Ultrasonographic-guided retrieval and in vitro maturation of eland (Taurotragus oryx) and bongo (Tragelaphus eurycerus isaaci) antelope oocytes

The limited availability of gametes is a major factor hindering the development and application of assisted reproductive technologies (ART) in large non-domestic ungulates. This is partly due to the small number of captive animals and handling difficulties associated with procedures for gamete recovery. In the present study, results are reported of multi-year studies on ovarian stimulation and oocyte retrieval by ultrasonographic-guided transvaginal follicular aspiration and subsequent in vitro maturation (IVM) in eland and bongo antelopes. All procedures were conducted on sedated females handled in a hydraulic chute without inducing general anesthesia. Five estrous synchronization/ovarian stimulation protocols were evaluated and data are presented on 73 and 15 procedures in eland and bongo, respectively. Repeating procedures (< or =once/month) on the same female did not affect ovarian response or number oocytes recovered in either species. Eland females, but not the ovarian stimulation treatment, affected ovarian response. Ovarian stimulation treatment affected oocyte recovery rate in eland, but not in bongo. In both species, ovarian hormone stimulation treatment affected the distribution of follicles by size and the status of expansion of the cumulus cell investment of oocytes, but not the frequency of metaphase II oocytes during IVM. The timing of extrusion of the first polar body during IVM was more synchronous in bongo than in eland oocytes. It is concluded that Transvaginal oocyte retrieval (TVOR) can be safely and repeatedly applied in gonadotropin-treated eland and bongo females to recover oocytes that can mature in vitro. The methods described for the present study can be adapted to improve the availability of non-domestic ungulate oocytes for basic and applied studies.     

Hand-rearing reduces fear of humans in European starlings, Sturnus vulgaris

Pending changes in European legislation ban the use of wild-caught animals in research. This change is partly justified on the assumption that captive-breeding (or hand-rearing) increases welfare of captive animals because these practices result in animals with reduced fear of humans. However, there are few actual data on the long-term behavioural effects of captive-breeding in non-domestic species, and these are urgently needed in order to understand the welfare and scientific consequences of adopting this practice. We compared the response of hand-reared and wild-caught starlings to the presence of a human in the laboratory. During human presence, all birds increased their general locomotor activity but the wild-caught birds moved away from the human and were less active than the hand-reared birds. After the human departed, the wild-caught birds were slower to decrease their activity back towards baseline levels, and showed a dramatic increase in time at the periphery of the cage compared with the hand-reared birds. We interpret these data as showing evidence of a greater fear response in wild-caught birds with initial withdrawal followed by a subsequent rebound of prolonged attempts to escape the cage. We found no effects of environmental enrichment. However, birds in cages on low shelves were less active than birds on upper shelves, and showed a greater increase in the time spent at the periphery of their cages after the human departed, perhaps indicating that the lower cages were more stressful. In demonstrating reduced fear of humans in hand-reared birds, our results support one of the proposed welfare benefits of this practice, but without further data on the possible welfare costs of hand-rearing, it is not yet possible to reach a general conclusion about its net welfare impact. However, our results confirm a clear scientific impact of both hand-rearing and cage position at the behavioural level.     

Chromosomal instability in the cattle clones derived by somatic cell nuclear-transfer

Cytogenetic analysis was performed on peripheral lymphocytes collected from 20 cattle clones (19 showed no overt phenotypic abnormalities except for high birth weight while 1 exhibited left forelimb contracture), the donor cell cultures from which they were derived and lymphocytes from six insemination produced control cattle. All animals and cell cultures had a modal chromosome number of 60. The frequency of abnormal cells for donor cell cultures, clones, and controls was 6.68+/-0.30%, 5.30+/-5.49%, and 5.08+/-1.04%, respectively, and did not differ significantly among the groups. There were, however, two clones derived from different donor cell cultures with high incidences of 21.29% and 20.13%, of abnormal cells consisting of pseudodiploid (near-diploid), near-triploid and near-tetraploid, and tetraploid cells. Among these two clones, one had only a few endoreduplicated nuclei although further studies are necessary to precisely define the cytological origin and nature of the abnormal cells. The clones were evaluated at multiple time points for up to 20 months of age and the incidence of abnormal lymphocytes remained stable indicating that the chromosomally abnormal nuclei found in cloned animals was not a transient event. These results show that the majority of phenotypically normal clones have normal chromosomal make up but that instability of chromosome number can occur in clones that are phenotypically normal. Therefore, cytogenetical evaluation of peripheral lymphocytes and other tissues with follow up of the phenotypical consequences of these abnormalities is warranted even in phenotypically normal clones.     

Cryopreservation of gametes and embryos of non-domestic species.

Many species of mammals are threatened or endangered. Methods of assisted reproduction that are being used with increasing frequency to produce offspring of domestic animals and humans are often viewed as offering innovative ways to reproduce non-domestic species as well. Uncounted millions of live young of domestic or laboratory species have been produced from gametes and embryos stored at -70 degrees C or below, sometimes for as long as 25 to 35 yrs. Such methods of cryopreservation are now being applied with increasing frequency and urgency to preserve gametes and embryos of non-domestic and threatened species to establish "genome resource banks" or "frozen zoos." But levels of success to produce live young from such cryopreserved gametes or embryos vary considerably from species to species, as well as from individual to individual. It is sometimes thought that differences among species in fundamental characteristics of their gametes may determine the efficacy of cryopreservation and the production of live young. However, it may not be that ineffective cryopreservation is responsible for low success rates. Rather, the limiting factor may be insufficient information and knowledge of the most basic reproductive biology of such non-domestic species. Even standard methods of cryopreservation may be completely adequate to act as a "temporary" expedient to preserve germplasm of non-domestic species to permit time to acquire a fuller understanding of the biology and behavior of non-domestic species.     

Chromosome variation in the embryos of domestic animals

Chromosome abnormalities in the embryos of domestic animals are mostly eliminated during development. De novo chromosome abnormalities in the embryos of domestic animals have been detected in a larger proportion of embryos produced by in vitro fertilization and somatic cell nuclear transfer than in those produced by natural mating or artificial insemination. The increased incidence of abnormalities in embryos produced in vitro provides evidence for an influence of the embryo production procedures on chromosome stability. Research strategies involving cytogenetics, molecular biology and reproductive biotechnologies hold the promise of yielding insight into the mechanisms underlying chromosome instability in embryos and the impact of the in vitro environment on the chromosome make-up of embryos.     

Modeling del(17)(p11.2p11.2) and dup(17)(p11.2p11.2) contiguous gene syndromes by chromosome engineering in mice: phenotypic consequences of gene dosage imbalance

Contiguous gene syndromes (CGS) are a group of disorders associated with chromosomal rearrangements of which the phenotype is thought to result from altered copy numbers of physically linked dosage-sensitive genes. Smith-Magenis syndrome (SMS) is a CGS associated with a deletion within band p11.2 of chromosome 17. Recently, patients harboring the predicted reciprocal duplication product [dup(17)(p11.2p11.2)] have been described as having a relatively mild phenotype. By chromosomal engineering, we created rearranged chromosomes carrying the deletion [Df(11)17] or duplication [Dp(11)17] of the syntenic region on mouse chromosome 11 that spans the genomic interval commonly deleted in SMS patients. Df(11)17/+ mice exhibit craniofacial abnormalities, seizures, marked obesity, and male-specific reduced fertility. Dp(11)17/+ animals are underweight and do not have seizures, craniofacial abnormalities, or reduced fertility. Examination of Df(11)17/Dp(11)17 animals suggests that most of the observed phenotypes result from gene dosage effects. Our murine models represent a powerful tool to analyze the consequences of gene dosage imbalance in this genomic interval and to investigate the molecular genetic bases of both SMS and dup(17)(p11.2p11.2).     

Measuring social tolerance: An experimental approach in two lemurid primates

Social tolerance crucially affects the life of group‐living animals as it can influence, among other things, their competitive regimes, access to food, learning behavior, and recruitment. However, social tolerance tests were mainly conducted in semi‐free or captive populations, and we know little about the behavioral mechanisms and consequences of social tolerance under natural conditions. We therefore developed a co‐feeding experiment to measure social tolerance in groups of wild and captive animals across two primate species. Specifically, we recorded the social tolerance level of redfronted lemurs (Eulemur rufifrons, four wild, one captive group) and ringtailed lemurs (Lemur catta, three wild, three captive groups) by presenting a clumped food resource in an experimental arena, and recorded patterns of resource use during the experiment. Because redfronted lemurs exhibit lower levels of decided conflicts than ringtailed lemurs, we predicted that they would be socially more tolerant. The probability for an individual to feed in the arena was higher in redfronted lemurs than in ringtailed lemurs. In addition, in both species, the probability for an individual to feed in the arena was higher in the captive populations than in their wild counterparts, suggesting that proximate factors, such as a relaxation of feeding competition in captivity, may adapt species‐specific levels of social tolerance to local levels of food availability. Hence, the number of individuals co‐feeding on a valuable food resource appears to be a useful proxy of social tolerance that could be measured with this experimental setup in other wild and captive species as well.     

The breeding of captive wild species by artificial methods

The growing interest in many zoos, wildlife parks and game ranches in the captive breeding of wild species has brought about much interest and research in developing and testing artificial methods of breeding. Much of this work has been concentrated in endangered species. The author outlines the relevance and utilization of such techniques and reviews successful attempts in this area and elaborates on future potential ones. A brief review is given of successful artificial methods of breeding domestic species and how this may be applied to non-domestic ones. Areas that are covered are semen collection, semen freezing, induction of estrus, artificial insemination, embryo transfer including interspecies transfer and embryo surgery. It is acknowledged that it is highly unlikely that an artificial program could save a species from extinction but such methods could greatly assist a comprehensive natural breeding program.     

Modeling population viability of captive elephants in Myanmar (Burma): implications for wild populations

Captive Asian elephants Elephas maximus , used as work animals, constitute up to 22–30% of remaining Asian elephants. Myanmar has the largest captive population worldwide (∼6000), maintained at this level for over a century. We used published demographic data to assess the viability of this captive population. We tested how this population can be self-sustained, how many elephants must be supplemented from the wild to maintain it, and what consequences live capture may have for Myanmar's wild population. Our results demonstrate that the current captive population is not self-sustaining because mortality is too high and birth rates are too low. Our models also suggest ∼100 elephants year⁻¹ have been captured in the wild to supplement the captive population. Such supplementation cannot be supported by a wild population of fewer than 4000 elephants. Given the most recent expert estimate of ∼2000 wild elephants remaining in Myanmar, a harvest of 100 elephants year⁻¹ could result in extinction of the wild population in 31 years. Continued live capture threatens the survival of wild and captive populations and must stop. In addition, captive breeding should be increased. These measures are essential to slow the decline and extinction of all of Myanmar's elephants.     

Evaluating and minimising social stress in the care of captive bottlenose dolphins (Tursiops aduncus)

Stress can increase an organism’s susceptibility to disease. Thus, managing stress and its causes are important elements of captive care. Social factors such as changes in group dynamics, competition over resources, and unstable dominance hierarchies are potential stressors for highly social animals such as bottlenose dolphins (Tursiops sp). We present three case studies of mortality and illness in captive bottlenose dolphins and suggest that stress, resulting from social instability and ensuing aggressive interactions, is likely to have played a role in these health consequences. Stress is implicated by blood profiles, loss of appetite, and gastric ulcers, and social problems and instability are evident in the quantitative analysis of individual activity levels and association patterns. This is a unique study on marine mammals in that it demonstrates a correlation between quantitative behavioral indices and physiological measures of stress and health. Recommendations are made for the management of captive dolphins including regular quantitative assessment of behavior and associations and maintenance of appropriate groupings of age and sex classes. Behavioral records can be an important early indicator of health problems and may also serve as a useful tool for recognizing potentially stressful social changes and circumstances. Zoo Biol 21:5–26, 2002. © 2002 Wiley‐Liss, Inc.     

Do experiments with captive non-domesticated animals make sense without population field studies? A case study with blue tits' breeding time

A complete understanding of the spatio-temporal variation in phenotypic traits in natural populations requires a combination long-term field studies with experiments using captive animals. Field studies allow the formulation of realistic hypotheses, but have the disadvantage that they do not allow the complete control of many potential confounding variables. Studies with captive animals allow tests of hypotheses that cannot be examined in the field, but have the disadvantage that artificial environments may provoke abnormal behaviour. Long-term studies that follow simultaneously captive and wild bird populations are rare. In a study lasting several years, we show here the unexpected patterns that two populations with a similar breeding time in the wild have non-overlapping breeding times in outdoor aviaries, and that two wild populations separated by a short geographical distance show differences in the expression of natural behaviour in captivity. The experimental design used is exceptional in the sense that the captive populations were held at similar latitudes and altitudes as the wild populations. Our case study shows that studies with captive animals can lead to wrong conclusions if they are carried out without population field studies, and without knowledge of the natural habits and habitats of the species involved. To examine the reliability of experiments with captive animals, comparisons with findings from population field studies are essential.     

The phenotypic costs of captivity

The breeding of threatened species in captivity for release is a central tool in conservation biology. Given gloomy predictions for biodiversity trends in the Anthropocene, captive breeding will play an increasingly important role in preventing future extinctions. Relative to the wild, captive environments drastically alter selection pressures on animals. Phenotypic change in captive animals in response to these altered selection pressures can incur fitness costs post-release, jeopardising their potential contribution to population recovery. We explore the ways in which captive environments can hinder the expression of wild phenotypes. We also stress that the phenotypes of captive-bred animals differ from their wild counterparts in multiple ways that remain poorly understood. We propose five new research questions relating to the impact of captive phenotypes on reintroduction biology. With better use of monitoring and experimental reintroductions, a more robust evidence base should help inform adaptive management and minimise the phenotypic costs of captivity, improving the success of animal reintroductions.     

Notes on the teeth and ovaries of an African elephant (Loxodonta africana) of known age

A captive female African elephant, known to be 27 years old, died as a result of trauma. Her growth rate was similar to that of other captive African elephants, and slightly greater than that of wild animals. The 5th molar was in full wear, and the 6th was just coming into wear. There was extensive dental caries of the labial, lingual and occlusal surfaces of the 5th molars, presumably due to the unnatural diet. The ovaries contained a number of large cystic follicles, and at least 50 regressing corpora lutea. These abnormalities are probably related to the fact that the elephant had never been mated.     

Managerial strategies in the captive propagation of endangered species

A captive propagation manager, committed to the welfare of captive populations of exotic animals, must often make decisions that are risky to individual animals. Innovative decisions that place animals at risk are essential to the progress of captive propagation. Such decisions must be grounded thoroughly on peer consultation, the scientific and zoo literature, and where possible on original applied research targeted specifically to the procedure in question. The management of two closely spaced births in a gorilla group is provided as an example.     

Chromosome abnormalities without phenotypic consequences

Some changes in chromosome morphology, detected during cytogenetic analysis, are not associated with clinical defects. Therefore a proper discrimination of harmless variants from true abnormalities, especially during prenatal diagnosis, is crucial to allow precise counseling. In this review we described chromosome variants and examples of chromosome anomalies that are considered to be unrelated to phenotypic consequences. The correlation between the presence of marker chromosomes and a risk of clinical signs is also discussed. Structural rearrangements of heterochromatic material, satellite polymorphism, or fragile sites, are well-known examples of common chromosome variation. However, the absence of clinical effects has also been reported in some cases of chromosome abnormalities concerning euchromatin. Such euchromatic anomalies were divided into 2 categories: unbalanced chromosome abnormalities (UBCAs), such as deletions or duplications, and euchromatic variants (EVs). Recently so-called molecular karyotyping, especially whole-genome screening by the use of high-resolution array-CGH technique, contributed to revealing a high number of previously unknown small genomic variations, which seem to be asymptomatic, as they are present in phenotypically normal individuals.     

Impact of naturally spawning captive-bred Atlantic salmon on wild populations: depressed recruitment and increased risk of climate-mediated extinction

The assessment report of the 4th International Panel on Climate Change confirms that global warming is strongly affecting biological systems and that 20–30% of species risk extinction from projected future increases in temperature. It is essential that any measures taken to conserve individual species and their constituent populations against climate-mediated declines are appropriate. The release of captive bred animals to augment wild populations is a widespread management strategy for many species but has proven controversial. Using a regression model based on a 37-year study of wild and sea ranched Atlantic salmon (Salmo salar) spawning together in the wild, we show that the escape of captive bred animals into the wild can substantially depress recruitment and more specifically disrupt the capacity of natural populations to adapt to higher winter water temperatures associated with climate variability. We speculate the mechanisms underlying this seasonal response and suggest that an explanation based on bio-energetic processes with physiological responses synchronized by photoperiod is plausible. Furthermore, we predict, by running the model forward using projected future climate scenarios, that these cultured fish substantially increase the risk of extinction for the studied population within 20 generations. In contrast, we show that positive outcomes to climate change are possible if captive bred animals are prevented from breeding in the wild. Rather than imposing an additional genetic load on wild populations by releasing maladapted captive bred animals, we propose that conservation efforts should focus on optimizing conditions for adaptation to occur by reducing exploitation and protecting critical habitats. Our findings are likely to hold true for most poikilothermic species where captive breeding programmes are used in population management.     

Inbreeding depression in ring-tailed lemurs (<Emphasis Type="Italic">Lemur catta</Emphasis>): genetic diversity predicts parasitism,immunocompetence, and survivorship

The consequences of inbreeding have been well studied in a variety of taxa, revealing that inbreeding has major negative impacts in numerous species, both in captivity and in the wild; however, as trans-generational health data are difficult to obtain for long-lived, free-ranging species, similar analyses are generally lacking for nonhuman primates. Here, we examined the long-term effects of inbreeding on numerous health estimates in a captive colony of ring-tailed lemurs (Lemur catta), housed under semi-natural conditions. This vulnerable strepsirrhine primate is endemic to Madagascar, a threatened hotspot of biodiversity; consequently, this captive population represents an important surrogate. Despite significant attention to maintaining the genetic diversity of captive animals, breeding colonies invariably suffer from various degrees of inbreeding. We used neutral heterozygosity as an estimate of inbreeding and showed that our results reflect genome-wide inbreeding, rather than local genetic effects. In particular, we found that genetic diversity affects several fitness correlates, including the prevalence and burden of Cuterebra parasites and a third (N = 6) of the blood parameters analyzed, some of which reflect immunocompetence. As a final validation of inbreeding depression in this captive colony, we showed that, compared to outbred individuals, inbred lemurs were more likely to die earlier from diseases. Through these analyses, we highlight the importance of monitoring genetic variation in captive animals—a key objective for conservation geneticists—and provide insight into the potential negative consequences faced by small or isolated populations in the wild. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Meiosis and sex chromosome aneuploidy: how meiotic errors cause aneuploidy; how aneuploidy causes meiotic errors

As a group, sex chromosome aneuploidies - the 47,XXY, 47,XYY, 47,XXX and 45,X conditions - constitute the most common class of chromosome abnormality in human live-births. Considerable attention has been given to the somatic abnormalities associated with these conditions, but less is known about their meiotic phenotypes; that is, how does sex chromosome imbalance influence the meiotic process. This has become more important with the advent of assisted reproductive technologies, because individuals previously thought to be infertile can now become biological parents. Indeed, there are several recent reports of successful pregnancies involving 47,XXY fathers, and suggestions that cryopreservation of ovarian tissue might impart fertility to at least some Turner syndrome individuals. Thus, the possible consequences of sex chromosome aneuploidy on meiotic chromosome segregation need to be explored.     

Genetic characterization of wild and captive rhesus macaques in China

The genetic structures of wild and captive rhesus macaque populations within China were compared by analyzing the mtDNA sequences of 203 captive-bred Chinese rhesus macaques with 77 GenBank sequences from wild-caught animals trapped throughout China. The genotypes of 22 microsatellites of captive Chinese rhesus macaques were also compared with those of captive Indian animals. The Chinese population is significantly differentiated from the Indian population and is more heterogeneous. Thus, compared with Indian rhesus macaques the phenotypic variance of traits with high heritability will be inflated in Chinese animals. Our data suggest that the western Chinese provinces have more subdivided populations than the eastern and southern Chinese provinces. The southern Chinese populations are the least structured and might have been more recently established. Human-mediated interbreeding among captive Chinese populations has occurred, implying that Chinese breeding strategies can influence the interpretation of biomedical research in the USA.