[Show abstract][Hide abstract] ABSTRACT: Exogenous gonadotrophins administered before AI can adversely alter endocrine dynamics and inhibit embryo development in felids. In the present study, we tested the hypothesis that priming the domestic cat ovary with progestin mitigates the negative influence of gonadotrophin therapy by normalising early embryogenesis and luteal function. Queens were given either: (1) progestin pretreatment plus chorionic gonadotrophins (n = 8; primed); or (2) gonadotrophins only (n = 8; unprimed). Ovulatory response was assessed laparoscopically, and cats with fresh corpora lutea (CL) were inseminated in utero. Ovariohysterectomy was performed 3 days later to recover intra-oviductal embryos for in vitro culture; one ovary was prepared for histology, and CL from the remaining ovary were excised and assessed for progesterone content and targeted gene expression. Of the six primed and seven unprimed queens inseminated, embryo(s) were recovered from five individuals per group. Embryos from progestin-primed donors more closely simulated normal stage in vivo development (P < 0.05). No 2- or 4-cell embryos from either group developed beyond 16-cells in vitro; however, 50% of unprimed and 66.7% of primed (P > 0.05) 5-16-cell embryos progressed to morulae or blastocysts by Day 4 of culture. Although histological characteristics were unaffected by progestin priming (P > 0.05), luteal progesterone was unusually high (P < 0.05) in unprimed compared with primed cats (72.4 +/- 5.8 vs 52.2 +/- 5.5 ng mg(-1), respectively). Two genes associated with progesterone biosynthesis (luteinising hormone receptor and 3 beta-hydroxysteroid dehydrogenase) were upregulated in unprimed versus primed individuals (P = 0.05 and P, 0.05, respectively), indicating potential mechanistic pathways for the protective influence of pre-emptive progestin treatment. Building on earlier findings that progestin priming prevents spontaneous ovulation, increases ovarian sensitivity to gonadotrophins and ensures a normative endocrine environment, the present study demonstrates that pretreatment with this steroid also benefits embryo development and normalisation of early luteal function.
Full-text · Article · Feb 2015 · Reproduction Fertility and Development
[Show abstract][Hide abstract] ABSTRACT: Due to strong intra-specific aggression and frequent adverse reactions to changes encountered in the captive setting, clouded leopards (Neofelis nebulosa) are particularly difficult to manage as a self-sustaining population in zoos. The aim of this study was to examine the efficacy of behavioral reaction tests in proactively assessing differences in male clouded leopard stress reactivity and temperament. If such tests can be applied to reliably predict which males show stronger adverse behavioral and physiological responses and increased aggression under stressful events, this information can be used for management decisions. Quantitative behavioral and hormonal data were collected before, during, and after a series of brief behavioral reaction tests, which included mirror image stimulation, airhorn, and exposure to unfamiliar people. Keeper questionnaires, validated through correlation with fecal glucocorticoid metabolite concentrations, were used to assess animal temperament (‘anxious’ vs. ‘calm’). Behavioral responses were compared with keeper temperament assessments and fecal androgen metabolite levels to assess individual responses. Results showed that differences in behavior correlated meaningfully and significantly with temperament assessments. During pre-behavior test periods, cats rated as ‘anxious’ tended to hide in the nest box more often (Rs = 0.80, P = 0.003) and lie down less often (Rs = −0.52, P = 0.04) than those rated as ‘calm’. Of the three tests, mirror image stimulation was the most effective in differentiating between ‘anxious’ and ‘calm’ cats and identifying potentially aggressive cats. Specifically, ‘anxious’ cats spent less time interacting with the mirror (Rs = −0.67, P = 0.005) while cats with higher mean fecal androgen metabolite levels exhibited the more aggressive behaviors of growling (Rs = 0.60, P = 0.01) and tail flicking (Rs = 0.54, P = 0.03). Our findings demonstrate that behavioral reaction tests may provide a useful indicator of detrimental fear-related and aggressive behaviors in clouded leopards for management decisions. These data also point to potential behavioral neuroendocrine mechanisms that operate in captive felids and contribute to our understanding of the basic biology of these species.
[Show abstract][Hide abstract] ABSTRACT: As the only domesticated species known to exhibit both induced and spontaneous ovulation, the cat is a model for understanding the nuances of ovarian control. To explore ovarian sensitivity to exogenous gonadotropins and the influence of progestin priming, we conducted a study of queens that were down-regulated with oral progestin or allowed to cycle normally, followed by 'low' or 'high' doses of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG). Our metrics included 1) fecal steroid metabolite profiles before and after ovulation induction, 2) laparoscopic examination of ovarian follicles and corpora lutea (CL) on Days 2 and 17 (Day 0 = hCG administration), and 3) ovariohysterectomy (Day 17) to assess CL progesterone concentrations, morphometrics, and histology. Reproductive tracts from time-matched, naturally-mated queens (n = 6) served as controls. Every progestin-primed cat (n = 12) produced the desired response of morphologically-similar, fresh CL (regardless of eCG/hCG dose) by Day 2, whereas 41.7% of unprimed counterparts (n = 12) failed to ovulate or had variable-aged CL suggestive of prior spontaneous ovulation (P < 0.05). The ovarian response to 'low', but not 'high', eCG/hCG was improved (P < 0.05) in primed compared to unprimed cats, indicating increased sensitivity to gonadotropin in the progestin-primed ovary. Progestin priming prevented hyper-elevated fecal steroid metabolites and normalized CL progesterone capacity, but only when combined with 'low' eCG/hCG. However, priming failed to prevent ancillary CL formation, smaller CL mass, or abnormal luteal cell density, which were common to all eCG/hCG-treated cats. Thus, the domestic cat exposed to eCG/hCG produces CL with structural and functional aberrations. These anomalies can be partially mitigated by progestin priming, possibly due to a protective effect of progestin associated with enhanced ovarian sensitivity to gonadotropins.
No preview · Article · Oct 2012 · Biology of Reproduction
[Show abstract][Hide abstract] ABSTRACT: The Black-footed Ferret Mustela nigripes, a carnivore indigenous to North America’s Great Plains, provides an example of species management that uses intensive population monitoring. Age class determination, however, is difficult because juveniles are adult-size at the time of dispersal in the wild. Our objective was to evaluate the use of body mass and canine width in aging Black-footed Ferrets. We measured known-aged captive-bred individuals and validated the findings in an intensively monitored
free-ranging population. Body mass could not be used to distinguish between juvenile and adult wild females, but could be used in wild and captive males, and in captive females. Canine width can be used to distinguish between juvenile and adult animals within sex. Canine width was similar between wild and captive individuals; therefore, results were grouped. For males, mean (± SE) canine width was smaller for juveniles (n = 40, 3.38 ± 0.04 mm, 95% confidence interval [CI] = 3.31–3.45 mm) than for adults (n = 33, 4.13 ± 0.06 mm, 95% CI = 4.01–4.24 mm). Similarly for females, canine width was smaller for juveniles (n = 49, 3.18 ± 0.04 mm, 95% CI = 3.11–3.25 mm) than for adults (n = 47, 3.66 ± 0.03 mm, 95% CI = 3.60–3.73 mm). Canine width changes with age apparently through recession of the gum-line and exposure of the tooth root. Therefore, visualisation of the canine tooth root may be a reliable indication of adulthood. Body mass may be inconsistent in the wild because of high variation in food availability. Canine width can allow age determination in the field, which will assist with the assessment of population dynamics of free-ranging Black-footed Ferrets and the success of recovery efforts.
[Show abstract][Hide abstract] ABSTRACT: Domestic cat oocytes are seasonally sensitive to FSH. Compared with those collected during the breeding season, oocytes from the nonbreeding (NB) season require more FSH during in vitro maturation to achieve comparable developmental competence. This study tested the hypothesis that this seasonal variation was due to altered expression of FSH receptors (FSHR) and/or FSH-induced genes. Relative expression levels of FSHR mRNA and FSH-enhanced gene estrogen receptor β (ESR2) were measured by qPCR in whole ovaries and immature cumulus-oocyte complexes (COCs) isolated from cat ovaries during the natural breeding vs NB seasons. Expression levels of FSH-induced genes prostaglandin-endoperoxide synthase 2 (PTGS2), early growth response protein-1 (EGR1), and epidermal growth factor receptor (EGFR) were examined in mature COCs from both seasons that were a) recovered in vivo or b) matured in vitro with conventional (1 μg/ml) or high (10 μg/ml) FSH concentrations. Overall, FSHR mRNA levels were lower in whole ovaries during the NB compared with breeding season but were similar in immature COCs, whereas ESR2 levels did not differ in either group between intervals. We observed changes in PTGS2, EGR1, and EGFR mRNA expression patterns across maturation in COCs within but not between the two seasons. The lack of seasonal differentiation in FSH-related genes was not consistent with the decreased developmental capacity of oocytes fertilized during the NB season. These findings reveal that the seasonal decrease in cat oocyte sensitivity to FSH occurs both in vivo and in vitro. Furthermore, this decline is unrelated to changes in expression of FSHR mRNA or mRNA of FSH-induced genes in COCs from antral follicles.
[Show abstract][Hide abstract] ABSTRACT: The female giant panda (Ailuropoda melanoleuca) experiences a brief (24-72 h) seasonal estrus, occurring once annually in spring (February-May). Our aim was to determine the existence and temporal profile of reproductive seasonality in the male of this species. The study was facilitated by 3 yr of access to eight giant panda males living in a large breeding center in China. Seasonal periods for the male were defined on the basis of female reproductive activity as prebreeding, breeding (early, peak, late), and nonbreeding seasons. Testes size, fecal androgen excretion, ejaculated sperm density, and frequency of reproductive behaviors (i.e., locomotion, scent marking, vocalizations) increased (P < 0.05) from the prebreeding period (October 1-January 31) to the early breeding season (February 1-March 21). Testes volume and sperm concentration were maximal from March 22 through April 15, a period coinciding with maximal female breeding activity. The occurrence of male reproductive behaviors and fecal androgen concentrations began declining during peak breeding and continued from April 16 through May 31 (late breeding period), returning to nadir throughout the nonbreeding interval (June 1-September 30). Reproductive quiescence throughout the latter period was associated with basal testes size/volume and aspermic ejaculates. Our results reveal that testes morphometry, fecal androgen excretion, seminal quality, and certain behaviors integrated together clearly demonstrate reproductive seasonality in the male giant panda. The coordinated increases in testes size, androgen production, sperm density, and sexual behaviors occur over a protracted interval, likely to prepare for and then accommodate a brief, unpredictable female estrus.
Full-text · Article · Apr 2012 · Biology of Reproduction
[Show abstract][Hide abstract] ABSTRACT: Non-invasive fecal steroid analyses were used to characterize gonadal activity in the fishing cat (Prionailurus viverrinus). Estrogen, progestagen and androgen metabolites were quantified in fecal samples collected for 12 months from four males and 10 females housed at seven North American zoological institutions. Male reproductive hormone concentrations did not vary (P>0.05) among season, and estrogen cycles were observed year-round in females and averaged (±SEM) 19.9±1.0 days. Mean peak estrogen concentration during estrus (460.0±72.6ng/g feces) was five-fold higher than baseline (87.3±14.0ng/g feces). Five of seven females (71.4%) housed alone or with another female demonstrated spontaneous luteal activity (apparent ovulation without copulation), with mean progestagen concentration (20.3±4.7μg/g feces), increasing nearly five-fold above baseline (4.1±0.8μg/g feces). The non-pregnant luteal phase averaged 32.9±2.5 days (n=13). One female delivered kittens 70 days after natural mating with fecal progestagen concentrations averaging 51.2±5.2μg/g feces. Two additional females were administered exogenous gonadotropins (150IU eCG; 100IU hCG), which caused hyper-elevated concentrations of fecal estrogen and progestagen (plus ovulation). Results indicate that: (1) male and female fishing cats managed in North American zoos are reproductively active year round; (2) 71.4% of females experienced spontaneous ovulation; and (3) females are responsive to exogenous gonadotropins for ovulation induction, but a regimen that produces a normative ovarian steroidogenic response needs to be identified.
No preview · Article · Oct 2011 · Animal reproduction science
[Show abstract][Hide abstract] ABSTRACT: Although the cheetah (Acinonyx jubatus) routinely lives for more than 12 yr in ex situ collections, females older than 8 yr reproduce infrequently. We tested the hypothesis that reproduction is compromised in older female cheetahs due to a combination of disrupted gonadal, oocyte, and uterine function/integrity. Specifically, we assessed 1) ovarian response to gonadotropins; 2) oocyte meiotic, fertilization, and developmental competence; and 3) uterine morphology in three age classes of cheetahs (young, 2-5 yr, n = 17; prime, 6-8 yr, n = 8; older, 9-15 yr, n = 9). Ovarian activity was stimulated with a combination of equine chorionic gonadotropin and human chorionic gonadotropin (hCG), and fecal samples were collected for 45 days before gonadotropin treatment and for 30 days after oocyte recovery by laparoscopy. Twenty-six to thirty hours post-hCG, uterine morphology was examined by ultrasound, ovarian follicular size determined by laparoscopy, and aspirated oocytes assessed for nuclear status or inseminated in vitro. Although no influence of age on fecal hormone concentrations or gross uterine morphology was found (P > 0.05), older females produced fewer (P < 0.05) total antral follicles and oocytes compared to younger counterparts. Regardless of donor age, oocytes had equivalent (P > 0.05) nuclear status and ability to reach metaphase II and fertilize in vitro. A histological assessment of voucher specimens revealed an age-related influence on uterine tissue integrity, with more than 87% and more than 56% of older females experiencing endometrial hyperplasia and severe pathologies, respectively. Our collective findings reveal that lower reproductive success in older cheetahs appears to be minimally influenced by ovarian and gamete aging and subsequent dysfunction. Rather, ovaries from older females are responsive to gonadotropins, produce normative estradiol/progestogen concentrations, and develop follicles containing oocytes with the capacity to mature and be fertilized. A more likely cause of reduced fertility may be the high prevalence of uterine endometrial hyperplasia and related pathologies. The discovery that a significant proportion of oocytes from older females have developmental capacity in vitro suggests that in vitro fertilization and embryo transfer may be useful for "rescuing" the genome of older, nonreproductive cheetahs.
Full-text · Article · May 2011 · Biology of Reproduction
[Show abstract][Hide abstract] ABSTRACT: The rediscovery of remnant Florida panthers (Puma concolor coryi) in southern Florida swamplands prompted a program to protect and stabilize the population. In 1995, conservation managers
translocated eight female pumas (P. c. stanleyana) from Texas to increase depleted genetic diversity, improve population numbers, and reverse indications of inbreeding depression.
We have assessed the demographic, population-genetic, and biomedical consequences of this restoration experiment and show
that panther numbers increased threefold, genetic heterozygosity doubled, survival and fitness measures improved, and inbreeding
correlates declined significantly. Although these results are encouraging, continued habitat loss, persistent inbreeding,
infectious agents, and possible habitat saturation pose new dilemmas. This intensive management program illustrates the challenges
of maintaining populations of large predators worldwide.
[Show abstract][Hide abstract] ABSTRACT: This study investigated the influence of progestin priming and ovarian quiescence on response to exogenous gonadotropin stimulation in the cat. Because a subpopulation of cats routinely ovulated spontaneously, there also was the opportunity to examine the ovary's reaction to the added impact of endogenously secreted progestagen. Queens were given 1) equine chorionic gonadotropin (eCG) plus human chorionic gonadotropin (hCG) only (control; n = 9 cats), 2) GnRH antagonist (antide) injections followed by eCG and hCG (n = 9), and 3) a progestin implant (levonorgestrel) followed by eCG and hCG (n = 9). Laparoscopy was used to assess ovarian activity and aspirate follicular oocytes that were graded on the basis of morphology. In five cats per treatment, half of the high-quality oocytes were assessed for glucose, pyruvate, and lactate metabolism as well as nuclear maturation. Remaining oocytes were inseminated in vitro, cultured, and examined at 72 h after insemination for cleavage. In the remaining four cats per treatment, all oocytes were inseminated in vitro and assessed at 72, 120, and 168 h after insemination for embryo developmental stage. Cats pretreated with progestin had more follicles and produced more embryos per donor (including at the combined morula/blastocyst stage) than controls or females treated with GnRH antagonist (P < 0.05). There were no differences among groups (P > 0.05) in oocyte carbohydrate metabolism, nuclear maturation metrics, or fertilization success, although there was a tendency toward improvements in all three (P < 0.2) in progestin-treated females. Interestingly, cats that spontaneously ovulated within 60 days of treatment onset also produced more embryos per cat than induced-ovulation counterparts (P < 0.05). Results indicate that prior exposure to exogenous progestin (via implant) or endogenous progestagen (via spontaneous ovulation) improves ovarian responsiveness to gonadotropins in the cat through a mechanism that is independent of the induction of ovarian quiescence.
Full-text · Article · May 2010 · Biology of Reproduction
[Show abstract][Hide abstract] ABSTRACT: Sperm cryopreservation, in combination with assisted reproductive techniques, is a valuable tool for the genetic management of endangered felids. However, the acrosome of the cheetah spermatozoon is especially sensitive to cryopreservation, with approximately 40% of spermatozoa experiencing acrosomal damage immediately after thawing and then another approximately 15% loss during the next 4 hours in vitro. Additionally, thawing causes a reduction in sperm motility by approximately 20% with another decrease of approximately 12% during subsequent incubation in vitro. We hypothesized that slow removal of glycerol from cryopreserved cheetah spermatozoa using an Accudenz gradient would improve acrosomal integrity, sperm motility longevity, and structural morphology. Accudenz was compared with traditional cheetah sperm processing methods for glycerol removal that involves washing, multistep resuspension, and swim-up processing. Electroejaculates (n = 21 total from 8 males) were washed in Ham F10 medium, and sperm pellets were resuspended in TEST-yolk buffer with 0% glycerol. Samples were cryopreserved in straws in 4% final glycerol, thawed, and assessed for percent intact acrosomes (% IA), percent motility (% M), and forward progressive status (FPS; scale, 0-5). Sperm motility index (SMI) was calculated as (% M + [FPS x 20]) / 2. In study 1, glycerol removal by centrifugation through an Accudenz gradient (4%, 10%) was compared with traditional sperm washing (control) and multistep resuspension protocols. At each time after centrifugation (hourly for 4 hours), % IA was improved (P < .05) for Accudenz (range, 36%-39%) compared with control (30%-33%) and multistep (29%-33%) treatments. In study 2, a modified Accudenz protocol was compared with traditional washing and was found to improve (P < .05) SMI (range, 52-64) compared with controls (range, 41-52) at each time postthaw after centrifugation. In study 3, swim-up processed sperm were compared with those treated by centrifugation through Accudenz and traditional sperm washing for improving sperm morphology. The percentage of structurally-normal sperm recovered postthawing increased (P < .05) for both the Accudenz (38%) and swim-up (33%) treatments compared with controls (21%). Percent IA and SMI also were improved (P < .05) for Accudenz (range, 39%-47% and 46-59, respectively) compared with controls (range, 26%-33% and 40-53, respectively). Results indicate that using Accudenz for glycerol removal from cryopreserved cheetah sperm mitigates the significant loss in sperm quality that occurs after freeze-thawing. This alleviation of cellular damage resulting from cryopreservation contributes to a more than 10% improvement in overall sperm motility and, more importantly, allows retention of 40% or more of sperm with intact acrosomes.
Preview · Article · Dec 2008 · Journal of Andrology
[Show abstract][Hide abstract] ABSTRACT: Ovarian sensitivity to exogenous gonadotropin stimulation (equine chorionic gonadotropin [eCG] and human chorionic gonadotropin [hCG]) following pre-treatment with a progestin (levonorgestrel) versus GnRH antagonist (antide) was studied in cats known to be induced versus spontaneous ovulators. Queens were assigned to one of three treatments: (1) levonorgestrel implants+eCG/hCG (n=7 cats); (2) antide injections+eCG/hCG (n=7) or (3) eCG/hCG alone (control; n=7). Hormonal metabolites were assessed in fecal samples collected daily for 60 days before and during the 37 days inhibitory pre-treatment and for more than 60 days after eCG/hCG. Fecal metabolites of estradiol and progesterone were measured by radioimmunoassay. Females that maintained baseline progesterone were considered induced ovulators, whereas cats that exhibited a luteal phase before inhibition treatment were classified as spontaneous ovulators. Based on fecal hormone profiles, levonorgestrel thoroughly inhibited ovarian activity, whereas antide synchronized follicular phases but did not induce complete ovarian down-regulation. Both treatments prevented ovulation in spontaneous ovulators, but neither caused regression of existing corpora lutea (CL). Levonorgestrel, but not antide, pre-treatment resulted in a quiescent ovary at the time of eCG injection, yet endocrine responses to eCG/hCG were not different among treatments. Interestingly, spontaneously ovulating females exhibited a prolonged estradiol response to gonadotropin stimulation compared to induced ovulators, and this prolonged estradiol surge was replicated by levonorgestrel pre-treatment. Thus, the progestin levonorgestrel effectively suppresses follicular and luteal activity in the cat, resulting in a more consistent response to gonadotropin stimulation, even in females prone to spontaneous ovulation.
No preview · Article · Mar 2008 · Domestic Animal Endocrinology
[Show abstract][Hide abstract] ABSTRACT: Disease can threaten the restoration of endangered species directly by substantially decreasing host survival or indirectly via incremental decreases in survival and reproduction. During a biomedical survey of reintroduced populations of the highly endangered black-footed ferret from 2002 to 2005, microfilariae discovered in the blood were putatively identified as Dirofilaria immitis, and widespread screening was initiated using a commercially available antigen-based ELISA test. A subset of animals (n=16) was screened for D. immitis using a highly sensitive PCR-based assay. Microfilariae were also molecularly and morphologically characterized. Of 198 animals at six reintroduction sites, 12% had positive results using the ELISA test. No antigen-positive animals which were screened via PCR (n=11) had positive PCR results, and all antigen-positive animals (n=24) were asymptomatic. No significant differences were found in body mass of antigen-positive (male: 1223±82 g [mean±SD], female: 726±75 g) vs. antigen-negative (male: 1,198±119 g, female: 710±53 g) individuals (P=0.4). Antigen prevalence was lower in juveniles (3%) than adults (12%; P=0.03), and higher in in situ, captive-reared individuals (33%) than wild-born individuals (10%; P=0.005). Morphologic analysis of microfilariae revealed they were neither D. immitis nor any other previously characterized North American species. PCR amplification of the 5S spacer region of rDNA revealed that the filarial sequence shared only 76% identity with D. immitis. This previously unidentified filarial sequence was present in all antigen positive animals (11 of 11 tested). It appears that black-footed ferrets were infected with a previously undescribed species of filaria whose antigen cross-reacted with the ELISA assay, although further analysis is needed to make a conclusive statement. Nonetheless, this previously undescribed filaria does not appear to threaten recovery for this highly endangered mammal.
Full-text · Article · Feb 2008 · Journal of wildlife diseases
[Show abstract][Hide abstract] ABSTRACT: Conservation strategies for the giant panda (Ailuropoda melanoleuca) include the development of a self-sustaining ex situ population. This study examined the potential significance of infectious pathogens in giant pandas ex situ. Serologic antibody titers against canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus (CAV), canine coronavirus (CCV), canine herpesvirus, canine parainfluenza virus (CPIV), Toxoplasma gondii, Neospora caninum, and Leptospira interrogans were measured in 44 samples taken from 19 giant pandas between 1998 and 2003 at the Chengdu Research Base of Giant Panda Breeding in Sichuan, China. Seroassays also included samples obtained in 2003 from eight red pandas (Ailurus fulgens) housed at the same institution. All individuals had been vaccinated with a Chinese canine vaccine that included modified live CDV, CPV, CAV, CCV, and CPIV. Positive antibody titers were found only against CDV, CPV, and T. gondii. Sera were negative for antibodies against the other six pathogens. Results indicate that the quality of the vaccine may not be reliable and that it should not be considered protective or safe in giant pandas and red pandas. Positive antibody titers against T. gondii were found in seven of the 19 giant pandas. The clinical, subclinical, or epidemiologic significance of infection with these pathogens via natural exposure or from modified live vaccines in giant pandas is unknown. Research in this area is imperative to sustaining a viable population of giant pandas and other endangered species.
Preview · Article · Jan 2008 · Journal of Zoo and Wildlife Medicine
[Show abstract][Hide abstract] ABSTRACT: Population augmentation with translocated individuals has been shown to alleviate the effects of bottlenecks and drift. The first step to determine whether restoration for genetic considerations is warranted is to genetically monitor reintroduced populations and compare results to those from the source. To assess the need for genetic restoration, we evaluated genetic diversity and structure of reintroduced (n = 3) and captive populations of the endangered black-footed ferret (Mustela nigripes). We measured genotypic changes among populations using seven microsatellite markers and compared phenotypic changes with eight morphometric characters. Results indicated that for the population which rapidly grew post-reintroduction, genetic diversity was equivalent to the captive, source population. When growth languished, only the population that was augmented yearly maintained diversity. Without augmentation, allelic diversity declined precipitously and phenotypic changes were apparent. Ferrets from the genetically depaupertate population had smaller limbs and smaller overall body size than ferrets from the two populations with greater diversity. Population divergence (F
ST = 0.10 ± 0.01) was surprisingly high given the common source of populations. Thus, it appears that 5–10 years of isolation resulted in both genotypic divergence and phenotypic changes to populations. We recommend translocation of 30–40 captive individuals per annum to reintroduction sites which have not become established quickly. This approach will maximize the retention of genetic diversity, yet maintain the beneficial effects of local adaptation without being swamped by immigration.
[Show abstract][Hide abstract] ABSTRACT: The science of cryobiology is essential to the effective, practical use of semen for assisted breeding to help manage small populations of rare wildlife species. In this review, we describe challenges associated with cryopreserving gametes from wild fauna. Based on more than 25 years of experience across a diversity of mammals, it appears that the primary driving force dictating cryo-survival of a spermatozoon is its initial pre-freeze quality and morphology, especially having a morphologically normal, intact acrosome. This assertion is supported through extensive studies of three animal groups that routinely ejaculate semen containing (1) normal sperm/acrosomal quality (examples, Eld's deer, Cervus eldi and giant panda, Ailuropoda melanoleuca), (2) normal acrosomal quality, but from teratospermic donors (>70% pleiomorphic sperm; cheetah, Acinonyx jubatus and black-footed ferret, Mustela nigripes) and (3) abnormal acrosomal quality and general teratospermia (clouded leopard, Neofelis nebulosa). Data revealed that species producing high quality sperm with > 70% normal, intact acrosomes were best able to survive cryopreservation (-80% intact acrosomes post-thaw). Species that were teratospermic, but with high proportions of intact acrosomes (72 to 88%) in ejaculates varied significantly (4 to 55% intact acrosomes post-thaw) in sperm survival to freeze-thawing. Spermatozoa from the clouded leopard (that was both teratospermic while producing only 11% normal acrosomes in fresh semen) failed to survive cryopreservation despite using an array of conventional and unconventional freezing approaches. These observations (combined with zona penetration assays and artificial insemination results) suggest that proportions of malformed sperm and especially initial structural integrity of the acrosome are more important predictors of sperm survivability post-thaw than initial sperm motility scores.
No preview · Article · Feb 2007 · Society of Reproduction and Fertility supplement
[Show abstract][Hide abstract] ABSTRACT: Among the 37 living species of Felidae, the clouded leopard (Neofelis nebulosa) is generally classified as a monotypic genus basal to the Panthera lineage of great cats. This secretive, mid-sized (16-23 kg) carnivore, now severely endangered, is traditionally subdivided into four southeast Asian subspecies (Figure 1A). We used molecular genetic methods to re-evaluate subspecies partitions and to quantify patterns of population genetic variation among 109 clouded leopards of known geographic origin (Figure 1A, Tables S1 ans S2 in the Supplemental Data available online). We found strong phylogeographic monophyly and large genetic distances between N. n. nebulosa (mainland) and N. n. diardi (Borneo; n = 3 individuals) with mtDNA (771 bp), nuclear DNA (3100 bp), and 51 microsatellite loci. Thirty-six fixed mitochondrial and nuclear nucleotide differences and 20 microsatellite loci with nonoverlapping allele-size ranges distinguished N. n. nebulosa from N. n. diardi. Along with fixed subspecies-specific chromosomal differences, this degree of differentiation is equivalent to, or greater than, comparable measures among five recognized Panthera species (lion, tiger, leopard, jaguar, and snow leopard). These distinctions increase the urgency of clouded leopard conservation efforts, and if affirmed by morphological analysis and wider sampling of N. n. diardi in Borneo and Sumatra, would support reclassification of N. n. diardi as a new species (Neofelis diardi).
[Show abstract][Hide abstract] ABSTRACT: The objective was to examine the influence of animal age, season and captivity status on seminal quality in wild-born cheetahs (Acinonyx jubatus) in Namibia, Africa. Animals were divided into three age categories: juvenile (14-24 months; n = 16 males, 23 ejaculates); adult (25-120 months; n = 76 males, 172 ejaculates); and aged (>120 months; n = 5 males, 5 ejaculates). Seasons were categorised into hot-wet (January-April), cold-dry (May-August) and hot-dry (September-December). A comparison between freshly wild-caught (n = 29 males, 41 ejaculates) and captive-held cheetahs (n = 68 males, 159 ejaculates) was also conducted. Raw ejaculates contained 69.0 +/- 1.1% motile spermatozoa (mean +/- s.e.m.) with 73.6 +/- 1.5% of these cells containing an intact acrosome. Overall, 18.4 +/- 0.9% of spermatozoa were morphologically normal, with midpiece anomalies being the most prevalent (approximately 39%) defect. Juvenile cheetahs produced ejaculates with poorer sperm motility, forward progressive status, lower seminal volume and fewer total motile spermatozoa than adult and aged animals. Spermatogenesis continued unabated throughout the year and was minimally influenced by season. Proportions of sperm malformations were also not affected by season. Ejaculates from captive cheetahs had increased volume and intact acrosomes, but lower sperm density than wild-caught counterparts. In summary, Namibian cheetahs produce an extraordinarily high proportion of pleiomorphic spermatozoa regardless of age, season or living (captive versus free-ranging) status. Young males less than 2 years of age produce poorer ejaculate quality than adult and aged males. Because (1) all study animals were wild born and (2) there was little difference between freshly caught males and those maintained in captivity for protracted periods, our results affirm that teratospermia in the cheetah is mostly genetically derived. It also appears that an ex situ environment for the Namibian cheetah can ensure sperm quality comparable with that for free-living males.
Full-text · Article · Jan 2007 · Reproduction Fertility and Development
[Show abstract][Hide abstract] ABSTRACT: Fundamental knowledge of spermatozoa cryobiology can assist with optimizing cryopreservation protocols needed for genetic management of the endangered black-footed ferret. Objectives were to characterize semen osmolality and assess the influence of two media at various osmolalities on sperm viability. We examined the influence of Ham's F10 +Hepes medium (H) at 270, 400, 500 or 700 mOsm (adjusted with sucrose, a nonpermeating cryoprotectant) and TEST Yolk Buffer (TYB) with 0% (300 mOsm) versus 4% (900 mOsm) glycerol (a permeating cryoprotectant). Electroejaculates (n=16) were assessed for osmolality using a vapor pressure osmometer. For media comparison, semen (n=5) was collected in TYB 0%, split into six aliquots, and diluted in H270, H400, H500, H700, and TYB 0% or TYB 4%. Each sample was centrifuged (300 g, 8 min), resuspended in respective medium, and maintained at 37 degrees C for 3h. Sperm motility and forward progression were monitored every 30 min for 3h post-washing. Acrosomal integrity was monitored at 0 and 60 min post-washing. Results demonstrated that black-footed ferret semen has a comparatively high osmolality (mean+/-SEM, 513.1+/-32.6 mOsm; range, 366-791 mOsm). Ferret spermatozoa were sensitive to hyperosmotic stress. Specifically, sperm motility was more susceptible (P<0.01) to hyperosmotic conditions than acrosomal integrity, and neither were influenced (P>0.05) by hypotonic solutions. Exposure to TYB 4% glycerol retained more (P<0.01) sperm motility than a hyperosmotic Ham's (700 mOsm). These findings will guide the eventual development of assisted breeding with cryopreserved sperm contributing to genetic management of this rare species.
[Show abstract][Hide abstract] ABSTRACT: Teratospermia (production of >60% morphologically abnormal sperm/ejaculate) is relatively common among various species in the family Felidae, which is comprised of 37 species. Over two decades of research in this area have produced a significant understanding of the phenotypic expression, its impacts on sperm function and etiology. There is good evidence suggesting that a reduction in genetic diversity contributes to this phenomenon. Results to date demonstrate that spermatozoa from teratospermic donors are compromised in the ability to undergo capacitation and the acrosome reaction, penetrate the zona-pellucida, fertilize conspecific oocytes and survive cryopreservation. Recent studies also reveal abnormalities in chromatin integrity in sperm from teratospermic donors, which, interestingly, fails to impact fertilization or embryo development after intracytoplasmic sperm injection. Through planned inbreeding studies, we now have established that teratospermic cats also produce more spermatozoa by virtue of more sperm producing tissue, more germ cells per Sertoli cell and reduced germ cell loss during spermatogenesis. Overall, it now is clear that gain in sperm quantity is achieved at the expense of sperm quality, suggesting an extensive disruption of normal testicular function in teratospermic donors. Preliminary studies on testicular gene expression in teratospermic cats have also revealed abnormal expression patterns. These findings have markedly increased our understanding of testis biology in the teratospermic donor and reaffirm the value of cats, including wild species, as models for studying novel regulatory mechanisms controlling spermatogenesis and spermiogenesis.