128 Comparison of multiple maturation times on juvenile invitro embryo transfer (JIVET)-derived oocytes and embryo development in the goat

Juvenile invitro embryo transfer (JIVET) is an assisted reproductive technology (ART) with the potential to produce numerous offspring from a single young female goat at 4 to 8 weeks of age. It has been reported in small ruminants that there can be a marked variable response to the administration of exogenous hormones for superovulation, the subsequent number of oocytes generated, and subsequent embryo developmental potential. The industry standard (as well as the recommendation of commercial media suppliers) invitro maturation time is 21 to 24h for conventionally derived oocytes. This study investigated multiple maturation times for JIVET-derived oocytes: 16, 22, and 28h. Oocytes were collected from four JIVET animals at 6 to 8 weeks of age. The hormonal superovulation regimen used on the juvenile animals consisted of 4×40-mg FSH injections at ∼12h apart and a 400IU of PMSG injection given with the first FSH injection. Surgical recovery of the oocytes via a midline laparotomy was performed the day following the last FSH injection. All of the oocytes were collected via aspirating follicles that were 4mm and larger. Oocytes with compact cumulus cells subsequently underwent IVM, IVF, and invitro culture (IVC) utilising IVF Bioscience media and methods. A single straw of identical cryopreserved/thawed semen from the same buck was utilised for each of the IVF procedures. The results were (37/88) 42%, (37/85) 44%, and (39/91) 43% cleaved and (23/88) 26%, (24/85) 28%, and (28/91) 31% blastocyst rate based on respective maturation times for JIVET-derived ova. Development rate during the cleavage stage and blastocyst stage was analysed using a repeated-measures logistic regression model utilising generalized estimating equations (GEE), with maturation time as fixed effect and a compound symmetry within subject (juvenile goat) covariance structure. The main effect of maturation time on the odds of development during the cleavage stage (P=0.8727) and blastocyst stage (P=0.3857) was not significant. These results indicate that the time in maturation media does not have as profound an effect on development to blastocysts as a factor in the variability reported by other laboratories. The development rate of embryos from one juvenile goat produced very high blastocyst rates of (5/12) 42%, (11/12) 92%, and (11/15) 73%, respectively. Additional logistic regression analysis showed that the odds of development in this juvenile donor was significantly different compared with the other donors (pooled) during the cleavage stage at 16h (P=0.0083) and 28h (P=0.0021) maturation times. Likewise, the odds of development in this donor was significantly different than that of the other donors (pooled) during the blastocyst stage at 22h (P=0.0002) and 28h (P=0.0003) maturation times. This further indicates the wide variation of oocyte quality from JIVET-derived oocytes and indicates potential for higher development rates at 22 and 28h in this specific goat.

Generation of goats by nuclear transfer: a retrospective analysis of a commercial operation (1998-2010)

At LFB USA, Inc., the ultimate use for transgenic cloned goats is for the production of recombinant human protein therapeutics in their milk. This retrospective analysis of the Somatic Cell Nuclear Transfer (SCNT) program, spanning from 1998 to 2010, examined parameters potentially affecting the outcomes and efficiencies in this commercial operation. Over 37,000 + ova were utilized in the SCNT protocol producing a total of 203 cloned goats. Fifty one (51) clones were produced from non-transfected (transgenic and non-transgenic animal donor) cell lines and 152 clones were produced from transfected cell lines. Comparisons and summaries of (a) transfected versus non-transfected cell lines, (b) relationship of SCNT parameters to offspring produced, (c) skin versus fetal cells, (d) fresh versus cryopreserved cells, (e) parameters from all cell lines used versus those producing SCNT offspring, (f) variation among cell sources, (g) methods of SCNT parturition management and effects on live offspring, and lastly (h) SCNT variation by program are reported. Findings indicate that (a) non-transfected cell lines were more efficient versus transfected cell lines in generating viable cloned offspring on a per reconstructed embryo transferred basis, (b) transfected fetal fibroblasts had improved efficiency versus transfected skin fibroblasts, (c) the percentage of non-transfected cell lines that produced offspring was statistically higher than transfected cell lines, (d) and induction of parturition improved the percentage of viable offspring. In summary, this retrospective analysis on the SCNT process has identified certain parameters for improved efficiency in producing viable cloned goats in a commercial setting.

154 A method of oviductal semen deposition for use in the goat

The objective of this study was to investigate a method of oviducal semen deposition as a strategy for producing offspring from poor-quality cryopreserved goat sperm. Invitro fertilisation (IVF) and AI are common assisted reproductive technologies used in small ruminants, but they have varied results in the goat. The use of poor-quality cryopreserved-thawed sperm (<50% live/dead ratio at post-thaw) can decrease the rate of success. These procedures were performed in the month of November in Central Massachusetts in the United States (42° N). Seven 10-year-old dairy goats (Saanen, Toggenburg, and Alpine breeds) were synchronised and superovulated using a progesterone implant on Day 0, a prostaglandin injection at Day 7, two daily injections of 36mg of FSH ~12h apart on Days 12-15, and progesterone implant removal on Day 14 followed by an injection of 50µg of gonadotrophin-releasing hormone. Sperm deposition was performed on Day 17 (72 h after implant removal). The animals were anaesthetised using a standardised protocol, intubated, and maintained using isoflurane, and sterile prep was performed before a midline laparotomy procedure. Straws from a single ejaculate from a transgenic founder that was cryopreserved using a commercial two-step glycerol-egg yolk-based extender were used. A straw from this collection was post-thawed 30 days after collection and, using a commercial live/dead stain, 67% live sperm was determined. The optimal type of sperm prep and sperm concentration is unknown and may be dependent on sperm quality. Therefore, different gradient preps using Vitrolife SpermGrad at three volumes (1.5 (used on two animals), 1.0, and 0.5mL) as well as two volumes of IVF Bioscience Bovine BO-SemenPrep (4.0mL (used on two animals) and 2.0mL) were used. All five pellets were diluted in 1.0mL of IVF Bioscience Bovine BO-IVF media. Sperm concentrations ranging from 75×106 to 27×106 spermmL−1 were deposited into one oviduct; then, a 10:1 dilution was performed and 7.5×106 to 2.7×10 spermmL−1 were deposited into the contralateral oviduct. The depositions were performed just proximal to the uterotubal junction in a volume of 0.1mL of diluent via a tuberculin syringe attached to a 20-gauge needle. Two days following the procedure, oviducts were flushed postmortem from three of the seven randomly selected goats. All three had fertilised embryos, and nineteen 8-cell embryos were retrieved. Three of these embryos were surgically transferred to the distal uterine horn of a suitable recipient. The recipient became pregnant and produced a single offspring. The remaining four of seven goats were killed 41 days post-surgery. Two of the four goats were pregnant, with one carrying one fetus and the other carrying five fetuses. Further studies are needed to optimise this method, but these initial results indicate that oviducal semen deposition directly into the oviduct proximal to the uterotubal junction may be a suitable alternative for producing offspring from suboptimal cryopreserved-thawed goat sperm.

194 Superovulation response does not affect embryo development of pronuclear microinjected embryos in the goat

Superovulation of donor animals is essential in the production of transgenic founder goats generated through microinjection. There can be a marked variable response to the exogenous hormones used for superovulation. The objective of this study was to examine how the superovulatory response of individual goats affected the ability of the fertilized, microinjected embryos to develop into offspring. The donors were superovulated using a progesterone implant on Day 0, a prostaglandin injection at Day 7, 2 injections ~12h apart of 32 to 36mg of FSH on Day 12 to 15, progesterone implant removal on Day 14, bred by intact bucks several times starting on Day 15 to 16, an injection of 50μg of gonadotropin-releasing hormone, and surgical collection of 1- to 2-cell embryos from retrograde flushing of the oviduct on Day 17 (~24-48 h, 1-2 days after breeding). Surgical collection allows for an accurate ovulation point (OP) count before the oviduct being retrograde flushed and ova collected and counted. Data from donor animals were grouped by superovulatory response based on OP counts of 1-10, 11-20, 21-30, or >30. The number of donors that contributed per group were 130, 280, 175, and 52, respectively. The recovery rate was 76, 72, 68, and 62%, respectively. After collection, ova were viewed under a dissecting microscope and assessed for fertilization by identifying pronuclei, and 1 pronucleus was microinjected. The fertilization rate was 47, 52, 51, and 56%, respectively. The survivability rate after microinjection was 80, 76, 75, and 76%, respectively. Surviving embryos were transferred (3-5) into recipient goats following a 2- to 6-h in vitro culture (as 1- to 2-cell embryos), allowing for a suitable period to assess viability post-injection. Further in vitro development rates were not assessed because of the short timeframe the embryos stayed in culture. The conception rates were 71, 56, 65, and 53%, respectively, and abortion rates were 23, 10, 14, and 9%, respectively. As some recipients received embryos from multiple donors, this data could not be included in the analysis as identifying which offspring were from the corresponding embryo group could not be confirmed. Data were analysed using SAS software (version 9.4, SAS Institute Inc., Cary, NC, USA). The Wald chi square test under linear regression was used to analyse the number of offspring produced per embryo transferred. No significant differences were found between groups (all P-values were>0.05). This analysis indicated that the range of superovulation response does not affect the developmental competence of the pronuclear microinjected embryo or the ability to produce viable offspring. Table 1.Comparison of the donor ovulation counts, number of embryos transferred, offspring produced and overall efficiency

94 Impact of number of embryos transferred on the number of offspring produced in a commercial transgenic founder production operation

The production of transgenic founder dairy goats (cross-bred Saanens, Alpines, Toggenburgs, and Nubians) involves the collection, microinjection, and transfer of numerous embryos into suitable recipient goats to ultimately produce a transgenic founder(s). The objective of this study was to determine the most efficient number of microinjection embryos to transfer to suitable recipients for transgenic founder generation. This is critically important in a commercial production program, as it impacts the goal for the number of embryos collected from donors, number of recipients utilised, and, hence, the overall number of surgical procedures being performed. The entire embryo collection, transfer, and founder-generation process is continuously being evaluated for ways to become more efficient in producing transgenic animals. During LFB USA’s commercial founder-production campaigns over the years (1997-2017), pronuclear microinjection was performed and 3, 4, or 5 embryos were transferred to female goat recipients. The recipients were synchronized using a progesterone implant on Day 0, a prostaglandin injection at Day 7, an injection of 300-500IU of pregnant mare serum gonadotropin on Day 13, progesterone implant removal on Day 14, and surgical transfer of pronuclear microinjected 1- or 2-cell embryos into the oviduct on Day 17. The individual totals and calculation for offspring per embryos transferred was compared for 3, 4, and 5 embryos transferred per recipient and was determined to be (1659/8637) 0.19, (912/4548) 0.20, and (112/675) 0.17, respectively. These embryo efficacy ratios were not significantly different (P>0.05) using the Wald Chi-squared test under logistic regression, and suggests that the number of offspring born is not impacted by number of embryos transferred. Seasonality was also evaluated in this production environment located in North America, with in-season being considered September to December and out-of-season being January to July. Nulliparous recipients during in-season (September to December) embryo transfer operations produced a significant difference, with totals and calculation for (offspring per embryo transferred) of (470/2346) 0.20, (260/1088) 0.24, and (23/190) 0.12 for 3, 4, and 5 embryo transfers, respectively (Table 1). This data indicates that when using nulliparous recipients during the in-season, transferring 4 embryos is optimal for offspring produced. Table 1.Comparison of the individual totals and the calculation of (offspring/embryo) by parity and season

Non-viral transfection of goat germline stem cells by nucleofection results in production of transgenic sperm after germ cell transplantation

Germline stem cells (GSCs) can be used for large animal transgenesis, in which GSCs that are genetically manipulated in vitro are transplanted into a recipient testis to generate donor-derived transgenic sperm. The objectives of this study were to explore a non-viral approach for transgene delivery into goat GSCs and to investigate the efficiency of nucleofection in producing transgenic sperm. Four recipient goats received fractionated irradiation at 8 weeks of age to deplete endogenous GSCs. Germ cell transplantations were performed 8-9 weeks post-irradiation. Donor cells were collected from testes of 9-week-old goats, enriched for GSCs by Staput velocity sedimentation, and transfected by nucleofection with a transgene construct harboring the human growth hormone gene under the control of the goat beta-casein promoter (GBC) and a chicken beta-globin insulator (CBGI) sequence upstream of the promoter. For each recipient, transfected cells from 10 nucleofection reactions were pooled, mixed with non-transfected cells to a total of 1.5 × 10(8) cells in 3 ml, and transplanted into one testis (n = 4 recipients) by ultrasound-guided cannulation of the rete testis. The second testis of each recipient was removed. Semen was collected, starting at 9 months after transplantation, for a period of over a year (a total of 62 ejaculates from four recipients). Nested genomic PCR for hGH and CBGI sequences demonstrated that 31.3% ± 12.6% of ejaculates were positive for both hGH and CBGI. This study provides proof-of-concept that non-viral transfection (nucleofection) of primary goat germ cells followed by germ cell transplantation results in transgene transmission to sperm in recipient goats.

211 INTRODUCING NEW GENETICS INTO A CLOSED BIOSECURE HERD OF DAIRY GOATS

Transgenic dairy goats expressing recombinant molecules in their milk have been validated as a viable method for producing human therapeutic proteins. Although maintaining a closed herd ensures biosecurity within a facility, the ability to introduce new genetics into the herd can be difficult. In this work we determined the ability to use cryopreserved caprine semen, imported from New Zealand into the United States, for IVF as a method to increase the genetic diversity of the GTC Biotherapeutics closed caprine herd. Semen was collected from bucks owned by GTC Biotherapeutics and maintained in New Zealand. The bucks were serologically screened for goat pathogens prior to collection, and were maintained in quarantine during semen collection. Separate single experiments were performed using cryopreserved semen from each of 2 different bucks (NZ1 and NZ2). One or 2 straws of semen (107/0.25 mL straw) from each buck were thawed and then purified using a Percoll gradient. Ovulated oocytes surgically collected from superovulated does were co-incubated with sperm (5 × 105 mL–1) in Brackett-Oliphant medium supplemented with 10% fetal bovine serum, 7.7 mm calcium lactate plus 2.5 μg mL–1 of heparin for 18 h at 38°C. Presumptive zygotes were transferred to equilibrated SOF plus 0.8% BSA and cultured in vitro for 24 h. On Day 2 cleavage was determined and, as an added precaution, embryos selected for transfer were washed per the IETS protocol for the sanitary handling of embryos. Five 2-cell to 8-cell embryos from individual donors were surgically transferred to a single oviduct of each synchronized surrogate recipient. Pregnancies were determined by ultrasonography. Pregnancy rates for recipients at Day 50 of gestation (71 v. 67% pregnant), at term (100 v. 100%), and the proportion of offspring born from total embryos transferred (17 v. 23% offspring) were comparable for buck NZ1 and buck NZ2, respectively (P > 0.05). A total of 13 offspring (6 bucks and 7 does) were produced from 9 different oocyte donors. These results demonstrate that cryopreserved caprine semen, imported from New Zealand into the United States, can be used for IVF to introduce new genetics into a closed biosecure caprine herd. The use of IVF, compared with AI, allows more offspring to be produced per straw of semen. In addition, IVF offers the advantage of accelerated genetic gain by producing multiple offspring from elite does with more desirable lactation, reproduction, and conformation traits. Beyond the new F1 animals produced by IVF, several techniques (natural mating, AI, or IVF) can then be used to quickly disseminate the new genetics into both the nontransgenic and transgenic herds. Finally, skin cells obtained from the female IVF offspring or fetal cells derived from any pregnancies of the initial IVF offspring could also be used to generate transfected cells as karyoplast donors for future somatic cell nuclear transfer work. Table 1. Summary of caprine IVF

Effect of macromolecule supplementation during in vitro maturation of goat oocytes on developmental potential

In vitro maturation (IVM) of goat oocytes with serum-supplemented media results in oocytes with reduced developmental potential. The objective of this study was to develop a defined medium for IVM of goat oocytes that better supports subsequent embryonic development. Cumulus oocyte complexes (COC) were matured for 18-20 hr in: Experiment (1), tissue culture medium 199 (TCM199) with 10% (v/v) goat serum or modified synthetic oviduct fluid maturation medium (mSOFmat) with 2.5, 8.0, or 20.0 mg/ml bovine serum albumin (BSA); Experiment (2), mSOFmat with 4.0, 8.0, 12.0, or 16.0 mg/ml BSA; or Experiment (3), 1.0 mg/ml polyvinyl alcohol (PVA; control), 4.0 mg/ml BSA, 0.5 mg/ml hyaluronate plus 0.5 mM citrate, or hyaluronate, citrate, and BSA. Mature COC were coincubated for 20-22 hr with 12-15 x 10(6) sperm/ml in modified Brackett and Oliphant (mBO) medium. Embryos were cultured for a total of 7 days in G1/2, and evaluated for cleavage, and blastocyst development, hatching, and total cell numbers. In the first experiment, more (P < 0.05) blastocysts developed per cleaved embryo following maturation in mSOFmat with 2.5 or 8.0 mg/ml BSA than with 20.0 mg/ml BSA or TCM199 with 10% goat serum. The various concentrations of BSA used in the second experiment did not affect (P > 0.05) any of the developmental endpoints examined. In the third experiment, developmental potential of oocytes matured with PVA or hyaluronate with citrate was not different (P > 0.05) from oocytes matured in the presence of BSA. These results demonstrate that developmentally competent goat oocytes can be matured under defined conditions.

314EFFECT OF MACROMOLECULE SUPPLEMENTATION DURING IN VITRO MATURATION ON THE DEVELOPMENTAL COMPETENCE OF GOAT OOCYTES

In vitro maturation of goat oocytes has traditionally involved the use of serum or BSA. However, these products introduce variability and complicate evaluation of the effects of other medium components. The objective of this study was to examine the effects of citrate and hyaluronate in the absence or presence of BSA during IVM on the developmental competence of goat oocytes. Abattoir-derived, cumulus-oocyte complexes (COC) were matured for 20–22h (6.0% CO2 in air, 38.7°C) in modified SOF medium (1.5mM glucose, 3.0mM L-lactate, 0.1mM pyruvate, 1.0mM glutamine, 0.1mM taurine) supplemented with 1×MEM nonessential amino acids, 0.5×MEM essential amino acids, 1×MEM vitamins, 0.1mM cysteamine, 5μg mL−1 insulin, 5μgmL−1 transferrin, 5ng mL−1 selenium, 50ngmL−1 EGF, 0.01U mL−1 LH and FSH, and 50μgmL−1 gentamicin. Treatments were: (1) 1mgmL−1 PVA (protein-free, defined); (2) 4mgmL−1 BSA (semi-defined); (3) 0.5mM citrate and 0.5mgmL−1 hylauronate (C+H, defined); and (4) 0.5mM citrate and 0.5mgmL−1 hylauronate with 4mgmL−1 BSA (C+H+BSA, semi-defined). At the end of IVM, COC were transferred to modified Brackett and Oliphant’s medium with 7.7mM Ca-(l)-lactate and 20% FCS for IVF. Frozen-thawed sperm were processed through a 45%:90% Percoll gradient and added to IVF drops (50μL) containing COC at a final concentration of 14–15×106 spermmL−1. Gametes were coincubated in the presence of heparin (25μgmL−1) for 22–24h in 7% CO2 in air at 38.7°C. After coincubation, cumulus cells were removed and zygotes were cultured (6% CO2, 5% O2, 89% N2, 38.7°C) in G1 v.3 for 3 days followed by 4 days in G2 v.3. Cleavage was evaluated when embryos were moved to G2, and development to the blastocyst stage was assessed at the end of culture. All blastocysts were fixed and stained with Hoechst 33342 for total cell counts. Analysis of variance was performed using the general linear mixed model macro of SAS. Means are presented ±SEM and probability values P&lt;0.05 were considered significant. The use of BSA did not improve (P&gt;0.05) the developmental potential of goat oocytes (Table 1). Furthermore, a similar proportion (P&gt;0.05) of oocytes developed to the blastocyst and hatching blastocyst stage after maturation under defined conditions compared to oocytes matured with BSA. In conclusion, developmentally competent goat oocytes can be produced by IVM under defined conditions. Table 1 Development of goat oocytes following IVM with different macromolecules.

Cryopreservation of epididymal sperm obtained at necropsy from goats

In the field of transgenic production, the ability to carry a male's genetic contribution beyond its natural life span is remarkably important. The ability to successfully collect and cryopreserve sperm from the epididymis at necropsy may prove to be a useful technique for preserving valuable genes. Thirty-two bucks ranging in age from 13 days to 7 years were examined in this study and 25 had epididymal sperm extracted at necropsy. Seven bucks yielded clear fluid with no spermatozoa; all were under four months of age. Testes were removed from the scrotal sac, small lateral incisions made across the convoluted tubules, pressure applied to the tail of the epididymis and small droplets of sperm pipetted into equilibrated extender. The average initial analysis of wave motion (0 to 5, 5 being rapid wave motion), live/dead sperm percentage and acrosomal integrity of 25 fresh epididymal samples were 5.0, 92%, and 100%, respectively. By comparison, the same parameters obtained from 206 fresh ejaculated samples were 3.0, 86%, and 95%, respectively. After being cryopreserved in liquid nitrogen, one straw from each sample was thawed after 3 to 60 days of cryostorage. Results of post-thaw analysis of 25 cryopreserved epididymal sperm samples for live/dead percentage and acrosomal integrity were 82% and 84%, respectively. By comparison, results of post-thaw analysis of 206 cryopreserved ejaculated sperm samples for live/dead percentage and acrosomal integrity were 60% and 89%, respectively. To assess the competence of the frozen epididymal sperm, IVF and AI were performed. In parallel IVF experiments, 40% of the oocytes showed cleavage patterns, with 6% developing to the blastocyst stage using frozen epididymal sperm, while 37% of the oocytes showed cleavage patterns and 4% developed into blastocysts using frozen ejaculated sperm. One artificial insemination out of 20 resulted in a pregnancy using frozen epididymal sperm, while 7 of 18 artificial inseminations resulted in a pregnancy using frozen ejaculated sperm. This data documents the successful collection and cryopreservation of epididymal sperm from the goat and its use for in vitro fertilization and artificial insemination.