Increasing age influences uterine integrity, but not ovarian function or oocyte quality, in the cheetah (Acinonyx jubatus)

Anti-Müllerian hormone concentration measured before gonadotropin stimulation is associated with quality of subsequent ovarian response in the cheetah (Acinonyx jubatus) and domestic cat (Felis catus)†

Relationships between anti-Müllerian hormone concentrations and subsequent ovarian stimulation outcomes have been demonstrated in several mammalian species, but comprehensive reports are lacking in felids. Our objective was to characterize relationships between anti-Müllerian hormone concentrations and responses to exogenous gonadotropin stimulation in cheetahs and domestic cats. Blood samples collected before stimulation were used to measure serum anti-Müllerian hormone concentrations, which were compared to post-stimulation outcomes, including counts of retrievable oocytes or ovulation sites, oocyte quality, embryonic cleavage after in vitro fertilization, and progestogen concentrations. Anti-Müllerian hormone concentrations were also compared to outcomes in domestic cats induced to ovulate by mechanical stimulation of the vagina and cervix (simulated coitus). Greater anti-Müllerian hormone concentrations were associated with greater ovulatory response, progestogen production, and embryonic cleavage success among gonadotropin-treated cheetahs, and with greater ovulatory response among gonadotropin-treated domestic cats. Associations were moderated by age, with anti-Müllerian hormone concentration generally a greater determinant of these outcomes in older animals. Anti-Müllerian hormone concentrations alone could distinguish domestic cats with high and low ovulatory responses to exogenous hormones. However, this marker was unrelated to ovulatory response in domestic cats after simulated coitus. These results demonstrate the potential for anti-Müllerian hormone concentrations to predict responses of cheetahs and domestic cats to ovarian stimulation treatment commonly used in assisted reproductive technologies. Associations between anti-Müllerian hormone concentrations and ovarian stimulation outcomes in these species might reflect relationships between anti-Müllerian hormone concentration and antral follicle count or oocyte/embryo cellular function, as reported in other mammals; however, this remains to be tested.

What Makes a Mother? Investigating Maternal Success in Ex Situ Cheetahs

Understanding the factors influencing the likelihood of breeding success is essential to the sustainable management of ex situ populations. Using keeper questionnaires and studbook data, we investigate maternal success in Southern Cheetahs (Acinonyx jubatus jubatus) in relation to life history and husbandry factors. Maternal success was measured using five maternal success indicators: (i) overall litter size; (ii) proportion of liveborn cubs in a litter; (iii) proportion of liveborn cubs raised by their mother surviving the 6-week neonatal stage; (iv) proportion of liveborn cubs raised by their mother surviving to 12 months; and (v) absence of maternal neglect. Cheetahs rep the feeding of ruminant meat and carcasses to cheetahs was found to be significantly related to a larger average litter size while the practice of starve days was associated with a higher stillbirth rate. Females who were moved to new enclosures for the pregnancy, lactation and parenting period also had poorer maternal success. While enrichment provision did not appear to result in a more positive mothering outcome, feederballs and catnip use were associated with lower mothering success, highlighting the importance of evidence-based practice in ex situ collections.

The Effect of a Synthetic Scent on Cheetah Behaviour

In cheetahs, age at first parturition correlates negatively with reproductive lifespan (asymmetric reproductive aging); therefore, breeding cheetahs at a young age is essential to maximize reproductive performance in this species. However, younger females display a significantly reduced frequency of copulatory behaviour, which negatively affects breeding. Volatile organic compounds (VOCs) are known to regulate appropriate behavioural responses in various species, including reproductive behaviour; moreover, they have proven to play a role in captive breeding methods in cheetahs, as well as mate choice. Therefore, the objective of this study was to evaluate the effect of a synthetic scent (SS) on the frequency of the five oestrous behaviour(s) (sniff, rub, roll, spray, and meow-chirp) known to be indicative of oestrus in female cheetahs. Based on the results of a previous study from our research group, five VOCs, identified in the marking fluid of male cheetahs, and known to be pheromones involved in reproductive behaviour, were used to create the SS. This was accomplished by mixing benzaldehyde, acetophenone, indole, dimethyl disulphide and phenol with (99.9%) ethanol. Seven female cheetahs were then observed for one oestrus cycle without stimulation (control) and then once again while exposed to the SS (treatment), which was sprayed on foil trays placed around the outside of each enclosure. The occurrence of the five oestrous behaviours was recorded and tallied per day of observations. Although the SS did not have a significant effect on the frequency of oestrous behaviours displayed by the females used in this study, five of the seven (71%) did show an increase in their behaviour with the SS when oestrogen concentrations were at their highest (peak oestrus), including three of the four younger females. The SS also significantly increased the sniffing behaviour in general. Although the results of this study do indicate that VOCs influence cheetahs and their behaviour, firm conclusions cannot be drawn due to the low number of animals used, as well as the significant effect the observation methods had on the results. Nonetheless, this study represents the first of this kind in cheetahs, therefore representing an important step in determining the role of VOCs in aiding breeding in captivity.

Current knowledge in the biology of gametes and embryos from Carnivora

In addition to companion animals and laboratory species, about 270 carnivore species play fundamental ecological roles in different ecosystems. However, almost 40% of carnivore species are now threatened or endangered in the wild because of human activities. While protection of natural habitats is critical, it is equally important to better understand carnivore reproduction, including a solid knowledge in sperm, oocyte, and embryo biology, to maintain sustainable populations in the wild and in conservation breeding centers. Characterizing gamete and embryo biology is also needed to develop cryopreservation and assisted reproductive technologies to enhance conservation efforts. The objective of this review is to provide the most recent knowledge in the biology of sperm cells, oocytes, and early embryos across all carnivore families. Overall, most data originate from populations maintained in breeding centers or zoos. Characterizations of sperm biology and cryopreservation are far more advanced than for oocytes and embryos. Currently, sperm biology is mainly studied in Canids, Felids, Ursids, and Mustelids, with more emphasis on structural than functional properties. Importantly, fundamental studies of gamete and embryo biology in domestic dogs, cats, and ferrets have paved the way for more precise characterizations in wild counterparts as well as the development of cryopreservation and assisted reproductive technologies. A striking feature of spermatozoa across a wide range of Canids and Felids is the presence of teratospermia (>60% of abnormal sperm cells), which is related to the loss of genetic diversity in some populations. Although sperm structures differ across carnivore families, sperm biology remains difficult to compare because of the small amount of data in many species. Regarding oocyte biology and embryology, data are much scarcer than in sperm cells, with too few studies going beyond structural descriptions. More carnivore species and more individuals (especially from wild populations in addition to captive ones) must be studied to improve our understanding about comparative germplasm biology and develop adequate conservation breeding strategies including the use of cryobanking and assisted reproductive technologies.

An Investigation of Ovarian and Adrenal Hormone Activity in Post-Ovulatory Cheetahs (Acinonyx jubatus)

Cheetahs have been the subject of reproductive study for over 35 years, yet steroid hormone activity remains poorly described after ovulation. Our objective was to examine and compare fecal progestagen (fPM), estrogen (fEM), and glucocorticoid (fGM) metabolite concentrations post-ovulation in pregnant and non-pregnant animals to better understand female physiology (1) during successful pregnancy, (2) surrounding frequent non-pregnant luteal phases, and (3) after artificial insemination (AI) to improve the low success rate. Secondarily, the authors also validated a urinary progestagen metabolite assay, allowing pregnancy detection with minimal sample collection. Fecal samples were collected from 12 females for ≥2 weeks prior to breeding/hormone injection (the PRE period) through 92 days post-breeding/injection. Samples were assessed for hormone concentrations using established enzyme immunoassays. Urine samples were collected for 13 weeks from 6 females after natural breeding or AI. There were no differences among groups in fGM, but in pregnant females, concentrations were higher (p < 0.01) in the last trimester than any other time. For pregnant females that gave birth to singletons, fGM was higher (p = 0.0205), but fEM tended to be lower (p = 0.0626) than those with multi-cub litters. Our results provide insight into the physiological events surrounding natural and artificially stimulated luteal activity in the cheetah.

Assessing puberty in female cheetahs (Acinonyx jubatus) via faecal hormone metabolites and body weight

With fewer than 7500 cheetahs remaining in the wild, ex situ cheetah populations serve as an insurance policy against extinction and a resource to study species' biology. This study aimed to identify the age of pubertal onset in ex situ female cheetahs using non-invasive faecal steroid hormone monitoring and body weights. Faecal samples from nine female cheetahs were collected two to three times weekly from 2 to 36months of age and body weights were recorded every 3months. Faecal oestrogen metabolites (FOM) and faecal glucocorticoid metabolites (FGM) were analysed using enzyme immunoassays and samples were categorised into 6-month intervals to compare endocrine characteristics. Faecal hormone and body weight data were analysed using generalised linear mixed models. Age was a significant predictor of mean and baseline FOM concentrations, number of FOM peaks, mean and maximum FOM peak concentrations and the number of cycles. Female cheetahs aged 24-30months exhibited a marked rise in mean FOM concentration and the number of FOM peaks and cycles increased with age until 24-30months. Females attained adult body weight by 21months of age. Mean and baseline FGM concentrations were highest at the 0-6 and 12-18months of age groups and did not follow the same FOM patterns. Based on body weight data, the FOM concentrations and peak patterning, females were considered pubertal from 24 to 30months of age. Characterisation of cheetah puberty has direct and significant implications for the improvement of management and reproductive success of cheetahs under human care. This information is particularly informative for identifying important windows of development, littermate dispersal and breeding introductions.

Understanding the Role of Semiochemicals on the Reproductive Behaviour of Cheetahs (Acinonyx jubatus)-A Review

Simple Summary

This review aims to provide an in-depth overview of the reproductive physiology and behaviour of cheetahs (Acinonyx jubatus). Specifically, it focuses on the role that pheromones (a class of semiochemicals) play by directly affecting the reproductive (e.g., precopulatory and copulatory) behaviour. Furthermore, it aims to critically analyze current research and provide new insights on study areas needing further investigation. It is clear, for instance, that further research is necessary to investigate the role of semiochemicals in the reproductive behaviour of cheetahs in order to rectify the current behavioural difficulties experienced when breeding younger females. This, in turn, would aid in improving captive breeding and the prevention of asymmetric reproductive aging.

Abstract

The cheetah species (Acinonyx jubatus) is currently listed as vulnerable according to the International Union for Conservation of Nature (IUCN). Captive breeding has long since been used as a method of conservation of the species, with the aim to produce a healthy, strong population of cheetahs with an increased genetic variety when compared to their wild counterparts. This would then increase the likelihood of survivability once released into protected areas. Unfortunately, breeding females have been reported to be difficult due to the age of these animals. Older females are less fertile, have more difficult parturition, and are susceptible to asymmetric reproductive aging whereas younger females tend to show a significantly lower frequency of mating behaviour than that of older females, which negatively affects breeding introductions, and therefore mating. Nonetheless, the experience from breeding methods used in some breeding centres in South Africa and the Netherlands, which also rely on the role that semiochemicals play in breeding, proves that cheetahs can be bred successfully in captivity. This review aims to give the reader an in-depth overview of cheetahs’ reproductive physiology and behaviour, focusing on the role that pheromones play in this species. Furthermore, it aims to provide new insight into the use of semiochemicals to improve conservation strategies through captive breeding.

Understanding Reproductive Aging in Wildlife to Improve Animal Conservation and Human Reproductive Health

Similar to humans and laboratory animals, reproductive aging is observed in wild species-from small invertebrates to large mammals. Aging issues are also prevalent in rare and endangered species under human care as their life expectancy is longer than in the wild. The objectives of this review are to (1) present conserved as well as distinctive traits of reproductive aging in different wild animal species (2) highlight the value of comparative studies to address aging issues in conservation breeding as well as in human reproductive medicine, and (3) suggest next steps forward in that research area. From social insects to mega-vertebrates, reproductive aging studies as well as observations in the wild or in breeding centers often remain at the physiological or organismal scale (senescence) rather than at the germ cell level. Overall, multiple traits are conserved across very different species (depletion of the ovarian reserve or no decline in testicular functions), but unique features also exist (endless reproductive life or unaltered quality of germ cells). There is a broad consensus about the need to fill research gaps because many cellular and molecular processes during reproductive aging remain undescribed. More research in male aging is particularly needed across all species. Furthermore, studies on reproductive aging of target species in their natural habitat (sentinel species) are crucial to define more accurate reproductive indicators relevant to other species, including humans, sharing the same environment. Wild species can significantly contribute to our general knowledge of a crucial phenomenon and provide new approaches to extend the reproductive lifespan.

Endometrial receptivity and embryo implantation in carnivores-commonalities and differences with other mammalian species

Endometrial receptivity and embryo implantation processes are a major point of pregnancy failure in many mammalian species, including humans. Although reproductive biology in many carnivore species remains enigmatic, the few that have been studied so far are invaluable comparative models. The goals of this review are to (1) summarize current data on the mechanisms involved in uterine receptivity and embryo implantation in carnivores, including commonalities and differences with other mammalian species and (2) identify research priorities to better understand a key phenomenon in a critical group of mammals. Besides unique reproductive traits in some carnivores (induced vs. spontaneous ovulation in cats, ovulation at the germinal vesicle stage in dogs), preimplantation embryo development is comparable with other orders. However, the timing of implantation varies, especially in species having an embryonic diapause. Mechanisms involved in endometrial receptivity and decidualization still remain to be fully understood, but specific markers have already been identified. Importantly, the use of endogenous hormones to control the ovarian activity may impact endometrial receptivity and subsequent embryo implantation. Next, research efforts should take advantage of advanced technologies to further study embryo implantation in carnivores and to provide more relevant models to reproductive medicine or for the conservation of rare and endangered species.

First Birth of Cheetah Cubs from In Vitro Fertilization and Embryo Transfer

Simple Summary

Although the cheetah is the most studied of all wild felid species, reproduction of cheetahs in zoological settings has never been self-sustaining. A large proportion (~30%) of the Association of Zoos and Aquariums population is excluded from breeding due to advanced age, health, behavior, or management issues. Development of assisted reproductive technologies (ARTs) to enable the genetic contribution of sub-fertile individuals is now a priority research and management focus. We have previously demonstrated that aging females produce eggs that have the same developmental competence as young females. The objective of the present study was to produce embryos in vitro from older donor oocytes and transfer them into younger recipients to obtain pregnancies and live births. Good quality oocytes were collected from three synchronized donors, fertilized in vitro with frozen-thawed semen, and cultured for two days. Resulting embryos were transferred into the oviduct of three synchronized recipients. Pregnancies were monitored via fecal levels of progestogens, ultrasonography, and radiography. Two cubs were born naturally after 90 days of gestation, representing the first cheetah births resulting from the transfer of embryos produced in vitro.

Abstract

Approximately 30% of the Association of Zoos and Aquariums cheetah population (~350 total animals) is unlikely to breed naturally due to advanced age, health, or behavioral issues. Aging cheetah females (≥9 y old) are unlikely to become pregnant via natural breeding if they are nulliparous. We previously demonstrated that oocytes recovered from aged females were of similar quality compared with those recovered from younger females (2–8 y old). We hypothesize that transfer of 4–8 cell embryos produced by in vitro fertilization with oocytes from old donors could result in pregnancy after transfer into younger recipients. Female cheetahs (n = 3 aging donors and n = 3 young recipients) received 300 IU equine Chorionic Gonadotropin (eCG) and 3000 IU Luteinizing Hormone (LH) while fecal metabolites of estrogens and progestogens were closely monitored. At 28 h post-LH injection, oocytes were aspirated laparoscopically from donors and inseminated in vitro with cryopreserved sperm. After 48 h of in vitro culture, resulting embryos (4–8 cells) were transferred into the oviducts of recipient females. Pregnancy was confirmed in one recipient via ultrasound 32 days after transfer and by radiograph 62 days after transfer. Two cubs were born naturally after 90 days of gestation, representing the first cheetah births resulting from transfer of embryos produced in vitro.

Distribution of uterine histological changes in aged captive cheetahs (Acinonyx jubatus)

The histological effect on the felid uterus of sterilization, via ovariectomy or salpingectomy, is currently unknown. To investigate the association of ovariectomy or salpingectomy with uterine health, it is first necessary to establish if changes are distributed evenly throughout the uterus. Both laparoscopic ovariectomy and salpingectomy with concurrent sampling of the tip of the uterine horn are possible in the cheetah. Currently accepted practice for histopathological screening of the uterus utilizes four biopsy samples. It is not known whether this method accurately reflects the status of the entire uterus. In this study we histologically examined the uteri of six older cheetahs (one 7-year-old and five 10-10.5-year-old animals) via 21 tissue samples (three samples from seven different anatomical regions) per cheetah to determine overall uterine health. Although no defined lesions were detected, mild endometrial gland dilation, assumed to be of no functional consequence, was observed in multiple samples. The odds of observing this dilation was lowest in the uterine body and progressively increased in a cranial direction, being significantly higher at the tip of the uterine horns (OR = 11.5; 95% CI, 2.0-65.1; p = 0.006). This supported the reliability of sampling the tip of the uterine horn to screen for endometrial gland dilation.

Assisted reproductive technologies for endangered species conservation: developing sophisticated protocols with limited access to animals with unique reproductive mechanisms

Assisted reproductive technologies (ARTs) have been proposed as a means of overcoming the significant challenges of managing small, isolated populations of endangered species in zoos. However, efficient protocols for ARTs do not exist for most endangered species. This review will focus on research efforts to characterize unique reproductive mechanisms and develop species-specific ARTs. Central to these studies are assays to measure steroid metabolites in urine or feces and/or training programs to allow unrestrained blood collections and ultrasound evaluations. The resulting information about estrous cycle dynamics, combined with studies of semen collection and processing, provides the foundation for the development of artificial insemination (AI). In vitro fertilization and embryo transfer are also discussed in relation to the advantages these techniques could provide relative to AI, as well as the significant challenges involved with technologies that require oocytes and embryos. Finally, an argument is made for additional research of nontraditional model species (e.g., domestic cats and dogs) and the development of novel models representing unique taxa. Whether these species are studied by zoo-based researchers with the expressed intent of developing ARTs for conservation or academic scientists interested in basic biology, the resulting information will provide a unique, evolutionary perspective on reproduction that could have wide-reaching benefits. The more information we have available, the better our chances will be of developing effective ARTs and making a difference in conservation efforts for endangered species.

Immunoglobulin J chain as a non-invasive indicator of pregnancy in the cheetah (Acinonyx jubatus)

The North American cheetah population serves as a reservoir for the species, and acts as a research population to help understand the unique biology of the species. Little is known about the intrauterine physiology of the cheetah, including embryo differentiation, implantation, and the development of the placenta. After mating, cheetah females frequently experience (30–65% of matings) a non-pregnant luteal phase where progestogen metabolite levels match those found in pregnant females for the first ~55 days of gestation, but parturition does not occur. Immunoglobulin J chain (IgJ) is a molecule that is involved in the activation of the secretory immune response and has been found to be indicative of pregnancy in the cheetah using fecal monitoring. In this study, western blotting was employed to track IgJ abundance in pooled weekly fecal samples following natural breeding or exogenous stimulation to ovulate, and IgJ levels were compared between individuals undergoing a pregnant (n = 12) and non-pregnant (n = 19) luteal phase. It was revealed that IgJ abundance was increased in pregnant females compared to non-pregnant females at week 4 and week 8 post-breeding, indicating the potential modulation of maternal immunity in response to sensitive events such as implantation and the increased secretory activity of the placenta. IgJ levels also tended to be higher early after breeding in females that were bred naturally with intact males compared to exogenously stimulated females with no exposure to seminal plasma, potentially indicating a response to the act of intromission or the stress of breeding, or possibly demonstrating an immune response resulting in the promotion of maternal tolerance to seminal antigens present upon embryonic implantation. Monitoring fecal IgJ may be a potential method to determine gestational status in the cheetah and will aid future conservation efforts of the species.

Responsiveness of the cheetah (Acinonyx jubatus) ovary to exogenous gonadotropins after preemptive oral progestin treatment

Control of ovarian function in cheetahs is sub-optimal, which currently limits the integration of assisted reproductive techniques into the genetic management of that endangered species. The objective of this study was to determine the effect of preemptive progestin treatment on the quality of ovarian responses after exogenous gonadotropin stimulation in cheetahs. Adult females received either 1) 200 IU equine chorionic gonadotropin (eCG) followed with 3,000 IU porcine luteinizing hormone (pLH) (intramuscular route) (n = 5; control group) or 2) similar eCG/pLH administration preceded by a 7-day treatment with oral progestin (0.1 mg/kg altrenogest; ALT group; n = 7). At 42 h post-pLH administration, a series of metrics was assessed via laparoscopy (number of follicles ≥ 2 mm, number of corpora lutea, oviduct and uterine cornua diameter and overall vascularization). Concentrations of fecal estradiol, progesterone and glucocorticoid metabolites (FEM, FPM, and FGM, respectively) were measured by enzyme immunoassay for 3 wk before ALT treatment (Period 1), 7 d during ovarian suppression period (Period 2), throughout eCG/LH treatment and laparoscopy (Period 3), and 6 wk following laparoscopy (Period 4). Overall, nine out of 12 cheetahs (4/5 in control and 5/7 ALT group) had freshly-formed corpora lutea at the time of laparoscopy. Mean follicle and corpora lutea numbers in the control versus ALT group were not different (P > 0.05). Overall measurements and vascularization scores also did not differ (P > 0.05) among groups. FEM average concentrations increased (P ≤ 0.05) in response to eCG for the ALT-treated females between Periods 2 and 3 and were sustained during Period 4. However, FEM average concentrations did not vary (P > 0.05) for control females throughout Periods 1-4. Post-ovulatory FPM average concentrations (Period 4) did not differ (P > 0.05) between the ALT-treated females and controls. FPM average concentration from both groups increased in Period 4 compared to Periods 1-3 (P ≤ 0.05). Females receiving the ALT treatment also had lower (P ≤ 0.05) FGM metabolite average concentrations than control females during ovarian suppression (suggesting adrenal suppression). Collective results suggest that ovarian response to gonadotropin treatment in the cheetah was improved following oral progestin administration due to the normative increase in estradiol following stimulation for these females compared with control. This treatment should lead to more effective timed assisted reproduction procedures for this species.

Morphology of the Uterotubal Junction of the Cheetah (Acinonyx jubatus)

Less than 7,000 cheetahs survive in the wild. Captive breeding has proved notoriously difficult. The uterotubal junction acts as major barrier and regulator to the passage of sperm. This study describes the morphology of the uterotubal junction of the cheetah. Reproductive tracts were obtained from seven cheetahs that succumbed from natural causes or were euthanized for humane reasons. The uterotubal junction was isolated and examined macroscopically and microscopically. The extramural isthmus made a characteristic 90° bend before entering the mesometrial border of the uterus close to its tip. The intramural isthmus had approximately four primary folds lined by nonciliated cuboidal to low cuboidal epithelium. The Tunica muscularis was robust, merged with its uterine counterparts and consisted of an inner circular layer and outer longitudinal smooth muscle layer. The uterine ostium opened via a muscular and glandular papilla that projected from the apex of the uterine lumen. A sharply demarcated circular zone of simple columnar epithelial cells surrounded the uterine ostium and separated the simple cuboidal to low cuboidal cells of the isthmus and uterine epithelium from each other. Branched tubulo-alveolar glands, some with dilated lumens, were present in the papilla and sometimes extended into the adjacent endometrium. These glands might act as sperm storage areas, and could easily be confused with cystic endometrial hyperplasia. Low transverse endometrial ridges surrounded the papilla and extended caudally for a short distance before disappearing. The uterine glands were lined by a simple cuboidal epithelium. Anat Rec, 302:1855-1864, 2019. © 2019 American Association for Anatomy.

Maternal age affects oocyte developmental potential at both ends of the age spectrum

Maternal age has a significant effect on oocyte developmental competence. Overall, evidence suggests that oocytes from both prepubertal females and reproductively aged females are inherently less competent. Reduced oocyte quality in both age groups is problematic for human medicine and agriculture. Some of the cellular mechanisms implicated in poor oocyte quality associated with maternal age are mitochondrial function and location, reduction of oxygen radicals, balance of metabolic pathways, regulation of maternal mRNAs and appropriate communication between the oocyte and cumulus cells. However, additional knowledge must be gained about the deficiencies present in prepubertal and reproductively aged oocytes that result in poor developmental potential before significant improvement can be achieved. This review discusses the evidence currently available regarding oocyte quality at both ends of the maternal age spectrum, what we know, or hypothesise, about the mechanisms involved and current thoughts regarding potential treatment for improvement.

Circumventing the natural, frequent oestrogen waves of the female cheetah (Acinonyx jubatus) using oral progestin (Altrenogest)

Cheetah are induced ovulators, experiencing short, variable oestrogen waves year-round. Exogenous gonadotrophin administration induces ovulation, but success is variable and often improves if ovaries are quiescent. After affirming the presence of short-term oestrogenic waves, we examined the effect of the timing of administration of exogenous equine and human chorionic gonadotrophins (eCG-hCG) within the oestrogen concentration pattern on subsequent follicle development and oocyte and corpus luteum quality. We also investigated ovarian suppression using an oral progestin (Altrenogest, 7 days) and assessed whether Altrenogest moderated adrenal activity by reducing glucocorticoid metabolites. All cheetahs exhibited short (every ~7-10 days), sporadic, year-round increases in faecal oestradiol punctuated by unpredictable periods (4-10 weeks) of baseline oestradiol (anoestrous). Gonadotrophin (eCG-hCG) efficacy was not affected by oestradiol 'wave' pattern if administered ≥3 days after an oestrogen peak. Such cheetahs produced normative faecal progestagen patterns and higher numbers (P<0.06) of mature oocytes than females given gonadotrophins ≤2 days after an oestradiol peak. Altrenogest supplementation expanded the interval between oestradiol peaks to 12.9 days compared with 7.3 days without progestin pretreatment. Altrenogest-fed females excreted less (P<0.05) glucocorticoid metabolites than non-supplemented counterparts. Results show that Altrenogest is effective for suppressing follicular activity, may contribute to reduced glucocorticoid production and may result in more effective ovulation induction via gonadotrophin therapy.

Group management influences reproductive function of the male cheetah (Acinonyx jubatus)

Although the free-ranging cheetah is generally socially solitary, as many as 60% of males live in same-sex (usually sibling) coalitions. Under ex situ conditions, the cheetah experiences low reproductive success with only ~18% of males having ever produced young. Most male cheetahs (85%) are managed in captivity in coalitions, but with no data on the influence of social grouping on reproductive parameters. We examined the influence of singleton versus coalition management on various male cheetah physiological traits, including ejaculate quality and gonadal and adrenal hormone metabolite concentrations. We also assessed behaviour within coalitions for evidence of social hierarchy through initiation of interactions with group mates and relatedness to physiological traits. Ejaculate quality (including total motile and structurally normal spermatozoa per ejaculate) and androgen concentration profiles were higher (P<0.05) in coalition compared with singleton males. These results support the conclusion that testis function in the cheetah, specifically related to the development of normal, motile spermatozoa and androgen production, is influenced by management with same-sex conspecifics. The findings have implications for ex situ conservation breeding programs by suggesting that reproductive quality can be enhanced through group maintenance of cheetah males.

The mutual benefits of research in wild animal species and human-assisted reproduction

Studying the reproductive biology of wild animal species produces knowledge beneficial to their management and conservation. However, wild species also share intriguing similarities in reproductive biology with humans, thereby offering alternative models for better understanding the etiology of infertility and developing innovative treatments. The purpose of this review is to raise awareness in different scientific communities about intriguing connections between wild animals and humans regarding infertility syndromes or improvement of fertility preservation. The objectives are to (1) highlight commonalities between wild species and human fertility, (2) demonstrate that research in wild species-assisted reproductive technologies can greatly enhance success in human reproductive medicine, and (3) recognize that human fertility preservation is highly inspiring and relevant to wild species conservation. In addition to having similar biological traits in some wild species and humans, the fact of sharing the same natural environment and the common needs for more options in fertility preservation are strong incentives to build more bridges that will eventually benefit both animal conservation and human reproductive medicine.

Overactive mTOR signaling leads to endometrial hyperplasia in aged women and mice

During aging, uncontrolled epithelial cell proliferation in the uterus results in endometrial hyperplasia and/or cancer development. The mTOR signaling pathway is one of the major regulators of aging as suppression of this pathway prolongs lifespan in model organisms. Genetic alterations in this pathway via mutations and/or amplifications are often encountered in endometrial cancers. However, the exact contribution of mTOR signaling and uterine aging to endometrial pathologies is currently unclear. This study examined the role of mTOR signaling in uterine aging and its implications in the development of endometrial hyperplasia. The hyperplastic endometrium of both postmenopausal women and aged mice exhibited elevated mTOR activity as seen with increased expression of the pS6 protein. Analysis of uteri from Pten heterozygous and Pten overexpressing mice further confirmed that over-activation of mTOR signaling leads to endometrial hyperplasia. Pharmacological inhibition of mTOR signaling using rapamycin treatment suppressed endometrial hyperplasia in aged mice. Furthermore, treatment with mTOR inhibitors reduced colony size and proliferation of a PTEN negative endometrial cancer cell line in 3D culture. Collectively, this study suggests that hyperactivation of the mTOR pathway is involved in the development of endometrial hyperplasia in aged women and mice.

A Brief History of Cheetah Conservation

The cheetah, Acinonyx jubatus, is a charismatic, and iconic species that, due to its uniqueness and extreme popularity over the epochs, has been exploited to near extinction. Once found on three continents, this streamline carnivore is disappearing rapidly from its former range and faces a bleak future due to numerous factors, including, popularity by nobility as pets and hunting companions, human population growth, human-wildlife conflict, illegal trafficking, loss of genetic diversity, and many others. The conservation crisis this species is facing is overwhelming, yet a core of hard-working conservationists has been working diligently for decades to slow, and in some areas try to even reverse, their downward spiral. This narrative will give the reader an insight into the history of the conservation efforts for this species, what has been done to date, and what still needs to be developed to save this unique species.

Non-invasive identification of protein biomarkers for early pregnancy diagnosis in the cheetah (Acinonyx jubatus)

Approximately 80% of cheetahs living in typical zoological collections never reproduce. In more than 60% of breedings, the female is confirmed to ovulate, but parturition fails to occur. It is unknown if these non-pregnant intervals of elevated progesterone (deemed luteal phases) are conception failures or a pregnancy terminating in embryonic/fetal loss. There have been recent advances in metabolic profiling and proteome analyses in many species with mass spectrometry used to identify ‘biomarkers’ and mechanisms indicative of specific physiological states (including pregnancy). Here, we hypothesized that protein expression in voided cheetah feces varied depending on pregnancy status. We: 1) identified the expansive protein profile present in fecal material of females; and 2) isolated proteins that may be candidates playing a role in early pregnancy establishment and diagnosis. Five hundred and seventy unique proteins were discovered among samples from pregnant (n = 8), non-pregnant, luteal phase (n = 5), and non-ovulatory control (n = 5) cheetahs. Four protein candidates were isolated that were significantly up-regulated and two were down-regulated in samples from pregnant compared to non-pregnant or control counterparts. One up-regulated candidate, immunoglobulin J chain (IGJ; an important component of the secretory immune system) was detected using a commercially available antibody via immunoblotting. Findings revealed that increased IGJ abundance could be used to detect pregnancy successfully in >80% of 23 assessed females within 4 weeks after mating. The discovery of a novel fecal pregnancy marker improves the ability to determine reproductive, especially gestational, status in cheetahs managed in an ex situ insurance and source population.

Age-associated and deslorelin-induced declines in serum anti-Müllerian hormone concentrations in female cheetahs, Acinonyx jubatus

Anti-Müllerian hormone (AMH) is widely used in human medicine to non-invasively estimate the size of the ovarian follicle reserve and to predict the ovarian response to gonadotropin stimulation in the context of assisted reproductive technologies (e.g., IVF). These applications of AMH testing have recently expanded to non-human mammals, with production animals, such as cows, goats and sheep being the primary focus of AMH research. However, few investigations have involved exotic species, and in particular carnivores. In this study, we measured AMH concentrations (0.078-3.078ng/mL) in archived serum samples that had been collected from 36 adult female cheetahs across their reproductive lifespan (2-15years of age). Similar to other mammals, AMH concentration in cheetahs declined with age, and its variability among females of the same age was considerable. The rates at which AMH declined over time in individual cheetahs were also highly variable. Five cheetahs had been contracepted with the long-acting GnRH agonist deslorelin for 6-18months prior to sample collection, and their AMH concentrations were relatively low compared to untreated females. In this first study of AMH in an exotic carnivore, the findings demonstrate that the age-associated decline in AMH is highly variable and that deslorelin appears to suppress AMH concentration in serum. Owing to the increased use of assisted reproductive technologies in ex situ populations of threatened and endangered species, such as cheetahs, the present study's findings will need to be taken into consideration if AMH is to be used successfully to optimize breeding management decisions in exotic species.

Public exposure and number of conspecifics have no influence on ovarian and adrenal activity in the cheetah (Acinonyx jubatus)

Cheetahs in managed zoological collections do not reproduce efficiently, a problem that may be related to environmental/management stressors. In this study, we examined 17 adult female cheetahs to determine the influence of two environmental factors, (1) being housed on- or off-exhibit and (2) number of adult conspecifics (males and/or females) in nearby enclosures, on profiles and concentrations of ovarian and adrenal hormones. Secondarily, we assessed a subset of group-housed siblings (n=5 females in groups of 2 or 3) for effects of long-term cohabitation. All of the females demonstrated waves of estrogen excretion (indicative of ovarian activity) as well as occasional periods of no estrogen production (anestrus). Glucocorticoid and estrogen concentrations were correlated within an individual (r_s=0.53; P<0.05), and overall there was a higher frequency of days with elevated glucocorticoid concentrations in association with elevated estrogen excretion. However, none of the management factors had an impact (P>0.05) on estrogen or glucocorticoid metabolite excretory patterns. Although we recently reported that public exposure can negatively affect sperm production, ovarian steroidogenesis in females was unaffected. There also was no evidence of hyper-adrenal activity. Thus, different methods of ex situ management appear to have minimal influence on ovarian function or stress susceptibility of female cheetahs.

Intrinsic factors, adrenal gland morphology, and disease burden in captive cheetahs (Acinonyx jubatus) in South Africa

Adrenal gland weight (AW) and corticomedullary ratio (ACMR) are used as indicators of stress in animals. Captive cheetahs (Acinonyx jubatus) have higher ACMRs than free-ranging ones and stress has been linked to gastritis, amyloidosis, glomerulosclerosis, and myocardial fibrosis. We reviewed age, sex, body weight (BW), kidney weight (KW), and left AW and ACMR with necropsy findings in 51 South African captive cheetahs. Eleven common histopathologic lesions were counted for each animal as measure of its disease burden. Adrenal corticomedullary hyperplasia was significantly correlated with left AW and ACMR. Males had significantly higher AWs than females; other parameters showed no difference between the sexes. Disease burden, gastritis, and myocardial fibrosis were moderately correlated with adrenal morphology supporting prior evidence that gastritis and myocardial fibrosis are linked to stress. Glomerulosclerosis was not correlated with adrenal morphology and neither kidney nor liver amyloidosis contributed significantly to variation in AW or ACMR on multivariate analyses. Interstitial nephritis showed much stronger correlations with kidney and liver amyloidosis than gastritis. All three adrenal parameters were correlated with age; age was the only significant variable affecting ACMR on the multivariate analyses; and disease burden as well as systemic amyloidosis and kidney disease (except for fibrosis) showed moderate correlations with age. Age may, therefore, be important in the pathogenesis of disease in captive cheetahs, particularly of amyloidosis and kidney disease. None of the intrinsic measurements or adrenal parameters were sufficiently closely linked to disease to be used as ante-mortem proxies for disease burden or specific diseases. Zoo Biol. 36:40-49, 2017. © 2016 Wiley Periodicals, Inc.

Effect of portal access system and surgery type on surgery times during laparoscopic ovariectomy and salpingectomy in captive African lions and cheetahs

Background

A prospective randomized study was used to compare surgery times for laparoscopic ovariectomy and salpingectomy in female African lion (Panthera leo) (n = 14) and cheetah (Acinonyx jubatus) (n = 20) and to compare the use of a multiple portal access system (MPAS) and single portal access system (SPAS) between groups. Two different portal techniques were used, namely MPAS (three separate ports) in lions and SPAS (SILS™ port) in cheetahs, using standard straight laparoscopic instruments. Portal access system and first ovary was not randomized. Five different surgery times were compared for the two different procedures as well as evaluating the use and application of MPAS and SPAS. Carbon dioxide volumes for lions were recorded.

Results

In adult lionesses operative time (OPT) (P = 0.016) and total surgical time (TST) (P = 0.032) were significantly shorter for salpingectomy compared to ovariectomy. Similarly in cheetahs OPT (P = 0.001) and TST (P = 0.005) were also shorter for salpingectomy compared to ovariectomy. In contrast, in lion cubs no difference was found in surgery times for ovariectomy and salpingectomy. Total unilateral procedure time was shorter than the respective bilateral time for both procedures (P = 0.019 and P = 0.001) respectively and unilateral salpingectomy was also faster than unilateral ovariectomy (P = 0.035) in cheetahs. Port placement time, suturing time and TST were significantly shorter for SPAS compared to MPAS (P = 0.008). There was, however, no difference in OPT between SPAS and MPAS. Instrument cluttering with SPAS was found to be negligible. There was no difference in mean volume CO₂ required to complete ovariectomy in lions but the correlation between bodyweight and total volume of CO₂ in lions was significant (r_s = 0.867; P = 0.002).

Conclusions

Laparoscopic salpingectomy was faster than ovariectomy in both adult lions and cheetahs. Using SPAS, both unilateral procedures were faster than bilateral procedures in cheetahs. Placement and suturing of SPAS in cheetahs was easier and faster compared to three separate ports in lions and lion cubs. The use of standard straight instruments during SPAS did not prolong surgery. Surgery was faster in cubs and CO₂ required for laparoscopic sterilization in lions could be determined. Predictable surgery times and CO₂ volumes will facilitate the accurate planning and execution of surgery in lions and cheetahs.

Characterization of Ovarian Steroid Patterns in Female African Lions (Panthera leo), and the Effects of Contraception on Reproductive Function

Because of poor reproduction after the lifting of an 8-year breeding moratorium, a biomedical survey of female lions in U.S. zoos was initiated in 2007. Fecal estrogen (FEM), progestagen (FPM) and glucocorticoid (FGM) metabolites were analyzed in samples collected 3-4 times per wk from 28 lions at 17 facilities (0.9-13.8 yr of age) for 4 mo-3.5 yr and body weights were obtained ~monthly from 17 animals at eight facilities (0.0-3.0 yr of age). Based on FEM, estrous cycle length averaged 17.5 ± 0.4 d in duration, with estrus lasting 4.4 ± 0.2 d. All but one female exhibited waves of estrogenic activity indicative of follicular activity; however, not all females expressed estrous behaviors (73%), suggesting silent estrus was common. Female lions experienced puberty earlier than expected; waves of estrogenic activity were observed as young as 1.1 yr of age, which may be related to a faster growth rate of captive vs. wild lions. Mean gestation length was 109.5 ± 1.0 d, whereas the non-pregnant luteal phase was less than half (46.0 ± 1.2 d). Non-mating induced increases in FPM were observed in 33% of females housed without a male, consistent with spontaneous ovulation. A number of study animals had been contracepted, and the return to cyclicity after treatment withdrawal, while variable, was ~4.0 yr and longer than the 1-yr expected efficacy, especially for those implanted with Suprelorin. For FGM, there were no differences in overall, baseline or peak mean concentrations among the age groups or across seasons, nor were there any relationships between reproductive parameters and FGM concentrations. Overall, results suggest that poor reproduction in lions after the breeding moratorium was not related to altered adrenal or ovarian steroid activity, but for some females may have been a consequence of individual institutions' management decisions.

Motile Sperm Output by Male Cheetahs (Acinonyx jubatus) Managed Ex Situ Is Influenced by Public Exposure and Number of Care-Givers

The collective cheetah (Acinonyx jubatus) population in zoological institutions has never been self-sustaining because of challenges in natural reproduction. A retrospective analysis of North American zoo-breeding records has revealed that >90% of litters produced since 2003 occurred in facilities ‘off-display’ from the public. We examined seminal, endocrine, and behavioral traits of 29 adult male cheetahs that were: 1) managed in public exhibit or off-display facilities; 2) maintained by different numbers of cheetah-specific care-givers; and 3) living adjacent to varying numbers of adult conspecifics. Cheetahs housed off-display produced more total motile sperm/ejaculate (P = 0.04) than on-exhibit males. This finding was mirrored in our laboratory’s historical records where two-fold more total motile sperm (P < 0.01) were measured in ejaculates from individuals with no public exposure (n = 43) compared to on-exhibit (n = 116) counterparts. Males at institutions with ≤3 care-givers also produced more total motile sperm/ejaculate (P < 0.03) and spent more time behaviorally active (P < 0.01) than at facilities using >3 care-givers. Exposure to high numbers of conspecifics within the same institution did not impact (P > 0.05) seminal traits, and presence of the public, care-giver number, or animals/facility had no influence (P > 0.05) on androgen or glucocorticoid excretion or other behavioral metrics. Findings indicate that male cheetahs are sensitive to general public exposure and too many care-givers, resulting in compromised motile sperm output/ejaculate with mechanism of action unrelated to altered androgen or glucocorticoid excretion.

Reproductive performance: at the cross-road of genetics, technologies and environment

Sexual reproduction depends on a negotiation between the sexes at the level of the cells (gametes), tissue (trophectoderm of the blastocyst and endometrium in the uterus) and organisms (to allow sexual intercourse). This review evaluates new questions linked to sexual reproduction in the biosphere in the context of the 21st century, in light of current knowledge in genetics and epigenetics. It presents the challenge of ‘forcing reproductive efficiency’ using ineffective gametes, or despite other fertility problems, through medically assisted reproduction and presents the reproductive challenge of high production farm animals, which are in a situation of chronically negative energy balance. It also analyses the situation created by the release of endocrine disruptors into the environment and discusses the possible transgenerational consequences of environmental modifications linked to these compounds.

Absence of seasonal changes in FSHR gene expression in the cat cumulus-oocyte complex in vivo and in vitro

Domestic cat oocytes are seasonally sensitive to FSH. Compared with those collected during the breeding season, oocytes from the nonbreeding (NB) season require more FSH during in vitro maturation to achieve comparable developmental competence. This study tested the hypothesis that this seasonal variation was due to altered expression of FSH receptors (FSHR) and/or FSH-induced genes. Relative expression levels of FSHR mRNA and FSH-enhanced gene estrogen receptor β (ESR2) were measured by qPCR in whole ovaries and immature cumulus-oocyte complexes (COCs) isolated from cat ovaries during the natural breeding vs NB seasons. Expression levels of FSH-induced genes prostaglandin-endoperoxide synthase 2 (PTGS2), early growth response protein-1 (EGR1), and epidermal growth factor receptor (EGFR) were examined in mature COCs from both seasons that were a) recovered in vivo or b) matured in vitro with conventional (1 μg/ml) or high (10 μg/ml) FSH concentrations. Overall, FSHR mRNA levels were lower in whole ovaries during the NB compared with breeding season but were similar in immature COCs, whereas ESR2 levels did not differ in either group between intervals. We observed changes in PTGS2, EGR1, and EGFR mRNA expression patterns across maturation in COCs within but not between the two seasons. The lack of seasonal differentiation in FSH-related genes was not consistent with the decreased developmental capacity of oocytes fertilized during the NB season. These findings reveal that the seasonal decrease in cat oocyte sensitivity to FSH occurs both in vivo and in vitro. Furthermore, this decline is unrelated to changes in expression of FSHR mRNA or mRNA of FSH-induced genes in COCs from antral follicles.

Mummified papyraceous fetuses in the abdominal cavity of an elderly female dog with pyometra

This paper reports on a rare case of fetal papyraceous mummification after asymptomatic uterine rupture in an elderly female dog with pyometra. The patient had a history of mating six months before the examination but no apparent signs of gestation or parturition. Exploratory laparotomy was used to identify a rupture of the left uterine horn and the presence of cystic endometrial hyperplasia and pyometra. Two mummified papyraceous fetuses were observed in the abdominal cavity and had adhered to the spleen, pancreas, intestine and omentum. Ovariehysterectomy and corrective surgery were performed. The patient had remained healthy after uterine rupture until a new estrous cycle and the development of pyometra. Bitches that are 10 years old or more are predisposed to implantation failure, pregnancy or parturition problems and they should not be breed to avoid complications.

Why is chromosome segregation error in oocytes increased with maternal aging?

It is well documented that female fertility is decreased with advanced maternal age due to chromosome abnormality in oocytes. Increased chromosome missegregation is mainly caused by centromeric cohesion reduction. Other factors such as weakened homologous recombination, improper spindle organization, spindle assembly checkpoint (SAC) malfunction, chromatin epigenetic changes, and extra-oocyte factors may also cause chromosome errors.