Theriogenology wild最新文献

This review summarizes the available literature on the knowledge of reproduction in white whales or belugas (Delphinapterus leucas). We discuss reproductive anatomy, physiology, endocrinology, and behavior prior to conception. Following a description of these basic reproductive parameters for each sex, the review describes the mating system of belugas as it is currently understood and summarizes the ontogeny of reproductive behavior and its relationship with hormones. Finally, we highlight gaps that currently exist in our functional understanding of reproductive behavior in belugas. Future research emphasizes the need to understand mate choice in belugas and how it manifests across the lifespan and potentially settings. Specifically, does the quality of belugas’ display behaviors influence reproductive success? Managing wild populations of belugas and caring for belugas in human care both benefit from the knowledge that can be gained from the research topics discussed in this review.

Assisted reproductive technologies enable the transportation and exchange of genetic material, so it is an essential complementary tool in conservation programs. Unfortunately, the difficulty of accessing a significant number of animals under suitable physiological conditions hampers the advancement of these technologies. Pharmacological semen collection in jaguars is effective in acquiring a sufficient amount of sperm. However, the outcomes of artificial insemination (AI) and in vitro fertilization operations are impacted by poor sperm quality and limited freezability of the cells. Hormonal stimulation with eCG and hCG may be used to collect oocytes in jaguars; however, proximity to males influences ovarian response to exogenous hormones. Thus, the non-copulatory ovulation stimuli pattern must be considered in AI and laparoscopic ovum pick-up protocols in this species. Somatic cells may be an alternative for biobanks since they are easier to collect and transport and can be obtained from any age, sex, or origin of an animal, including post-mortem samples. Our research group recently succeeded in cultivating cells from three jaguars that were found dead on highways, demonstrating that cultivation is effective even in degenerating tissues. In this instance, xenotransplantation of cryopreserved fragments improved culture effectiveness and brought cell quality back up to par with that of fresh tissue.

Monitoring wildlife health in remote and vast regions of the Arctic can be difficult and expensive, but community-based monitoring programs can help alleviate these issues. Reliable bio-monitoring tools, compatible with sample types collected from remote regions, are needed to determine indicators of population health, such as reproductive rates. We sought to establish methods to diagnose pregnancy in muskoxen (Ovibos moschatus) using samples that are commonly collected in harvester-based sampling programs: blood on filter paper and feces. We first evaluated three pregnancy tests, pregnancy-associated glycoproteins (PAG) on filter paper blood samples and fecal progesterone and estrogen metabolites (FPM and FEM), using 12 captive female muskoxen of known pregnancy status. Pregnancy diagnostics using PAG were highly sensitive (100 %) and specific (100 %), with a diagnostic threshold of 19.4 percent positivity (%P) relative to the positive control of the test kit. FPM and FEM diagnostic accuracy differed by hormone and time period. FPM was most accurate in mid-gestation and FEM most accurate in late gestation (sensitivities and specificities of 100 %), but both were overall less accurate than the PAG test during gestation. PAG %P followed a biphasic pattern during gestation, FPM peaked in mid-gestation, and FEM peaked in late-gestation. Following the captive trial, we applied these tests to fecal samples and blood on filter paper samples from 159 adult female muskoxen that were submitted by harvesters through community-based monitoring programs in the Canadian Arctic. The observed patterns of PAG, FPM, and FEM in wild muskoxen throughout gestation were similar to captive muskoxen, though with lower levels of the respective biomarker, requiring different diagnostic thresholds for each test. This work with captive and wild muskoxen provides guidelines for pregnancy diagnostics in muskoxen throughout gestation using samples that can be easily collected by harvesters, allowing for improved monitoring of difficult to access populations through community-based approaches.

Fishes are by far the most species-rich group of vertebrates, with 36,105 species currently recognised, approximately the same number of species as that of all non-fish vertebrates combined. Recent decades have witnessed dramatic population declines for many fish species, together with a loss in overall fish biodiversity. Globally, fish biodiversity is being threatened by a multitude of anthropogenic impacts including overfishing, habitat loss, pollution, aquaculture, loss of river connectivity, climate change and the impact of alien species. Nowhere is the world’s biodiversity crisis more acute than in freshwater ecosystems. While rivers, lakes and wetlands cover less than 1% of the planet’s total surface, they are home to over half the world´s fish species. One third of freshwater fishes are now threatened with extinction, and 80 species are already extinct. This review covers the main drivers of declining fish biodiversity, and details remedial strategies aimed at conserving both marine and freshwater fish biodiversity. The preservation of genetic resources through the cryobanking of reproductive cells and tissues, collectively known as germplasm, will be a valuable tool in the conservation of fish biodiversity. With the help of a range of emerging reproductive technologies, frozen germplasm will play a key role in future in situ and ex situ conservation initiatives. The ability to establish cryo-banks for the full range of fish germplasm, including sperm, oocytes, embryos and germ cells represents a powerful tool for use in the conservation of threatened fish species. The rapid advance in next-generation sequencing technologies, together with the proliferation of resources such as fully sequenced fish genomes is expected to result in a rapid expansion in the application of conservation genomics to the conservation and management of fish populations, and be instrumental in formulating mitigations directed at conserving fish biodiversity, through both in situ and ex situ conservation initiatives.

The increasing presence of pumas (Puma concolor) in ex situ environments poses challenges in managing individual accommodations, necessitating contraceptive practices to allow more individuals to cohabit in the same enclosure. The current pioneering study aimed to assess the effectiveness of laparoscopic tubal ligature (LTL) as a contraceptive alternative to vasectomy in pumas. It sought to contribute to ex situ conservation strategies by enabling the cohabitation of couples without reproduction. With appropriate management authorizations and ethical evaluation, the LTL technique was applied to three adult females, followed by ovarian hormonal stimulation and laparoscopic ovum pick-up (LOPU). The findings affirmed the efficacy and safety of LTL, which proved to be a robust contraceptive method without postoperative complications and effective in preventing gestation after multiple matings attempts. Notably, the ovarian function was preserved, allowing for successful oocyte collection via LOPU. This approach offers a less invasive alternative to traditional surgical ligature, aligning more closely with ethical standards for animal conservation by allowing for the minimally invasive acquisition of female gametes and embodying the One Conservation concept, which advocates a holistic approach to reproductive conservation.

Phractocephalus hemioliopterus, Hemisorubim platyrhynchos, and Zungaro zungaro are native of South American rivers whose population is being threatened by the damming of rivers to build hydroelectric dams, fishing pressure and environmental degradation. Basic information on these species’ reproductive characteristics is necessary to enable production in captivity. The aim of this study was to present descriptive data regarding the sperm parameters of these three species maintained in captivity, the correlations between these parameters, and relevant factors, and how these issues can affect sperm quality. Sperm was collected and diluted in Beltsville Thawing Solution after hormonal induction with carp pituitary extract. The evaluated parameters for Hemisorubim platyrhynchos, Phractocephalus hemioliopterus, and Zungaro zungaro were, respectively: Sperm concentration (×10⁹) was 3.00, 1.77, and 1.40 sperm mL⁻¹; Sperm total length was 93.2, 91.4, and 79.4 μm; Motility rate was 71.8, 73.5, and 61.7%; Normal sperm was 35.5, 38.8, and 30.2%. Describing sperm characteristics is extremely important for the artificial reproduction of fish in captivity, contributing to the knowledge on the reproductive biology of the species. In the present study, we discuss these issues to build the knowledge necessary for sperm characterization of these little-studied species. Our results suggest that the morphological abnormalities can affect motility and sperm movement kinetics.

Okapi (Okapia johnstoni) belong to the Giraffidae family and is the only representative of the Okapia genus. The species has been declared as endangered and due to its very elusive nature, little is known about its reproductive behavior. The wild population has continued to decrease over the last decades despite the different conservation programs developed worldwide. Captive breeding is difficult and the European population is not self-sustaining. An alternative tool to prevent the extinction of this charismatic species is the use of assisted reproductive technologies (ART). Specifically, we introduce a novel protocol for the in vitro maturation (IVM) and cryopreservation of matured oocytes obtained post-mortem. Out of sixteen cumulus-oocytes complexes isolated from one deceased individual, four matured metaphase II (MII) oocytes were successfully obtained following IVM. Furthermore, these matured oocytes demonstrated resilience during the vitrification/warming process and underwent sperm injection. Although no embryos were obtained, this study represents the first step towards the application of ART in okapi, providing a foundation for future reproductive interventions aimed at preserving self-sustaining captive populations.

Female rhinoceroses have an ovarian reserve that consists of immature oocytes in primordial follicles. Establishing methods to grow and culture these oocytes from those follicles in the laboratory might fuel efforts towards in vitro embryo production in this species without the need for repeated in vivo oocyte collection. In depth understanding of the biology behind and improvement of assisted reproductive techniques (ARTs) is the only option for preventing the disappearance of functionally extinct species such as the northern white rhinoceros. In vitro follicle development can only be obtained by in depth knowledge on rhinoceros ovarian histology. In addition to known ovarian features, we identified numerous undescribed structural and molecular ovarian characteristics from adult southern white rhinoceros (n=3). Ovarian sections were stained with H&E, PAS or Masson Trichrome and molecular analyses (hyaluronic acid detection, immunohistochemistry and TUNEL assay) were performed to identify proliferation, extracellular matrix, pluripotency markers, hormones, enzymes, markers for inflammation or endocrine glands, blood vessel presence, oocyte markers and apoptosis. Besides degenerating, deformed, or luteinized follicles, analysis revealed several ‘follicle-like structures’ (FLS) that deviated from the expected follicle appearance. Most importantly, the majority of FLS did not contain any oocyte and were comprised of a collection of cells organised around fluid islands with or without an antral cavity. The discovery and description of FLS in aged southern white rhinoceroses may play a role in poor oocyte recovery rates in ovum pick-up (OPU) in older rhinoceroses. It remains to be investigated whether FLS might be present on ovaries from other rhinoceros species and whether they might serve as a general indicator for oocyte recovery success in aged females.

This study explored the relationships between sperm quality and the activities of antioxidant enzymes (superoxide dismutase, SOD, and glutathione peroxidase, GPx) in sperm (S) and seminal plasma (SP) of Asian elephants, as well as the potential protective role of glutamine in semen extenders during chilled storage. In experiment 1, twenty ejaculates from 11 bulls were analyzed for percentages (%) of sperm motility (%MOT), viability (%VIA), and activities of SOD and GPx. A significant negative correlation was found between %VIA and SP-SOD (r = − 0.71), and positive correlations between %MOT and both S-GPx (r = 0.49) and SP-GPx (r = 0.57). Following these findings, glutamine, a precursor of glutathione and semen antioxidant was introduced in Experiment 2. Each ejaculate (in a total of 8 ejaculates obtained from four bulls) was diluted in Tris-fructose- (EYT) and Tris-glucose-egg yolk extender (TCG), respectively, supplemented with 0 (control), 20 and 40 mM glutamine and stored at 4 °C. Sperm parameters including %MOT, %VIA, functional membrane integrity (%sHOST), and DNA integrity (%DNA) were assessed after 24 and 48 h of storage. Results demonstrated that glutamine did not significantly affect %VIA or %DNA. A significant reduction in %MOT was observed at 24 h, but 20 mM glutamine added in extenders reversed this decline at 48 h. A 40 mM addition of glutamine in TCG markedly reduced %sHOST at 24 h. In conclusion, SOD and GPx activities in the sperm and seminal plasma are indicative of sperm quality. During chilling, using a higher level of glutamine may damage the spermatozoa of Asian elephants.

Prolactin is a protein hormone that plays a regulating role in many physiological processes across mammalian species, but the two primary functions it exerts are the development of the mammary glands and milk production. This review will focus on the potential key role of prolactin in the hormonal control of maternal investment and survival in mammals. Prolactin has been demonstrated to influence maternal investment throughout the complete investment process from ovulation and implantation to gestation and lactation, highlighting its essential role in this balance. Different stressors may affect prolactin secretion, and therefore, be a trigger to lower or stop maternal investment. Hence, comprehending prolactin's function in maternal investment and survival strategies can have important implications for our understanding of reproductive success and failure, potentially benefiting conservation efforts to protect endangered species. Since the role of prolactin is inconsistent in different mammalian species, species-specific research is mandatory to determine the exact role of prolactin in individual maternal survival-investment strategies. The current knowledge on this topic is highlighted in the present review but is also illustrative of the fact that many areas of prolactin related research remain underexposed.