Theriogenology wild最新文献

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.

Molecular characterisation of testicular cells is a pivotal step towards a profound understanding of spermatogenesis and developing assisted reproductive techniques (ARTs) based on germline preservation. To enable the identification of testicular somatic and spermatogenic cell types in felids, we investigated the expression of five molecular markers at the protein level in testes from domestic cats (Felis catus) at different developmental phases (prepubertal, pubertal I and II, postpubertal I and II) classified by single-cell ploidy analysis. Our findings indicate a prominent co-labelling for two spermatogonial markers, UCHL1 and FOXO1, throughout postnatal testis development. Smaller subsets of UCHL1 or FOXO1 single-positive spermatogonia were also evident, with the FOXO1 single-positive spermatogonia predominantly observed in prepubertal testes. As expected, DDX4+ germ cells increased in numbers beginning in puberty, reaching a maximum at adulthood (post-pubertal phase), corresponding to the sequential appearance of labelled spermatogonia, spermatocytes and spermatids. Furthermore, we identified SOX9+ Sertoli cells and CYP17A1+ Leydig cells in all of the developmental groups. Importantly, testes of African lion (Panthera leo), Sumatran tiger (Panthera tigris sumatrae), Chinese leopard (Panthera pardus japonesis) and Sudan cheetah (Acinonyx jubatus soemmeringii) exhibited conserved labelling for UCHL1, FOXO1, DDX4, SOX9 and CYP17A1. The present study provides fundamental information about the identity of spermatogenic and somatic testicular cell types across felid development that will be useful for developing ART approaches to support endangered felid conservation.

Chimaerods represent an enigmatic lineage of cartilaginous fishes and the least studied group within Chondrichthyans. They have a widespread global distribution with a high degree of endemism. In addition, this group has been considered among the least threatened species of Chondrichthyans, but also the most data-deficient group, with biological information lacking for most species. This study represents the first microanatomical, histological, and ultrastructural description of the different stages of folliculogenesis in Callorhinchus callorhynchus, and the first ultrastructural study about this topic within chimaeroids. Specimens of different maturity stages were collected from landings of the commercial fleet operating in San Matías Gulf, Argentina. Folliculogenesis shows some differences compared to other elasmobranchs. Oogonia were present in immature and mature females. Atretic follicles of different sizes were present in mature female ovaries. There is a significant difference between the macroscopic (∼10 mm) and microscopic (∼ 2 mm) follicular size at the beginning of vitellogenesis. There is no evidence of an epigonal organ. The results are discussed in a physiological and reproductive context. This study provides valuable information that will contribute to the understanding of the reproductive biology of the chimaeroids species and its potential for fishery exploitation recovery.

Studies of the reproductive functional morphology of chelonians are important to understand the reproductive physiology, anatomy, and endocrinology of these species. However, data on the reproduction of this group have been difficult to obtain because of their cryptic habits and as a result the consequent inefficiency of conventional field methods in detecting individuals in the wild. In this study, we obtained reproductive organs from 347 adult female yellow-footed tortoises (Chelonoidis denticulatus), one of the most hunted and traded land vertebrates in South America, donated by local sellers in a wild meat market in the Peruvian Amazon. We described the species’ reproductive cycle and the influence of climatic factors on reproductive performance. Of the sampled females, 116 (33.4%) were gravid and 231 (66.6%) were non-gravid, including 215 vitellogenic (62.0%) and 16 non-vitellogenic (4.6%). The mean number of ovarian follicles per female declined from 28.5 (<10 mm diameter), to 7.1 follicles (20–40 mm) to 3.2 follicles> 40 mm. Gravid females had in average 3.7 shelled eggs in the oviduct, with a mean egg diameter of 53.7 mm. The estimated annual reproductive potential in gravid females was 5.1 eggs per clutch, ranging from one to 22 eggs. There was a strong positive relationship between the diameter of shelled eggs and the straight carapace length of gravid females. The final phase of the folicular growth, the most demanding energetic process in chelonian reproduction, correlated with annual rainfall peak, while oviposition was estimated to occur in the dry season. The yellow-footed tortoise should be considered an opportunistic seasonal breeder, though capable of reproducing throughout the year. Reproductive yields are linked to climatic events that influence food availability in the environment. To improve the sustainable use of this species, adult females should be harvested primarily during reproductive quiescence, from the end of the laying period in the late dry season to the mid-rainy season when large follicles appear, to avoid taking gravid females. Our results are useful not just to better understand the reproductive biology of terrestrial chelonians but can inform the conservation management of harvested species.

Humpback whales (Megaptera novaeangliae) in Southeast Alaska have been studied for over 50 years, and are largely considered a recovery success since the cessation of commercial whaling. Reproductive physiology is an important factor to consider in studying population health and can provide important insights into the drivers contributing to population abundance fluctuations. Validated assays for progesterone and testosterone were used on blubber biopsies from humpback whales (N = 33 whales, 71 samples) near Juneau, Alaska, in 2020 and 2021. Long-term sighting histories were used to confirm detected pregnancies with calf sightings the following year. Blubber samples were divided into two seasonal bins (early and late summer). Pregnant females sampled in both early and late summer of both 2020 and 2021 showed elevated progesterone concentrations compared to other reproductive states (p < 0.05). Progesterone concentrations in adult male whales (0.3 ± 0.2 ng/g) were not significantly different from lactating or resting female whales. Blubber testosterone concentrations in adult male humpback whales ranged from 0.05 to 1.1 ng/g, and mean concentrations were approximately double those of female whales in any reproductive state. Pregnancy was detected in 5 of 11 and 4 of 9 adult females in 2020 and 2021 respectively, yielding summer season pregnancy rates for sexually mature females at 0.45, and 0.44, respectively. Calving rates were 0.36 and 0.22 in 2020 and 2021, respectively, and the annual growth rate for this subpopulation was calculated at 2.6 % per annum. One female had successful pregnancies for four consecutive years. These results demonstrate the synergistic value of combining immunoreactive assays and long-term sighting histories to further knowledge of reproductive physiology in individual humpback whales, which can be expanded to assessing the health of a population or ecosystem.

Semen cryopreservation is one common tool for extended genome storage and serves as insurance for declining biodiversity. In the endangered Bornean sun bear, semen was collected with electroejaculation and this is the first attempt at semen cryopreservation for this subspecies. Chilled semen with motility of more than 50 % was extended with Caniplus freezing medium, and cryopreserved with slow freezing protocol. A total of 22 cryopreserved semen straws were evaluated with computer-assisted sperm analysis and conventional semen evaluation tests as well as additional functional tests including evaluation of the acrosome (Rose Bengal Fast Green stain), plasma membrane (hypoosmotic swelling test), and chromatin (toluidine blue stain). Post-thaw semen quality was compromised with poor viability (27.6 ± 11.2 %), motility (8.3 ± 7.1 %), and progressive movement (1.3 ± 2.0 %) but maintained high integrity for the acrosome (71.1 ± 10.8 %), plasma membrane (54.7 ± 9.6 %), and chromatin (89.7 ± 7.6 %). The total post-thaw sperm abnormality was 51.7 ± 10.7 %, predominantly bent tail (28.0 ± 7.6 %) and proximal droplets (20.0 ± 11.8 %). Although this current cryopreservation was not a success, the compromised frozen-thawed semen may be a valuable resource in assisted reproductive technologies such as intracytoplasmic sperm injection. The three additional functional tests demonstrated were simple and affordable and hence are recommended to be part of the routine semen evaluation. Further research is required to develop species-specific cryopreservation protocols and to explore other assisted reproductive technologies in the Bornean sun bear.