Theriogenology wild最新文献

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.

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.

This study explores a novel surgical method for population control in pregnant capybaras (Hydrochoerus hydrochaeris) within areas endemic to Brazilian spotted fever (BSF), a disease caused by the bacterium Rickettsia rickettsii and transmitted by the Amblyomma sp. tick. The proposed technique involves fetus removal and sterilization through a cesarean section performed along the linea alba. Conducted on 43 capybaras in São Paulo, Brazil, with all necessary ethical and legal clearances, the surgical procedure featured a periumbilical incision through the linea alba for direct uterine access, facilitation fetal removal and subsequent uterine horn ligature for complete sterilization. The technique proved efficient, with surgeries lasting between 60 and 90 minutes and incisions spanning 5–7 cm, offering minimal hemorrhage, and avoiding excessive abdominal viscera manipulation. Post-surgery, anesthetic recovery was smooth, and no sterilized females produce offspring after the procedure, underscoring the method's effectiveness for capybara population control. This is particularly significant in urban areas where human-capybara interactions are increasing due to residential expansion. The proposed surgical approach demonstrated herein presents a time-efficient and effective strategy for BSF prevention by controlling capybara population. In conclusion, the cesarean section along the linea alba emerges as a viable option for reproductive control in capybaras, with positive outcomes observed in tissue samples and overall animal health condition supporting its application in BSF-endemic regions to help reduce disease incidence.

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.

Computer-aided sperm morphology analysis (CASMA) is quickly becoming the industry standard for objective morphometric analysis of sperm. For efficient and accurate sperm analysis via CASMA, species-specific optimization of fixation and staining techniques is necessary. This is especially true for novel species, such as marine mammals, where information regarding the spermatozoon is significantly limited. Adding to the growing knowledge of marine mammal sperm, this study investigated the effects that different fixatives and stains had on sperm head morphometry and morphology of Florida manatee (Trichechus manatus latirostris) sperm. Sperm were collected postmortem from four recently deceased Florida manatees and fixed in one of three different fixatives: Formalin 10 Equine Semen Diluent, 2.5 % glutaraldehyde in 0.1 M sodium cacodylate buffer, or 4 % paraformaldehyde. Sperm were then stained using one of four different stains: SpermBlue®, Quick III™, Hemacolor™, or Coomassie blue. A total of 200 sperm from each manatee were analyzed for each fixative:stain combination using the Sperm Class Analyzer® computer-aided sperm analysis (CASA) system for the eight standard head morphometric parameters. Sperm morphology was assessed visually using brightfield microscopy for different morphological abnormalities. Both fixation and staining independently had significant effects on sperm head size and shape when compared across all treatments. As the true morphometry of unfixed and unstained Florida manatee sperm is still unknown, it is unable to be determined which fixative:stain combination imposes the least effect on sperm head morphometry and is thus optimal for the analysis of Florida manatee sperm using CASMA. Opportunistic field sampling of marine mammal sperm imposes logistical constraints which may limit the ability to compare methodologies utilizing different fixatives and staining combinations. Continued research is needed for optimization and standardization of sperm processing, fixation, staining, and analysis of Florida manatee sperm as well as sperm from other marine mammal species.

Male elephants regularly undergo a unique sexual period of musth that is characterized by elevated testosterone, analogous to the heightened reproductive seasonality of other mammals but distinct because it is nonseasonal and asynchronous among males. Our knowledge of male reproductive biology in elephants is limited compared to females, restricting our ability to effectively manage breeding and ensure optimal welfare, especially during musth. In this study, we analyzed the relationship between serum testosterone concentrations and sperm motility, a measure of semen quality. Semen (n = 152 samples) was collected from four male Asian elephants aged 8 to 47 years housed at the Denver Zoo between 2018 and 2022. For approximately half of the samples (n = 72), serum was also collected within a week of semen collection. Using paired semen and serum samples, we identified significant positive relationships between testosterone concentration and sperm motility in three elephants; the relationship in a fourth elephant trended towards significance. Three elephants exhibited musth during the study; in one elephant, sperm motility was significantly higher during musth, while in the other two, although samples were too limited for statistical analysis, patterns trended the same. Furthermore, two males exhibited increasing motility approaching the start of musth or as musth progressed. Together, these results provide the first evidence of a relationship between testosterone (and perhaps by extension, musth status) and a measure of semen quality in elephants. While further systematic research is warranted, this study has implications for understanding male reproductive activity in a non-seasonally breeding species and motivates innovation in semen collection techniques among Asian elephants to obtain high quality samples even during musth.

Ex-situ conservation programs are useful tools for preserving endangered species, and knowledge of their reproductive physiology is essential for achieving conservation objectives in captive breeding programs. The North African houbara bustard (Chlamydotis undulata) is a vulnerable bird species bred in captivity to restore its natural populations. To better understand the reproductive biology of this species, we first described the anatomy and histology of the reproductive tracts of male and female North African houbara bustards. We described and classified the normal and abnormal sperm morphologies for the species. The reproductive tracts of males and females were collected during the breeding season (BS) (21 males and 14 females) and the non-breeding season (NBS) (four males and two females). Pictures and measurements of the testes and oviducts were taken, and testis colour was graded from 1 (black) to 6 (white). Organs were fixed and processed for histological analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The testis, epididymis, oviduct size, testicular capsule thickness, seminiferous tubule (ST) diameter, and histological layers of the oviduct were compared between the BS and NBS groups. Sperm morphometry was evaluated using fixed ejaculates (n=22, from 22 males). Ejaculates (n=417, 166 males) were collected and fixed during the BS, and their morphology and morphometry were evaluated using phase-contrast microscopy. Ejaculate mixes (n=12) were fixed and analysed using SEM and TEM. Overall, the anatomical structure and histology of the male and female reproductive tracts were similar to those of other avian species. The testes were symmetric, and a regression of testis and oviduct size, the thickness of the mucosa and serosa of the oviduct, and ST diameter (p<0.001) were observed during NBS compared with those during BS. Sperm storage structures are located inside the oviduct at the uterovaginal junction and infundibulum. Melanin granules were observed in the interstitial space of the seminiferous epithelium, which explains the testis pigmentation. Melanin was also found in the ovaries and the uterus. Houbara sperm have an elongated nuclear form and a round-shaped acrosome lacking perforatorium and rostrum. Most analysed samples were limitrophe normospermic (normal= 68.5 ± 14.7%), houbara sperm morphology could be classified into eight categories: normal sperm, acrosome, head, midpiece, tail, and teratogenic defects, swollen head, and cytoplasmic droplet. This study provides the first anatomical and histological descriptions of the male and female reproductive tracts of the North African houbara bustard. Further investigation into the functional role of melanin in the testes is warranted.

Population management is becoming critically important for species that inhabit urban areas, particularly due to the public health risks they pose. The South American coatis (Nasua nasua), recognized as synanthropic species in Brazil, have raised increasing concerns due to their cohabitation with humans, especially in recreational settings such as parks, where the potential for zoonotic disease transmission is heightened. This study aimed to assess the effectiveness of a minimally invasive sterilization method for female South American coatis, employing tubal ligation via mini-laparotomy. A total of nine females were selected for this procedure, which was performed in both an ecological park and a zoo setting. The techniques employed involved either the application of titanium hemostatic clips (n = 2) or a nylon suture (n = 7). The results demonstrated that the nylon suture technique was not only quicker (12.7 ± 1.7 vs. 47.5 ± 2.5 min) and more cost-effective but also maintained effective contraception. There were no recorded instances of pregnancy among the sterilized females, whether they were later exposed to males in captivity or recaptured in the wild. Furthermore, the procedure did not alter the social dynamics or sexual behaviors of the coatis upon their return to their natural habitat. The methods used in this study were proven to be safe, enabling quick recovery and showing no post-surgical complications, highlighting their viability for managing populations of synanthropic species in urban environments.

Due to the high value of its fur, indiscriminate hunting reduced Chinchilla lanigera wild populations virtually to the verge of extinction (IUCN critically endangered, CITES Appendix I). A key aspect for the implementation of ex-situ breeding programs for wild chinchilla depends on the integration of data obtained from assisted reproduction techniques applied to its domestic congener. One of the most widely used techniques is ovulation induction through the injection of exogenous synthetic drugs. In farm animals, ovarian inactivity allows for a more consistent response to inducer injection. Therefore, the objective in this study was to monitor and evaluate the endocrine patterns of ovarian dynamics and in vivo fertilization rates after exogenous ovarian activation in chinchillas using GnRH analogue and eCG. Seven ovulation induction protocols were tested in females (2–5 years of age) and urine samples were collected before, during and one week after inductor injections. Samples were analyzed for creatinine (Sigma #C3613), estrone conjugates and pregnanediol glucuronides (PdG-R13904, EC-R522–2, C.Munro) by EIA. The endocrine patterns of this species are not necessarily associated with behavioral signs of estrus. Therefore, non-invasive hormonal monitoring remains the only method that allows us to accurately explore ovarian activity. A longitudinal profile was obtained for each hormone and female. The results of our first experiment clearly showed that GnRH administration elicited a regular response only after a threshold value of 10 µg, although of little significance. The use of lower doses was not sufficient to achieve ovarian stimulation while higher doses of GnRH apparently resulted in the suppression of follicular activity, probably due to the effects of a negative feedback of GnRH over its release in the hypothalamus. Although both eCG doses produced similar responses, the 50 I.U. (0.1 I.U./g) dose caused a more powerful and steady response. A progressive increase in the concentrations of EC and PdG metabolites was also evidenced. Finally, the results regarding the pregnancy percentages obtained after the use of any of the protocols in farm animals were very limited, reaching maximum values of 17.2% whereas the control animals reached a percentage of 6.2%.