Theriogenology wild最新文献

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) are important estrogen precursors, secreted mainly by the adrenal cortex. At late gestation, both DHEA and DHEAS (DHEA(S)) are produced at high concentrations in some species due to the developing fetal adrenal gland. Failure in DHEAS increase during late gestation can indicate fetal death, which prompts its use as a biomarker of pregnancy and fetal health in wildlife. Here, we review the most common non-invasive biomarkers of reproduction in wildlife, the molecular mechanisms of DHEAS synthesis and action during gestation, in addition to the advantages and limitations of incorporating DHEA(S) in these studies. Using previously published data, we tested the specificity and sensitivity of fecal DHEAS as a predictor of successful gestation in four captive primate species (orangutans (Pongo pygmaeus), siamangs (Symphalangus syndactylus), Japanese macaques (Macaca fuscata), and howler monkeys (Alouatta caraya)). Using data from non-pregnant/non-lactating females, we set a threshold on fecal DHEAS levels for detecting successful pregnancy per species, controlling for age and housing condition (social vs single). We found that DHEAS had 100% specificity for all species (non-pregnant samples were below the threshold for pregnancy), and 100% sensitivity for Japanese macaques housed individually, and for orangutan and siamangs (all samples from successful pregnancies were above the threshold, and all samples from stillbirth were below the threshold). However, the sensitivity was 80% in howler monkeys and 50% in Japanese macaques housed socially. Our preliminary results indicate that, while DHEAS is a promising biomarker of fetal health, it is limited to late gestation and to some species. We suggest increasing the sample size to calculate the pregnancy threshold per species and to test multiple samples from the same individual when using this method.

Male reproductive cycles in lizards can be continuous or seasonal depending on the environmental conditions and female availability. The aim of this study is to investigate whether adult males of the psammophilus lizard Liolaemus cuyanus present seasonal changes of reproductive traits throughout the reproductive cycle. In order to carry out this task, sampling of specimens (N = 27) was carried out monthly from October to March in Valle de Matagusanos, Ullúm, San Juan, Argentina (31°06′46.08′’ S, 68°38′03.84′’ W; altitude: 945 m), a semi-arid zone. The animals captured in different months were grouped based on reproductive criteria according to three relevant periods: pre-reproductive (PrR), reproductive (R) and post-reproductive (PsR). In order to identify and characterize these periods, several male reproductive traits were obtained, like morphometric parameters (body mass, snout-vent length, testes and abdominal fat body mass), tubular surface and estimation of the interstitial tissue coverage, combined with histological and cell seminiferous tubule observations (germ cells types, histological and ultrastructural details) and presence of sperm in the cauda epididymis. During the PrR period, which occurred during spring, well-developed testes with free tubular sperm cells were present, but these were less frequent than during the R period. On the other hand, luminal sperm cells were evident at the seminiferous tubules from the beginning of the R period, in conjunction with the maximum testes mass and seminiferous tubular surfaces. This was also coincident with a higher abundance of sperm cells in the cauda epididymal lumen. At the end of this period, the initial regression of the seminiferous epithelium was corroborated by organelle regression which was observed in the ultrastructure of spermatogenic cells. At the beginning of the PsR period, before autumn, a marked decrease in male reproductive traits above described was detected. Instead, an increase in abdominal fat body mass could be observed indicating the onset of the lethargy period. The results obtained suggest that this population of L. cuyanus has a seasonal reproductive cycle, with its reproductive activity occurring during the spring-summer months (PrR-R periods) and finishing in late summer (PsR).

Artificial insemination (AI) can aid conservation of African wild dogs (AWD), but methods to determine the appropriate timing of AI in females are not feasible without immobilization. This study determined whether certain behaviors coupled with fecal estrogen (fEM) and progestogen (fPM) metabolite concentrations, could be used as non-invasive parameters to predict the fertile period in female AWDs. Behavior was observed in three alpha females before, during and after the mating period, and feces analyzed for hormone metabolites. During the periovulatory period, females were immobilized 2–3 times to evaluate vulvar condition, blood hormone concentrations and vaginal cytology, and to conduct vaginoscopy. Late estrus (fertile period) could be distinguished from pro-estrus, early estrus, and diestrus using behavior; with a 2- to 5-fold higher rate of male-female affiliative behavior, sexual and non-sexual follow, alpha male initiating behavior, ride-up and copulation (P ≤ 0.05). Sexual behaviors, and male-female resting patterns declined significantly or ceased the day after last mating. Two females showed a 2.5- to 3-fold increase in fPM concentrations during late estrus compared to the pro-estrus period (P ≤ 0.05) and elevated fEM levels that rose in pro-estrus, declined to baseline by late estrus. The one anovulatory female showed no distinct pattern in fPM or fEM concentrations. Vaginal cytology and vaginoscopy could not discriminate between different phases. In summary, behavioral observations coupled with rising fPM and declining fEM can determine the fertile period in African wild dog females, whereas infrequent measurement of blood hormone concentrations, vaginal cytology and vaginoscopy are unreliable.

Wolverines (Gulo gulo) populations are under threat by increased human activities. A better understanding of their reproductive physiology would benefit research and monitoring of this species. The use of enzyme immunoassay (EIA) to measure fecal progesterone metabolites (FPM) is a powerful tool to understand wildlife reproductive physiology, and a non-invasive method for use in both zoo and wild populations. The main objective of this study was to determine reproductive status in female wolverines using FPM levels, first by monitoring of longitudinal changes in FPM in zoo housed females in breeding situations and second to compare those values to FPM measured in feces obtained from wild females observed in the field during reproductively active periods (Dec–Apr). Female reproductive physiology was assessed by measuring FPM in three zoo housed wolverines to determine species-specific levels arising from ovulation encompassing embryonic diapause and ovarian reactivation (resumption of ovarian luteal activity after diapause) during pregnancy or pseudopregnancy, which in turn enabled verification of reproductive status in 15 wild wolverines, monitored over three years. In the zoo females, FPM levels were sustained at basal levels if ovulation and/or breeding did not occur. After ovulation, both pregnancy or pseudopregnancy exhibited a bi-phasic pattern of FPM increases, with a 4.9-fold increase above baseline during embryonic diapause and a further 4.4-fold increase after ovarian reactivation. FPM levels during pregnancy and pseudopregnancy were indistinguishable, thus increases in FPM levels are only a confirmation of ovulation, and not diagnostic for pregnancy. In wild females, assessment of FPM levels in samples collected from December to February was able to predict a potentially pregnant/reproductively active female with levels above 8200 ng/g dried feces, or non-reproductive (nonovulatory) female during that period with levels below 1700 ng/g. Wild wolverine FPM levels indicative of pregnancy aligned with field observations of denning and/or lactation. FPM levels from samples collected from March and April were inconclusive as levels could be attributed to females being either postpartum or non-reproductive at that time. Timing of ovarian reactivation, and subsequent elevation of FPM, varied among individuals suggesting caution is warranted when assessing only one fecal sample per female. Understanding all factors that may impact reproductive success is essential for effective species conservation, particularly for species with low reproductive rates, like the wolverine. This study has demonstrated the potentially useful incorporation of non-invasive fecal hormone analysis for investigation of physiological parameters and reproductive status in wild wolverine females.

The Felidae family is composed of 43 species, all of which — except for the domestic cat — face extinction threats in the wild, not only due to poaching and loss of habitat but also to reproductive challenges such as endogamy. To overcome such obstacles, assisted reproduction technologies (ART) have been employed to improve the species' reproductive success. However, the knowledge on wild cats' reproductive physiology is limited, with their domestic relative often being employed as a model organism. The present report is a comprehensive review on the sperm physiology of Neotropical felids, performing a vertical analysis of the data available on spermatic parameters such as ejaculates volumes and concentrations, seminiferous epithelium cycles duration, spermatic efficiency, and prevalence of morphological defects as well as discusses the role of hormonal control of spermatogenesis and its influence on teratospermia. The objective of the present report was to assemble information that would deepen our knowledge of male reproductive physiology and anatomy in Neotropical felids, and also to contrast it with the domestic cat.

Mature female giant pandas usually ovulate once a year. This is followed by an obligatory luteal phase, consisting of a long-lasting corpus luteum dormancy phase (CLD; primary increase in progestogens) and a much shorter active luteal phase (AL; secondary increase in progestogens). Varying duration of both the dormant (embryonic diapause) and AL (post-embryo reactivation) phases has hampered unambiguous pregnancy length determination in giant pandas until today. Additionally, progestogen profiles have been considered not to differ between pregnant and pseudopregnant cycles. Only ceruloplasmin, 13,14-dihydro-15-keto-PGF_2α (PGFM) and – more recently – estrogens have been assigned diagnostic power so far. Our study investigated the competence of metabolic (fecal output) and Urinary Specific Gravity (USpG)-normalized urinary endocrine (progestogens, PGFM, glucocorticoids (GCM) and ceruloplasmin) markers for pregnancy monitoring including defining the duration of the AL phase length. Research on 24 (6 pregnant, 8 pseudopregnant and 10 non-birth) cycles of 6 giant pandas revealed a fixed AL phase length of 42 days in giant pandas, e.g. representing 6 weeks of post- diapause development in case of pregnancy. Progestogen concentrations were significantly higher in pregnant cycles throughout the majority of the AL phase, with significant higher values during the AL phase in healthy twin compared to singleton pregnancies. GCM concentrations were also markedly higher in giant pandas expecting offspring, with a clear increase towards birth in the final 2 weeks of pregnancy. This increase in GCM was running in parallel with elevating estrogen and PGFM concentrations, and decreasing progestogens. In addition, during the AL phase, a more pronounced decrease in fecal output was obvious for pregnant females. The combined profiles of non-invasive metabolic and endocrine markers, the latter normalized based on USpG, showed a true pregnancy signature during the AL phase. The findings of this study are applicable to retrospective evaluations of non-birth cycles facilitating categorizing those into pseudopregnant or lost pregnancies, with USpG-normalization of the urinary endocrine markers as a prerequisite.

Cold sperm storage is a simple and inexpensive technique to assist reproduction programs for endangered species. This study aimed to describe sperm quality indicators and develop a cold sperm storage protocol for Algansea lacustris. A total of 8 storage conditions were evaluated: Control 1 (undiluted sperm), Control 2 (sperm diluted in extender BTS™), and 6 different combinations of the extender (Control 2) + : (1) 2.5 % Me₂SO, (2) 5 % Me₂SO, (3) 7.5 % Me₂SO, (4) 10 % Me₂SO, (5) 12.5 % Me₂SO, and (6) 15 % Me₂SO for 0, 24, 48, 72, and 96 h. The motility and duration of moving sperm were assessed daily for each treatment. Samples diluted in the highest concentrations of Me₂SO (12.5 % and 15 %) showed a lower motility rate (60–79 %) immediately after dilution (0 h). Undiluted sperm samples (Control 1) showed a higher motility rate (62 %) after 72 h and higher duration of motility (33.8 s) after 48 h. The optimal storage condition for obtaining about 60 % motility is storing undiluted sperm for up to 72 h. However, the combination of extender BTS™ at 5 % and cryoprotectant Me₂SO at 10 % present future potential for enhancing the spermatic cryopreservation protocol in Algansea lacustris.

Until recently, mammalian sex differentiation was thought to be finalized in the embryo. Development of the tubular genital tract, external genitalia, secondary sexual characteristics and sexual behavior are determined largely by the developing gonad. In the last decade, however, it has been shown that continuous sex maintenance is required throughout life. We document proposed ovary to testis transdifferentiation in six captive South African lionesses. These lions were phenotypically female until, as older adults, they began to develop manes, clitoromegaly and increased levels of restlessness and aggression. Similar phenotypic and behavioral changes have been reported very rarely in free-ranging lionesses. Five of the lionesses had been treated repeatedly with deslorelin until they stopped showing estrus. Serum levels of testosterone were similar to those recorded in domestic tom cats in the three lionesses tested. Histological examination revealed an absence of ovarian follicles and small to large scattered islands of interstitial-like cells associated, in larger lesions, with Sertoli-like cells arranged in tubular structures. Oviduct and uterus were present in the four animals in which these were sampled. To date, most studies on this phenomenon have been conducted in laboratory animals. This is the first report of this condition in felids.

This study aimed to contribute to the knowledge about the reproductive physiology of wild lowland tapirs (Tapirus terrestris) by describing the serum testosterone concentrations, testicular biometry, and testicular tone of individuals living in the Pantanal and Cerrado biomes of Brazil, and to check for reproductive seasonality for the species, and to investigate correlations among these reproductive parameters and individual age and weight. Meteorological data (air temperature, wind speed, relative humidity, and global radiation) of the study sites were characterized through automated stations of the National Institute of Meteorology (INMET). From 2015–2020, field data were collected from 22 and 11 wild male lowland tapirs from the Pantanal and Cerrado biomes, respectively. After capture and chemical restraint, the age and weight of the animals were estimated. Blood samples were collected to determine serum testosterone concentrations using radioimmunoassay. Testicular biometry measurements included width, length, height, and volume, while testicular tone was assigned using scores from 3 (firm) to 1 (soft). Animal age, weight, and testosterone concentrations did not differ between the two biomes (P > 0.05). Positive correlations were found between age and weight (ρ = 0.86; P < 0.001), and serum testosterone levels with both estimated age (ρ = 0.45; P = 0.0047) and weight (ρ = 0.51; P = 0.0011). Testicular volume was positively correlated with age (ρ = 0.75; P < 0.0001), weight (ρ = 0.65; P = 0.0011), and serum testosterone levels (ρ = 0.42; P = 0.0081). In addition, testicular tone in adult subjects (>48 months) was significantly higher than in younger subjects (P < 0.05). Testicular consistency was positively correlated with weight (ρ = 0.36; P = 0.0241) and serum testosterone levels (ρ = 0.38; P = 0.0174). Seasonal effect on tapir reproduction was not identified, but testicular tone was influenced by wind speed (ρ = 0.37; P = 0.0211) and air humidity (ρ = 0.37; P = 0.0262). This study is the first scientific description of reproductive parameters of male lowland tapirs.

The brown brocket deer is a species of neotropical deer that is found in several regions of Brazil. Although not considered an endangered species, it can be used as a model for studies with somatic cell nuclear transfer (SCNT) in endangered species. Thus, this study aimed to verify the embryo development and nuclear gene expression in intraSCNT (bovine-bovine), interSCNT (deer-bovine) and in vitro fertilized (IVF) bovine embryos. Thus, from a culture of brown brocket deer fibroblasts and enucleated bovine oocytes, inter and intraspecific embryos were produced. In addition, a group of IVF bovine embryos was prepared. Quantitative PCR (qPCR) was performed from the blastocysts obtained from each experimental group to analyze the expression of OCT4, T-FAM, GJA1, BAX and BCL2. The blastocyst rate was higher (P < 0.05) in IVF group (44.0%) when compared to intraSCNT (11.3%) and inter SCNT (5.9%). The expression of BCL2 was close to null and for GJA1 was similar (P > 0.05) among experimental groups. In conclusion, bovine cytoplast was able to reprogram the brown brocket deer karyoplast and these cloned embryos were able to reach the blastocyst stage. The inverse relationship for BAX and BCL2 can indicate a high degree of apoptosis in blastocysts from interSCNT.