Entity

Time filter

Source Type

Yulee, FL, United States

Terrell K.A.,Smithsonian Conservation Biology Institute | Terrell K.A.,University of New Orleans | Wildt D.E.,Smithsonian Conservation Biology Institute | Anthony N.M.,University of New Orleans | And 5 more authors.
Biology of Reproduction | Year: 2010

Cheetahs and certain other felids consistently ejaculate high proportions (≥60%) of malformed spermatozoa, a condition known as teratospermia, which is prevalent in humans. Even seemingly normal spermatozoa from domestic cat teratospermic ejaculates have reduced fertilizing capacity. To understand the role of sperm metabolism in this phenomenon, we conducted a comparative study in the normospermic domestic cat versus the teratospermic cat and cheetah with the general hypothesis that sperm metabolic function is impaired in males producing predominantly pleiomorphic spermatozoa. Washed ejaculates were incubated in chemically defined medium containing glucose and pyruvate. Uptake of glucose and pyruvate and production of lactate were assessed using enzyme-linked fluorescence assays. Spermatozoa from domestic cats and cheetahs exhibited similar metabolic profiles, with minimal glucose metabolism and approximately equimolar rates of pyruvate uptake and lactate production. Compared to normospermic counterparts, pyruvate and lactate metabolism were reduced in teratospermic cat and cheetah ejaculates, even when controlling for sperm motility. Rates of pyruvate and lactate (but not glucose) metabolism were correlated positively with sperm motility, acrosomal integrity, and normal morphology. Collectively, our findings reveal that pyruvate uptake and lactate production are reliable, quantitative indicators of sperm quality in these two felid species and that metabolic function is impaired in teratospermic ejaculates. Furthermore, patterns of substrate utilization are conserved between these species, including the unexpected lack of exogenous glucose metabolism. Because glycolysis is required to support sperm motility and capacitation in certain other mammals (including dogs), the activity of this pathway in felid spermatozoa is a target for future investigation. © 2010 by the Society for the Study of Reproduction, Inc. Source


Hendricks K.E.M.,University of Florida | Penfold L.M.,White Oak Conservation Center | Evenson D.P.,SCSA Diagnostics | Kaproth M.T.,Genex Cooperative Inc. | And 2 more authors.
Theriogenology | Year: 2010

Biological samples, including cryopreserved sperm, are routinely X-rayed during air shipment. The goal was to investigate the impact of X-irradiation used for checked and carry-on luggage on bovine sperm chromatin integrity and postfertilization in vitro embryonic development. Frozen domestic bull sperm (Bos taurus) (n = 9 bulls) stored in a dry shipper (-160 °C) was screened by X-irradiation 0, 1, 2, and 3 times as either carry-on or checked luggage. Duplicate straws were thawed, and sperm were assessed for chromatin damage using the sperm chromatin structure assay (SCSA) and by postfertilization in vitro developmental competence of mature oocytes. Multiple exposure to X-rays did not significantly affect sperm chromatin integrity assessed by SCSA. There were lower proportions of oocytes cleaved (P = 0.07; 21.6 ± 3.1% vs. 29.4 ± 3.1%, 24.9 ± 3.1%, and 25.7 ± 3.3% for 3 vs. 0, 1, and 2 times, respectively; least-squares means ± SEM) and that developed to blastocysts (P = 0.06; 9.0 ± 1.7% vs. 13.8 ± 1.7%, 11.5 ± 1.7%, and 12.6 ± 1.9%, respectively) when fertilization was performed with sperm X-rayed 3 times using checked luggage irradiation; developmental competence (percentage cleaved embryos becoming blastocysts) was unaffected. There were no deleterious effects of other X-irradiation treatments on embryo development. We inferred that screening by X-irradiation may reduce the ability of sperm to activate oocyte cleavage after multiple exposures at the checked luggage dose. However, there was no evidence that competence of embryos to become blastocysts was reduced by X-irradiation (45.4 ± 5.7%, 40.4 ± 5.7%, 46.4 ± 6.1%, and 41.8 ± 5.7% for 0, 1, 2, and 3 doses, respectively), but potential long-term epigenetic effects are unknown. © 2010. Source


Barnes S.A.,White Oak Conservation Center | Andrew Teare J.,International Species Information System | Staaden S.,Jacksonville Zoo and Gardens | Metrione L.,South East Zoo Alliance for Reproduction and Conservation | Penfold L.M.,South East Zoo Alliance for Reproduction and Conservation
General and Comparative Endocrinology | Year: 2016

Basic reproductive information in female jaguars (. Panthera onca) is lacking, thus longitudinal fecal samples from seven females were analyzed via enzyme immunoassay to measure estradiol and progestin metabolites throughout the year. Mean estrus length of 194 estrus periods measured hormonally was 6.5 ± 0.3 d, mean peak fecal estradiol concentration was 138.7 ± 5.7 ng/g; and in one female, estrus resumption occurred approximately 15 d post-partum. Ovulation, as indicted by sustained elevated progestin concentrations (>20 d), was successfully induced one time by treatment with exogenous hormones in one female and by physical vaginal stimulation in two females a combined total of three times. Elevated fecal progestin was observed outside exogenous stimulation on five occasions, suggesting ovulation occurred spontaneously. Mean length of physically induced and spontaneous pseudopregnancies was 24.7 ± 4.2 d and 29.6 ± 2.6 d, respectively, and mean length of pregnancy (n = 2) was 98.0 ± 0.0 d. Mean peak progestin concentration for spontaneous and induced pseudopregnancies, and pregnancy was 7.4 ± 1.4 μg/g, 6.4 ± 1.2 μg/g, and 13.7 ± 1.0 μg/g, respectively. This data suggests jaguars are polyestrous and generally induced ovulators, with a moderate incidence of spontaneous ovulation. Additionally, two protocols to successfully stimulate ovarian activity in jaguars are described. © 2015 Elsevier Inc. Source


Ganswindt A.,University of Pretoria | Brown J.L.,Smithsonian Conservation Biology Institute | Freeman E.W.,George Mason University | Kouba A.J.,Memphis Zoological Society | And 6 more authors.
Biology Letters | Year: 2012

Hormone analysis is a precise and widely accepted tool formonitoring reproductive function and responses to stressors. Although hormones are present and can be measured in various biological matrices, non-invasive methods have gained popularity over the past 30 years as a more practical approach for assessing ovarian, testicular and, more recently, adrenocortical activity in intractable wildlife species. Noninvasive hormone monitoring also has been key to understanding biological mechanisms related to observed behaviours of captive and free-ranging animals. Despite the increasing popularity of this research field, wildlife endocrinologists have not had a specific forum for sharing and discussing their latest findings, technical developments and common challenges. To provide such a communication platform, the International Society for Wildlife Endocrinology (ISWE) was established in 2010, followed by an international meeting held on 3-4 November 2011 at the Toronto Zoo, Canada. Over several sessions, keynote speakers and participants discussed recent developments of new and innovative methods for hormone monitoring, as well as the latest advances in basic endocrinology as applied to adrenal function, reproductive physiology, animal health, ecology and evolution. Here, we introduce ISWE to the scientific community and discuss how this new society will serve as a resource for wildlife endocrinologists worldwide. © 2011 The Royal Society. Source


Assisted reproduction includes simple strategies, such as oral progestin to maintain pregnancy and hormone monitoring to predict oestrus for breeding introductions, as well as complex procedures, such as oestrous synchronization and artificial insemination (AI). The primary focus of research at White Oak Conservation Center, Yulee, FL, has been to work towards techniques allowing movement of frozen semen to manage metapopulations rather than translocate animals. Using the Gerenuk Litocranius walleri walleri as a model for threatened antelope, oestrous synchronization and AI were refined to produce four live offspring (from six attempts) using hand restraint rather than anaesthesia for inseminations. Conversely, similar progress with Okapi Okapia johnstoni has been slower. Okapi sperm are highly susceptible to osmotic changes and the physical pressures of the freezing process, which has limited the ability to develop suitable cryopreservation protocols. Storage of frozen semen from highly threatened animals provides insurance against loss of the individual's genes to the population and, if used for future insemination, can potentially provide new 'founders'. Biomaterials from both species, including blood and blood products, are preserved in genome resource banks together with samples from other threatened species, including the Florida panther Felis concolor coryi. It is important to note that assisted reproduction in novel species requires significant commitment and continuity from zoological institutions for optimal results. © 2010 The Authors. International Zoo Yearbook © 2010 The Zoological Society of London. Source

Discover hidden collaborations