, HSPA1A; heat shock protein-A8, HSPA8; annexin A1, ANXA1; annexin A5, ANXA5; and myosin-9, MYH9) known to be involved in early reproduction in the oviduct fluid (OF) of anestrous goats; and ii) the functional effect of during IVF on polyspermy modulation and embryonic development. In vitro-matured oocytes were co-cultured with spermatozoa (1.0, 2.0, or 4.0 x 10⁶ cells/mL) for 18 h in SOF medium supplemented with 5 μg/mL of heparin, 4 μg/mL gentamicin, and 10% estrus sheep serum (CTRL1, CTRL2, and CTRL4 groups) or the same medium plus 10% OF (OF1, OF2, and OF4 groups) obtained from anestrus goats. The analysis of OF by western blotting confirmed the presence of the six proteins tested for. The increase in sperm concentration had no effect (P > 0.05) on the penetration rate in any group; however, monospermy rate decreased as sperm concentration was increased in both OF and CTRL. Regardless of the concentration used, when data were pooled, OF supplementation improved (P < 0.05) monospermy and tended (P = 0.057) to enhance IVF efficiency. Additionally, IVF efficiency was higher (P < 0.05) in OF1 than in OF4 [60 ± 13 vs 37 ± 5%). The development capacity was not affected (P > 0.05) by the sperm concentration and OF treatment, and the average values were cleavage (72 ± 2.6%), blastocyst (37 ± 3.0%), blastocyst in relation to the cleaved (51 ± 4.8%), hatched (62 ± 1.2%), and number of cells per blastocyst (174 ± 1.8%). In conclusion, the six proteins analyzed are present in the OF of anestrous goats, and the supplementation of this OF during IVF may modulate the polyspermy incidence and enhance IVF efficiency, especially when 1x10⁶ sperm per mL is used.

Oviduct fluid extracellular vesicles regulate polyspermy during porcine in vitro fertilisation

High polyspermy is one of the major limitations of porcine invitro fertilisation (IVF). The addition of oviductal fluid (OF) during IVF reduces polyspermy without decreasing the fertilisation rate. Because extracellular vesicles (EVs) have been described as important OF components, the aim of this study was to evaluate the effect of porcine oviductal EVs (poEVs) on IVF efficiency compared with porcine OF (fresh and lyophilised). OF was collected from abattoir oviducts by phosphate-buffered saline flush, and poEVs were isolated by serial ultracentrifugation. Four IVF treatments were conducted: poEVs (0.2mgmL-1), OF (10%), lyophilized and reconstituted pure OF (LOF; 1%) and IVF without supplementation (control). Penetration, monospermy and IVF efficiency were evaluated. Transmission electron microscopy showed an EVs population primarily composed of exosomes (83%; 30-150nm). Supplementation with poEVs during IVF increased monospermy compared with control (44% vs 17%) while maintaining an acceptable penetration rate (61% vs 78% respectively) in a similar way to OF and LOF. Western blotting revealed poEVs proteins involved in early reproductive events, including zona pellucida hardening. In conclusion, our finding show that poEVs are key components of porcine OF and may play roles in porcine fertilisation and polyspermy regulation, suggesting that supplementation with poEVs is a reliable strategy to decrease porcine polyspermy and improve invitro embryo production outcomes.

82 Invitro embryo production outcomes in adult goats is affected by season

In seasonal breeders, reproductive seasonality can have a substantial influence on the efficiency of assisted reproductive technologies. This study assessed seasonal effects on cleavage and blastocyst rates, as well as on quality of invitro-produced (IVP) goat embryos over 18 months. In total, 2348 (autumn: 811, spring: 404, summer: 639, and, winter: 494) cumulus–oocyte complexes (COC) were recovered from slaughterhouse ovaries during 49 replicates (autumn: 17, spring: 7, summer: 15, and, winter: 10) and matured in TCM-199 with 10ng mL−1 epidermal growth factor and 100µM cysteamine for 22h at 38.8°C (5% CO2 in air). Matured oocytes were fertilized with frozen/thawed semen in synthetic oviductal fluid (SOF) with 10% oestrus sheep serum. Sperm and oocytes were co-incubated for 16h at 38.8°C in a humidified atmosphere of 5% CO2 in air. Presumptive zygotes were cultured in SOF medium supplemented with bovine serum albumin (3mg mL−1) for 8 days at 38.8°C in a humidified atmosphere of 5% O2, 5% CO2 and 90% N2. At Day 2, 10% fetal calf serum was added to the culture droplets. The embryos produced were fixed and stained with Hoechst to count their total number of cells, under an epifluorescence microscope. The results of cleavage and blastocyst rates, including hatching rate, from each routine of IVEP were considered as replicates. These data were tested for normality by the Shapiro-Wilk test, before being subjected to ANOVA, followed by Tukey HSD test. The odds ratio (OR) among seasons (autumn: breeding; spring: anoestrus) were calculated. Values of P&lt;0.05 were considered as significant, and the data reported are mean±s.e.m. Cleavage rate was lower (P&lt;0.05) in spring (51±7.1%) than in either autumn (72±2.1%) or summer (71±2.0%) while winter (66±4.1%) had an intermediate value, being similar (P&gt; 0.05) to all others. Indeed, greater possibility of cleavage was observed in autumn (OR: 2.43) and summer (OR: 2.39) compared with spring. The blastocyst rate from cleaved embryos was greater (P &lt;0.05) in autumn (73±2.7%) than in spring (55±2.6%; OR: 2.18). As a result, the blastocyst formation rate from the initial number of COC entering IVM was greater (P&lt;0.05) in autumn (52±2.5%) than in spring: 28±4.7%, summer: 45±2.3%, and winter: 42±2.1%; indeed, the spring season resulted in the lowest rate (P&lt;0.05), compared with other seasons. Moreover, the OR in the blastocyst rate from initial number of COC was greater (P&lt;0.05) in autumn compared with all other seasons and lower in spring compared with winter (OR: 0.54) and summer (OR: 0.48). There were no differences (P&gt; 0.05) in the embryo hatching (mean: 66±2.0%) and blastocyst cell number (mean: 193±2.0 cells). In conclusion, the breeding season (autumn) leads to improved oocyte developmental competence, resulting in greater cleavage and blastocyst yield, whereas embryo quality remained similar throughout the year. Further studies at the molecular level might indicate the mechanisms involved and provide clues to alleviate the negative effect of season.

26 Effect of different cryoprotectant concentrations on vitrification of invitro-matured bovine oocytes in paper containers

A great challenge for successful oocyte vitrification is the development of a low-cytotoxic cryoprotectant solution in a safe device allowing ultra-rapid cooling. This study compared different concentrations of cryoprotectants for bovine IVM-oocyte vitrification in a safe paper container device on oocyte survival and cleavage rates. Abattoir ovaries were obtained and cumulus–oocyte complexes (COCs) were recovered by aspirating follicles of 3 to 6mm in diameter. A total of 470 COCs with homogeneous cytoplasm oocytes, surrounded by several layers of cumulus cells were selected, in 5 replicates. Groups of ∼50 COCs were matured in 500µL of semi-defined IVM medium for 22h at 38.8°C in a humidified atmosphere with 5% CO2. After IVM, COCs were allocated to 1 of 3 groups of 20 to 30 COCs, differing only in final concentration of cryoprotectants. A nonvitrified control group (CG) was also tested, totalling 4 groups. Before vitrification, each group was transferred to 500µL of TCM-199 HEPES with 20% fetal bovine serum (FBS) (Base medium, BM) for 5min at 34°C, and COCs were partially denuded by gentle pipetting. Vitrification followed a 3-step protocol at room temperature and groups of 4 to 5 COCs were transferred to BM solution drops containing (1) 5% ethylene glycol (EG) + 5% dimethyl sulfoxide (DMSO) for 30 s; (2) 10% EG + 10% DMSO + 0.25M sucrose for 30 s; and (3) vitrification solution (VS), according to each group: high (HG), 20% EG + 20% DMSO + 0.5M sucrose; medium (MG), 15% EG + 15% DMSO + 0.5M sucrose; or low (LG), 10% EG + 10% DMSO + 0.5M sucrose for 30s. Afterwards, COCs were loaded in &lt;1µL of solution and placed in a homemade paper container device, and immediately plunged in liquid nitrogen. Warming was performed placing the paper container in 3mL of 1M sucrose in BM for 2min. After warming, a 3-step protocol was conducted and COCs were transferred to (1) 500µL of 0.5M sucrose in BM for 2 min; (2) 500µL of 0.25M sucrose for 2 min; (3) 500µL of BM for 2min. Then, COCs from each group were transferred to 250µL of semi-defined IVF medium. Motile sperm were recovered by Percoll washing from one bull and added to IVF medium (Day 0) at final concentration of 106 sperm mL−1 for 18h. At Day 1, all presumptive zygotes were cultured in 25µL of SOF medium with 5% FBS under mineral oil at 38.8°C with 5% CO2 and 5% O2. Normal data were subjected to ANOVA and post hoc Tukey test. Cleavage rate was recorded at Day 2 after IVF. Oocyte survival rate was similar (P&gt;0.05) among vitrified groups (HG, 80%; MG, 86%; LG,87%). Cleavage rate differed (P&lt;0.05) in all vitrified groups compared with control (CG, 82%; HG, 10%; MG, 16%; LG, 16%). Although no difference (P&gt;0.05) was observed among vitrified groups, MG and LG showed a slightly increased oocyte survival and cleavage rates compared with HG. In conclusion, the use of either medium or low concentrations of cryoprotectants may be a less toxic alternative for vitrification of IVM bovine oocytes on paper device. This research was funded by CAPES/COFECUB (#88881.142966/2017-01).

65 Effect of oviductal fluid extracellular vesicle supplementation during invitro culture on development and quality of bovine embryos

Recently, it has been postulated that oviductal extracellular vesicles (oEV) might act as natural nanoshuttles bringing key components (small noncoding RNAs and proteins) of the oviduct into gametes and embryos. Furthermore, co-incubation of frozen-thawed oEV with invitro-produced bovine embryos was reported to increase blastocyst rate and quality (Almiñana et al. 2017 Reproduction 154, 153-168). The objective of this study was to determine the dose-dependent effect of oEV supplementation of embryo culture medium on the invitro development and cryotolerance of embryos. Briefly, oEV were isolated by ultracentrifugation from a pool of oviductal fluids (8 cows/sample) collected at the slaughterhouse at the post-ovulatory stage and ipsilateral to ovulation and stored at −80°C until used. Slaughterhouse-derived bovine oocytes were invitro matured and fertilised with frozen-thawed semen from one bull (4 replicates; 194 presumptive zygotes per group), according to our standard procedures. After IVF, groups of presumptive zygotes (n=20/drop) were cultured under humidified air with 5% CO2, 5% O2 at 38.8°C for 7 days in 30µL of synthetic oviductal fluid-bovine serum albumin supplemented with oEV at different protein concentrations: 0.5, 0.05, or 0.005mgmL−1 and without (control). Cleavage rates were evaluated on Day 2 and blastocyst rates were assessed on Days 6 and 7 (IVF as Day 0). At Day 7, expanded grade 1 blastocysts were evaluated (International Embryo Technology Society classification) and embryos at the expanded grade 1 blastocyst stage were slow frozen in 1.5M ethylene glycol + 0.1M sucrose and stored in liquid nitrogen. For cryotolerance evaluation, embryos were thawed and cultured for 48h in synthetic oviductal fluid-bovine serum albumin + 1% estrous cow serum. Hatching rates were assessed at 48h post-thawing. Data were analysed by a logistic regression mixed model (SAS, SAS Institute Inc.; Glimmix procedure) followed by post-hoc Tukey for multiple comparisons. Differences were considered significant at P&lt;0.05. No differences were observed among the different oEV concentrations tested for cleavage and Day 6 blastocysts. A tendency (P=0.0535) was observed for Day 7 blastocyst rates (19.1±2.8, 29.4±3.3, 16.0±2.6, and 20.6±2.9 for 0.5, 0.05, 0.005mgmL−1, and control, respectively) in favour of the 0.05mgmL−1 group. However, a significant difference (P&lt;0.0288) for Day 7 grade 1 expanded blastocyst rates in favour of the 0.05mgmL−1 group was observed (5.2±1.6, 12.9±2.4, 3.1±1.2, and 9.8±2.2 for 0.5, 0.05, 0.005mgmL−1, and control, respectively). For cryopreserved embryos, hatching rates of frozen-thawed embryos were not significant among experimental groups (81.6±10.2 (n=19), 89.6±6.6 (n=27), 77.2±12.2 (n=10), and 60.2±13.6 (n=23) for 0.5, 0.05, 0.005mgmL−1, and control, respectively). In conclusion, under our experimental conditions, the supplementation of the embryo culture medium with frozen-thawed post-ovulatory oEV at the protein concentration of 0.05mgmL−1 increased the Day 7 grade 1 expanded blastocyst rate. Moreover, we showed a tendency to improve Day 7 blastocyst rates but with no apparent effects on the cryotolerance of embryos. This work was supported by APIS GENE.

In vitro survival of follicles in prepubertal ewe ovarian cortex cryopreserved by slow freezing or non-equilibrium vitrification

PURPOSE

Vitrification is a well-accepted fertility preservation procedure for cryopreservation of oocytes and embryos but little is known regarding ovarian tissue, for which slow freezing is the current convention. The aim of the present study was to assess the efficiency of non-equilibrium vitrification compared to conventional slow freezing for ovarian cortex cryopreservation.

METHODS

Using prepubertal sheep ovaries, the capacity of the tissue to sustain folliculogenesis following cryopreservation and in vitro culture was evaluated. Ovarian cortex fragments were cultured in wells for 9 days, immediately or after cryopreservation by conventional slow freezing or non-equilibrium vitrification in straws. During culture, follicular populations within cortex were evaluated by histology and immunohistochemistry for PCNA and TUNEL. Steroidogenic activity of the tissue was monitored by assay for progesterone and estradiol in spent media.

RESULTS

No significant differences in follicle morphology, PCNA, or TUNEL labeling were observed between cryopreservation methods at the initiation of culture. Similar decreases in the proportion of primordial follicle population, and increases in the proportion of growing follicles, were observed following culture of fresh or cryopreserved ovarian tissue regardless of cryopreservation method. At the end of culture, PCNA and TUNEL-positive follicles were not statistically altered by slow freezing or vitrification in comparison to fresh cultured fragments.

CONCLUSIONS

Overall, for both cryopreservation methods, the cryopreserved tissue showed equal capacity to fresh tissue for supporting basal folliculogenesis in vitro. Taken together, these data confirm that both non-equilibrium vitrification and slow-freezing methods are both efficient for the cryopreservation of sheep ovarian cortex fragments.

Oral propylene glycol modifies follicular fluid and gene expression profiles in cumulus-oocyte complexes and embryos in feed-restricted heifers

Dietary supplementation with propylene glycol (PG) increases in vitro production of high-quality embryos in feed-restricted heifers. The aim of the present study was to evaluate the effects of PG in feed-restricted heifers on follicular fluid insulin and insulin-like growth factor (IGF) 1 concentrations, expression of IGF system genes in oocytes and cumulus cells and the expression of selected genes in blastocysts. Feed-restricted (R) heifers were drenched with water or PG during induced oestrous cycles (400mL of PG or water/drench, daily drenching at 1600 hours for the first 9 days of the oestrous cycle). Ovum pick-up (OPU) was performed after superovulation to produce in vitro embryos and without superovulation to recover oocytes, cumulus cells and follicular fluid. OPU was also performed in a control group (not feed restricted and no drenching). Follicular fluid IGF1 concentrations were reduced by R, and PG restored IGF1 concentrations to those seen in the control group. In cumulus cells, expression of IGF1, IGF1 receptor (IGF1R) and IGF binding protein 4 (IGFBP4) was decreased in the R group, and fully (IGF1 and IGF1R) or partially (IGFBP4) restored to control levels by PG. Blastocyst perilipin 2 (PLIN2; also known as adipophilin), Bcl-2-associated X protein (BAX), SCL2A1 (facilitated glucose/fructose transporter GLUT1), aquaporin 3 (AQP3), DNA (cytosine-5)-methyltransferase 3A (DNMT3A) and heat shock 70-kDa protein 9 (HSPA9B) expression were decreased in R heifers; PG restored the expression of the last four genes to control levels. In conclusion, these results suggest that, during follicular growth, PG exerts epigenetic regulatory effects on gene expression in blastocyst stage embryos.

Deciphering the oviductal extracellular vesicles content across the estrous cycle: implications for the gametes-oviduct interactions and the environment of the potential embryo

Background

The success of early reproductive events depends on an appropriate communication between gametes/embryos and the oviduct. Extracellular vesicles (EVs) contained in oviductal secretions have been suggested as new players in mediating this crucial cross-talk by transferring their cargo (proteins, mRNA and small ncRNA) from cell to cell. However, little is known about the oviductal EVs (oEVS) composition and their implications in the reproductive success. The aim of the study was to determine the oEVs content at protein, mRNA and small RNA level and to examine whether the oEVs content is under the hormonal influence of the estrous cycle.

Results

We identified the presence of oEVs, exosomes and microvesicles, in the bovine oviductal fluid at different stages of the estrous cycle (postovulatory-stage, early luteal phase, late luteal phase and pre-ovulatory stage) and demonstrated that their composition is under hormonal regulation. RNA-sequencing identified 903 differentially expressed transcripts (FDR < 0.001) in oEVs across the estrous cycle. Moreover, small RNA-Seq identified the presence of different types of ncRNAs (miRNAs, rRNA fragments, tRNA fragments, snRNA, snoRNA, and other ncRNAs), which were partially also under hormonal influence. Major differences were found between post-ovulatory and the rest of the stages analyzed for mRNAs. Interesting miRNAs identified in oEVs and showing differential abundance among stages, miR-34c and miR-449a, have been associated with defective cilia in the oviduct and infertility. Furthermore, functional annotation of the differentially abundant mRNAs identified functions related to exosome/vesicles, cilia expression, embryo development and many transcripts encoding ribosomal proteins. Moreover, the analysis of oEVs protein content also revealed changes across the estrous cycle. Mass spectrometry identified 336 clusters of proteins in oEVs, of which 170 were differentially abundant across the estrous cycle (p-value< 0.05, ratio < 0.5 or ratio > 2). Our data revealed proteins related to early embryo development and gamete-oviduct interactions as well as numerous ribosomal proteins.

Conclusions

Our study provides with the first molecular signature of oEVs across the bovine estrous cycle, revealing marked differences between post- and pre-ovulatory stages. Our findings contribute to a better understanding of the potential role of oEVs as modulators of gamete/embryo-maternal interactions and their implications for the reproductive success.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-4982-5) contains supplementary material, which is available to authorized users.

90 Risk of Coxiella burnetii Transmission via Embryo Transfer Using In Vitro Early Caprine Embryos

Previous experiments using in vitro infection have shown that Coxiella burnetii has a strong tendency to adhere to the zona pellucida (ZP) of in vivo-derived goat embryos, and the washing procedure recommended by the International Embryo Technology Society (IETS) for bovine embryos failed to remove it (Alsaleh et al. 2013 Theriogenology 80, 571-575). The aim of this study was, for in vitro-produced caprine embryos infected in vitro, to (1) evaluate the ability of C. burnetii to adhere to intact ZP, (2) test the efficacy of IETS recommended rules for the washing of bovine embryos to eliminate C. burnetii, and (3) determine, by confocal microscopy, the bacteria location. One hundred ZP-intact caprine embryos, produced in vitro, at the 8- to 16-cell stage were randomly allocated into 11 batches of 8 to 9 embryos. Nine batches were incubated for 18 h with 109 Coxiella/mL of CbB1 strain (ISP, INRA, Val de Loire, France). The embryos were then recovered and washed in batches in 10 successive baths following the IETS guidelines. In parallel, 2 batches of embryos were subjected to similar procedures but without exposure to C. burnetii to serve as the control group. One of the 9 batches of infected embryos and 1 of the 2 non-infected control batches were used to perform immunolabelling to localise the bacteria. Coxiella burnetii DNA was detected by conventional PCR in all 8 batches of infected embryos after 10 successive washings. However, bacterial DNA was not detected in the embryos of the control group. The first 5 washing media of the infected groups were consistently positive and Coxiella DNA was detected up to the tenth wash in 2 batches. After immunolabelling, the observation of embryos under confocal microscopy allowed us to localise C. burnetti on the external part of the ZP without deep penetration. The presence of C. burnetii was seen on the surface of the ZP, with bacterial loads differing from one embryo to another in the same batch. This study clearly demonstrates that C. burnetii, after in vitro infection at 109 Coxiella mL−1, stick strongly to the external part of the ZP of in vitro-produced early caprine embryos without profound penetration. The 10-washings protocol recommended by IETS to eliminate the pathogenic agents of bovine embryos is unable to eliminate these bacteria in caprine embryos. Nevertheless, the finding of C. burnetii DNA by conventional PCR does not imply that the bacteria found remain infective. Further studies are required to investigate whether enzymatic or antibiotic treatment of caprine embryos infected by C. burnetii would eliminate or inactivate the bacteria from the ZP of in vitro-produced goat embryos.

Different co-culture systems have the same impact on bovine embryo transcriptome

During the last few years, several co-culture systems using either BOEC or VERO feeder cells have been developed to improve bovine embryo development and these systems give better results at high oxygen concentration (20%). In parallel, the SOF medium, used at 5% O2, has been developed to mimic the oviduct fluid. Since 2010s, the SOF medium has become popular in improving bovine embryo development and authors have started to associate this medium to co-culture systems. Nevertheless, little is known about the putative benefit of this association on early development. To address this question, we have compared embryo transcriptomes in four different culture conditions: SOF with BOEC or VERO at 20% O2, and SOF without feeders at 5% or 20% O2. Embryos have been analyzed at 16-cell and blastocyst stages. Co-culture systems did not improve the developmental rate when compared to 5% O2. Direct comparison of the two co-culture systems failed to highlight major differences in embryo transcriptome at both developmental stages. Both feeder cell types appear to regulate the same cytokines and growth factors pathways, and thus to influence embryo physiology in the same way. In blastocysts, when compared to culture in SOF at 5% O2, BOEC or VERO seems to reduce cell survival and differentiation by, at least, negatively regulating STAT3 and STAT5 pathways. Collectively, in SOF medium both blastocysts rate and embryo transcriptome suggest no influence of feeder origin on bovine early development and no beneficial impact of co-culture systems when compared to 5% O2.

108 IS THE BINDING OF COXIELLA BURNETII TO THE ZONA PELLUCIDAE FOLLOWING IN VITRO INFECTION OF IN VITRO-PRODUCED GOAT EMBRYOS CONCENTRATION DEPENDENT?

Previous experiments using in vitro infection have shown that at concentrations of 109 bacteria/mL, Coxiella burnetii strongly adheres to the zona pellucidae (ZP) of caprine embryos produced in vitro or in vivo (Alsaleh et al., 2013). However, spontaneous infection results in bacterial concentrations of between 106 and 107 bacteria/mL (Rodolakis, 2006; Alsaleh et al., 2011). The aim of this study was to determine whether the concentration of Coxiella burnetii affected its ability to bind to the ZP in vitro. A total of 120 ZP-intact 8- to 16-cell embryos, produced in vitro from ovaries collected at slaughter, were infected with Coxiella burnetti (strain CbC1) produced via ovoculture at 109 mL−1 (3 batches of 10 embryos), 107/mL (5 batches of 10 embryos), 105 mL−1 (3 batches of 8 embryos). After overnight incubation at 37°C in 5% CO2, the embryos were recovered and washed in batches, in 10 successive baths of PBS with 5% FCS, in accordance with International Embryo Technology Society guidelines. The 10 wash baths were collected separately and centrifuged for 1 h at 13,000 × g. The presence of C. burnetii was determined by conventional PCR in each batch of embryos and in the pellets of the 10 wash baths (Table 1). As demonstrated previously, Coxiella DNA was detected in embryo batches after 10 washes when a concentration of 109 bacteria/mL was used for in vitro infection, but this binding property did not occur at lower bacterial concentrations. We can conclude that the attachment of Coxiella burnetii to the zona pellucida of in vitro-produced embryos is concentration dependent. This finding illustrates the limitations of in vitro experiments to study the risk of pathogen transmission via embryo transfer. Table 1. Detection of Coxiella burnetii (CB) in successive embryo washing baths and batches of 8 to 10 infected ZP-intact 8- to 16-cell embryos after 10 wash cycles, using conventional PCR (C-PCR), as a function of the concentration of CB used for in vitro infection and determined by quantitative PCR (Q-PCR)

Cell Therapy for Parkinson's Disease: A Translational Approach to Assess the Role of Local and Systemic Immunosuppression

Neural transplantation is a promising therapeutic approach for neurodegenerative diseases; however, many patients receiving intracerebral fetal allografts exhibit signs of immunization to donor antigens that could compromise the graft. In this context, we intracerebrally transplanted mesencephalic pig xenografts into primates to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Parkinsonian primates received WT or CTLA4-Ig transgenic porcine xenografts and different durations of peripheral immunosuppression to test whether systemic plus graft-mediated local immunosuppression might avoid rejection. A striking recovery of spontaneous locomotion was observed in primates receiving systemic plus local immunosuppression for 6 mo. Recovery was associated with restoration of dopaminergic activity detected both by positron emission tomography imaging and histological examination. Local infiltration by T cells and CD80/86+ microglial cells expressing indoleamine 2,3-dioxigenase were observed only in CTLA4-Ig recipients. Results suggest that in this primate neurotransplantation model, peripheral immunosuppression is indispensable to achieve the long-term survival of porcine neuronal xenografts that is required to study the beneficial immunomodulatory effect of local blockade of T cell costimulation.

The activity of three glycosidases (β-Ν-acetyloglucosaminidase, α-mannosidase, and β-galactosidase) in the follicular fluid and in the maturation medium affects bovine oocyte maturation

We studied the role of follicular fluid's (FF) glycosidase (α-mannosidase [α-ΜΑΝ], β-Ν-acetyloglucosaminidase [NAGASE], β-galactosidase [β-GAL]) activity during IVM of bovine oocytes. Oocytes were allocated into two groups according to the follicular size (small follicle [SF]: 2-5 mm, large follicle [LF]: >5-8 mm). In experiment 1, cumulus-oocyte complexes (COCs) quality was evaluated according to morphologic criteria (grades A, B-C, D); oocyte (n = 801) nuclear maturation was assessed after 24 hours of incubation. Bovine embryos were produced in vitro in groups (experiment 2, n = 1503 oocytes) or individually (experiment 3, n = 50 oocytes). More grade-A and -BC COCs were collected from SF and LF groups, respectively (P < 0.05). Maturation rate (experiment 1) and cleavage rate (experiments 2 and 3) were similar in SF and LF groups. Activity of all glycosidases in FF was higher (P < 0.05) in SF group than in LF group, whereas in maturation medium of SF group it was, overall, significantly lower than in that of LF (experiments 2 and 3). In FF of SF group, NAGASE positively associated with grade-A oocytes and negatively with BC oocytes; increased β-GAL was associated with degenerated oocytes. Cleavage rate in LF group, related negatively to NAGASE and positively to α-MAN in maturation medium. These results indicate that during maturation, COCs release NAGASE and consume β-GAL, but differences probably exist between individual and group maturation.

161 EFFECT OF OVIDUCTAL FLUID ON BOVINE OOCYTE ZONA PELLUCIDA HARDENING AND SPERM BINDING, AND ON EARLY EMBRYO DEVELOPMENT

This study was designed to evaluate the effects of oviductal fluid at different periovulatory times on oocyte maturation, modification of the zona pellucida (ZP), fertilization and embryo development. Bovine oviducts were collected at a slaughterhouse and classified as preovulatory (pre-ov: 1 pre-ov follicle and a regressing corpus luteum) or post-ovulatory (post-ov: a corpus haemorrhagicum or recent corpus luteum; n = 10 cows/stage). Both oviducts were flushed with 1 mL of sterile TCM-199, and oviductal flushes (OF) were aliquoted and stored at –80°C. Abattoir-derived bovine ovaries were aspirated and cumulus‐oocyte complexes (COC) with at least 3 cumulus layers and homogeneous oocyte cytoplasm were in vitro matured for 22 h in standard maturation medium (control group, n = 319) or in standard medium with 2× concentrated additives supplemented (50% v/v) with pre-ov OF (n = 255) or post-ov OF (n = 248). After in vitro maturation (IVM), subgroups of COC were denuded, and the time of digestion of the ZP by pronase 0.1% (v/v in TCM-199) was determined to evaluate ZP hardening. After IVM, COC were fertilised in vitro for 18–20 h at a final concentration of 1.106 million spermatozoa (spz)/mL. After in vitro fertilization (IVF), COC were denuded, washed twice and cultured for 8 days more under standard conditions. After IVM, IVF, and embryo culture, oocytes/embryos were fixed with ethanol, stained with Hoescht, and examined under fluorescence microscopy for determination of (1) maturation and developmental stages, (2) numbers of fertilised and polyspermic oocytes, and (3) spz bound to the ZP. Percentages were compared between groups by chi-square. Times of ZP digestion were compared by Kruskal‐Wallis test. Numbers of spz bound to the ZP were compared by ANOVA on normalised data followed by Newman-Keuls tests. Data are presented as mean ± SEM. A P < 0.05 was considered significant. Addition of OF during IVM had no effect on maturation rates compared with the control. However, the digestion time of the ZP by pronase was reduced after IVM with pre-ov OF (313 ± 21 s; n = 26) compared with post-ov OF (459 ± 23 s; n = 23) but not with the control (416 ± 30 s; n = 25). After IVF, the number of spermatozoa bound to the ZP was increased after IVM with pre-ov OF (57 ± 5 spz/oocyte; n = 67) and decreased after IVM with post-ov OF (34 ± 3 spz/oocyte; n = 76) compared with the control (42 ± 5 spz/oocyte; n = 60). Addition of OF during IVM had no effect on rates of IVF and polyspermia. However, the rate of development to the blastocyst stage was less after IVM with post-ov OF (10%, n = 97 cleaved oocytes) compared with control (24%, n = 130) and pre-ov OF (29%, n = 101). In conclusion, the OF collected before ovulation decreased the resistance of the ZP to protease digestion and increased its ability to bind spz, whereas it was the opposite for the post-ov OF. Furthermore, the post-ov OF decreased the developmental competence of fertilised oocytes.

78 INTERCEPTION OF EXOSOMAL MESSAGES BETWEEN THE OVIDUCT AND THE EMBRYO: WHAT ARE THEY TWEETING ABOUT?

Successful pregnancy requires an appropriate communication between the mother and the embryo(s). Recent studies indicate that exosomes, small (30–100 nm) membrane-bound vesicles of endocytotic origin, could act as intercellular vehicles in this unique communication system in the uterus. However, little is known about the role of these vesicles in the oviduct. Our study aimed at (1) demonstrating the existence of oviducal-embryo communication via exosomes, (2) deciphering the exosomal dialogue between them at the proteomic level, and (3) comparing the exosomal proteomic content to the oviducal fluid proteomic content in order to highlight the key role of exosomes in this dialogue. Cow oviducts (pool of 6 oviducts at different stages of the cycle in 4 replicates) were flushed, and exosomes were isolated by serial ultracentrifugation. Exosomes were measured by dynamic light scattering analysis, resulting in exosomes (63.25–97.03 nm) and microvesicle observations (>100 nm). Bovine embryos were produced in vitro up to the blastocyst and hatching/hatched blastocyst stages. To demonstrate the existence of the oviducal-embryo communication via exosomes, oviducal exosomes were labelled with green fluorescent dye (PKH67), filtered (0.22 µm) to remove microvesicles, and co-incubated with blastocysts and hatching/hatched (H) blastocysts for 20 h, under 5% CO2 and 5% O2 conditions. Subsequently, embryos were washed in exosome-free medium, fixed in 4% paraformaldehyde, and labelled with Hoechst 33342 and Actin Red Phallodin. Confocal microscopy observations confirmed that exosomes were internalized by blastocysts and H-blastocysts and located around the nucleus, demonstrating the existence of an oviducal-embryo communication via exosomes. Moreover, our results showed that the zona pellucida does not represent a barrier for exosomes and they act as natural nanoshuttles bringing oviducal signals into the embryo. Then, proteomic analysis by LC1D-nanoESI-LTQ-Orbitrap was used to decipher oviducal exosomal content, identifying 480 proteins. Gene ontology analysis revealed that a high number of these proteins were involved in metabolism (24.9%), cellular process (19.3%), and 0.8% reproductive processes. Further analysis revealed that more than 56% of exosomal proteins involved in cellular process were associated with cell-to-cell communication. Finally, exosomal proteins were compared with proteins present in oviducal fluid from a pool of samples from cows at Day 0 and Day 10 of the oestrous cycle. Comparative analysis showed that from a total of 607 proteins identified in both oviducal exosomes and fluid sources, 105 were specific to exosomes, 127 were specific to fluid, whereas 375 were common to both sources. Our findings provide the first evidence of oviducal-embryo communication via exosomes, an important first step in furthering the understanding of the oviducal environment and the role of exosomes as early mediators of embryo-maternal cross talk. This research was supported by the EU AgreenSkills fellowship n° 267196 and EU FECUND Project no 312097.

74 ANALYSIS OF STEROID HORMONES IN BOVINE OVIDUCTAL FLUID BY GAS CHROMATOGRAPHY COUPLED WITH TANDEM MASS SPECTROMETRY

Steroid hormones play key roles in the regulation of physiological changes in the mammalian genital tract, including the oviduct. The aim of this study was to determine the variations in steroid hormone concentrations in bovine oviducal fluid (OF) during the oestrous cycle. Bovine oviducts were collected at a local slaughterhouse and classified into 4 stages according to the ovarian and corpus luteum (CL) morphologies (n = 18–25 cows/stage): post-ovulatory (postov), mid luteal (mid-lut), late luteal (late-lut), and preovulatory (preov). Follicular fluid was also collected from the preov follicles. Animals with follicular oestradiol-17β (E2) <40 ng mL–1 or progesterone (P4) >160 ng mL–1 (cystic follicles) or E2 : P4 ratio <1 (atretic follicles) were excluded. Oviducal fluids were collected from contra- and ipsilateral (to the CL) ampullas by squeezing. They were then centrifuged and stored at –80°C. Steroids were extracted from pools of 150 to 200 µL of OF (4–10 cows/pool; 3–4 pools per “stage × side” group), purified, fractioned by high-performance liquid chromatography, derivatized, and analysed by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). Comparisons between groups were made with a two-way ANOVA followed by Bonferroni post-tests. Data are expressed as means ± SEM. A P-value < 0.05 was considered as significant. In ipsilateral OF, the concentrations of P4 increased from postov (56.9 ± 13.4 ng mL–1) to mid-lut (120.3 ± 34.3 ng mL–1; P < 0.01) then decreased from late-lut (76.7 ± 1.8 ng mL–1) to preov (6.3 ± 1.7 ng mL–1; P < 0.001) stages, and were 4 to 16 times more concentrated than in contralateral OF. Several P4 reduced metabolites (5α-dihydroP4, 20α-dihydroP4, 17α-hydroxyP4, 3α5α20α-hexahydroP4, 3β5α20α-hexahydroP4) followed the same pattern of variation. Concentrations of the P4 precursor pregnenolone were highest at postov (4.2 ± 0.3 ng mL–1 in ipsilateral OF) then decreased from mid-lut to preov (3.4 ± 0.6 to 1.3 ± 0.1 ng mL–1; P < 0.001) and were higher than in contralateral OF at postov (P < 0.001) and mid-lut (P < 0.01) stages. Concentrations of E2 were higher in preov (290.5 ± 63.2 pg mL–1 in ipsilateral OF) compared to all other stages (P < 0.05) with no difference between ipsi- and contralateral sides at any stage. Concentrations of the oestrogen precursors androstenedione and testosterone displayed the same pattern of variation as E2. In contrast, concentrations of dehydroepiandrosterone and estrone did not vary between stages or sides relative to the CL. In addition, high concentrations of cortisol and cortisone were found in ipsi- and contralateral OF at all stages of the oestrous cycle (on average 48.6 and 31.9 ng mL–1, respectively). In conclusion, numerous steroids, steroid precursors, and metabolites were found in the bovine OF. The local transfer of ovarian steroids creates a highly concentrated and fluctuating hormonal environment in the ipsilateral OF during the oestrous cycle. These results could be useful to improve media for IVF, development, and oviducal cell culture.

108 CHARACTERIZATION OF BOVINE OVIDUCTAL EXOSOMES FROM IN VIVO AND IN VITRO ORIGIN

Successful pregnancy requires an appropriate communication between the mother and the embryo(s). Recent studies indicate that exosomes, small (30–200 nm) membrane vesicles of endocytotic origin, could act as intercellular vehicles in this unique communication system. Exosomes have been identified in vivo in all body fluids including follicular, uterine, and oviductal fluids and can be secreted by most cell types in vitro. Bovine oviductal epithelial cells (BOEC) have been thoroughly used to study embryo-maternal communication and to improve embryo development in vitro. Hence, our objective was to provide a morphologic and proteomic characterisation of exosomes secreted by BOEC in vivo in the oviductal fluid and in vitro in the conditioned media. Oviducts from cows were flushed to recover in vivo exosomes and then BOEC were scraped in order to derive primary cultures. In vitro exosomes were collected from conditioned media of BOEC primary cultures after reaching confluence (10 days). Isolation of exosomes from in vivo and in vitro origin was performed by ultracentrifugation. The presence of exosomes was confirmed in oviductal flushings and conditioned media by electron microscopy. Further characterisation of exosomes was carried out based on morphology (transmission electron microscopy), size (dynamic light scattering, DLS), and protein composition (protein profile analysis by SDS-PAGE and Western immunoblotting). Preliminary results by DLS revealed different size distribution profiles in exosome samples (in vivo: mean size of 93.41 nm; in vitro: 433.5 nm). Because exosomes are considered as “micromaps” of the originating cells, protein patterns expressed by in vivo exosomes and in vitro exosomes were compared with scraped and cultured BOEC, respectively. Protein profile analysis by SDS-PAGE showed quantitative and qualitative differences among the exosome samples, their cells of origin, and the milieu (conditioned media or flushing). Exosome-specific protein bands were detected and will be further characterised. In addition, exosomes from in vivo and in vitro origin exhibited distinct proteomic profiles. Western blot analysis demonstrated that (1) both exosomal protein samples were positive for HSP70, a known exosomal protein, and negative for Grp78, an endoplasmic reticulum marker detected in BOEC; (2) in vivo exosomes expressed oviductal glycoprotein (OVGP), heat shock protein A8 (HSPA8), and myosin 9 (MYH9), 3 oviductal proteins with known roles in fertilization and early pregnancy. However, only HSPA8 and MYH9 were detected in in vitro exosomes. Our results provide the first extensive characterisation of oviductal exosomes from in vivo and in vitro origin, an essential step in furthering our understanding of the early embryo-maternal cross talk.

124 CRYOPRESERVED BOVINE OVIDUCTAL EPITHELIAL CELLS SURVIVAL, GROWTH, AND ABILITY TO SUPPORT EARLY EMBRYO DEVELOPMENT

Previous experiments demonstrated that co-culture of bovine embryos with bovine oviducal epithelial cells (BOEC) improved blastocyst rate and quality (Cordova et al. 2014). However, the use of primary cell support for improving embryo development in vitro may introduce a higher variability of the results between different BOEC batches used, as well as sanitary risks. The use of well-controlled large batches of frozen BOEC may help to solve these problems. Therefore, the aim of the present study was to characterise the survival and functionality of frozen-thawed BOEC. Bovine oviducts attached to ovaries showing recent ovulation were collected at a local slaughterhouse during 4 replicates (3 oviducts per replicate). Epithelial cells were expelled by gentle squeezing and washed 3 times. Half of the cell pellet was diluted 100-fold in culture medium (TCM199 + 10% FCS) for culture of fresh cells. The other half was diluted 10-fold in cell freezing medium (TCM199 + 20% FCS + 10% dimethyl sulfoxide), allowed to equilibrate in this medium for 10 min, and frozen at –80°C in a container filled with isopropyl alcohol. After 4 h, the tubes were transferred into LN for at least 1 h. The tubes were then thawed (5 min in 37°C water bath), diluted 1 : 1 in cell culture medium, and centrifuged for 10 min at 100 × g. The pellet was then diluted 100× in cell culture medium. Fresh or frozen-thawed cells were seeded in 4-well NUNC plates for 7 days at 38.8°C in a humidified atmosphere with 5% CO2 in air. The medium was renewed every 48 h, and the viability of cells was assessed by calcein-AM and ethidium homodimer labelling. After 7 days of culture, the medium was replaced by SOF medium + 5% FCS, and bovine in vitro-produced zygotes were added the day after and co-cultured for 8 days at 38.8°C in a humidified atmosphere with 5% CO2 in air to evaluate embryo development. Half of the medium was renewed every 48 h. Frozen-thawed cells showed the same viability than fresh ones at Days 0 and 7 of culture and reached confluence at the same time (Day 7). Development results are shown in Table 1. Frozen and fresh cells support early embryo development at the same rate. In conclusion, the present study showed that BOEC frozen on the day of collection are equivalent to fresh BOEC in regards to their survival and proliferation and their ability to support early embryo development. At collection, the cells may face stresses that are just as considerable as freezing/thawing (temperature shock, scrapping, change of environment). This may explain why they are not affected by freezing than at collection. The differentiation status of these cells is now under analysis by immunocytochemistry. Table 1.Cleavage rate and blastocyst rate in 3 different types of culture systems

5 PROPYLENE GLYCOL FEEDING SUPPLEMENTATION MODIFIES INSULIN-LIKE GROWTH FACTOR SYSTEM GENE EXPRESSION IN CUMULUS–OOCYTE COMPLEXES AND THE EXPRESSION OF SELECTED CANDIDATE GENES IN EMBRYOS PRODUCED IN VITRO IN FEED-RESTRICTED HEIFERS

Dietary supplementation with propylene glycol (PG) increases the rate of grade 1 embryos produced from feed restricted females (Gamarra et al. 2014 Reprod. Fertil. Dev.). The aim of this study was to evaluate if a PG feeding supplement could modify the expression profile of selected candidate genes that are important for in vitro embryo development and the gene expression patterns of the insulin-like growth factor (IGF) system in oocytes and cumulus cells in feed-restricted heifers. Feed-restricted heifers (n = 16, growth rate of 600 g day–1) received a single daily drench of 400 mL of water (group restricted, R) from Day 1 to Day 9 of a first synchronized oestrous cycle followed by 400 mL of PG from Day 1 to Day 9 of the second synchronized oestrous cycle (group restricted + PG, RPG). Ovum pick-up (OPU) was performed following superovulation, on Day 5 of the oestrous cycle to produce embryos in vitro and on Day 9 without superovulation to obtain oocytes and cumulus cells. The same protocol was used in control animals (n = 6, growth rate of 800 g day–1). Real-time PCR was used to determine the relative abundance of genes involved in lipid metabolism and storage (PLIN2, SCD), energy metabolism (ATP5A1, GLUT1), membrane permeability (AQP3), epigenetic marks (DNMT3a), apoptosis (BAX, TP53), and protein processing (HSPA9B) in grade 1 blastocysts, IGF1, IGF1R, IGFBP2, IGFBP4 in cumulus cells, and IGF1R and IGFBP2 in oocytes. Mann-Whitney nonparametric tests were performed to analyse gene expression results. The expression of PLIN2, ATP5A1, GLUT1, AQP3, DNMT3a, BAX, and HSPA9B were decreased in embryos collected from restricted compared with control animals. The expression levels of these genes were restored when females were supplemented with PG. The expression of TP53 and SCD were not affected. In cumulus cells, the expression levels of IGF1, IGF1R, and IGFBP4 were decreased in restricted compared with control animals. The expression levels of IGF1 and IGF1R were restored with PG supplementation. No differences were observed for the IGFBP2 gene. In the oocytes, no differences were observed for the expression levels of IGF1R and IGFBP2 genes. In conclusion, this work shows for the first time that feed restriction and dietary supplementation by PG in heifers produced changes in gene expression in blastocysts and modified the pattern of the IGF system in cumulus cells. These results suggest the existence of an epigenetic regulation induced by PG during follicular growth, which can regulate the level of gene expression up to the blastocyst stage. In general, PG supplementation of feed-restricted donors restored gene expression at the levels observed after normal feeding.

306 EFFECT OF DIFFERENT IN VITRO MATURATION MEDIA ON DEVELOPMENTAL POTENTIAL OF GOAT OOCYTES ALREADY FOUND DENUDED AT COLLECTION

A grade classification (I, II, and III) based on the number of cumulus layers and oocyte morphology is currently used by many laboratories. Oocytes found denuded at collection (grade III) are considered not suitable and routinely discarded. Thus, if a particular strategy could be applied to their use in labour-intensive processes, such as ovum pickup, it would be a benefit. This experiment was performed to examine the effect of IVM medium composition to produce goat embryos in vitro using oocytes already found denuded at collection (DOC). In total, 411 DOC and 141 intact COC (control treatment) obtained by slaughterhouse ovaries were analysed in 4 replicates. The maturation medium consisted in TCM199 supplemented either with (1) 10 ng mL–1 of EGF and 100 µM cysteamine (simplified); (2) 10 ng mL–1 of EGF, 5 IU mL–1 of hCG, 10 IU mL–1 of eCG, 19 ng mL–1 of IGF-1, 2.2 ng mL–1 of FGF, 5 µg mL–1 of ITS, 90 µg mL–1 of l-cystein, 0.1 mM β-mercaptoethanol, 75 µg mL–1 of vitamin C, 720 µg mL–1 of glycine, 0.1 mg mL–1 of glutamine, and 110 µg mL–1 of pyruvate (semidefined); or (3) 10% fetal calf serum (FCS), 100 µM cysteamine, and 50 ng mL–1 of oFSH (complex). Both DOC and COC were subjected to IVM, IVF, and IVD as previously described (Souza-Fabjan et al. 2014, Theriogenology 81, 1021–31). The COC were matured only in simplified medium. On Day 8, all expanded blastocysts were fixed and stained with Hoechst for cell counting. Statistical analysis was performed using all tests with a significant interval of 95%. All variables were compared among treatments using ANOVA and SNK test. The results are described as mean per replicate ± s.e.m. No significant differences were found in simplified, semidefined, or complex medium, respectively, in cleavage rate (52 ± 7.5, 60 ± 9.4, or 51 ± 15.0%), blastocyst from cleaved (36 ± 3.9, 39 ± 9.3, or 41 ± 4.8%), blastocyst from initial DOC (19 ± 5.0, 23 ± 8.1, or 21 ± 3.3%), hatching rate (55 ± 22.9, 55 ± 15.9, or 52 ± 14.8%), or total blastomeres number (184 ± 12.6, 179 ± 12.4, or 190 ± 13.8). The control COC showed no significant differences to any DOC treatment on cleavage (77 ± 3.4%) and blastocyst from cleaved (60 ± 2.2%). However, the blastocyst rate from initial COC was higher (46 ± 0.5%; P < 0.05) than all DOC treatments. Even though the blastocyst yield was lower than COC (~21 v. 46%), it is reasonable to affirm that it is possible to produce embryos from oocytes that would not be utilised, which may represent additional number of embryos. The blastocyst cell numbers in COC (192 ± 13.7) were similar (P > 0.05) to DOC, indicating that the goat embryos produced were of good quality. In conclusion, the inclusion of more complex substances in IVM media did not increase the development rate of DOC and, therefore, more simple IVM media could be used for this purpose. Finally, the goat embryos produced had satisfactorily number of blastomeres, demonstrating that the in vitro development step is able to generate good quality embryos from grade III oocytes. Therefore, some oocytes that in general would be discarded will develop to blastocysts and may represent benefits, especially after ovum pick-up from genetically valuable goats.

Relative mRNA expression and immunolocalization for transforming growth factor-beta (TGF-β) and their effect on in vitro development of caprine preantral follicles

This study aimed to evaluate the immunolocalization and messenger RNA (mRNA) expression for transforming growth factor-beta (TGF-β) and its receptors (TGF-βRI and RII), as well as mRNA expression for P450 aromatase and FSH receptor in caprine preantral follicles. The effects of TGF-β, FSH alone, or in association on the in vitro follicular development were also assessed. Immunohistochemical analyses showed the expression of TGF-β and its receptors in oocytes of all follicle stages and granulosa cells of primary and secondary follicles. mRNA for TGF-β receptors and for FSH receptor (FSHR) was present in preantral follicles as well as in oocytes and granulosa cells of antral follicles. Isolated secondary follicles were cultured in α-minimum essential medium (MEM) alone or supplemented with either FSH (100 ng/ml), TGF-β (10 ng/ml), or TGF-β + FSH for 18 d. TGF-β increased significantly oocyte diameter when compared to FSH alone and control. After 18 d of culture, all groups showed a significant reduction in P450 aromatase and FSHR mRNA levels in comparison to fresh control. In contrast, treatment with FSH significantly increased the mRNA expression for TGF-β in comparison to fresh control and other treatments. In conclusion, the findings showed that TGF-β and its receptors are present in caprine ovarian follicles. Furthermore, they showed a positive effect on oocyte growth in vitro.

Effect of different culture systems on adipocyte differentiation-related protein (ADRP) in bovine embryos

Bovine embryos cultured in serum-containing media abnormally accumulate lipid droplets, compared to their in vivo counterparts. The objective of this study was to investigate the effect of different culture systems on the mRNA expression and on the quantification and localisation of adipocyte differentiation-related protein (ADRP), a protein associated with lipid accumulation in bovine blastocysts. Two experiments were independently performed for ADRP mRNA expression analysis. In experiment A, blastocysts were produced in modified synthetic oviduct fluid (mSOF)+10% foetal calf serum (FCS), in coculture (bovine oviduct epithelial cells, Boec) and in ewe oviducts, whereas in experiment B, they were produced in mSOF+10μM docosahexaenoic acid (DHA) and in vivo. Control groups were also performed. ADRP mRNA expression was downregulated in the Boec, ewe oviduct and in vivo groups compared to the 10% FCS or DHA groups, respectively. Moreover, the expression of this protein was downregulated in the Boec group compared to the control group (P<0.05). A third experiment (experiment C) was performed to quantify and localise ADRP protein. Boec, in vivo and control groups were tested. After immunofluorescence staining followed by confocal microscopy analysis, embryonic ADRP was clearly localised around lipid droplets, indicating that ADRP is also a lipid droplet coat protein in bovine embryos. In conclusion, our results demonstrate that bovine embryos at the blastocyst stage expressed ADRP mRNA and protein, and that the embryonic culture system modified this expression.

[Use of an in vitro model in bovine to evidence a functional and molecular dialogue between preimplantation embryo and oviduct epithelial cells]

Beyond being a pipe between ovary and uterus, the oviduct is an active player in different aspects of early reproductive processes, in particular in the transport of embryos to the site of implantation and the regulation of its early development. Different studies evidenced a communication between oviduct and early embryo at the molecular and functional levels. Since the study of these interactions is difficult in vivo, different in vitro systems have been developed to mimic the maternal milieu during early development. These systems allowed to confirm the action of the cells on the quality of early development (blastocyst rate and viability). In turn, the embryos are producing signals that are able to modify and adapt the activity of maternal cells.

190 JNK SIGNALLING IN FOLLICLE ACTIVATION

Primordial follicles are maintained in a quiescent state until they receive a signal to activate and join the growing pool. It is essential that the rate of follicle activation is well coordinated as it determines the reproductive lifespan of the female. This finely tuned process is under the control of a variety of positive and negative factors, and there is evidence that the JNK pathway is involved. The aim of this study was to assess the effect of a JNK inhibitor (SP600125) on follicle activation in vitro. Ovaries from 6 prepubertal sheep were dissected into 1-mm3 fragments and cultured in the presence or absence of SP600125 (0, 5, or 25 µM; SP0, SP5, and SP25, respectively). After 0, 2, 5, or 9 days, fragments were fixed, sectioned, and analysed by histological morphometry to determine the number and type of follicles in addition to TUNEL analysis for apoptosis. In total, 21 584 follicles were assessed. Follicles were classified as either primordial, intermediate, primary, secondary, or antral. Culture media were also assayed for steroid content. After multinomial regression analysis, there were no differences in the rate of follicle activation between groups on Day 2 of culture. However, after 5 days of culture there were significantly more primordial follicles in SP25 (69 ± 9.15%; P < 0.01) and SP5 (52 ± 8.12%; P < 0.05) groups when compared with SP0 (34 ± 3.98%). At the end of culture (Day 9), these differences continued to be observed (SP25: 63 ± 8.47%; SP5: 51 ± 6.62%; SP0: 34 ± 5.61%; P < 0.05). On Day 9 there were more intermediate follicles following treatment with SP0 (52 ± 3.27%) compared with SP5 and SP25 (42 ± 4.72% and 31 ± 7.41% respectively; P < 0.05). There was also a tendency for more primary follicles on Day 9 for the control (11 ± 4.29%) when compared with the other treatments (4 to 7%; P = 0.06). The proportion of apoptotic primordial follicles was greatest in the SP25 group when compared with SP5 and SP0 at all timepoints (P < 0.05). After 2 days of culture, progesterone concentration was highest in the SP25 group (4.1 ± 0.45 ng mL–1) compared with the SP5 and SP0 groups (2.9 ± 0.39 ng mL–1 and 1.6 ± 0.79 ng mL–1, respectively; P < 0.05). However, this dose effect was lost by the end of culture. There was no effect of the inhibitor on oestradiol synthesis. By using SP600125, we have observed a dose-dependent block on follicle activation. These results suggest that the JNK pathway is a novel regulator of follicle activation and development. However, further confirmation is required to determine its specific action. The mechanisms by which SP25 promotes progesterone synthesis and increases apoptosis are unknown and also require clarification.

Expression of maternal transcripts during bovine oocyte in vitro maturation is affected by donor age

The primary objective of this study was to compare expression of maternal transcripts in bovine oocyte populations with differential developmental competence: oocytes from prepubertal and pubertal animals; and oocytes from small (3-4 mm) and large (6-10 mm) follicles from pubertal animals. All transcripts were examined in oocytes prior to and after in vitro maturation (IVM). Genes were selected based on their known maternal effect in mouse (ZAR1, STELLA, HSF1, MATER/NLRP5 and its paralogue NLRP9), or their identification as markers of oocyte maturation, either involved in redox metabolism (PRDX1, PRDX2) or meiotic progression (AURKA). Total or polyadenylated forms of the transcripts were followed by reverse transcription coupled to real-time PCR. Six polyadenylated transcripts were found significantly reduced after maturation irrespective of donor age or follicle diameter (p<0.05). Within these six polyadenylated transcripts, ZAR1, NLRP9, HSF1, PRDX1 and PRDX2 were significantly reduced in oocytes from prepubertal animals compared to adult animals (p<0.05). A younger age was also associated with lower abundance (total form) of PRDX2/PRDX1 irrespective of maturation. Total HSF1, PRDX1 and polyadenylated NLRP9 showed a tendency (p values from 0.053 to 0.08) for a higher detection in oocytes from small follicles, thus encouraging further investigation of the follicle diameter model. However, at the present time, follicle size did not significantly affect expression of transcripts examined. In conclusion, this study demonstrates differences in the maternal store of RNA and its regulation during IVM which is dependent on donor age.

Bovine embryos cultured in serum-poor oviduct-conditioned medium need cooperation to reach the blastocyst stage

Immature bovine oocytes were matured and fertilized in vitro, and the resulting zygotes were cultured to the blastocyst stage in droplets of tissue culture medium 199 (TCM 199) conditioned by oviduct cells in the absence of serum. In Experiment 1, the effect of the number of zygotes in a constant culture volume was investigated by culturing 1, 4 or 40 zygotes in 40 microl of culture medium. The cleavage rate was low with a single embryo (36%) but increased with the number of embryos, to reach 50% with 4 embryos/40 microl and 59% with 40 embryos/40 microl. Blastocyst formation was nil with 1 embryo per 40 microl, reaching 2.5% with 4 embryos/40 microl and 18% with 40 embryos/40 microl. The effect of the size of the drop was assessed in Experiment 2, the concentration of embryos remaining constant (1 embryo/1 microl). The volumes tested were 10, 20, 30 and 40 microl. Development into blastocysts increased gradually from 12% in the 10 10 group to 20% in the 40 40 group. Experiment 3 was designed to find a minimal droplet volume able to support the development of a single embryo to the blastocyst stage. The minimum tested volume was 5 microl and was not successful. These results show that bovine embryos cultured in oviduct-conditioned TCM 199 need to cooperate to reach the blastocyst stage. The mechanism of this cooperation is not known, but some autocrine/paracrine factors, probably growth factors, could promote embryo development as was demonstrated in mice. From Experiment 2 we can hypothesize that the surface volume ratio of the droplets could play a role in the culture conditions by interfering with the exchanges between the culture medium and the surrounding environment.

Factors affecting oocyte quality: who is driving the follicle?

Mammalian ovaries contain a large stock of oocytes enclosed in primordial follicles. Ovarian cyclic activity induces some of these follicles to initiate growth towards a possible ovulation. However, most of these follicles terminate their growth at any moment and degenerate through atresia. In growing follicles, only a subset of oocytes are capable to support meiosis, fertilization and early embryo development to the blastocyst stage, as shown through embryo in vitro production experiments. This proportion of competent oocytes is increasing along with follicular size. Growing lines of evidence suggest that oocyte competence relies on the storage of gene products (messenger RNA or protein) that will be determinant to support early stages of embryo development, before full activation of embryonic genome. Given these facts, the question is: are these gene products stored in oocytes during late folliculogenesis, allowing an increasing proportion of them to become competent? Alternatively, these transcripts may be stored during early folliculogenesis as the oocyte grows and displays high transcription activity. Several arguments support this latter hypothesis and are discussed in this review: (i) many attempts at prolonged culture of oocytes from antral follicles have failed to increase developmental competence, suggesting that developmental competence may be acquired before antral formation; (ii) the recent discovery of oocyte secreted factors and of their ability to regulate many parameters of surrounding somatic cells, possibly influencing the fate of follicles between ovulation or atresia, suggests a central role of oocyte quality in the success of folliculogenesis. Finally, in addition to their role in interfollicular regulation of ovulation rate, late folliculogenesis regulation and atresia could also be seen as a selective process aimed at the elimination through follicular atresia of oocytes that did not succeed to store proper gene products set during their growth.

161 SUCCESSFUL INTERSPECIFIC PREGNANCY AFTER TRANSFER OF IN VITRO-PRODUCED SIKA DEER (CERVUS NIPPON NIPPON) EMBRYO IN RED DEER (CERVUS ELAPHUS HIPPELAPHUS) SURROGATE HIND

The aim of the present study was to assess the in vivo competence of in vitro-produced sika deer (Cervus nippon nippon) embryos after freezing–thawing and transfer into red deer (Cervus elaphus hippelaphus) recipients. During the breeding season, 11 adult sika deer hinds were synchronized as oocyte donors with an intravaginal sponge (45 mg of fluorogestone acetate, FGA) inserted for 12 days and removed immediately after laparoscopic ovum pick-up (LOPU), and renewed after 3 days. Ovarian stimulation was induced with an i.m. injection of 75 µg of cloprostenol (Estrumate) given on Day 8, followed by 3 i.m. injections of 0.1, 0.1, and 0.05 IU of ovine FSH (Ovagen) on Days 10 and 11 at 12-h intervals. On Day 12, hinds were anesthetized and oocytes were collected by LOPU from follicles >2 mm using an 18 G needle under moderate vacuum. COC were recovered and morphologically evaluated for quality (graded from 1 to 5). COC were then submitted to in vitro maturation, fertilization, and culture (IVM, IVF, and IVC) as described previously (Locatelli Y et al. 2005 Theriogenology 64, 1729–1739). For IVC, embryos were co-cultured with a monolayer of ovine oviduct epithelial cells in synthetic oviduct fluid medium supplemented with 10% FCS. On Day 8 post-insemination, all sika deer embryos at the blastocyst stage were cryopreserved via a standard bovine slow-freezing protocol. Of 44 LOPU sessions performed during the 1-month study, an average of 7.5 � 0.38 follicles were aspirated (mean � SEM), allowing the recovery of 3.65 � 0.38 COC per hind and per session, of which 80.0% were suitable for IVM (grades 1 and 2). Of 142 oocytes recovered, 57 cleaved after IVF (40.1%), and 14 embryos (24.6% of cleaved) reached the blastocyst stage after 8 days. At the end of the breeding season, 7 adult red deer hinds were synchronized as embryo recipients by inserting 2 intravaginal sponges per female (90 mg of FGA), for 13 days. Injections (i.m.) of 400 IU of eCG and 125 µg of cloprostenol (Estrumate) were administered 72 h before sponge removal. At Day 8 after sponge removal, straws containing frozen embryos were thawed and cryoprotectant was removed as described previously (see Locatelli Y et al. 2005 Theriogenology 64, 1729–1739). Two sika deer embryos were surgically transferred into uterine horn (unilaterally) of each red deer recipient. One of 7 red deer recipients was diagnosed pregnant by ultrasonography on Day 56. A healthy male sika deer fawn was born unassisted after 224 days of gestation. No complications were observed in initial recognition of the sika deer fawn by the red deer surrogate mother, nor in subsequent interactions. To our knowledge, this is the first report of an interspecific pregnancy obtained after in vitro embryo production and embryo transfer in deer species. In conclusion, interspecific embryo transfer after IVP may represent a useful tool for the preservation and amplification of captive residual populations of endangered deer species. Further studies are required to increase the rate of cleavage after LOPU-IVF as well as viability of frozen–thawed IVP embryos.

102 IDENTIFICATION OF CONTRASTED PHENOTYPES IN THE BOVINE FROM REPEATED IN VIVO AND IN VITRO EMBRYO PRODUCTION FOLLOWING SUPEROVULATION

This study was initiated to evaluate maternal influence on in vivo and in vitro bovine embryo production and identify animals with contrasted phenotypes for reproductive parameters. Nine Montbéliard cows raised on the same farm and with various genetic origins were included in the study. In vivo-derived embryos were collected nonsurgically from superovulated cows on day 7 after AI (34 collections). Immature oocytes were collected by ovum pickup from the same (superovulated) cows (36 sessions) then matured, fertilized (day 0) with the same bull, and cultured in vitro until day 7 on Vero cell monolayers in B2 medium. Grade 1 to 3 in vivo and grade 1 and 2 in vitro produced embryos deemed viable according to IETS criteria. The mean numbers of blastocysts and viable blastocysts per session per cow were, respectively, 8.3 ± 5.5 and 4.8 ± 3.6 in the in vivo system and 2.5 ± 2.6 and 1.8 ± 2.2 in the in vitro system. Individual cow data of in vivo and in vitro embryo production were analyzed by ANOVA (GLM program in SAS; SAS Institute Inc., Cary, NC, USA). Results are presented in Table 1: mean ± SD. Quantity and quality of produced embryos varied significantly among females, and production in vivo and in vitro was not systematically related. Contrasted phenotypes were identified according to their viable blastocyst rates in both systems (in vivo: no viable/recovered; in vitro: no viable/inseminated). Two females presented a relatively high percentage of viable blastocysts in both systems (over 30% in vitro and over 70% in vivo, Table 1). On the contrary, 2 females showed low percentages of blastocysts in the 2 systems (<10% in vitro and <50% in vivo). For most other females, the percentage of in vivo-produced blastocysts was relatively high (>50%), but in vitro development rates were low. Only one female (C3) presented the inverse situation. Oocytes collected from animals with contrasted phenotypes will be analysed for gene expression to identify marker genes associated with oocyte developmental competence. Table 1. This study was conducted with financial support of ‘Genanimal’ – French Ministry of Research (#03P409) and Apis-Gene.

207 IN VITRO MATURATION TREATMENT AFFECTS DEVELOPMENTAL COMPETENCE OF LAPAROSCOPIC OVUM PICKUP-DERIVED OOCYTES IN FOLLICLESTIMULATING HORMONE-STIMULATED GOATS

The aim of the present study was to assess the effect of IVM treatment on the developmental competence of oocytes recovered from repeated laparoscopic ovum pickukp (LOPU) in goats. A total of 94 LOPU sessions were performed on 33 adult goats of the Saanen and Alpine breeds. Females were synchronized (Day 0) during the nonbreeding season by inserting vaginal sponges (45 mg of fluorogestone acetate, Intervet, Boxmeer, The Netherlands). At Day 8, an i.m. injection of 50 μg of cloprostenol (Estrumate; Schering-Plough Animal Health, Pointe-Claire, Quebec, Canada) was administered. Porcine FSH (Stimufol, Merial, Brussels, Belgium, 160 mg/goat) was administered in 5 injections at 12-h intervals, starting on Day 8. The LOPU took place under general anesthesia on Day 11, and follicles ≥2 mm were aspirated with an 18-gauge needle connected to a controlled vacuum system. Vaginal sponges were removed at the time of LOPU. Treatments were repeated 2 times in a 2-week interval scheme (2 goats and 1 goat were excluded from the experiment during the second and third LOPU sessions, respectively). Cumulus–oocyte complexes were washed and evaluated for quality (graded from 1 to 3). Oocytes recovered from unstimulated slaughterhouse-derived ovaries served as a control. Cumulus–oocytes complexes from Grades 1 and 2 were submitted to IVM in TCM-199, supplemented with 100 μm of cysteamine and either 10 ng mL–1 of epidermal growth factor (EGF) or 10% follicular fluid and 100 ng mL–1 of ovine FSH (FF-FSH). Matured oocytes were then submitted to IVF and in vitro development as described by Cognié et al. (2004 Reprod. Fertil. Dev. 16, 437–445). Over the 94 LOPU sessions, 20.4 ± 0.9 follicles were aspirated (mean ± SEM), allowing the recovery of 12.3 ± 0.7 COC per goat and per session, of which 80.1% were suitable for IVM (Grades 1 and 2). Results of in vitro production are detailed in the table. The IVM treatment did not significantly affect cleavage or blastocyst development rates in oocytes derived from slaughterhouse ovaries. Cleavage rates were significantly decreased in LOPU-derived oocytes when compared with control oocytes. For LOPU-derived oocytes, cleavage and final blastocyst development rates were increased significantly and kinetics of embryo development were accelerated when FF-FSH was used during IVM as compared with EGF. The IVM with FF-FSH allowed us to produce 4.1 blatocysts per goat per LOPU session. These results demonstrate the interest in LOPU for goat embryo production once appropriate IVM treatment is used. The difference observed between LOPU and slaughterhouse oocytes in terms of response to IVM treatments may be related to FSH stimulation prior to the LOPU session or to postmortem changes in oocyte responsiveness in the slaughterhouse group. Table 1. Effects of oocyte origin [laparoscopic ovum pickukp (LOPU) or slaughterhouse derived] and maturation treatment [epidermal growth factor (EGF) or follicular fluid (FF)-FSH] on in vitro embryo production (6 replicates)

Effect of coculture with oviduct epithelial cells on viability after transfer of vitrified in vitro produced goat embryos

This study evaluates the effect of coculture with goat oviduct epithelial cells (GOEC) on the pregnancy rate, embryo survival rate and offspring development after direct transfer of vitrified/thawed caprine in vitro produced (IVP) embryos. Oocytes were recovered from slaughterhouse goat ovaries, matured and inseminated with frozen/thawed capacitated semen, and presumptive zygotes were randomly cultured in synthetic oviduct fluid (SOF) (n=352) or GOEC (n=314). The percentage of cleaved embryos reaching the blastocyst stage was 28% and 20% in SOF and GOEC, respectively (P<0.05). Overall, 26 blastocysts of SOF were transferred freshly in pairs to recipient goats, whereas 58 of SOF and 36 of GOEC were vitrified and transferred directly in pairs to recipient goats after thawing without removal of cryoprotectants or morphological evaluation. The kidding rate was 92% for SOF fresh, 14% for SOF vitrified (P<0.001) and 56% for GOEC vitrified (P<0.05); the difference was also significant between vitrified groups (P<0.01). The embryo survival rate was 62% for SOF fresh, 9% for SOF vitrified (P<0.001) and 33% for GOEC vitrified (P<0.05) with a significant difference between vitrified groups (P<0.01). The results showed that the coculture of IVP goat embryos with GOEC significantly improves the pregnancy and embryo survival rates and leads to the birth of healthy offspring. However, further research using more defined GOEC coculture is required to confirm its capacity to increase the success rate of IVP embryo technology in goat.

Improved vitrification method allowing direct transfer of goat embryos

The aim of this study was to design a vitrification method suited to field embryo transfer experiments in goat. In a first experiment, a standard vitrification protocol, previously designed for sheep embryos was compared to slow freezing of goat embryos. No significant difference was observed on kidding rate (48% versus 69%, respectively), nor on embryo survival rate (35% versus 45%). Second experiment: all embryos were vitrified. After warming, embryos were either transferred directly (direct transfer), or after in vitro dilution of the cryoprotectants (conventional transfer). The kidding rate was not affected by the transfer method (38% versus 23%, respectively). However, embryo survival rate tended to be higher after direct transfer (26% versus 14%). Third experiment: OPS vitrification was compared to standard vitrification. The kidding rate was not affected (22% versus 39%, respectively), but the embryo survival rate was lower after OPS (14% versus 28%). Fourth experiment: 0.4M sucrose was added with cryoprotectants in vitrification. The kidding rate after direct transfer was significantly enhanced after addition of sucrose (56% versus 27%, respectively), whereas embryo survival rate was not significantly affected (32% versus 18%). Fifth experiment: vitrification with sucrose supplementation was compared to slow freezing. No significant difference was observed after direct transfer on kidding rate (52% versus 31%, respectively), but embryo survival rate tended to be higher after vitrification (34% versus 21%). In conclusion, our results indicate that addition of 0.4M sucrose in association with direct transfer improves significantly the viability of goat vitrified embryos.

Laparoscopic ovum pick-up and in vitro production of sika deer embryos: effect of season and culture conditions

Amongst the 200 deer subspecies worldwide, more than 40 are considered as endangered. In vitro embryo production may represent an efficient way to produce and disseminate offspring from sparse remaining individuals in these species. With a view to establishing a method of in vitro embryo production, we assessed the ovarian response after hormonal stimulation (oFSH), oocyte yield following laporoscopic ovum pick-up (LOPU) and oocyte developmental competence according to seasonal reproductive status in sika deer (Cervus nippon nippon). Twelve adult sika deer hinds were allocated between two groups and submitted weekly to oFSH follicular growth stimulation followed by LOPU. Hinds in Group A (n=6) were treated first during the breeding season (5 weeks), and then during the non-breeding season (3 weeks). Hinds in Group B (n=6) were submitted to similar procedures but in the reverse order (treated first during the non-breeding season). Cumulus-oocytes complexes (COC) recovered from Group B were allowed to mature in vitro for 24 h in TCM-199 medium supplemented with oFSH, goat follicular fluid and 100 microM cysteamine. In vitro fertilization was performed with frozen/thawed semen in SOFaa medium supplemented with 20% estrous sheep serum and presumptive zygotes were cultured in the presence or absence of ovine oviductal epithelial cell monolayer (oOEC) in SOFaa-BSA medium. Mean number of follicles aspirated per hind per session decreased significantly between breeding and non-breeding season in Group A (9.8+/-0.7 versus 3.2+/-0.7, mean+/-S.E.M., respectively, P<0.001) but did not change between the non-breeding and the subsequent breeding season in Group B (5.3+/-0.7 and 5.7+/-0.7, respectively, P>0.05). Irrespective of the season, good quality COC with complete and compact cumulus investments were recovered allowing a high cleavage rate after in vitro maturation and fertilization. Whereas development to the blastocyst stage did not occur in SOF medium alone, high development rates to the blastocyst stage were observed in oOEC co-culture regardless of season (22% and 34% of total oocytes in co-culture during non-breeding and breeding season, respectively).

Comparison of cell proliferation index in equine and caprine embryos using a modified BrdU incorporation assay

The measurement of cell proliferation and cell viability using 5'bromo-2'deoxy-uridine (BrdU) labelling has been described in several cell types and species. The aim of this study was to adapt this technique to equine embryos and to compare the index of DNA replication (S-phase) between equine and caprine embryos. Seventeen equine embryos were recovered at day 6.5 post-ovulation and 20 caprine embryos were recovered at day 7 after the onset of estrus. Equine embryos were incubated during 1h at 39 degrees C in PBS containing 1mM of BrdU. Embryos were then treated in 0.05% trypsin during 15 min at 39 degrees C to permeabilise the capsule, and then embryos were rinsed in PBS containing 10% of foetal calf serum. After washing, embryos were immediately fixed in 2.5% paraformaldehyde with 0.3M NaOH during 15 min at ambient temperature. The S-phase was detected by immunocytochemistry technique. In caprine embryos, BrdU was visualised by the same technique but without the trypsin treatment. The percentage of cells (+/-S.E.M.) with BrdU incorporated into newly synthesised DNA strands was significantly higher in equine embryos (74+/-1) than in caprine (38+/-2). Our results demonstrated that BrdU incorporation assay can be used in equine embryos. This assay allows the determination of the proliferation index of live cells and could be used as an additional tool for evaluating the viability of embryos. The high percentage of cells incorporating BrdU during 1h of incubation with BrdU suggests that in comparison with the caprine embryos the cellular activity of proliferation is more intense in equine embryos and suggests that the cellular cycle is shorter in equine embryos.

91 PRELIMINARY RESULTS OF SURGICAL EQUINE EMBRYO TRANSFER AFTER OPEN PULLED STRAW VITRIFICATION

In equine species, embryo cryopreservation is not as widely developed as in some other species. Slow freezing has been applied to equine embryos but with relatively low success rates. This higher sensitivity to conventional freezing procedures may be explained by the presence of a capsule surrounding the equine embryo that may impair cryoprotectant penetration. Recently, good in vitro embryo survival rate was obtained after open pulled straw (OPS) vitrification (Moussa et al. 2005 Theriogenology 64, 1619–1632). The aim of the present study was to evaluate in vivo survival of vitrified embryos five days after surgical transfer into Welsh pony mares. Morulae (M), early blastocysts (EB), and blastocysts (B) ranging from 140 to 320 μm in diameter were collected (n = 20) in a Ringer lactate solution on Day 6.75 after ovulation. Before vitrification, embryos were assessed morphologically and their size was measured (McKinnon and Squires 1988 J. Am. Vet. Med. Assoc. 192, 401–406). Then, embryos were vitrified using the OPS method described by Berthelot et al. (2001 Reprod. Nutr. Dev. 41, 267–272). Briefly, embryos were washed twice in HEMES-TCM-199 + 20% newborn calf serum (NBCS) for 1 min, equilibrated in HEPES-TCM-199 + 20% NBCS with 7.5% dimethyl sulfoxide (DMSO) + 7.5% ethylene glycol (EG) for 3 min, and then with 18% DMSO + 18% EG + 0.4 M sucrose for 45 s. One embryo was then loaded per straw. For transfer, four straws were quickly thawed (5 s in air) and the narrow end of the straw containing the embryo was immersed in HEPES-TCM-199 + 20% NBCS + PBS + 0.2 M sucrose. Five to 8 min after thawing, four embryos were surgically transferred into the cranial portion of the uterine horn in each of five pony mare recipients. Five days after transfer, embryos recovered by transcervical flushing of the uterus were classified as viable if morphology was normal, no dark inner cells were present, the capsule was intact, and the diameter was at least 1000 μm. The results are shown in the table. One recipient of vitrified embryos had an endometritis and no embryo was recovered. From the four other recipients, nine embryos were recovered out of 16 (56%) transferred, seven of which were viable (44%). The results of the present preliminary study demonstrating survival of equine embryos transferred after OPS vitrification is very encouraging. However, the results should be confirmed by birth of foals after transfer of OPS-vitrified embryos to recipients. Table

Successful use of oviduct epithelial cell coculture for in vitro production of viable red deer (Cervus elaphus) embryos

Techniques for in vitro production (IVP) of viable embryos have been thoroughly developed in several domestic species in view to improve breeding efficiency. When applied to wild life, these techniques may also help the maintenance of biodiversity through amplification of sparse animals offspring and facilitation of genetic material exchange. During the successive steps of IVP, i.e. oocyte in vitro maturation (IVM), fertilization (IVF) and early embryo development (IVD) to the blastocyst stage, gametes and embryos are faced with unusual environment, including oxidative stress, known to be detrimental to their survival. In the present study, starting from methods developed in domestic species, we have adapted IVP to produce viable red deer embryos. In a first experiment, cumulus cells were removed from in vitro matured oocytes either before or after IVF. The presence of cumulus cells during IVF did not affect final cleavage or development rates. In a second experiment, in vitro matured oocytes were fertilized in the presence of cumulus cells and cultured in SOFaaBSA medium alone or in the presence of ovine oviduct epithelial cell (oOEC) monolayer. Whereas, oviduct cells did not improve the cleavage rate, they significantly increased the rate of embryos reaching the blastocyst stage (from 3 to 25% of total oocytes). Ten blastocysts from oOEC coculture were transferred after freezing and thawing to five recipient hinds and gave rise to three pregnancies. The three pregnant hinds gave birth to three live and normal calves.

In vitro comparisons of two cryopreservation techniques for equine embryos: Slow-cooling and open pulled straw (OPS) vitrification

Vitrification using open pulled straw (OPS) has provided encouraging results with embryos from other species. The aim of this study was to compare the survival of 6.5- and 6.75-day-old equine embryos after OPS vitrification and slow-cooling. Eighteen embryos were frozen using a slow-cooling method. Embryos were placed in modified PBS with increasing glycerol concentration (2.5%, 5%, 7.5% and 10% (v/v) 5 min each). Embryos were loaded into 0.25 ml straws then placed in a programmable freezer and subsequently plunged into liquid nitrogen. After thawing, cryoprotectant was removed by five steps with decreasing glycerol and sucrose concentrations. Twenty embryos were vitrified using the OPS method. Embryos were exposed to 7.5% dimethyl-sulfoxide (DMSO)+7.5% ethylene glycol (EG) for 3 min and in 18% DMSO+18% EG+0.4M sucrose for 1 min, loaded in OPS and plunged into liquid nitrogen. After warming, embryos were placed in decreasing sucrose concentrations. All embryos were cultured in synthetic oviduct fluid (SOF) medium for 3h and evaluated using 4',6-diamidino-2-phenylindole (DAPI) staining. The percentage of cells entering in S-phase (%SC) was evaluated by incorporation of BrdU. No significant differences were observed for mean diameter, morphological grade and percentage of degenerate embryos after 3h of culture for slow-cooling and OPS methods. The percentage of dead cells per embryo was similar for the two procedures (42+/-6 versus 46+/-9). The percentage of cells entering in S-phase did not differ significantly between the two procedures (27+/-5 versus 26+/-6). OPS vitrification may be as efficient as slow-cooling for the cryopreservation of equine embryos. However, these results should be confirmed by the transfer of OPS vitrified embryos to recipient mares.