SUCCESSFUL NONSURGICAL ARTIFICIAL INSEMINATION AND HORMONAL MONITORING IN AN ASIATIC GOLDEN CAT ( CATOPUMA TEMMINCKI )

Postmortem Collection of Gametes for the Conservation of Endangered Mammals: A Review of the Current State-of-the-Art

The collection of gametes from recently deceased domestic and wildlife mammals has been well documented in the literature. Through the utilization of gametes recovered postmortem, scientists have successfully produced embryos in 10 different wildlife species, while in 2 of those, offspring have also been born. Thus, the collection of gametes from recently deceased animals represents a valuable opportunity to increase genetic resource banks, obviating the requirement for invasive procedures. Despite the development of several protocols for gamete collection, the refinement of these techniques and the establishment of species-specific protocols are still required, taking into account both the limitations and the opportunities. In the case of wildlife, the optimization of such protocols is impeded by the scarcity of available animals, many of which have a high genetic value that must be protected rather than utilized for research purposes. Therefore, optimizing protocols for wildlife species by using domestic species as a model is crucial. In this review, we focused on the current advancements in the collection, preservation, and utilization of gametes, postmortem, in selected species belonging to Equidae, Bovidae, and Felidae, both domestic and wildlife.

The challenge of assisted reproduction for conservation of wild felids - A reality check

Threats to the Earth's biodiversity are increasing exponentially, driven by human population growth and resource consumption. As many as one million wildlife species may disappear within the next few decades due to this human-induced extinction event. This represents our current reality and has profound implications for wildlife conservation. Within this context, application of assisted reproductive technology (ART) to conservation management is unlikely to mitigate broad-scale species loss, but for select species, such as wild cats, ART may determine if populations survive or disappear. In North American and European zoos, 20 of the world's 38 wild felid species are managed within structured breeding programs, but most are not sustainable with natural breeding alone. Zoo-based breeding programs are facing tenuous futures due to triage-based responses to this growing sustainability crisis. Theoretically, ART could benefit conservation management, but only by recognizing and addressing its present challenges. The application of ART to wildlife has been rarely successful, with only 62 mammal species (including 15 cat species) ever propagated by AI, and just 35 of these species (6 cats) reproduced following frozen semen AI. Even this most basic form of ART has a minimal impact on wildlife sustainability. The drivers of this deficit include lack of species-specific reproductive knowledge and limited access to animals for study, but also is exacerbated by a science-conservation disconnect that attempts to apply advanced reproductive technologies to species in which basic ART remains unproven. For a few felid species, these scientific challenges have been overcome and AI with frozen semen is becoming feasible as a practical management tool; for other felids, further research is needed. Non-scientific issues also impair our ability to use ART to implement global management plans. Political dysfunction, regulatory barriers and societal indifference create inertia that interferes with achieving meaningful progress in applying ART to wildlife. Collectively, these challenges may seem insurmountable but human resiliency is essential if we are to resolve these issues in a systematic manner. It will require expanding collaborative efforts substantially and intensifying efforts to conserve wildlife species that are literally running out of time. Our goal is to create a new reality that includes a sustainable future for wild felids and other imperiled wildlife species.

How Can We Introduce ART into Wild Felid Conservation in Practice? Joint Experience in Semen Collection from Captive Wild Felids in Europe

Simple Summary

Artificial reproductive techniques (ART), such as cryopreservation of sperm cells and artificial insemination, are useful tools for species conservation. However, there is relatively little information published about their introduction into clinical practice for wild felids. The aim of this paper was to describe how those techniques were applied by three European teams in various species of wild felids. In total, this article presents 22 semen collection attempts in 12 species of wild felids, 15 of which were successful and resulted in the collection of at least one million spermatozoa. The failures in obtaining spermatozoa were most probably due to (1) male infertility, (2) wrong age/non-breeding season, or (3) recent multiple copulations. The cases presented in the article confirm that although ART have been introduced into clinical practice, they are mostly used in cases of infertility, not as routine breeding tools. Greater involvement of zoological gardens and private breeders is required, as many chances for preservation of valuable material are lost.

Abstract

Although artificial reproductive techniques (ART) are considered to be a valuable tool for species conservation, information about their introduction into clinical practice for wild felids is limited. The aim of this paper was to jointly describe cases of non-experimental sperm collection from males of various species of wild felids, performed by three European centers focused on feline reproduction. In total, the article presents 22 attempts of semen collection in 12 species of wild felids. The reasons for semen collection were: fertility assessment (10 cases), artificial insemination (5 cases), sperm rescue (postmortem collection for cryopreservation, 5 cases), and sperm banking (in vivo collection for cryopreservation, 2 cases). Semen collection was successful (defined as at least 1 × 10⁶ spermatozoa) in 15 cases. The failures in obtaining spermatozoa were most probably due to (1) male infertility, (2) wrong age/non-breeding season, or (3) recent multiple copulations. The cases presented here confirm that although ART have been introduced into clinical practice, they are mostly used in cases of infertility, not as routine breeding tools. Higher involvement of zoological gardens and private breeders is required, as many chances for preservation of valuable material are lost.

Successful Laparoscopic Oviductal Artificial Insemination in the Endangered Tsushima Leopard Cat (Prionailurus bengalensis euptilurus)

Simple Summary

The Tsushima leopard cat is an endangered wild felid that lives solely on Tsushima Island, Nagasaki, Japan. Approximately, only 100 Tsushima leopard cats can be found in the wild, and there are concerns that the population will further reduce due to habitat degradation and traffic accidents. In 1994, Japan’s Ministry of the Environment (MOE) developed a conservation and breeding project for the Tsushima leopard cat. The MOE is working with the Japanese Association of Zoo and Aquariums for ex situ conservation of this species. However, considering genetic diversity, it is difficult to conduct captive breeding programs using only natural breeding; hence, assisted reproductive technologies are required. This study aimed to breed Tsushima leopard cats using artificial insemination (AI) by depositing sperms into the oviducts. Ovulation was artificially induced in two females, laparoscopically inseminated with fresh sperms into the oviducts. The pregnancies were monitored via fecal levels of progestogens and radiography. One female had spontaneous delivery of a female kitten 66 days post-AI. This is the first successful case of AI in a Tsushima leopard cat.

Abstract

The Tsushima leopard cat (Prionailurus bengalensis euptilurus) is an endangered wild felid that lives solely on Tsushima Island, Nagasaki, Japan. Japan’s Ministry of the Environment is working with the Japanese Association of Zoo and Aquariums for ex situ conservation of this species. However, considering genetic diversity, it is difficult to conduct captive breeding programs by natural breeding alone; hence, assisted reproductive technologies are required. This study aimed to breed Tsushima leopard cats, which otherwise cannot be paired, using laparoscopic oviductal artificial insemination (AI). Female Tsushima leopard cats (female 1, aged 7 years; female 2, aged 6 years) were treated with 200 IU equine chorionic gonadotropin, followed by administration of 1000 IU porcine luteinizing hormone (pLH) after 96 h to induce ovulation. Laparoscopic AI was performed 32 h post-pLH administration. Females 1 and 2 were inseminated in the oviduct with 2.4 × 10⁶ and 3.3 × 10⁶ motile spermatozoa, respectively, collected from two males. Pregnancy was confirmed by radiography 45 and 51 days post-AI in females 1 and 2, respectively; one fetus was found in female 2. Moreover, female 2 had spontaneous delivery of a female kitten 66 days post-AI. This is the first successful case of AI in a Tsushima leopard cat.

Maturation and fertilization of African lion (Panthera leo) oocytes after vitrification

The African lion is an excellent model species for the highly endangered Asiatic lion. African lions reproduce well in zoos, leading to the fact that occasionally ovaries and testis are available for in-vitro experiments. We previously performed in-vitro maturation (IVM) and fertilization of lion oocytes and were able to produce advanced embryos after intracytoplasmic sperm injection (ICSI) with cryopreserved sperm. Here we examined whether our in-vitro method is also applicable after vitrification of immature oocytes. Oocytes of four lionesses (5-7 years old) were obtained after euthanasia and immediately processed on site. Half of the oocytes (n = 60) were subjected to IVM for a total of 32-34 h at 39 °C, 5% CO₂ and humidified air atmosphere. The second group (59 oocytes) was vitrified instantly using the Cryotop method. Following 6 days of storage in liquid nitrogen, oocytes were warmed and subjected to IVM as well. Mature oocytes of both groups were fertilized with frozen-thawed African lion sperm using ICSI. Maturation rate was 55% and 49.2% for the control and vitrified group, respectively. In the control group, three oocytes cleaved and another three were arrested at the pronuclei stage. Due to the low fertilization result, a sperm sample of another male was used for the vitrified group. Of the vitrified oocytes 7 cleaved and 9 more oocytes stopped at pronuclei stage. All embryos of the vitrified group did not develop beyond 4 cell stage. This is the first time that African lion in-vitro-derived embryos have been produced following oocyte vitrification.

Urethral catheterization as an alternative method for collecting sperm in the black-footed ferret (Mustela nigripes)

The endangered black-footed ferret (BFF; Mustela nigripes) is an important example of the benefits of assisted reproduction in species conservation with both semen evaluation and artificial insemination using fresh and frozen sperm being successfully incorporated into the breeding program. Currently, electroejaculation (EE) is routinely utilized for semen collection in BFFs, a technique that requires custom equipment and experienced operators, and does not consistently yield viable samples in this species. In this case study, we evaluated the feasibility of urethral catheterization (UC) for semen collection, a method predominately tested in domestic and non-domestic felids, on four occasions (three BFF males). After general anesthesia with a combination of ketamine, midazolam and α2-agonist dexmedetomidine (thought to promote semen release into the urethra), a lightly lubricated, flexible feeding tube was passed into the urethral opening and advanced ~7-8 cm into the urethra. A syringe attached to the feeding tube was used to apply mild negative pressure to collect sperm. Semen samples were successfully collected on all four attempts. Sperm characteristics ranged as follows: 10.5-26.0 × 10⁶ sperm/ml concentration, 50-90% motility and 36-61% normal sperm morphology. This is the first report of the use of UC as a potential alternative to EE in the BFF, a more field-friendly technique that is less invasive and more consistent for obtaining samples free of urine contamination.

Monitoring ovarian function and detecting pregnancy in felids: A review

Reliable detection and monitoring of estrus and pregnancy is essential to the effective ex situ conservation of endangered felids. Here, we review the current methods used to detect estrus and pregnancy in felids and describe the advantages and limitations of each. A total of 194 felid-focused publications were reviewed. The methods used included behavioral assessments (61 publications across 24 species), hormone monitoring (124 studies across 28 species), fecal protein monitoring (two studies in cheetah), ultrasonography (31 publications across seven species), vaginal cytology (22 publications across nine species), and laparoscopy (70 publications across 19 species). Behavior-based assessments of reproductive state are often inconsistent and unreliable in felids; thus hormone measurement is the most frequently used method for monitoring estrous cycles (66% of studies). In non-domestic felids, non-invasive fecal- or urine-based hormone metabolite analyses are preferred to blood assessments (66% of endocrine-based publications). While the measurement of fecal estrogen and progestin metabolites are useful for the retrospective assessment of ovarian activity, their use for real-time detection of estrus is limited. Vaginal cytology, laparoscopy and ultrasonography provide an acute and immediate determination of reproductive state but usually require anesthesia or sedation, which can prevent ovulation and cause abortions; thus, their use for pregnancy diagnosis is limited. Fecal progesterone or prostaglandin F_2α metabolites can be used to detect pregnancy in most felids (the exception being fecal progestins for Lynx spp.), but only during mid-to-late gestation. Urinary relaxin measurement is a promising method for earlier pregnancy diagnosis (30-40% duration of gestation) but is presently limited by poor assay sensitivity due to the lack of a feline-specific relaxin antibody. Elevated levels of fecal immunoglobulin J chain have been investigated as a tool to detect pregnancy in cheetah (>80% accuracy), but research is lacking on other species. We conclude that there is no single 'best method' for monitoring ovarian activity and detecting pregnancy in felids, and current best practice would involve a combination of existing methods. Non-invasive methods for detecting estrus and pregnancy in felids (e.g., accelerometry and infrared thermography) should also be considered to augment existing methods.

Preservation of female genetic resources in feline species

The development of assisted reproduction techniques (ART) specifically for felids has been propagated for two main reasons: (i) most felids are threatened and faced with extinction in all or part of their native habitats (IUCN Red List of Threatened Species, www.catsg.org), and (ii) the domestic cat (Felis catus) can serve as a research model for the implementation of advanced assisted reproductive techniques (ART) to be applied in exotic cats. Domestic cat ovaries can be freshly obtained from veterinary clinics and are frequently used for research on preservation of genetic resources in feline species. The presented review will summarize recent advances and obstacles in biobanking of female genetic resources and discuss alternative approaches which are under investigation.

Colheita farmacológica de sêmen de onças-pardas (Puma concolor: Mammalia: Carnivora: Felidae)

RESUMO Objetivou-se, por meio do presente estudo, avaliar o método de colheita farmacológica de sêmen com sondagem uretral, em machos de onças-pardas (Puma concolor) mantidos em cativeiro. A técnica proposta (Cat; N=3) foi comparada com a eletroejaculação (EE; N=4). Para a colheita farmacológica, utilizou-se medetomidina para induzir a liberação de sêmen na uretra e sonda uretral para gatos, sem janela lateral, para colheita do sêmen por capilaridade. O método foi eficaz em todos os animais usados. Por meio dessa técnica, colheram-se amostras com menor volume (106,7±30,5aµL) e maior concentração (524,1±54,3b x 106 espermatozoides/mL) em relação à EE (450,0±0,1bµL e 205,0±141,8a x 106 espermatozoides/mL). As avaliações de vigor, motilidade e patologia espermática demonstraram que a técnica não afeta a qualidade do sêmen em relação à EE (P>0,05). Dessa forma, o método proposto consiste em uma técnica mais prática e eficiente para a colheita de sêmen com boa qualidade, dispensando o eletroejaculador.

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.

ARTs in Wild Felid Conservation Programmes in Poland and in the World

With the exception of the domestic cat, all felid species (Felidae) are currently threatened with extinction in their natural habitat. To develop effective and optimal wild cat conservation programmes with assisted reproductive technology (ART) it is necessary to combine advances from different disciplines of science, starting from the biology of the species, through research into the population and habitat, assisted reproductive technologies, establishment of gene banks, developing bioinformatic systems, and ending with biodiversity and endangered species management. In the last few years knowledge of felid reproduction has expanded considerably thanks to comparative studies utilising the domestic cat as a research model for endangered wild cats. Basic reproductive techniques utilised in both domestic cat breeding and rescuing wild felid populations that are threatened with extinction include semen collection and cryopreservation, artificial insemination, oocyte collection, in vitro maturation, in vitro fertilisation, somatic cloning, and embryo transfer. The main directions in which assisted reproductive technologies are being developed in wild cat conservation implementations and the contribution of Polish research centres in advancing these methods are presented.

Non-surgical artificial insemination using a GnRH analogue for ovulation induction during natural oestrus in African lions (Panthera leo)

Despite postulated potential for wildlife conservation, success of assisted reproduction techniques (ART) in ex-situ feline breeding remains <25%. The aim of this project was to develop a simplified, non-surgical artificial insemination (AI) protocol for African lions (Panthera leo), using an exogenous GnRH analogue to induce ovulation in females presenting natural oestrus, and minimizing manipulation of the animals. Four protocols were tested in five trained lionesses (3.5-8 years), for a total of 14 inseminations (2-4 per lioness). These protocols differed in the time lapse between GnRH injection and insemination, on days 4, 5, or 6 from onset of natural oestrus, determined by daily behavioural observation and vaginal cytology. Semen was collected from 8 different males by urethral catheterization and electro-ejaculation, during full anaesthesia. Females were immediately immobilized for AI after semen collection. After transrectal ultrasound examination of the reproductive tract, insemination was performed either intravaginal or transcervical using a commercial dog urinary catheter (2.0 × 500 mm, Buster^®, Krusse, South Africa) with a metal stylet. A single intramuscular dose of exogenous GnRH (20 μg burserelin-acetate, Receptal^®, MSD, Intervet, South Africa) administered 30 or 48 h before AI or during the AI procedure induced ovulation successfully, as all females entered either a non-pregnant luteal phase of 59.6 ± 0.95 days (n = 10) or a pregnant luteal phase of 111.7 ± 0.33 days (n = 3). However, the timespan between GnRH injection and end of behavioural and/or cytological oestrus differed widely (range: 0-120 h). The final pregnancy success rate was 33.3%.

Effectiveness of urethral catheterization under ultrasound guidance for semen collection from Asiatic black bears (Ursus thibetanus)

The Asiatic black bear (ABB; Ursus thibetanus ussuricus) is a globally endangered species, and measures to help increase their population are necessary. For the successful restoration of this species, artificial breeding as well as conservation translocation are considered important. The aims of the present study were to evaluate the feasibility and effectiveness of urethral catheterization (UC), which is effectively used in feline species, for semen collection from ABBs and establish the optimal protocol for semen collection via this technique. Seven clinically healthy, adult male ABBs (age, 6-13 years; weight, 130-180 kg) housed at the Species Restoration Technology Institute, Korea were included in this study. All study procedures were performed during the breeding season (June to August) over 3 consecutive years. Semen samples were collected once or three times from all bears by ultrasound-guided UC or electroejaculation (EE) under general anesthesia, and their characteristics, including sperm motility, were evaluated. The day of semen collection was defined as Day 0. The semen collected by the UC method was stored at 4 °C, and sperm motility was evaluated at the same time every day for 16 days. The successful collection rates for the UC and EE methods were 92.3% and 53.8%, respectively. The sperm concentration (4718.9 ± 1526.1 vs. 185.0 ± 34.2 × 10⁶/ml), total sperm count (1196.6 ± 955.5 vs. 100.9 ± 70.0 × 10⁶), sperm motility score (4.39 ± 0.78 vs. 3.00 ± 1.73), viability (98.2 ± 2.3 vs. 82.7 ± 19.6), and the proportion of spermatozoa with intact acrosomes (92.2% ± 9.3% vs. 75.6% ± 10.6%) were higher with the UC method than with the EE method, whereas the proportion of spermatozoa with an abnormal morphology (23.1% ± 4.6% vs. 45.6% ± 19.5%) was lower with the former than with the latter. Over the course of cool storage, there was an overall decrease in the total motility, progressive motility, and viability, although viability was >50% until Day 10. These findings suggest that ultrasound-guided UC is a useful and feasible tool for the collection of high-quality semen from ABBs. The collected semen remains viable for up to 10 days, with high sperm motility maintained for up to 7 days, when stored at 4 °C.

Practical application of laparoscopic oviductal artificial insemination for the propagation of domestic cats and wild felids

AI was first reported in cats almost 50 years ago but, unlike AI in other domesticated animals (e.g. dogs, cattle, horses), has not been widely used for routine propagation by veterinarians or breeders. Anatomical and physiological challenges with cats have hindered the efficiency of AI using standardised transcervical approaches applied to other species. Development of laparoscopic oviductal AI (LO-AI) has helped overcome some of these barriers and, during the past 7 years, produced high pregnancy percentages (>70%) in domestic cats using both fresh collected and frozen-thawed semen and resulted in the birth of full-term offspring in three cat hereditary disease models and six wild cat species (ocelot, Pallas's cat, fishing cat, sand cat, tiger, clouded leopard). The standard approach involves exogenous gonadotrophin treatment (typically equine chorionic gonadotrophin followed by porcine LH) to induce ovarian follicular growth and ovulation, with laparoscopic visualisation of the oviductal ostium for direct intraluminal insemination with low numbers of spermatozoa. Similar ovarian synchronisation and insemination approaches have been used with wild felids, but frequently must be refined on a species-by-species basis. From a practical perspective, LO-AI in domestic cats now has adequate efficiency for applied use as a reproductive service in veterinary practices that possess basic laparoscopy expertise.

Characterization and cryopreservation of Amur leopard cats (Prionailurus bengalensis euptilurus) semen collected by urethral catheterization

The Amur leopard cat (Prionailurus bengalensis euptilurus) is a globally endangered species, and there is thus an urgent need to increase its population. The objectives of this study were to: (1) confirm the utility of urethral catheterization (UC) for semen collection from Amur leopard cats; (2) investigate proper dilution media for fresh semen; and (3) investigate the effectiveness of sperm cryopreservation, including examining the effect of glycerol concentration. Six adult males in captivity (mean weight 5.03 ± 0.44 kg, aged 2-6 years) were included. All study procedures were performed during the breeding season (February to April) over two consecutive years. Semen samples (n = 28) were collected four or five times from each animal (four times for two animals and five times for four animals) by UC under general anaesthesia, and their characteristics (including sperm motility) were evaluated. First, the sperm motility in semen diluted in Ham's F-10 or phosphate buffer saline (PBS) was compared. Next, semen diluted with TEST-yolk buffer containing 2%, 4%, or 6% glycerol was frozen in a liquid nitrogen tank, and sperm motility and acrosome integrity were evaluated after thawing. No difference in motility was observed between sperm diluted in Ham's F-10 and PBS. The percentages of sperm motility and kinetic values in semen frozen in 2% or 4% glycerol were higher than those in semen stored in 6% glycerol. In conclusion, the UC method for semen collection is recommendable for Amur leopard cats and should be useful for artificial insemination. Although sperm motility decreased after thawing, samples thus preserved may be usable for advanced reproductive techniques, such as intracytoplasmic sperm injection or in-vitro fertilization.

Comparison of semen samples collected from wild and captive jaguars (Panthera onca) by urethral catheterization after pharmacological induction

This study was designed to evaluate the efficiency of medetomidine anesthesia for semen collection through urethral catheter in wild and captive jaguars. Six captive and five wild jaguars were chemically restrained with a combination of medetomidine (0.08-0.1 mg/kg) and ketamine (5 mg/kg). After medetomidine administration the urethra was catheterized using a urinary tomcat catheter (1 mm diameter × 130 mm length) to collect semen from all animals. By using this technique, we could collect an average of 347.2 μl of semen containing 2,635.2 sperm/ml. Forward progressive motility, sperm progressive motility, and sperm morphology analysis demonstrated that the methodology did not affect sperm quality. Thus, urethral catheterization after medetomidine administration is a practical and efficient method to collect high-quality semen from wild and captive jaguars; this will enable the development of reproductive assisted technologies for jaguars.

Intrauterine insemination with fresh semen in Amur leopard cat (Pionailurus bengalensis eutilura) during non-breeding season

Equine and human chorionic gonadotropins were administered to two female Amur leopard cats to induce estrus and ovulation during non-breeding season. Fresh semen collected from male cats was surgically inseminated into the uterine horn of the females. In one animal, two fetal sacs without heartbeats were observed on abdominal ultrasonography 31 days after insemination, which indicated that embryo death had occurred. In the other animal, fetal heartbeats were detected in two fetal sacs 29 days after insemination, which confirmed as pregnancy. This animal delivered two newborns 68 days after insemination; the one of the kittens was assumed to be stillbirth, and the other grew normally. In this study, we successfully obtained a kitten from an Amur leopard cat by artificial breeding for the first time in Japan.