Comprehensive genome assembly reveals genetic diversity and carcass consumption insights in critically endangered Asian king vultures

The Asian king vulture (AKV), a vital forest scavenger, is facing globally critical endangerment. This study aimed to construct a reference genome to unveil the mechanisms underlying its scavenger abilities and to assess the genetic relatedness of the captive population in Thailand. A reference genome of a female AKV was assembled from sequencing reads obtained from both PacBio long-read and MGI short-read sequencing platforms. Comparative genomics with New World vultures (NWVs) and other birds in the Family Accipitridae revealed unique gene families in AKV associated with retroviral genome integration and feather keratin, contrasting with NWVs' genes related to olfactory reception. Expanded gene families in AKV were linked to inflammatory response, iron regulation and spermatogenesis. Positively selected genes included those associated with anti-apoptosis, immune response and muscle cell development, shedding light on adaptations for carcass consumption and high-altitude soaring. Using restriction site-associated DNA sequencing (RADseq)-based genome-wide single nucleotide polymorphisms (SNPs), genetic relatedness and inbreeding status of five captive AKVs were determined, revealing high genomic inbreeding in two females. In conclusion, the AKV reference genome was established, providing insights into its unique characteristics. Additionally, the potential of RADseq-based genome-wide SNPs for selecting AKV breeders was demonstrated.

Detection of Protein Biomarkers Relevant to Sperm Characteristics and Fertility in Semen in Three Wild Felidae: The Flat-Headed Cat (Prionailurus planiceps), Fishing Cat (Prionailurus viverrinus), and Asiatic Golden Cat (Catopuma temminckii)

Effective wild cat conservation programs with assisted reproductive technologies are being developed in different parts of the world. The flat-headed cat, fishing cat, and Asiatic golden cat are three species among nine wild Felidae in Thailand that are in need of urgent conservation efforts. Here, we assessed routine sperm characteristics and we report the detection of protein biomarkers related to the fertilization process, IZUMO1 and the CRISP family, and apoptotic markers, active or cleaved caspase-3, in semen samples collected from these wild cats. IZUMO1 was located in the equatorial segment of the sperm head, which is the region involved in gamete interaction. The highest levels of IZUMO1 were found in both the sperm pellet and the seminal plasma of the flat-headed cat, as determined by immunoblotting. CRISP2, a sperm-egg fusion assisting protein, and CRISP3 were found in both the sperm pellet and the seminal plasma, and the highest levels were observed in the fishing cat. Positive correlations between certain semen parameters and IZUMO1, CRISP2, and CRISP3 expression were also demonstrated. Cleaved caspase-3 was found in all sperm samples in all three species and was associated with an increase in DNA fragmentation and a decrease in certain semen characteristics such as motility, viability, and intact acrosomes. Our results suggest that the analysis of IZUMO1, the CRISP family, and cleaved caspase-3, along with the routine sperm characteristics, may allow for better success in breeding management in wild Felidae, particularly in the flat-headed cat and the fishing cat.

Serum anti-Müllerian hormone around the time of ovulation simulated by exogenous hormones in clouded leopards (Neofelis nebulosa)

Anti-Müllerian hormone (AMH) is produced by granulosa cells of the antral follicles. It serves as a promising biomarker for ovarian reserve and responsiveness to ovarian stimulation in humans and domestic animals. This study aimed to validate the AMH Gen II enzyme-linked immunosorbent assay (ELISA) and correlate ovarian structures with serum AMH concentrations after stimulation treatment in clouded leopards (Neofelis nebulosa). Serum samples were collected from 12 women (age 6.21 ± 3.56 years), and serum AMH concentrations were analysed using AMH Gen II ELISA. The animals were divided into two groups based on ovarian structures [preovulatory follicles (>2 mm) and/or corpora hemorrhagica] along with the presence of uterine tonicity visualized laparoscopically around the time of ovulation. Animals that exhibited these reproductive features were identified as the responder group (n = 9, aged 7.59 ± 2.96 years), whereas those lacking the corresponding features were assigned to the nonresponder group (n = 3, aged 2.06 ± 0.53 years). The intra-assay coefficient of variation (CV) and interassay CV was 3.56% and 7.75%, respectively. The linearity of AMH dilution was confirmed (r2  = .998), and the percentage of recovery ranged from 93% to 115%. The results demonstrated that overall serum AMH concentrations around the time of ovulation were negatively correlated with age (rs  = -.692, p = .013). However, serum AMH concentrations were not correlated with the average number of ovarian structures (rs  = -.535, p = .074). Thus, AMH Gen II ELISA was validated in clouded leopards. Around the time of ovulation, serum AMH decreased with advancing age and ovarian responsiveness cannot be evaluated using serum AMH.

Establishment of fishing cat cell biobanking for sustainable conservation

The fishing cat (Prionailurus viverrinus) is a vulnerable wild felid that is currently under threat from habitat destruction and other human activities. The zoo provides insurance to ensure the survival of the fishing cat population. Creating a biobank of fishing cats is a critical component of recent zoo strategies for securely stocking cell samples for long-term survival. Here, our goal was to compare cell biobanking techniques (tissue collection, primary culture, and reprogramming) and tissue sources (ear skin, abdominal skin, testis) from captive (n = 6)/natural (n = 6) vs. living (n = 8)/postmortem (n = 4) fishing cats. First, we show that dermal fibroblasts from the medial border of the helix of the ear pinna and abdominal tissues of living fishing cats can be obtained, whereas postmortem animals provided far fewer fibroblasts from the ears than from the testes. Furthermore, we can extract putative adult spermatogonial stem cells from the postmortem fishing cat's testes. The main barrier to expanding adult fibroblasts was early senescence, which can be overcome by overexpressing reprogramming factors through felid-specific transfection programs, though we demonstrated that reaching iPSC state from adult fibroblasts of fishing cats was ineffective with current virus-free mammal-based induction approaches. Taken together, the success of isolating and expanding primary cells is dependent on a number of factors, including tissue sources, tissue handling, and nature of limited replicative lifespan of the adult fibroblasts. This study provides recommendations for tissue collection and culture procedures for zoological research to facilitate the preservation of cells from both postmortem and living felids.

Semen characteristics and second successful artificial insemination of Asian elephant (Elephas maximus) in Thailand

Background and Aim:

As the number of wild Asian elephants (Elephas maximus) continues to decline, maintaining healthy populations under human care is vital. Male fertility assessment is essential for understanding the reproductive status, which can help to uncover underlying problems and improve the rate of pregnancy success. The objectives of this study in Asian elephants were as follows: (1) To investigate the semen characteristics; (2) to compare the relative seminal vesicle size and semen characteristics; (3) to compare the semen characteristics between good-motile (>60% progressive motility) and poor-motile (<60% progressive motility) ejaculates; and (4) to investigate the pregnancy success rate after artificial insemination (AI) with combined chilled and frozen semen.

Materials and Methods:

In total, 153 ejaculates were collected by manual rectal stimulation from 25 bulls. The volume, pH, sperm concentration, progressive motility, viability, morphology, and membrane integrity were investigated in each ejaculate. Assessment of accessory sex glands was conducted using transrectal ultrasonography to compare the relative seminal vesicle size and semen characteristics, and the bulls were divided into two groups according to the size of the ampulla (<7 or ≥7 cm²). For the comparison of good and poor-motile ejaculates and semen characteristics, the samples were divided into two groups: Good-motile (>60% progressive motility) and poor-motile (<60% progressive motility) ejaculates. Semen ejaculates for AI were collected from three bulls. The estrous cycles of four females were monitored using an enzyme immunoassay. Seven AI attempts were conducted using frozen and/or chilled semen by endoscopic visualization. AI was repeated 1 day before the luteinizing hormone surge, on the day of the surge, and 1 day after the surge. Pregnancy was confirmed by monitoring the serum progesterone profile and the abdomen and mammary glands changes.

Results:

From 153 ejaculates, the mean±standard error values of progressive motility, semen volume, sperm concentration, pH, and viability were 40.18%±2.28%, 40.94±3.86 mL, 1,205.58±62.26×10⁶ sperm/mL, 7.50±0.10, and 56.17%±1.96%, respectively. Comparing ampulla size and semen characteristics revealed that the bulls with ampullae of ≥7 cm² yielded significantly larger volume ejaculates. However, there were no significant differences in sperm motility and concentration. The comparison of semen characteristics between good- and poor-motile ejaculates revealed that the former had significantly higher pH, viability, normal acrosomes, intact membranes, and normal head and tail morphology but often had a significantly lower volume and sperm concentration. From seven AI attempts in four females, one female had a confirmed pregnancy (14.3% pregnancy rate), and delivered a healthy live female baby weighing 128 kg at 21 months and 12 days of gestation. The baby is now 3 years old and in a healthy condition, with normally developing growth and behavior.

Conclusion:

The semen characteristics of Asian elephants can be used as the baseline reference for further applications. The ampullae size indicates semen quantity but not quality. Our success in producing an elephant calf from AI using frozen and chilled semen demonstrated that AI can be used as an alternative approach for the breeding management of Asian elephants. However, the semen of Asian elephants is of poor quality, especially in terms of membrane integrity; thus, the improvement in semen quality through intensive and careful management of elephant health and fertility remains a challenge for the future. Furthermore, a sperm bank should be established to develop sperm cryopreservation, which will be invaluable for improving the genetic diversity of the Asian elephant.

Avian Embryonic Culture: A Perspective of In Ovo to Ex Ovo and In Vitro Studies

The avian embryos growing outside the natural eggshell (ex ovo) were observed since the early 19th century, and since then chick embryonic structures have revealed reaching an in-depth view of external and internal anatomy, enabling us to understand conserved vertebrate development. However, the internal environment within an eggshell (in ovo) would still be the ideal place to perform various experiments to understand the nature of avian development and to apply other biotechnology techniques. With the advent of genetic manipulation and cell culture techniques, avian embryonic parts were dissected for explant culture to eventually generate expandable cell lines (in vitro cell culture). The expansion of embryonic cells allowed us to unravel the transcriptional network for understanding pluripotency and differentiation mechanism in the embryos and in combination with stem cell technology facilitated the applications of avian culture to the next levels in transgenesis and wildlife conservation. In this review, we provide a panoramic view of the relationship among different cultivation platforms from in ovo studies to ex ovo as well as in vitro culture of cell lines with recent advances in the stem cell fields.

In Vitro Culture of Deer Embryos

In vitro embryo production of deer species has the potential to increase valuable traits for the agricultural sector, and from a conservation perspective, it is a propagation tool which can improve genetic diversity in small captive populations. In vitro embryo production is a multistep process consisting of oocyte maturation, fertilization, and embryo culture. These techniques provide the backbone for more advanced assisted reproductive technologies such as intracytoplasmic sperm injection (ICSI), somatic cell nuclear transfer (SCNT), a source of embryonic stem cells, and embryos for gene editing. In vitro-produced embryos are a readily available resource for comparative embryology studies and a functional assay to assess oocyte competence and evaluate in vitro embryo requirements during culture. A semidefined fertilization and culture medium system, deer synthetic oviduct fluid (DSOF), has been formulated based on deer oviduct fluid. Red deer calves (Cervus elaphus) and Thamin Eld's deer fawn (Rucervus eldii thamin) have been produced after the transfer of in vitro embryos (IVF and SCNT) grown in DSOF culture. Here we describe the in vitro method of maturation, fertilization, and embryo culture for deer species.

Reproductive biology and biotechnologies in wild felids

Conservation strategies in natural habitats as well as in breeding centers are necessary for maintaining and reinforcing viable populations of wild felids. Among the fundamental knowledge that is required for conservation breeding, a solid understanding of reproductive biology is critical for improving natural breeding and enhance genetic diversity. Additionally, it offers the opportunity to develop assisted reproductive technologies (ARTs) in threatened and endangered species. Conservation breeding and reproductive biotechnologies of wild felids have advanced in the past decade. It has been clearly shown that female felids have species and individual patterns of reproductive cycles and respond differently to exogenous hormones. In males, several species still have poor semen quality often due to the loss of genetic diversity in small populations. To overcome the challenges of natural breeding (incompatibility between individuals or suboptimal environment) and mitigate inbreeding, artificial insemination, embryo production and embryo transfer have been further developed in 24 wild cat species. Major factors limiting ART success are inconsistent responses to ovarian stimulation, variable quality of gametes and embryos, and preparation of recipient females. Additional approaches including stem cell technologies have been explored for future medical applications. However, there still is a critical need for better knowledge of feline reproductive biology and improvement of ARTs efficiency to increase the genetic diversity and create sustainable populations of wild felids.

Identification of feline Kiss1 and distribution of immunoreactive kisspeptin in the hypothalamus of the domestic cat

In recent years, the Kiss1 gene has been reported in a number of vertebrate species, and a substantial dataset has been acquired to demonstrate the critical role of kisspeptins in the reproductive system; yet limited information is available for carnivores. In the present study, we identified and characterized feline Kiss1 by isolating and cloning its full-length cDNA in the domestic cat hypothalamus and caracal testis, using the method of rapid amplification of cDNA ends. Additionally, we isolated and cloned the 3′ end of Kiss1 cDNA, containing kisspeptin-10 (Kp10), from the ovaries of a clouded leopard and Siberian tiger. Nucleotide sequencing revealed that domestic cat Kiss1 cDNA is of 711 base pairs and caracal Kiss1 cDNA is of 792 base pairs, both having an open reading frame of 450 base pairs, encoding a precursor protein Kiss1 of 149 amino acids. The core sequence of the feline kisspeptin Kp10 was found to be identical in all species analyzed here and is highly conserved in other vertebrate species. Using an anti-Kp10 antibody, we found the immunoreactive kisspeptin to be localized in the periventricular and infundibular nuclei of the cat hypothalamus. The results show that kisspeptin is highly conserved among different feline families, and its immunoreactive distribution in the hypothalamus may indicate its physiological function in the domestic cat.

181 Establishment of Induced Pluripotent Stem Cells from Fishing Cat and Clouded Leopard Using Integration-Free Method for Wildlife Conservation

Fishing cat (Prionailurus viverrinus) and clouded leopard (Neofelis nebulosa) are wild felids, currently in vulnerable status according to the International Union for Conservation of Nature red list (2017). Several measures in assisted reproductive technology (e.g. AI, embryo transfer) have been used by the Zoological Park Organization of Thailand (ZPO) to increase their offspring in captivity. Recently, the generation of induced pluripotent stem cell (iPS cells) becomes popular and provides alternative way to preserve good genetics in the form of cell with diverse capacities. This great potential of iPS cells is unlimited self-renewal and pluripotency, similar to embryonic stem cells (ESC). Under the right cell culture conditions, pluripotent stem cells can differentiate into all cell types of the body. Here, we aimed to find the optimal condition to generate integration-free iPS cells from fishing cat and clouded leopard. At first, to obtain somatic cells for cellular reprogramming, adult dermal fibroblast cell lines from both species were established from belly skin tissues. Subsequently, several nucleofection programs of AmaxaTM 4D-nucleofectorTM (Lonza, Basel, Switzerland) were examined to introduce integration-free DNA vectors carrying reprogramming factors into the felid fibroblasts. The transfected cells were cultured under numerous conditions: (1) matrix/defined surface including irradiated mouse embryonic fibroblast, gelatin, vitronectin, and Geltrex® (Thermo Fisher Scientific, Waltham, MA, USA); (2) ESC/iPS cell medium including Essential 8TM (Thermo Fisher Scientific) DMEM containing KnockOutTM Serum Replacement (KOSR; Thermo Fisher Scientific) and/or fetal bovine serum (FBS); and (3) supplement including basic fibroblast growth factor (bFGF), leukemia inhibitory factor (LIF), l-ascorbic acid, nicotinamide, ALK5 inhibitor (A83-01) and RevitaCellTM (Thermo Fisher Scientific). We found that optimal nucleofection programs for human dermal fibroblast including FF-135 and EN-150 were able to transfer episomal vectors and excisable piggyBAC transposon carrying reprogramming factors into fishing cat and clouded leopard fibroblasts, respectively. The iPS-like colonies appeared around 26 to 30 days post-nucleofection. The culture of transfected cells on either Geltrex® or Vitronectin-coated surface supports the formation of iPS-like colonies with different derivation efficiency (0.01 and 0.005%, respectively). In addition, all colonies were formed under medium containing FBS, together with both bFGF and LIF supplements. Taken together, we have developed a platform to generate iPS cells from tissue collection to the establishment of iPS cell culture. This will further enable us to apply the technique to obtain iPS cells from other endangered and vulnerable felid species.

Annual ovarian activity monitored by the noninvasive measurement of fecal concentrations of progesterone and 17β-estradiol metabolites in rusa deer (Rusa timorensis)

To clarify the reproductive cycle of female Rusa deer (Rusa timorensis), the fecal concentrations of progesterone and 17β-estradiol metabolites were measured. Fecal samples were collected on a weekly basis for one year (between October, 2012 and September, 2013) from five healthy adult hinds in Thailand. At the beginning of the study, three hinds were pregnant. Two hinds delivered one healthy offspring, and one hind delivered a stillborn calf. The mating period of Rusa hinds in Thailand is from November to April. In pregnant hinds, fecal progesterone metabolite concentration was high in late pregnancy and abruptly declined to the baseline around parturition, suggesting that the placenta secretes a large amount of progesterone. Fecal 17β-estradiol metabolite concentration remained elevated around the day of parturition. Both concentrations of fecal progesterone and 17β-estradiol metabolites in non-lactating hinds were significantly higher than those in lactating hinds, indicating that ovarian activity of lactating hinds is suppressed by the suckling stimulus of fawn during lactation. The present study demonstrated that monitoring of fecal steroid hormones is useful method for assessing ovarian function in this species.

54 IN VITRO AND IN VIVO DEVELOPMENT OF FLAT-HEADED CAT (PRIONAILURUS PLANICEPS) CLONED EMBRYOS

The objectives of the study were to investigate (1) the effect of individual cell line and gender of donor cells on flat-headed cat (FC) cloned embryo production (Study I) and (2) pregnancy establishment of recipients receiving cloned FC embryos with or without domestic cat (DC) IVF embryo co-transfer. The DC IVF embryos were used as a control (Study II). Study I Three cell lines of FC fibroblasts (passage 3–5) collected from 2 females (L1 and L2; biopsied from muscle and skin, respectively) and a male (L3; biopsied from skin) were used as donor cells for nuclear transfer. Donor cells were fused with enucleated in vitro matured DC oocytes. Fused couplets were induced by electrical pulses and subsequently incubated in activation medium containing 10 μg mL–1 cycloheximide and 5 μg mL–1 cytochalasin B for 4 h. Reconstructed embryos were cultured in SOFaa medium supplemented with 5% fetal bovine serum (FBS) at 38.5°C in air, and monitored for 7 days. Differences in the percentages of fusion and embryo development to a particular stage between cell lines and genders of donor cells were determined by chi-square analysis. Variations of fusion efficiency and embryo developmental success were observed between the cell lines. Greater cleavage number (P < 0.05) was observed when L1 was used as donor cells than that of L2 and L3. Developmental success to morula stage of embryo reconstructed from L1 was greater (P < 0.05) than that of L3 but not L2 (P > 0.05). However, there was no difference in the blastocyst formation success among cell lines. The development of the embryos derived from female and male donor cells at subsequent stages was not different. Study II Estrus and ovulation were induced in 15 DC recipients using 100 to 150 IU of pregnant mare serum gonadotropin (PMSG) and 100 IU of hCG (subcutaneous injection). Recipients were divided into 3 groups; (1) cloned group (n = 5) receiving FC cloned embryos (mean 41.4 ± 13), (2) co-transferred group (n = 4) receiving FC cloned and DC IVF embryos (mean 55 ± 15; 43.3 ± 15 of FC cloned and 10.8 ± 1.5 of DC IVF embryos), and (3) IVF/control group (n = 6) receiving only DC IVF embryos (mean 25 ± 9). Control DC IVF embryos were produced by co-incubation of DC oocytes with fresh DC semen for 18 h. Day 1 embryos were transferred into oviducts of recipients. Pregnancy evaluation using ultrasonography at Day 30 post-transfer demonstrated that pregnancy was not observed in any recipients in cloned group. One recipient from co-transferred group became pregnant and delivered DC IVF stillbirths (n = 2) and live kittens (n = 6). All recipients in IVF group became pregnant and 3 recipients delivered 5 DC kittens. These results indicate that (1) the individual cell line but not the gender of donor cells influences the development of FC cloned embryos and (2) with or without co-transfer of FC cloned and DC IVF embryos, FC cloned offspring was not able to be produced in the study. Table 1.Developmental success of FC cloned embryos This study was supported by the Zoological Park Organization under the Royal Patronage of H.M. the King, and the Reproductive Biotechnology Research Unit, Chulalongkorn University. A. Thongphakdee is supported by the Royal Golden Jubilee Ph.D. Program, and the Thailand Research Fund.

81 MOUSE CLONING BY USING A LASER-ASSISTED ZONA OPENING AND ELECTRO-FUSION TECHNIQUE

Mouse cloning can be performed by a direct microinjection of donor nuclei using a conventional or a piezo-actuated technique (Rybouchkin et al. 2002 Reproduction 124, 197–207; Wakayama et al. 1998 Nature 394, 369–374). However, a high percentage of lysed oocytes was observed during the pipette penetration of the cytoplasmic membrane through the zona pellucida. The aim of this experiment was to investigate the possibility of a combination of a laser-assisted zona opening and electro-fusion for mouse cloning. Mature oocytes were obtained from FSH-superovulated B6D2F1 female mice. Enucleation and transfer of donor cell were performed in HEPES-buffered CZB medium. Spindle-chromosome complexes (SCCs) together with first polar body were removed by blunt-end pipette via a small hole in the zona pellucida which was cut by a laser beam. An adult fibroblast cell was introduced into the perivitelline space and fused to the enucleated oocyte by using a single DC pulse of 1.5 kV cm-1, 20 �s, in a fusion medium (Liu and Aoki 2003 Animal Sci. J. 75, 125–129). The fusion rate was checked 30 min later and only the fused oocytes were subjected to activation by 6 h culture in Ca2+-free CZB medium supplemented with 10 mM Sr2+ and 5 �g mL-1 cytochalasin B. The oocytes which presented the pseudo-pronuclei were considered as the activated oocytes and were cultured in CZB medium at 37�C, 5% CO2 in humidified atmosphere. The developmental rate was observed every 24 h for 4 days. The diploid parthenogenetically activated embryos serving as a control were obtained using the same activation protocol but without SCC removal. The percentages of survival after enucleation and after fusion were recorded. The formation of pseudo-pronuclei and the embryos developing to a particular stage were determined by chi-square analysis. The results show that most of the oocytes survived after enucleation (92.5%, 172/186) and the fusion rate was 71.9% (105/146). The formation of pseudo-pronuclei and the cleavage rate of cloned embryos was lower than in the control (87.6% (92/105) vs. 100% (90/90) and 69.6% (64/92) vs. 92.2% (83/90), respectively). The developmental rate to morula–blastocyst stage of cloned embryos was significantly lower than in the control [1.1% (1/92) vs. 44.4% (40/90); P &lt; 0.05]. These results indicate that using laser-assisted zona opening and electro-fusion technique is practical for mouse cloning and provides an alternative method when injection of donor nuclei into the recipient oocytes using a conventional or a piezo-driven method is technically difficult. This study was supported by grants from The National Research Council of Thailand and The Thailand Research Fund (Loyal Golden Julilee Ph.D. program).

71 THE DEVELOPMENT OF INTRA- AND INTER-SPECIES CLONED EMBRYOS DERIVED FROM RABBIT OOCYTES: THE EFFECT OF DONOR CELL SOURCES

Generating cloned embryos using rabbit oocytes as the recipient cytoplasm is useful for studying the interaction between a foreign donor nucleus and the recipient cytoplasm. The aims of the study were to (1) investigate the development of inter-species cloned embryos derived from rabbit oocytes, using cow (no. 1 and no. 2), swamp buffalo, pig, and elephant ear fibroblasts as donor cells, and (2) observe the developmental capacity of cloned rabbit embryos derived from adult and fetal fibroblasts. Mature oocytes were collected from superovulated rabbit does by oviductal flushing. A single fibroblast (passages 3–5) in the starvation stage (1–3 days prior to nuclear transfer) was transferred into an enucleated oocyte, which was confirmed by Hoechst staining. Reconstructed oocytes were later fused by electrical stimulation using 3 DC pulses, 3.2 kV.cm-1, for 20 �s. Fused couplets were activated by inducing the same electrical stimulation, and subsequently incubated in activation medium comprised of 5 �g mL-1 cycloheximide, 2 mM mL-1 6-DMAP and 10% fetal bovine serum (FBS), in synthetic oviduct fluid (SOF), for 1 h. They were then cultured in SOF supplemented with 10% FBS for 5 days. Differences in the percentages of fusion and embryo development to a particular stage between source of donor cells were determined by chi-square analysis. The fusion rates of cow no. 1 (62%; 82/133), cow no. 2 (54%; 41/76), buffalo (63%; 53/84), pig (69%; 60/87), elephant (59%; 44/74), adult rabbit (55%; 41/74), and fetal rabbit couplets (70%; 56/80) did not differ significantly. The cleavage rates of cows no. 1 and 2, buffalo, pig, and elephant embryos were 33%, 83%, 57%, 67%, and 100%, respectively. The rabbit fibroblasts derived from an adult gave a significantly lower cleavage rate than those derived from a fetus (54% vs. 95%) (P &lt; 0.05). The developmental rates at morula and blastocyst of cloned embryos reconstructed from fetal rabbit fibroblasts were significantly greater than those reconstructed from adult rabbit, buffalo, pig, and elephant (morula: 39%, 12%, 4%, 7%, and 14%; blastocyst: 23%, 7%, 0%, 3%, and 9%, respectively; P &lt; 0.05). While cow no. 2 donor cells provided a significant embryo development success rate in terms of blastocyst formation, cow no. 1 cloned embryos could not develop beyond the cleavage stage (morula: 10% vs. 0%; and blastocyst: 7% vs. 0%). In conclusion, cow, swamp buffalo, pig, and elephant fibroblasts can be produced by using enucleated rabbit oocytes as recipient cytoplasm. The developmental capacity of cloned embryos is affected by the sources and the individual ability of donor cell used, and varies according to the species. This study was supported by Ratchadaphiseksomphot Endowment Fund, Reproductive Biotechnology Research Unit, Chulalongkorn University, and Royal Golden Jubilee, PhD program of Thailand Research Fund.

92 INTER-GENERIC MARBLED CAT AND FLAT-HEADED CAT CLONED BLASTOCYSTS GENERATED FROM DOMESTIC CAT AND RABBIT OOCYTES

Marbled cats (Pardofelis marmorata; MC) and flat-headed cats (Prionailurus planiceps; FC), the endangered, small wild cats of southeast Asia, are currently at risk of becoming extinct in Thailand. Producing embryos by inter-generic somatic cell nuclear transfer (SCNT) is a way to preserve their genetics, as well as to understand their embryo chronology. The aim of the study was to investigate the development of MC and FC embryos produced from domestic cat (DC) and rabbit (RB) oocytes by SCNT. Intra-species cloned DC served as control. The MC-, FC-, DC-DC, and FC-RB (donor fibroblast cell–recipient oocyte) couplets were prepared as previously described (Thongphakdee et al. 2006 Reprod. Dom. Anim. 41, 219–226), but MC-, FC-, and DC-DC couplets were fused by inducing 3 direct current pulses of 2.4 kV cm-1, for 50 �s, and subsequently activated in synthetic oviduct fluid (SOF) medium, supplemented with 10% fetal bovine serum (FBS), 10 �g mL-1 cycloheximide, and 5 �g mL-1 cytochalasin B, for 4 h. Activated couplets were cultured in SOF medium supplemented with 5% FBS, at 38.5�C, under 5% CO2 in air, for 5–7 days. Differences in the percentages of fusion and embryo development to a particular stage between species were determined by chi-square analysis. The fusion efficiency of DC-DC couplets (38%; 36/94) was significantly lower than those of MC-DC (74%; 60/81), FC-DC (79%; 60/76), and FC-RB (78%; 47/60) couplets (P &lt; 0.05). No differences in the cleavage rates of MC-DC, FC-DC, FC-RB, and DC-DC fused couplets were found (93%, 97%, 87%, and 89%, respectively). The FC-DC couplets yielded a greater percentage of morulae (53%) than did MC-DC (23%), FC-RB (25.5%), and DC-DC (11%) couplets (P &lt; 0.05). However, the number of couplets that achieved blastocyst expansion did not significantly differ (MC-DC: 5%, FC-DC: 8.3%, FC-RB: 8.5%, and DC-DC: 8.5%). These results demonstrate that MC and FC embryos are successfully produced with reasonable blastocyst formation rates by inter-generic SCNT. This study was supported by the Zoological Park Organization under the Royal Patronage of H.M. the King, Reproductive Biotechnology Research Unit, Chulalongkorn University, and Royal Golden Jubilee, PhD program of Thailand Research Fund.

In Vitro Development of Marbled Cat Embryos Derived from Interspecies Somatic Cell Nuclear Transfer

The objective of the study was to investigate interspecies Somatic Cell Nuclear Transfer (iSCNT) techniques in marbled cats (Pardofelis marmorata), using domestic cat and rabbit oocytes as the recipient cytoplasm. The recipient oocytes were obtained from ovariohysterectomized cats and superovulated rabbits. The donor cells were collected from a male marbled cat that had died in captivity. Experiment 1 was conducted to observe the development of cloned marbled cat embryos (marbled cat donor cells-domestic cat oocytes; MC-DC), derived from oocytes matured for 24, 36 and 42 h. The result showed that the developmental rates of MC-DC cloned embryos at the 4-8 cell and the morula stages derived from oocytes cultured for 24 h were significantly greater than those cultured for 36 and 42 h (p < 0.05). Experiment 2 was conducted to compare the fusion rate of MC-DC couplets, fused by inducing different fusion voltages, 2.1 or 2.4 kV/cm. The result showed that there was no difference in fusion efficiency between the 2.1 and 2.4 kV/cm fusion protocols. Experiment 3 was conducted to compare the developmental rate of MC-DC and domestic cat (DC-DC) cloned embryos. In vitro fertilized cat embryos served as a control. The development of MC-DC and DC-DC cloned embryos to the 4- to 8-cell, morula and blastocyst stages was not significantly different. However, the development rates at morula and blastocyst stages of control were significantly greater than those of cloned embryos (p < 0.05). Experiment 4 rabbit (RB) oocytes were used as a recipient cytoplasm for marbled cat and domestic cat cloned embryos (MC- RB and DC-RB). RB-RB cloned embryos served as a control. There were no differences in the developmental rates between MC-RB, DC-RB and RB-RB embryos. In conclusion, marbled cat fibroblast cells can be reprogrammed in domestic cat and rabbit oocytes, and by using iSCNT it might be possible to produce marbled cat offspring in the future.