Proteomic Analysis of Domestic Cat Blastocysts and Their Secretome Produced in an In Vitro Culture System without the Presence of the Zona Pellucida

Domestic cat blastocysts cultured without the zona pellucida exhibit reduced implantation capacity. However, the protein expression profile has not been evaluated in these embryos. The objective of this study was to evaluate the protein expression profile of domestic cat blastocysts cultured without the zona pellucida. Two experimental groups were generated: (1) domestic cat embryos generated by IVF and cultured in vitro (zona intact, (ZI)) and (2) domestic cat embryos cultured in vitro without the zona pellucida (zona-free (ZF group)). The cleavage, morula, and blastocyst rates were estimated at days 2, 5 and 7, respectively. Day 7 blastocysts and their culture media were subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS). The UniProt Felis catus database was used to identify the standard proteome. No significant differences were found in the cleavage, morula, or blastocyst rates between the ZI and ZF groups (p > 0.05). Proteomic analysis revealed 22 upregulated and 20 downregulated proteins in the ZF blastocysts. Furthermore, 14 proteins involved in embryo development and implantation were present exclusively in the culture medium of the ZI blastocysts. In conclusion, embryo culture without the zona pellucida did not affect in vitro development, but altered the protein expression profile and release of domestic cat blastocysts.

Reproductive physiology with emphasis on endometrial cycles of woolly and uakari monkeys-A literature review

The ability of a species to withstand human impact depends on its life history characteristics, including social, ranging, and reproductive activity. The genera Lagothrix and Cacajao are more susceptible to anthropic action than small-sized primates due to their slower life histories, more restricted geographical ranges, and lower population densities. This narrative literature review aimed to gather scientific information available from the last 60 years on the reproductive biology of females of the genera Lagothrix and Cacajao. Most studies on the genus Lagothrix, mainly focused on L. lagothricha and L. l. poeppigii, present important advances on reproductive strategies, reproductive productivity, functional morphology and physiology, including seasonality, sexual cycle, gestation and fetal development in captive and free-living populations. Contrary, there is much less known about the reproductive biology of the genus Cacajao, with studies on free-living C. calvus and C. melanocephalus highlighting reproductive behavior, and basic description of the sexual cycle, gestation, and lactation. Unfortunately, the morphology of the female genital organs is only described in C. calvus, and there is still scarce information about the menstrual activity and the placenta. This literature review encourages primatologists, morphophysiologists, reproductive specialists, and ecologists to conduct comprehensive studies of these species to better understand the gaps in knowledge about reproduction, their relationship with their environment, including climatic and social variables. Understanding the integrative reproductive biology of these species will be a clue for improving the assessment of the resilience capacity of free-living populations and, consequently, establishing more appropriate management programs, and for the development of ex situ management techniques for the conservation of the species.

Epigenetic changes to gene pathways linked to male fertility in ex situ black-footed ferrets

Environmental variation can influence the reproductive success of species managed under human care and in the wild, yet the mechanisms underlying this phenomenon remain largely mysterious. Molecular mechanisms such as epigenetic modifiers are important in mediating the timing and progression of reproduction in humans and model organisms, but few studies have linked epigenetic variation to reproductive fitness in wildlife. Here, we investigated epigenetic variation in black-footed ferrets (Mustela nigripes), an endangered North American mammal reliant on ex situ management for survival and persistence in the wild. Despite similar levels of genetic diversity in human-managed and wild-born populations, individuals in ex situ facilities exhibit reproductive problems, such as poor sperm quality. Differences across these settings suggest that an environmentally driven decline in reproductive capacity may be occurring in this species. We examined the role of DNA methylation, one well-studied epigenetic modifier, in this emergent condition. We leveraged blood, testes, and semen samples from male black-footed ferrets bred in ex situ facilities and found tissue-type specificity in DNA methylation across the genome, although 1360 Gene Ontology terms associated with male average litter size shared functions across tissues. We then constructed gene networks of differentially methylated genomic sites associated with three different reproductive phenotypes to explore the putative biological impact of variation in DNA methylation. Sperm gene networks associated with average litter size and sperm count were functionally enriched for candidate genes involved in reproduction, development, and its regulation through transcriptional repression. We propose that DNA methylation plays an important role in regulating these reproductive phenotypes, thereby impacting the fertility of male ex situ individuals. Our results provide information into how DNA methylation may function in the alteration of reproductive pathways and phenotypes in artificial environments. These findings provide early insights to conservation hurdles faced in the protection of this rare species.

Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales

Serial measurements of hormone concentrations along baleen plates allow for reconstructions of mysticete whale reproductive histories. We assessed gestation and calving interval in bowhead whales (Balaena mysticetus) by measuring progesterone, oestradiol, corticosterone and nitrogen stable isotope ratios (δ¹⁵N) along baleen of 10 females from the eastern Canada-west Greenland population. Three immature females (body size < 14.32 m) had uniformly low progesterone concentrations across their baleen, while seven mature females (body size ≥ 14.35 m) had repeated, sustained elevations of progesterone indicative of pregnancies. The mean duration of progesterone elevations (23.6 ± 1.50 months) was considerably longer than the approximately 14 month gestation previously estimated for this species. We consider several possible explanations for this observation, including delayed implantation or sequential ovulations prior to gestation, strategies that would allow females to maximize their fitness in variable Arctic conditions, as well as suggest modified criteria defining gestation as a shorter component of the entire progesterone peak. Calving intervals varied within and among individuals (mean = 3.7 years; range = range 2.8-5.7 years), providing population-specific reproductive estimates for growth models used in bowhead whale management and conservation.

Effect of Electroejaculation Protocols on Semen Quality and Concentrations of Testosterone, Cortisol, Malondialdehyde, and Creatine Kinase in Captive Bengal Tigers

The Bengal tiger (Panthera tigris tigris) is critically endangered, so assisted reproductive technologies, including artificial insemination, are important conservation tools. For wild and domestic felids, electroejaculation (EE) is the most common semen collection method, with protocols optimized to obtain sufficient amounts of viable sperm for artificial insemination. However, less attention has been paid to ensuring animal wellbeing during the process. This study examined the effects of three EE protocols (Low, 2-5 volts; Medium, 3-6 volts; High, 4-7 volts) on semen quality, testicular size, serum testosterone, creatine kinase (CK), and malondialdehyde (MDA) concentrations, and serum cortisol as a proxy for stress. Blood samples were collected before, during, and after each EE series. Seminal plasma pH, and sperm motility, viability, and morphology were evaluated after each procedure. Seminal plasma and sperm pellet MDA concentrations were also determined. Primary sperm abnormalities and seminal plasma MDA were higher in the Low compared to Medium and High voltage groups (p < 0.05). Serum CK in the High voltage group increased during the EE series (p < 0.05), suggesting the potential for muscle damage. However, no significant changes were observed for serum cortisol, testosterone, or MDA concentrations. Results suggest the Medium voltage protocol produced good quality samples at lower voltages than the High protocol with no negative effect on muscle function, which might be better for animal welfare.

Thinking with Civets: The Role of Zoos in the Decolonisation of Animal Tourism

Civets belong to the family Viverridae, an ancient line of 'cat-like' animals. Despite their large geographic distribution across southeast Asia and parts of Africa, little scientific attention has been attributed to Viverrids or Viverrid-human relations. This paper applies the lens of civets to explore the tensive intersection between animal welfare, conservation, and colonialism within the tourism landscape. Through thinking with civets, this paper brings two forms of animal commodification into dialogue: (1) the management of civets in zoos around the globe and (2) the rising trend in civet coffee production and tourism in Asia. By qualitatively analysing the entanglements between colonialism, animal welfare, and conservation and how each impacts the lives and treatment of civets in tourism, this paper calls for enhanced reflexivity and thus the decolonisation of animal-based tourism. Suggestions are made on how zoos may progress towards the decolonisation of animal tourism, and the argument is made that zoos are well positioned and morally obligated to answer this call. By doing so, greater attention can be given to the animals whose lives are most affected by the global tourism landscape.

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.

Patterns of faecal glucocorticoid metabolite levels in captive roan antelope (Hippotragus equinus) in relation to reproductive status and season

Populations of roan antelope (Hippotragus equinus) in southern Africa have experienced a drastic decline over the past few decades and this situation has led to the development of intensive breeding programmes to support conservation efforts. However, little is known about related welfare aspects, including stress-related physiological biomarkers. The present study set out to establish a non-invasive method to monitor faecal glucocorticoid metabolite (fGCM) concentrations as a measure of stress and determine fGCM concentrations in relation to male reproductive activity and female reproductive status in the roan antelope. An adrenocorticotrophic hormone challenge was performed using two adult roan antelope (one male and one female) at Lapalala Wilderness Nature Reserve, South Africa, to determine the suitability of five enzyme immunoassays (EIA) for monitoring adrenocortical function in roan antelope. An 11-oxoaetiocholanolone I EIA detecting 11,17 dioxoandrostanes performed best showing 17-20 folds increases in fGCM concentrations after 12 h-17 h post-injection. The identified EIA was then used to monitor fGCM concentrations during active and non-active reproductive periods in males (n = 3), and during periods of cyclicity, gestation, and postpartum in females (n = 10). Males showed an overall 80% increase in fGCM concentrations when reproductively active and females showed a progressively significant increase in fGCM levels throughout pregnancy, with overall fGCM concentrations being 1.5 to 2.6-fold higher than the respective fGCM concentrations during periods of postpartum and cyclicity, respectively. Furthermore, fGCM concentrations remained above baseline for up to 21 days post-partum. A correlation between ecological parameters (rainfall and temperature) and fGCM concentrations revealed elevated fGCM concentrations during the dry season for males, but not females. The non-invasive method validated in this study provides a valuable tool to quantify stress-related biomarkers in roan antelope, and findings can be used to support management decisions in conservation breeding facilities.

Resurrecting biodiversity: advanced assisted reproductive technologies and biobanking

Biodiversity is defined as the presence of a variety of living organisms on the Earth that is essential for human survival. However, anthropogenic activities are causing the sixth mass extinction, threatening even our own species. For many animals, dwindling numbers are becoming fragmented populations with low genetic diversity, threatening long-term species viability. With extinction rates 1000–10,000 times greater than natural, ex situ and in situ conservation programmes need additional support to save species. The indefinite storage of cryopreserved (−196°C) viable cells and tissues (cryobanking), followed by assisted or advanced assisted reproductive technology (ART: utilisation of oocytes and spermatozoa to generate offspring; aART: utilisation of somatic cell genetic material to generate offspring), may be the only hope for species’ long-term survival. As such, cryobanking should be considered a necessity for all future conservation strategies. Following cryopreservation, ART/aART can be used to reinstate lost genetics back into a population, resurrecting biodiversity. However, for this to be successful, species-specific protocol optimisation and increased knowledge of basic biology for many taxa are required. Current ART/aART is primarily focused on mammalian taxa; however, this needs to be extended to all, including to some of the most endangered species: amphibians. Gamete, reproductive tissue and somatic cell cryobanking can fill the gap between losing genetic diversity today and future technological developments. This review explores species prioritisation for cryobanking and the successes and challenges of cryopreservation and multiple ARTs/aARTs. We here discuss the value of cryobanking before more species are lost and the potential of advanced reproductive technologies not only to halt but also to reverse biodiversity loss.

Common goals, different stages: the state of the ARTs for reptile and amphibian conservation

Amphibians and reptiles are highly threatened vertebrate taxa with large numbers of species threatened with extinction. With so many species at risk, conservation requires the efficient and cost-effective application of all the tools available so that as many species as possible are assisted. Biobanking of genetic material in genetic resource banks (GRBs) in combination with assisted reproductive technologies (ARTs) to retrieve live animals from stored materials are two powerful, complementary tools in the conservation toolbox for arresting and reversing biodiversity decline for both amphibians and reptiles. However, the degree of development of the ARTs and cryopreservation technologies differ markedly between these two groups. These differences are explained in part by different perceptions of the taxa, but also to differing reproductive anatomy and biology between the amphibians and reptiles. Artificial fertilisation with cryopreserved sperm is becoming a more widely developed and utilised technology for amphibians. However, in contrast, artificial insemination with production of live progeny has been reported in few reptiles, and while sperm have been successfully cryopreserved, there are still no reports of the production of live offspring generated from cryopreserved sperm. In both amphibians and reptiles, a focus on sperm cryopreservation and artificial fertilisation or artificial insemination has been at the expense of the development and application of more advanced technologies such as cryopreservation of the female germline and embryonic genome, or the use of sophisticated stem cell/primordial germ cell cryopreservation and transplantation approaches. This review accompanies the publication of ten papers on amphibians and twelve papers on reptiles reporting advances in ARTs and biobanking for the herpetological taxa.

Case Studies in Polar Bear (Ursus maritimus) Sperm Collection and Cryopreservation Techniques

Simple Summary

Polar bears are threatened by habitat loss, decreased food availability, and reduced reproductive success due to climate change. Zoo populations can support species survival through preservation of genetic diversity and maintenance of insurance populations, but in the US, the zoo polar bear population is currently not sustainable. The development of sperm collection and cryopreservation can help to support the population by providing the biomaterial needed for assisted reproductive techniques, such as artificial insemination. However, these procedures are not well described for polar bears. Data from 38 opportunistic sperm collections, that were conducted between 2011 and 2021, were assessed to establish best practices to date for collecting and preserving polar bear sperm. The information gathered demonstrates that urethral catheterization is an efficient method of sperm collection, sperm can be rescued postmortem from the vasa deferentia and epididymides, and polar bear sperm collection appears to be most effective during the breeding season. Furthermore, polar bear sperm can survive cryopreservation. Further studies will optimize these techniques, but this summary provides information that is immediately applicable to enhancing sample collection and cryopreservation success that could support the long-term genetic management of polar bears in zoos.

Abstract

Assisted reproductive technologies can aid conservation efforts via support of ex situ population management and preservation of genetic material. Data from 38 sperm collection attempts from 17 polar bears (1–5 procedures/bear) were evaluated. Sample collections were attempted via electroejaculation (EEJ; n = 6), urethral catheterization (UC; n = 25), or sperm rescue (SR; n = 7) during the breeding season (Jan. 1-May 21; n = 27) and nonbreeding season (May 22-Dec. 31; n = 11). Sperm retrieval was successful in 1 EEJ (16.7%), 18 UC (72.0%) and 4 SR (57.1%) collections. Initial sperm motility and viability were 50.0% and 77.0% for EEJ, 64.3 ± 7.4% and 80.9 ± 3.8% for UC, and 56.7 ± 8.8% and 80.5 ± 0.5% for SR. UC and SR were more likely to be successful during the breeding season (84.2–100%) than the nonbreeding season (25.0–33.3%). Testicular tumors were observed in four males (57%) during SR. In total, 13 samples were cryopreserved (n = 1 EEJ, 9 UC, and 3 SR) with egg-yolk-based equine extender (EQ) or OptiXcell (OP). For both extenders, post-thaw motility and viability were reduced by 20–60% and 30–65%, respectively. Further efforts to optimize procedures are warranted, but this summary provides data useful for enhancing the success of polar bear sperm collection and cryopreservation.

Optimal cooling rates for sperm cryopreservation in a threatened lizard conform to two-factor hypothesis of cryo-injury

Assisted reproductive technologies provide important tools for wildlife conservation but have rarely been developed for reptiles. A critical step in developing cryopreservation protocols is establishing optimal cooling rates for cell survival. The two-factor hypothesis explaining cryoinjury to cells originates from an inverted 'U' shape of recovery curves generated in many cell types thawed after cryopreservation, due to cell recovery declining at cooling rates either side of a single optimum. We generated such a curve for the yellow-spotted monitor lizard Varanus panoptes, the first for any reptile. We cryopreserved sperm using two cooling devices (LN₂ dry shipper; LN₂ bath vapour) and two sperm-holding vessels (Cassou sperm straws; Nunc CryoTubes) to generate four different cooling-rate curves during freezing. Sperm motility and viability (47.3% and 76.5% respectively) were highest when frozen in straws suspended in a LN₂ bath at an intermediate cooling rate of 73 ^°C/min between 0 and -50 °C, whereas sperm frozen in straws suspended in a dry shipper at the fastest cooling rate (231 ^°C/min between 0 and -50 °C) produced the lowest recovery (10.4% and 36.4% motility and viability, respectively). Sperm frozen in cryotubes at the lowest cooling rates in either LN₂ bath vapour or dry shipper produced intermediate recovery. The shape of the optimal cooling curve conformed to the two-factor hypothesis of cryoinjury, the first such evidence in reptile sperm. This in turn led to the identification of simple cryopreservation setups (LN₂ vapour with straws and cryotubes; dry shipper with cryotubes but not straws) suitable for cryopreserving lizard sperm in the field.

Differential expression of urinary volatile organic compounds by sex, male reproductive status, and pairing status in the maned wolf (Chrysocyon brachyurus)

The maned wolf (Chrysocyon brachyurus) is an induced ovulator. Though the mechanism of ovulation induction remains unknown, it is suspected to be urinary chemical signals excreted by males. This study assessed volatile organic compounds (VOCs) in weekly urine samples across 5 months from 13 maned wolves (6 intact males, 1 neutered male, 6 females) with the goal of identifying VOCs that are differentially expressed across sex, reproductive status, and pairing status. Solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) were used to extract and separate VOCs that were identified via spectral matching with authentic standards, with spectral libraries, or with new software that further matches molecular fragment structures with mass spectral peaks. Two VOCs were present across all 317 urine samples: 2,5-dimethyl pyrazine and 2-methyl-6-(1-propenyl)-pyrazine. Fifteen VOCs differed significantly (Adj. P < 0.001 and |log2 fold change| >2.0) between intact males and females. Using partial least squares-discriminant analysis, the compounds with the highest importance to the sex classification were delta-decalactone, delta-dodecalactone, and bis(prenyl) sulfide. Sixty-two VOCs differed between intact males and the neutered male. Important classifier compounds were 3-ethyl 2,5-dimethyl pyrazine, 2-methyl-6-(1-propenyl)-pyrazine, and tetrahydro-2-isopentyl-5-propyl furan. Several VOCs established as important here have been implicated in reproductive communication in other mammals. This study is the most robust examination of differential expression in the maned wolf thus far and provides the most comprehensive analysis of maned wolf urinary VOCs to date, increasing the sample size substantially over previous chemical communication studies in this species. New data analysis software allowed for the identification of compounds in the hormone-producing mevalonate pathway which were previously unreported in maned wolf urine. Several putative semiochemicals were identified as good candidates for behavioral bioassays to determine their role in maned wolf reproduction, and specifically in ovulation induction.

Assisted Reproductive Technology in Neotropical Deer: A Model Approach to Preserving Genetic Diversity

Simple Summary

Deer species in the Neotropical region have undergone a decline of their populations. Although conservation of their natural habitat is considered the best way to assist the species, the speed of occupation of these areas and the anthropic actions are so fast that the efforts are, at times, insufficient. As free-living populations decrease, there is a descent in the genetic diversity and an increase in crossbreeding between related individuals (inbreeding). Genetic diversity is essential for survival, since it enables natural selection to occur, providing adaptation and maintenance of the species. To protect the genetic diversity, it is possible to use reproductive techniques and conserve different types of cells, which can be used in the future to reestablish any alleles that have been lost by the populations.

Abstract

One of the most significant challenges in deer is the ability to maintain genetic diversity, avoiding inbreeding and sustaining population health and reproduction. Although our general knowledge of reproductive physiology is improving, it appears that the application of assisted reproductive technology (ART) will more efficiently advance wildlife conservation efforts and preserve genetic diversity. The purpose of this review is to present the most important results obtained with the use of ART in Neotropical deer. Thus, the state-of-the-art for estrus synchronization, semen technology, artificial insemination, and in vivo embryo production will be presented. In vitro embryo production (IVP) is also a biotechnology that is taking initial steps in deer. In this aspect, the approach with the proteomics of ovarian follicular fluid is being used as a tool for a better understanding of oocyte maturation. Finally, cell banks and the use of interspecific somatic cell nuclear transfer (iSCNT) as well as the use of stem cells for gametes differentiation are promising techniques.

Efficacy of short-term cold storage prior to cryopreservation of spermatozoa in a threatened lizard

Assisted reproductive technologies (ARTs) have a significant role to play in reptile conservation, yet are severely lacking. Previous attempts to cryopreserve spermatozoa in the threatened lizard Varanus panoptes achieved approximately 48% motile sperm post-thaw for samples frozen immediately after collection. However, the feasibility of extended cold storage before cryopreservation has not been tested. We held V. panoptes spermatozoa at either 25°C or 4°C for 8 days, assessing sperm motility at days 1, 2, 4 and 8. Subsamples were cryopreserved on days 1 and 4 following the previously reported protocol for this species. Percentage motility decreased rapidly at 25°C, but did not decrease significantly until 4 days after collection at 4°C, with >30% motility maintained after 8 days. There was no significant difference in post-thaw motility or viability of samples cryopreserved after 1 or 4 days storage at 4°C, yielding substantial results for both parameters (mean motility 23.8% and 28.1% and mean viability 50.1% and 57.5% after 1 and 4 days respectively). We demonstrate the capacity to extend sperm viability for up to 8 days in unfrozen samples and to produce acceptable post-thaw motility in samples frozen after 4 days of storage, contributing to the development of valuable ARTs for lizards and other reptiles.

Cryopreservation and Laser Nanowarming of Zebrafish Embryos Followed by Hatching and Spawning

This study shows for the first time the ability to rewarm cryopreserved zebrafish embryos that grow into adult fish capable of breeding normally. The protocol employs a single injection of cryoprotective agents (CPAs) and gold nanorods (GNRs) into the yolk and immersion in a precooling bath to dehydrate the perivitelline space. Then embryos are encapsulated within CPA and GNR droplets, plunged into liquid nitrogen, cryogenically stabilized, and rewarmed by a laser pulse. Postlaser nanowarming, embryos (n = 282) exhibit intact structure by 1 h (40%), continued development after 3 h (22%), movement after 24 h (11%), hatching after 48 h (9%), and swimming after Day 5 (3%). Finally, from fish that survives till Day 5, two larvae are grown to adulthood and spawned, yielding survival comparable to an unfrozen control. Future efforts will focus on improving the survival to adulthood and developing methods to cryopreserve large numbers of embryos for research, aquaculture, and biodiversity preservation.

Cross-species efficacy of a chemically-defined, soy lecithin-based cryomedium for semen banking in imperiled wild felids

Felid semen has historically been frozen using an egg yolk-based cryopreservation medium. However, the use of egg introduces several potential concerns, such as variability in composition, microbial contamination, and regulatory issues. In the present study, our aim was to compare a chemically-defined, soy-based medium (SOY) to a commercial egg yolk-based medium (TEY) for the cryopreservation of sperm in four imperiled small cat species. Semen was collected from adult male cats (n = 6 black-footed cats; n = 6 sand cats; n = 4 fishing cats; and n = 7 Pallas' cats) via electroejaculation, split into two aliquots, and cryopreserved in SOY or TEY. Frozen-thawed samples were evaluated for sperm motility and rate of progressive motility (up to 24 h post-thaw) and acrosome status (0 and 6 h). No difference in post-thaw traits were observed between treatments in all four species. Heterologous IVF using oocytes collected laparoscopically from domestic cats demonstrated no difference among freezing treatments in percentage of mature oocytes that cleaved or the mean number of blastomeres at 48 h post-insemination. More spermatozoa frozen with SOY were bound to the zona pellucida in the sand cat (P = 0.018), but no treatment effect was observed in the other three species. These findings collectively demonstrate that SOY may be a preferable alternative to TEY for sperm cryopreservation in these four wild felid species.

The Comparison of Semen Collection in Electroejaculation, Rectal Massage and Combination of Both Methods in the Critically Endangered Malayan Pangolin, Manis javanica

This article describes the semen characteristics from different collection methods between captive and confiscated Malayan pangolins, Manis javanica. Semen was collected from 15 pangolins; two captive and 13 confiscated individuals at the mean weight of 9.36 ± 1.94 kg. The three semen collection methods employed were electroejaculation, rectal massage and a combination of both techniques. The semen characteristics (mean ± standard deviation) of the Malayan pangolin are volume (73.75 ± 144.57 µL), pH (7.63 ± 0.53), spermatozoa concentration (997.19 ± 728.98 × 10⁶ /mL), total motility (59.60% ± 30.00%), progressive motility (48.95% ± 30.93%), mass motility (3.50 ± 1.50) and live spermatozoa (80.25% ± 13.45%). There was no significant difference in semen characteristics between the three collection methods. The percentages of live spermatozoa were significantly different, suggesting better samples from captive compared to confiscated animals. However, there was no significant difference in spermatozoa kinetics between the captive and confiscated samples, suggesting the potential of utilizing confiscated individuals for gamete recovery to conserve the genetic pool of pangolins. All three methods of semen collection were successfully performed in pangolins and should be considered; however, electroejaculation remains the most consistent method of obtaining semen from the species.

Cryopreservation of ferret (Mustela putorius furo) sperm collected by rectal massage and electroejaculation: Comparison of a decelerating and an accelerating freezing rate protocol

The domestic ferret (Mustela putorius furo) provides a good model for developing new reproductive technologies for use with threatened related species. Such technologies could also be used in the reproductive management of this pet species. The present work reports an improved freezing protocol for ferret sperm. Semen was collected by electroejaculation plus rectal massage (in an attempt to reduce the electrical stimulation necessary) from five adult male ferrets, and then subjected to one of two freezing protocols: (a) from 5 to −35°C at 40°C/min, then from −35 to −65°C at 17°C/min, and finally from −65 to −85°C at 3°C/min—a decelerating freezing rate; and (b) from 5 to − 10°C at 5°C/min, and then from −10 to −130°C at 60°C/min—an accelerating freezing rate. After thawing, the viability and acrosomal integrity of the sperm frozen via the two‐step accelerating method were better than those frozen via the three‐step decelerating method (43.3 ± 3.5% and 71.2 ± 3.4% compared with 29.7 ± 3.7% and 58.8 ± 3.4% respectively; p < .05). No differences were seen between the methods with respect to sperm motility variables; most sperm (>90%) remained static with both freezing methods. In conclusion, although the method with accelerating freezing rate was associated with better post‐thaw sperm viability and acrosome integrity values, neither of the two freezing methods tested provided adequate motility results after thawing. Combining rectal massage with electrical stimuli seemed to reduce the number of the latter required for successful sperm collection.

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.

Optimization of Sperm Cryopreservation Protocol for Peregrine Falcon (Falco peregrinus)

Sperm cryopreservation is a complex process that needs to be adapted to wild and domestic avian species to ensure proper efficiency. Because of its accessibility, the peregrine falcon may be used as a good model for studying other raptor species. To find the most optimal cryopreservation protocol for peregrine falcon ejaculates, sperm parameters such as motility, viability, DNA fragmentation, acrosome integrity, and mitochondrial activity were analyzed under different conditions by varying the freezing method (slow freezing in straws vs. ultrarapid freezing in pellets), thawing conditions (37 °C for 30 s vs. 5 °C for 1 min), type of cryoprotectant (DMA vs. DMSO), and concentration of DMSO (4% vs. 8%). Results show that slow cryopreservation in straws yielded greater percentages (p < 0.05) of motile spermatozoa (22.5% ± 4.4% vs. 0.0% ± 4.1%), viable spermatozoa with intact acrosomes (84.6% ± 4.3% vs. 77.4% ± 4.3%), and spermatozoa with active mitochondria (41.0% ± 6.7% vs.12.8% ± 6.7%), compared with those obtained by the ultrarapid freezing in pellets. However, no differences were found between different thawing conditions. Moreover, all sperm motility parameters were greater (p < 0.05) when DMSO was used during freezing compared with DMA, although the use of 3% and 8% DMSO produced similar results. In conclusion, these results represent important progress in the study of falcon semen cryopreservation protocol, highlighting the crucial steps of the process and the most suitable conditions.

Evaluating amphibian biobanking and reproduction for captive breeding programs according to the Amphibian Conservation Action Plan objectives

The Amphibian Conservation Action Plan (ACAP), published in 2007, is a formal document of international significance that proposed eleven relevant actions for global amphibian conservation. Action seven of the ACAP document addresses the use of amphibian captive programs as a conservation tool. Appendix material under this action explores the potential use of Genome Resource Banking (biobanking) as an urgently needed tool for these captive programs. ACAP proposed twelve objectives for Genome Resource Banking which exhibit little emphasis on reproduction as a vital underlying science for amphibian Captive Breeding Programs (CBP's). Here we have reassessed the original twelve ACAP objectives for amphibian reproduction and biobanking for CBP's as a contribution to future ACAP review processes. We have reviewed recent advances since the original objectives, as well as highlighted weaknesses and strengths for each of these objectives. We make various scientific, policy and economic recommendations based on the current reality and recent advances in relevant science in order to inform future ACAP towards new global objectives. The number of amphibian CBP'S has escalated in recent years and reproductive success is not always easily accomplished. Increases in applied and fundamental research on the natural history and reproductive biology of these species, followed by the appropriate development and application of artificial reproductive technologies (ART's) and the incorporation of genome resource banks (GRB's), may turn CBP's into a more powerful tool for amphibian conservation.

Optimal concentration of Rho-associated coiled-coil kinase (ROCK) inhibitor improved sperm membrane functionality and fertilizing ability of cryopreserved-thawed feline sperm

Sperm cryopreservation induces irreversible loss of viability and fertilizing ability. This study aimed at examining the effects of Rho-associated, coiled-coil kinase (ROCK) inhibitor on quality of frozen-thawed feline sperm. Ejaculated semen from individual cats (n = 6) was examined for the expression of LIMK1 and LIMK2 mediated ROCK cascade. The effects of ROCK inhibitor during cooling and cryopreservation on sperm quality and fertilizing ability were also examined. Feline sperm were treated with different concentrations of ROCK inhibitor (10, 20 and 40 μM) during cooling at 4 °C and cryopreservation. Sperm cooled and conventionally cryopreserved without ROCK inhibitor (0 μM) served as a control group. The ROCK cascade was confirmed in feline sperm as they expressed mRNA of LIMK1 and LIMK2 genes. Cryopreservation significantly reduced sperm quality in terms of viability (91.63 ± 3.96 vs. 60.11 ± 8.93), progressive motility (91.67 ± 3.54 vs. 46.67 ± 8.66) and acrosome integrity (93.49 ± 3.64 vs. 63.81 ± 5.31) for fresh and frozen-thawed sperm, respectively (p < 0.05). The positive effects of ROCK inhibitor on sperm quality were pronounced at 1 and 3 h post-thaw. ROCK inhibitor at 10 μM significantly improved sperm motility and membrane functionality compared to those observed in a control group (0 μM) (p < 0.05). In vitro fertilization revealed that supplement ROCK inhibitor at 10 μM during cryopreservation significantly improved in vitro fertilizing ability of the frozen-thawed sperm (p < 0.05). However, it did not subsequently increase morula and blastocyst rates (p > 0.05). Increased concentrations of ROCK inhibitor to 20 and 40 μM did not further improve the quality of frozen-thawed sperm. In conclusion, an optimal concentration (10 μM) of the ROCK inhibitor added into cooling medium could improve post-thaw sperm quality.

Semen cryopreservation in golden-headed lion tamarin, Leontopithecus chrysomelas

Wild animal genetic resource banking (GRB) represents a valuable tool in conservation breeding programs, particularly in cases involving endangered species such as the golden-headed lion tamarin (Leontopithecus chrysomelas). Thus, we aimed to assess a sperm freezing protocol for golden-headed lion tamarins using two different exenders: BotuBOV® (BB) and Test Yolk Buffer® (TYB). Ejaculates were collected by penile vibrostimulation from animals housed at São Paulo Zoological Park Foundation, São Paulo, Brazil, and after immediate analysis, two aliquots were diluted in BB and TYB. Postthawing samples were evaluated for total and progressive motility, plasma membrane and acrosome integrities, mitochondrial activity, susceptibility to oxidative stress, and sperm-egg-binding. No differences between BB and TYB were found for most seminal parameters, except for acrosome integrity and susceptibility to oxidative stress (in both cases BB showed higher values). However, in spite of these differences and regardless of the extender used, postthaw sperm motility and viability with the described protocol were encouraging (on average >50% and >80%, respectively), indicating that sperm cryopreservation may be a short-term measure for the conservation of golden-headed lion tamarins.

Assessment and preservation of liquid and frozen-thawed Black crested mangabey (Lophocebus aterrimus) spermatozoa obtained by transrectal ultrasonic-guided massage of the accessory sex glands and electroejaculation

The Black Crested Mangabey (Lophocebus aterrimus) is an African monkey listed as Near Threatened by the IUCN and in captivity the population is limited to 34 males. The aim of this study was to evaluate two Black Crested Mangabey males, maintained in captivity in a zoological garden and suspected of infertility, with a complete examination of their genital tract using ultrasonography, followed by recovery of semen using transrectal ultrasonic massage of the accessory sexual glands (TUMASG) and electroejaculation. One male had small testicular and accessory sex gland sizes indicative of senile hypoplasia. The other male was suspected of infertility. Four semen samples were obtained. Fresh semen was initially evaluated, diluted in Refrigeration Medium Test Yolk buffer, cooled at 15 °C and cryopreserved. Endocrine profiles (testosterone, oestradiol, FSH, LH, cortisol), prostatic specific antigen and semen variables (volume, concentration, motility by CASA, viability and acrosome status using flow cytometry, morphology, morphometry utilising TEM) were evaluated in raw, cooled and cryopreserved samples. There was no detrimental effect of cooling or cryopreservation on sperm viability and acrosomal integrity. Similar percentages of viable and acrosome-intact spermatozoa were present in cooled (for 6 h) and frozen-thawed semen samples (75.1% compared with 69.0%, P > 0.05), while progressive motility was greater in cooled, compared with frozen-thawed samples (81.5% compared with 67.3%). This study was the first in which there was evaluation of sperm variables in this species and, although this study is limited by the number of animals it provides background information for further studies using assisted reproductive technologies.

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%.

Advancing the science behind animal program sustainability: An overview of the special issue

Over the last ten years, zoos and aquariums around the world have been coming to grips with the "sustainability crisis" - the realization that most of our collaboratively managed animal populations are not viable for the long-term. Many initiatives have been launched at the regional, zoological association, program, and institutional levels to improve the long-term trajectories of these populations. This Special Issue of Zoo Biology highlights some of the scientific approaches that are aimed at addressing population viability and sustainability challenges. The approaches range from development of new analytical tools, to analysis of large datasets, and re-examination of population management principles and philosophies. While much progress has been made in the last ten years, it is clear that continued work on population viability and sustainability is critical and difficult management decisions must be made. In this paper, we identify some of the actions that the zoological community can take to fortify our animal programs and prevent the outright extinction of species.

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.

Tolerance of lamb and mouse oocytes to cryoprotectants during vitrification

SummaryMouse and lamb oocytes were vitrified with, or exposed to, different cryoprotectants and evaluated for their effects on their survival and developmental competence after in vitro fertilization (IVF) and activation treatments. Control oocytes remained untreated, whilst the remainder were exposed to three different combinations of vitrification solutions [dimethyl sulfoxide (DMSO) + ethylene glycol (EG), EG only, or propanediol (PROH) + EG] and either vitrified or left unfrozen (exposed groups). Oocytes in the control and vitrified groups underwent IVF and developmental competence was assessed to the blastocyst stage. In lambs, survival rate in vitrified oocytes was significantly lower than for oocytes in the exposed groups (P &lt;0.05). Blastocyst development was low in vitrified oocytes compared with controls (&lt;6% vs 38.9%, P &lt;0.01). Parthenogenetic activation was more prevalent in vitrified lamb oocytes compared with controls (P &lt;0.05). No evidence of zona pellucida hardening or cortical granule exocytosis could account for reduced fertilization rates in vitrified lamb oocytes. Mouse oocytes demonstrated a completely different response to lamb oocytes, with survival and parthenogenetic activation rates unaffected by the vitrification process. Treatment of mouse oocytes with DMSO + EG yielded significantly higher survival and cleavage rates than treatment with PROH + EG (87.8% and 51.7% vs 32.7% and 16.7% respectively, P &lt;0.01), however cleavage rate for vitrified oocytes remained lower than for the controls (51.7% vs 91.7%, P &lt;0.01) as did mean blastocyst cell number (33 ± 3.1 vs 42 ± 1.5, P &lt;0.05). From this study, it is clear that lamb and mouse show different tolerances to cryoprotectants commonly used in vitrification procedures, and careful selection and testing of species-compatible cryoprotectants is required when vitrifying oocytes to optimize survival and embryo development.

Collection planning for the next 100 years: What will we commit to save in zoos and aquariums?

The "sustainability crisis" in zoos and aquariums has been a sobering reminder of how limited our resources are for maintaining viable populations of species threatened with extinction. This, combined with increasing concern among the public about the value of zoos and aquariums, suggests that the zoological profession should engage in a thorough re-examination of our guiding principles, philosophies, and practices with regard to collection planning at global, regional, and institutional scales. An analysis of AZA cooperative breeding programs reveals that in order to make these populations viable, many more founders and tens of thousands more spaces for animals, either in existing facilities or new ones, are necessary if we want to maintain all of the species that are covered by cooperative breeding programs currently. Regional zoological associations and their associated cooperative breeding programs must be more strategic and make more scientifically defensible decisions about which species to try and safeguard in zoos and aquariums. This would enable the zoological profession to give society a "Promise List" of species that we will commit to save from total extinction. Developing such a list will require a collaborative, inclusive process that transcends zoological regions. Regional association leaders, zoo & aquarium directors, and curators must make commitments to safeguard the species on the Promise List regardless of other interests. As our profession re-examines its philosophies and practices and finds ways to increase its capacity to provide refuge for species facing extinction in the wild, it may be possible to expand the Promise List.

Comparison of soy lecithin, coconut water, and coconut milk as substitutes for egg-yolk in semen cryodiluent for black rhinoceros (Diceros bicornis) and Indian rhinoceros (Rhinoceros unicornis)

Semen cryopreservation for the black rhinoceros (Diceros bicornis) and Indian rhinoceros (Rhinoceros unicornis) relies on extenders containing egg-yolk (EY). Use of such media is not ideal as inter-batch composition varies and there is risk of pathogenic contamination. The goal of this study was to test animal protein-free extenders. Semen collected via electroejaculation from 10 rhinoceros (6 black, 4 Indian) was diluted with extender containing EY, 1% or 2% soy lecithin (1%SL; 2%SL), coconut water (CW), or coconut milk (CM), cryopreserved and evaluated for sperm motility, viability, morphology, progression, and acrosomal integrity at 0, 1, 3, 6 and 24 h post-thaw. Mean ± SD fresh ejaculate motility was 84.5 ± 7.6%, progression: 3.6 ± 0.6 (scale 0-5), viability: 83.4 ± 7.1%, intact acrosomes: 71.3 ± 6.9%, and morphologically normal: 78.8 ± 13.6%. Motility and progression decreased in all groups post-thaw, were greatest in EY, and decreased over time (P ≤ 0.05). Motility and progression did not differ (P > 0.05) between 1%SL and 2%SL, but were lower (P ≤ 0.05) in CM and CW, and acrosomal integrity was higher (P ≤ 0.05) in EY, 1%SL and 2%SL than in CM and CW. Post-thaw viability was greatest in EY and 2%SL followed by 1%SL, then CM and CW (P ≤ 0.05). Morphology did not differ among treatments (P > 0.05). Morphology, acrosomal integrity, and viability were maintained over time (P > 0.05). Although some rhinoceros sperm survived cryopreservation in SL treatments, reduced post-thaw motility rendered all treatments inadequate substitutes for EY-based extenders.

Urinary specific gravity as an alternative for the normalisation of endocrine metabolite concentrations in giant panda (Ailuropoda melanoleuca) reproductive monitoring

Reproductive monitoring for captive breeding in giant pandas is based on behavioural observation and non-invasive hormone analysis. In urine, interpretation of results requires normalisation due to an animal’s changing hydration. Correction of urinary concentrations based on creatinine is the gold standard. In this study, a largely unexplored, easy-to-perform normalisation technique, based on urinary specific gravity (USpG), was examined and compared to creatinine. To this extent, six cycles from two female pandas (SB741(1) and SB569(5)) were monitored through urine analysis for oestrogen, progesterone, ceruloplasmin and 13,14-dihydro-15-keto-PGF2a (PGFM). The Pearson’s correlation between creatinine and USpG was high (r = 0.805–0.894; p < 0.01), indicative for a similar performance of both normalisation methods. However, generally lower values were observed during pro-oestrus and primary (progesterone) rise. This could be associated with huge shifts in appetite, monitored by faecal output (kg) with an averaged > 50% decrease during oestrus and >50% increase during primary progesterone rise. In parallel, respectively highest and lowest creatinine and USpG levels, were measured, with creatinine obviously more affected as a result of linkage with muscle tissue metabolism affected by reproductive hormones. As a consequence, metabolite levels were significantly different between both corrected datasets with significantly higher oestrogen peak levels during oestrus ranging from 2.13–86.93 and 31.61–306.45 ng/mL (USpG correction) versus 2.33–31.20 and 36.36–249.05 ng/mL Cr (creatinine correction) for SB569 and SB741 respectively, and significant lower progesterone levels during primary progesterone rise ranging from 0.35–3.21 and 0.85–6.80 ng/mL (USpG correction) versus 0.52–10.31 and 2.10–272.74 ng/mL Cr (creatinine correction) for SB569 and SB741 respectively. Consequently, USpG correction rendered unbiased profiles, less subject to variation and metabolic artefacts and therefore allowed a more straightforward identification of peak oestrogen and onset of secondary progesterone rise, being potentially advantageous for future studies unravelling key giant panda reproductive events, including (delayed) implantation. The alternative application of USpG as a normalisation factor was further supported by its easy application and environmental and technical robustness.

Multi-year longitudinal profiles of cortisol and corticosterone recovered from baleen of North Atlantic right whales (Eubalaena glacialis)

Research into stress physiology of mysticete whales has been hampered by difficulty in obtaining repeated physiological samples from individuals over time. We investigated whether multi-year longitudinal records of glucocorticoids can be reconstructed from serial sampling along full-length baleen plates (representing ∼10years of baleen growth), using baleen recovered from two female North Atlantic right whales (Eubalaena glacialis) of known reproductive history. Cortisol and corticosterone were quantified with immunoassay of subsamples taken every 4cm (representing ∼60d time intervals) along a full-length baleen plate from each female. In both whales, corticosterone was significantly elevated during known pregnancies (inferred from calf sightings and necropsy data) as compared to intercalving intervals; cortisol was significantly elevated during pregnancies in one female but not the other. Within intercalving intervals, corticosterone was significantly elevated during the first year (lactation year) and/or the second year (post-lactation year) as compared to later years of the intercalving interval, while cortisol showed more variable patterns. Cortisol occasionally showed brief high elevations ("spikes") not paralleled by corticosterone, suggesting that the two glucocorticoids might be differentially responsive to certain stressors. Generally, immunoreactive corticosterone was present in higher concentration in baleen than immunoreactive cortisol; corticosterone:cortisol ratio was usually >4 and was highly variable in both individuals. Further investigation of baleen cortisol and corticosterone profiles could prove fruitful for elucidating long-term, multi-year patterns in stress physiology of large whales, determined retrospectively from stranded or archived specimens.

Population estimate and morphometry of ovarian preantral follicles from three recently recognized squirrel monkey species: a comparative study

We describe morphological and morphometrical characteristics of preantral ovarian follicles from three recently recognized Saimiri species: S. macrodon, S. cassiquiarensis and S. vanzolinii; the last one a threatened species. Ovaries from four adult monkeys were evaluated: one pair from a pregnant S. macrodon, two ovarian pairs from S. cassiquiarensis females (one of them pregnant), and one left ovary from a senile S. vanzolinii, applying classical histology. Follicular preantral population was quantified and morphology and morphometry of primordial, primary and secondary follicles were evaluated. Follicular preantral population varied among species, being 347,153 in the ovaries of the S. macrodon, 270,342 and 278,376 in the ovaries of both adult non-pregnant and pregnant S. cassiquiarensis females, and 28,149 in the ovary from a senile S. vanzolinii. Most follicles were at primordial or transition stages, except for the senile S. vanzolinii female, which presented the lowest percentages of primordial and transition follicles when compared with primary and secondary ones. Most preantral follicles (>70%) were morphologically normal in the ovaries from all studied S. macrodon and S. cassiquiarensis females, but the ovary of the senile S. vanzolinii female presented a significant decrease in the percentage of normal follicles (primordial: 61%, transition: 52%, primary: 54%, and secondary: 48%). In general, follicular diameter increased significantly from primordial to transition, and subsequently from primary to secondary follicles.

Follicular size predicts success in artificial insemination with frozen-thawed sperm in donkeys

In asses, semen collection, cryopreservation, and artificial insemination (AI) with frozen-thawed semen have been scarcely described and success rate, particularly following AI, is reportedly low. In the absence of reliable protocols, assisted reproductive technologies cannot support the conservation efforts aimed at endangered wild ass species and domestic donkey breeds. Two experiments were conducted in this study. In experiment 1 we evaluated freezing Abyssinian donkey (N = 5, 4 ejaculates each) spermatozoa using three freezing extenders (Berliner Cryomedium + glycerol, BC+G; BotuCrio, BOTU; INRAFreeze, INRA) and two cryopreservation techniques (liquid nitrogen vapour, LNV; directional freezing, DF). Post-thaw evaluation indicated that BOTU and INRA were similar and both superior to BC+G (P ≤ 0.004 for all motility tests), and that DF was superior to LNV (P < 0.002 for all evaluation parameters). In experiment 2, relying on these results, we used Abyssinian donkey sperm frozen in BOTU and INRA by DF for AI (N = 20). Prior to AI, thawed samples were diluted in corresponding centrifugation media or autologous seminal fluids at 1:1 ratio. No difference was found between BOTU and INRA or between the addition of seminal fluids or media, all resulting in ~50% pregnancy, and no differences were noted between males (N = 4). The size of pre-ovulatory follicle was a significant (P = 0.001) predictor for AI success with 9/10 pregnancies occurring when follicular size ranged between 33.1-37.4 mm, no pregnancy when it was smaller, and only one when larger. A number of ass species face the risk of extinction. Knowledge gained in this study on the Abyssinian donkey can be customised and transferred to its closely related endangered species and breeds.

Non-invasive hormonal characterization of the ovarian cycle, pregnancy, and seasonal anestrus of the female addra gazelle (Nanger dama ruficollis)

Non-invasive fecal hormone metabolite monitoring was used to characterize the estrous cycle, pregnancy, and seasonal anestrus of the critically endangered addra gazelle (Nanger dama ruficollis). With less than 250 animals remaining in the wild and ∼168 individuals managed in captivity, it is crucial to maintain sustainable populations. Progestogen and estrogen profiles were obtained from analysis of fecal samples collected approximately every other day, within varying intervals, over the course of 7 years (n = 8 adult females). Average estrous cycle length was 19.5 ± 0.4 days (range, 14-26 days), with a luteal phase length of 14.6 ± 1.2 days (range, 10-16 days), and an inter-luteal period of 5.2 ± 1.4 days (range, 2-7 days). Mean gestation length for six pregnancies was 200.7 ± 0.4 days (range, 200-202 days). Fecal progestogens increased at 12 weeks of gestation and remained elevated until parturition. Addra gazelle females exhibited a period of seasonal anestrus with consistently low progestogen concentrations and no cyclic activity from about September to March. Analysis of reproductive and climate records demonstrated a peak in U.S. births that coincided with maximal rainfall in the native habitat of the addra gazelle. Results show that estrous cycle, luteal phase, and inter-luteal phase lengths in addra are similar to those observed in other gazelle species, however, to our knowledge, this is the first study to demonstrate seasonal anestrus in the Nanger genus.

Urethral catheterization and sperm vitrification for simplified semen banking in felids

Semen banking of domestic cats and wild felids represents a vital resource for their long-term conservation, but current methods require access to advanced training and specialized equipment. A newer method of semen collection, urethral catheterization of medetomidine-treated cats, allows recovery of high sperm numbers, but it is unclear if this approach permits maximal sperm recovery or is feasible using less expensive alpha-2 agonists. Similarly, a newer sperm preservation approach, vitrification, offers advantages of simplicity and minimal equipment needs, but its efficacy in combination with urethral catheterization has not been investigated. Our specific objectives were to (i) evaluate sequential semen recovery with urethral catheterization and electroejaculation in domestic cats, (ii) assess the effectiveness of a weak (xylazine) versus strong (dexmedetomidine) alpha-2 agonist for inducing sperm release, and (iii) compare post-thaw sperm motility, acrosome status and fertilizing capacity of catheter-recovered samples after vitrification or straw freezing. Results indicated that electroejaculation following repeated catheterization allowed recovery of additional spermatozoa (range, 11-32 × 10⁶  sperm/male) and that xylazine was ineffective for inducing meaningful sperm release (range, 0-0.4 × 10⁶ sperm/male). Post-thaw motility and acrosome status of vitrified catheter samples did not differ (p > .05) from that of straw frozen samples. Preliminary results indicated that in vitro fertilization success (9/30, 30%) of vitrified catheter sperm did not differ (p > .05) from that observed with straw frozen samples (17/30, 57%). In conclusion, urethral catheterization of dexmedetomidine-treated cats allows recovery of substantial sperm numbers but electroejaculation still may be warranted for maximal sperm recovery. Xylazine is not suitable as an inexpensive alternative to dexmedetomidine for catheterization. Vitrification of catheter samples results in comparable post-thaw parameters to straw freezing and may be adequate for use with oviductal insemination procedures.