Theriogenology wild最新文献

Companion animals, non-domestic and endangered species (CANDES) encompass a group of animals that do not include traditional livestock species (cattle, pigs, sheep, goats). Historically, lack of commercial interest or need resulted in a lag in the development and application of assisted reproductive technologies (ARTs) in CANDES. A number of factors impeded progress, including the species-specific nature of reproductive biology and difficulties accessing research material. The past 25 years have seen a growth in cell-based technologies (stem cell derivation, genome editing), offering a new horizon of possibilities to the current state-of-the-art for assisted reproduction in CANDES. This review highlights some of the challenges and successes in working with these diverse species.

Despite dipping to perilously low numbers over the past century, all five rhinoceros (rhino) species still survive in the wild with four also in managed breeding programs. These managed populations have been essential for advancing rhino reproductive science and technology. Despite a plethora of challenges and the incremental nature of sound science, researchers have made significant progress over the past quarter century in broadening our knowledge of rhino reproduction, developing new technologies, and expanding the scope of existing research tools. When we compare the state of this scientific field a quarter century ago to where it stands today, there is much to celebrate. For example, at the turn of the century, the Sumatran rhino breeding program had failed to produce a single calf, the first rhino artificial insemination (AI) procedures had just been described, but no pregnancies had been documented, and in vitro fertilization (IVF) had not succeeded in any rhino species. As we reach the end of 2023, 8 Sumatran rhino calves have been born, a total of 17 white and greater one-horned rhino calves have been produced by AI, and 51 white rhino IVF embryos have developed into blastocysts. Furthermore, several theories based on the evidence available at that time have been disproven as additional scientific data have deepened our knowledge and understanding. However, many unanswered questions still exist, and reproductive technologies require refinement, development, or application to additional rhino species, so plenty of challenges remain on the landscape for future generations of rhino reproductive scientists to conquer.

The study of embryonic development in fish and how water temperature affects the life stage in this group is of pivotal importance to support works that aim at the conservation, management, and recovery of endangered or high economic valuable species. It allows a better evaluation of the species and the identification of morphophysiological changes related to the environmental factor in question. In addition, hybridization emerges as a biotechnological tool that may be applied as a technique for the creation of sterile animals that can be used as recipients for the germ cell transplantation approach, thus contributing to the conservation of different fish species. Based on this, we artificially reproduced two Amazonian fish species, Astyanax bimaculatus, and Moenkhausia oligolepis, and the resulting offspring of each species had their embryonic development followed at room temperature (25 °C) and at high temperature (30 °C). In addition, we performed interspecific crossbreeding between the species, and the offspring were also incubated and observed under the above conditions. The results showed that the high temperature accelerates the embryonic development of both, the offspring from A. bimaculatus and from hybridization. However, no larvae survived. Regarding M. oligolepis, the embryos did not develop, dying at 4:40 post-fertilization. For the hybridization, only the crossbreeding between females of A. bimaculatus and males of M. oligolepis resulted in normal larvae. They presented their own morphological characteristics, showing no total or partial characteristics from the parents, besides presenting atrophied and sterile gonads. Heat waters were proven to compromise the embryonic development of both Amazonian species. On the other side, the hybridization between those two Amazonian species has shown to be a tool with great potential for sterilization and the development of individuals suitable for use as surrogate breeders aiming for the ecological maintenance of various fish species.

This study describes the bone development during the intrauterine phase of the black agouti (Dasyprocta fuliginosa), discussing its relationship with the species’ adaptive strategies and comparing it with other precocial and altricial species. We analyzed 33 conceptuses (four embryos and twenty-nine fetuses) obtained through collaboration with local hunters in the Amazon. Mineralization measurements of the axial and appendicular skeletons were performed by ultrasonography using a 10–18 MHz linear transducer. The chronological order of occurrence of mineralization in relation to the total dorsal length (TDL) and to the percentage of the total gestational period (GP) was: skull, ribs, vertebral bodies, clavicle, scapula, humerus, radius, ulna, ilium, ischium, femur, tibia, and fibula (TDL = 8.2 cm, 48 % GP); metacarpi, metatarsi and pubis (TDL = 9 cm, 51 % GP); thoracic and pelvic limb phalanges (TDL = 13.2 cm, 65 % GP); carpus (TDL = 15.10 cm, 72 % GP) and distal row of tarsus (TDL = 19.6 cm, 87 % GP). Mineralization of the patella was not observed in any advanced fetus (fetus with> 80 % GP). Regarding secondary ossification centers, the first signs of mineralization were observed in the distal epiphysis of the radius, distal epiphysis of the femur, and proximal and distal epiphysis of the tibia (TDL = 13.2 cm, 65 % GP). Fetuses at birth (TDL > 21.5 cm, 93.5 % GP) showed mineralization in all primary centers, and in most secondary ossification centers. Black agouti neonates have a high level of precociality with well-developed skeletal system at birth, which promotes independent postnatal locomotion and dexterity to manipulate and forage in search of food. Our results can contribute to the monitoring of bone development in other wild species, providing parameters for the identification of gestational age and serving as a model for comparisons between precocial and altricial mammals, ultimately helping understand life history strategies in different species.

Data on the reproductive physiology of the Brazilian dwarf brocket deer (Mazama nana) is still scarce in many aspects, such as its reproductive cycle and endocrine pattern. Therefore, this study aimed to characterize the estrous cycle (length and fecal progestagen metabolites -FPM- profile) in captive females of M. nana, by non-invasive hormonal monitoring. The study was performed with females (n = 4), housed at two different facilities: 1) in a collective enclosure at the Danilo José Galafassi Municipal Zoo, in Cascavel, Paraná, Brazil, (n = 3). 2) in an individual pen at the Deer Research and Conservation Center (n = 1), from UNESP, Jaboticabal, São Paulo, Brazil. Fecal samples were collected three times a week during two complete estrous cycles, based on behavioral observations. FPM profiles were analyzed by enzyme immunoassay (EIA). The estrous cycle length was defined as the intervals between behavioral estrus observations and fecal hormonal monitoring. The mean duration (± SEM) of the estrous cycle was 23.9 ± 0.6 days, and the mean duration of behavioral estrus was 1.6 ± 0.3 days. Mean concentrations (± SEM) of FPM for the luteal phase and inter-luteal phase were 6183.0 ± 2268.7 ng/g and 754.5 ± 216.1 ng/g, respectively.

With the aim of contributing to the development of assisted reproduction for red-rumped agouti germplasm conservation, we compared different anesthetic protocols for electroejaculation in agoutis in terms of anesthetic parameters, functions of erection and ejaculation, and semen metrics. Ten sexually mature males underwent electroejaculation with 15-day intervals according to the following anesthetic protocols: Ketamine/xylazine, Ketamine/dexmedetomidine, Ketamine/xylazine/epidural anesthesia or Azaperone/meperidine/ketamine/xylazine plus epidural anesthesia. The following variables were evaluated: induction latency period, anesthetic recovery, and duration of epidural anesthesia. Regarding the reproductive variables, erection, the stimulation cycle in which ejaculation occurred, and the semen characteristics were observed. All the protocols were efficient for providing adequate induction of latency (ranging from 1.46 to 13.14 min) and recovery (average 2 h) periods. The use of a premedication did not influence the duration of epidural anesthesia (P<0.05). The administration of an azaperone/meperidine-based premedication prior to epidural anesthesia promoted an increase in the agouti erection process when compared to the other protocols (P < 0.05). All the protocols were efficient in stimulating ejaculation (100 %), even though most ejaculates were aspermic (85 %). The presence of sperm was only observed in 30 % of the animals anesthetized with ketamine/xylazine, 20 % with ketamine/dexmedetomidine, and 10 % with Ketamine/xylazine/epidural anesthesia. Ketamine/xylazine provided a lower volume (201.7±173.4 vs. 810.0±127.3 µL) and greater sperm concentration (270.0±200 vs. 25.0±15.0 × 10⁶ sperm/mL) than Ketamine/dexmedetomidine (P < 0.05). In conclusion, we suggest the use of the standard anesthetic protocol based on the Ketamine/xylazine combination to obtain sperm in red-rumped agouti.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Management of overabundant free-roaming horse (Equus ferus caballus) populations has become a divisive and challenging effort for natural resource managers worldwide. Controlling these populations requires land managers to balance socio-political issues, multiple use management concepts, and endearing affection of horses to some stakeholders against negative ecological alterations created by excessive densities of these animals. One potential solution to this dilemma is controlling the fertility of female horses. During 2013–2020, research was conducted to develop and test a prototype dart configuration system to deliver an effective dose of GonaCon-Equine to free-roaming horses. This remote dart delivery system was demonstrated to be safe and reliable in free-ranging horses with a 90% (71/79) success rate for first attempts and provided the opportunity to design an experiment to determine the long-term effectiveness, reversibility, and physiological side effects of different reimmunization schedules. Five experimental groups of mares were established consisting of a control (n = 25), and a 4-yr reimmunization interval (n = 25) of mares from a previous experiment that were treated with this same vaccine by hand injection in 2013. Additional booster intervals of horses were (2-yr (n = 11), 1-yr (n = 15), and 0.5-yr (n = 14) and vaccinated by remote dart delivery during 2013–2016. Weekly ground observations were utilized to estimate foaling proportions, foal survival, body condition, and injection site reactions related to treatment groups. All GonaCon-Equine booster intervals reduced (P ≤ 0.001) foaling proportions between treated and control mares for all years of the experiment. Effective contraception was also achieved when GonaCon-Equine was applied by remote dart delivery at post-primary intervals shorter than 4 years. Reversibility of GonaCon-Equine immunization occurred in all treatment groups and averaged 0.40 (26/65). The only detectable adverse side effect of vaccination was intramuscular swelling observed in 89% (115/129) of mares and occasional draining abscesses at the site of vaccine injection. However, regardless of method of vaccine delivery (hand vs dart), none of these mares displayed any evidence of lameness, altered gait, or abnormal range of movement during the 6 years of this study. These results support previous findings that effective contraception of free-roaming horses will require a primary vaccination followed by reimmunization but that timing from 6 months to 4 years result in similar success and together can achieve greater reduction in population growth rates.