Theriogenology wild最新文献

Photoperiod is the most reliable environmental cue, though other environmental factors may affect breeding. We hypothesized that exposure to high temperatures at the photorefractory stage suppresses photoperiodic responses during the photostimulatory phase. Male adult photorefractory tree sparrows (n=10/group) were exposed to short photoperiod (SD;16 L:8D) but either high (30 ± 2 ⁰C) or low temperature (20 ± 2 ⁰C) for five or seven weeks and then long photoperiod (LD; 16 L:8D) for 30 days. mRNA levels of thyroid-stimulating hormone-β (Tshβ), type 2 deiodinase (Dio2), type 3 deiodinase (Dio3), gonadotropin-releasing hormone (GnRh), gonadotropin inhibitory hormone (GnIh), and EYA transcriptional coactivator and phosphatase 3 (Eya3) were measured in hypothalamic and expression levels of StAR, ER, CYP17, CYP11B, FOXOL1, and Nr4A1 were measured in the testes. Results show that exposure to 5 weeks of high temperature coupled with Short days suppresses expression of Tshβ, Dio2, and GnRh in the hypothalamus and StAR, ER, CYP17A1, and CYP11B in the testes under long days. No such effects were observed in birds exposed to high temperatures along with SD for seven weeks. These findings suggest that exposure to high temperature during the photorefractory stage modulates photoperiodic responses during the photostimulatory stage in time dependent manner.

Effective management practices are critical for the successful reproduction of animals in captivity or in in situ environments. One of the techniques used in egg quality control is candling. In ex situ reproduction of Kinosternon scorpioides, it is important to establish incubation protocols, which, through egg management, allow control of embryonic development and improved birth rates. We incubated eggs and monitored embryonic development of K. scorpioides through egg candling. Fertile eggs were incubated, and candling analyses were performed weekly. Embryonic development in the early stages (first third of incubation) presented the following characteristics: presence of the vitelline circulatory system, expansion of this system, and descent of the embryo onto the yolk. Then, in the middle stages (second third of incubation), the intense pigmentation of the embryo was observed, with the body moving to prone position. Subsequently, in the late stages, the embryo grew, filling a large part of the internal space of the egg. The incubation period took on average 116.50 ± 13.11 days. Candling can be used to monitor the embryonic development of K. scorpioides. It is a useful tool to improve the production of hatchlings, from fertility detection to hatching.

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.

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.

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.

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.