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1.
Zoo Biol ; 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39239884

RESUMO

It has been suggested repeatedly that zoo-kept giant anteaters (Myrmecophaga tridactyla) have higher body masses than their free-ranging conspecifics. Here, we assess this hypothesis by comparing body mass data of 184 female and 173 male individuals kept in zoos to published and unpublished data of free-ranging animals (n = 215). In zoos, the average adult body mass of all individuals was 45.9 ± 9.6 kg (range 19.2-72.6 kg), whereas body mass for free-ranging specimens was 33.0 ± 2.3 kg (21-45.5 kg). Among those zoo animals in which a sufficient number of subsequent intra-annual measures had been taken, we assessed visually whether regular, annual fluctuations in body mass were evident. We observed regular, likely seasonal, cycles in body mass, which (i) may be plausibly attributed to ambient temperature changes that affect the body temperature of anteaters, and (ii) would likely not have occurred if the animals were affected by obesity. Additionally, we explain our hypothesis that in the case of giant anteaters, the discrepancy in body mass between natural habitats and zoos most likely is not indicative of a generally obese population in zoos, as is typically concluded in the case of similar comparisons in primates, but represents an unleashing of the full growth potential of the species by conditions of optimal energy and nutrient provision. Future recording of not only body mass but also body dimensions is recommended to better compare the body condition of free-ranging and zoo-managed individuals.

2.
Zoo Biol ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38973722

RESUMO

Ex situ breeding constitutes an important tool for species conservation; however, many reptile species are not managed sustainably under human care due to poor fecundity in ex situ settings. In this study, we tested whether the translocation of a seasonally reproducing species to a different environment results in decoupling of extrinsic signals and intrinsic conditions. The endocrinological patterns of plasma steroid sex hormones, follicular development, and mating behaviour of two female and two male sexually mature Aldabra tortoises (Aldabrachelys gigantea) in a zoological institution in the Northern hemisphere was aligned with enclosure climate data (mean monthly daylight duration, temperature, and precipitation) and compared with respective hormone patterns of wild individuals and climate conditions in the native habitat on the Aldabra Atoll in the Southern hemisphere. Whereas occurrence of mating behaviour was not considered a limiting factor, lack of ovulation and subsequent follicular atresia was the main reason for the lack of reproductive output. While it was impossible to elucidate the triggering factors of ovulation and the multifactorial complexity of reproduction was not fully addressed, this study indicates suboptimal temperature conditions and relative temporal shifts of interacting external triggers (temperature and photoperiod) in the zoo setting.

3.
Environ Microbiol ; 19(4): 1502-1517, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28229543

RESUMO

Improving host health through microbial manipulation requires untangling factors that shape the microbiome. There is currently little understanding of how initial community structure may drive the microbiota trajectory across host development or influence bacterial therapy outcomes. Probiotic baths of surface symbionts, Pseudomonas fluorescens and Flavobacterium johnsoniae were administered to 240 tadpoles of the midwife toad, Alytes obstetricans in semi-natural outdoor mesocosms originating from geographically and genetically distinct populations in Switzerland. Host bacterial and fungal assemblages were compared in tadpoles from the pond of origin, across metamorphosis, and in toadlets via microbial fingerprinting. Bacterial and fungal community structures differed significantly among populations and a microbial population signature persisted from the tadpole stage, through metamorphosis, and following probiotic treatment. A minimal core surface microbiota is described by persistence through development and by shared membership across populations. The impact of F. johnsoniae on the tadpole surface microbiome was assessed with shotgun metagenomics. Bacterial therapy reduced abundance, diversity, and functional repertoire compared to untreated controls. A correlation between host skin peptides and microbiota suggests a mechanism of host-directed symbiosis throughout development. Early developmental stages are ideal targets for amphibian bacterial therapy that can govern a microbiome trajectory at critical timepoints and may impact susceptibility to disease.


Assuntos
Anuros/microbiologia , Microbiota , Animais , Biodiversidade , Fungos , Larva/microbiologia , Metagenômica , Microbiota/efeitos dos fármacos , Probióticos , Pele/microbiologia , Suíça , Simbiose
4.
Gigascience ; 112022 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-36251273

RESUMO

BACKGROUND: The Aldabra giant tortoise (Aldabrachelys gigantea) is one of only two giant tortoise species left in the world. The species is endemic to Aldabra Atoll in Seychelles and is listed as Vulnerable on the International Union for Conservation of Nature Red List (v2.3) due to its limited distribution and threats posed by climate change. Genomic resources for A. gigantea are lacking, hampering conservation efforts for both wild and ex situpopulations. A high-quality genome would also open avenues to investigate the genetic basis of the species' exceptionally long life span. FINDINGS: We produced the first chromosome-level de novo genome assembly of A. gigantea using PacBio High-Fidelity sequencing and high-throughput chromosome conformation capture. We produced a 2.37-Gbp assembly with a scaffold N50 of 148.6 Mbp and a resolution into 26 chromosomes. RNA sequencing-assisted gene model prediction identified 23,953 protein-coding genes and 1.1 Gbp of repetitive sequences. Synteny analyses among turtle genomes revealed high levels of chromosomal collinearity even among distantly related taxa. To assess the utility of the high-quality assembly for species conservation, we performed a low-coverage resequencing of 30 individuals from wild populations and two zoo individuals. Our genome-wide population structure analyses detected genetic population structure in the wild and identified the most likely origin of the zoo-housed individuals. We further identified putatively deleterious mutations to be monitored. CONCLUSIONS: We establish a high-quality chromosome-level reference genome for A. gigantea and one of the most complete turtle genomes available. We show that low-coverage whole-genome resequencing, for which alignment to the reference genome is a necessity, is a powerful tool to assess the population structure of the wild population and reveal the geographic origins of ex situ individuals relevant for genetic diversity management and rewilding efforts.


Assuntos
Tartarugas , Animais , Cromossomos/genética , Genoma , Genômica , Filogenia , Tartarugas/genética
5.
Front Zool ; 8(1): 8, 2011 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-21496358

RESUMO

BACKGROUND: Rescuing amphibian diversity is an achievable conservation challenge. Disease mitigation is one essential component of population management. Here we assess existing disease mitigation strategies, some in early experimental stages, which focus on the globally emerging chytrid fungus Batrachochytrium dendrobatidis. We discuss the precedent for each strategy in systems ranging from agriculture to human medicine, and the outlook for each strategy in terms of research needs and long-term potential. RESULTS: We find that the effects of exposure to Batrachochytrium dendrobatidis occur on a spectrum from transient commensal to lethal pathogen. Management priorities are divided between (1) halting pathogen spread and developing survival assurance colonies, and (2) prophylactic or remedial disease treatment. Epidemiological models of chytridiomycosis suggest that mitigation strategies can control disease without eliminating the pathogen. Ecological ethics guide wildlife disease research, but several ethical questions remain for managing disease in the field. CONCLUSIONS: Because sustainable conservation of amphibians in nature is dependent on long-term population persistence and co-evolution with potentially lethal pathogens, we suggest that disease mitigation not focus exclusively on the elimination or containment of the pathogen, or on the captive breeding of amphibian hosts. Rather, successful disease mitigation must be context specific with epidemiologically informed strategies to manage already infected populations by decreasing pathogenicity and host susceptibility. We propose population level treatments based on three steps: first, identify mechanisms of disease suppression; second, parameterize epizootiological models of disease and population dynamics for testing under semi-natural conditions; and third, begin a process of adaptive management in field trials with natural populations.

6.
PLoS One ; 9(1): e87101, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24489847

RESUMO

Microbial communities can augment host immune responses and probiotic therapies are under development to prevent or treat diseases of humans, crops, livestock, and wildlife including an emerging fungal disease of amphibians, chytridiomycosis. However, little is known about the stability of host-associated microbiota, or how the microbiota is structured by innate immune factors including antimicrobial peptides (AMPs) abundant in the skin secretions of many amphibians. Thus, conservation medicine including therapies targeting the skin will benefit from investigations of amphibian microbial ecology that provide a model for vertebrate host-symbiont interactions on mucosal surfaces. Here, we tested whether the cutaneous microbiota of Panamanian rocket frogs, Colostethus panamansis, was resistant to colonization or altered by treatment. Under semi-natural outdoor mesocosm conditions in Panama, we exposed frogs to one of three treatments including: (1) probiotic - the potentially beneficial bacterium Lysinibacillus fusiformis, (2) transplant - skin washes from the chytridiomycosis-resistant glass frog Espadarana prosoblepon, and (3) control - sterile water. Microbial assemblages were analyzed by a culture-independent T-RFLP analysis. We found that skin microbiota of C. panamansis was resistant to colonization and did not differ among treatments, but shifted through time in the mesocosms. We describe regulation of host AMPs that may function to maintain microbial community stability. Colonization resistance was metabolically costly and microbe-treated frogs lost 7-12% of body mass. The discovery of strong colonization resistance of skin microbiota suggests a well-regulated, rather than dynamic, host-symbiont relationship, and suggests that probiotic therapies aiming to enhance host immunity may require an approach that circumvents host mechanisms maintaining equilibrium in microbial communities.


Assuntos
Anuros/imunologia , Bacillus/fisiologia , Quitridiomicetos/imunologia , Dermatomicoses/veterinária , Microbiota/imunologia , Proteínas de Anfíbios/fisiologia , Animais , Peptídeos Catiônicos Antimicrobianos/fisiologia , Anuros/microbiologia , Dermatomicoses/imunologia , Resistência à Doença , Interações Hospedeiro-Patógeno , Probióticos , Pele/metabolismo , Pele/microbiologia , Redução de Peso/imunologia
7.
PLoS One ; 9(4): e96375, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24789229

RESUMO

Pathogenesis is strongly dependent on microbial context, but development of probiotic therapies has neglected the impact of ecological interactions. Dynamics among microbial communities, host immune responses, and environmental conditions may alter the effect of probiotics in human and veterinary medicine, agriculture and aquaculture, and the proposed treatment of emerging wildlife and zoonotic diseases such as those occurring on amphibians or vectored by mosquitoes. Here we use a holistic measure of amphibian mucosal defenses to test the effects of probiotic treatments and to assess disease risk under different ecological contexts. We developed a non-invasive assay for antifungal function of the skin mucosal ecosystem (mucosome function) integrating host immune factors and the microbial community as an alternative to pathogen exposure experiments. From approximately 8500 amphibians sampled across Europe, we compared field infection prevalence with mucosome function against the emerging fungal pathogen Batrachochytrium dendrobatidis. Four species were tested with laboratory exposure experiments, and a highly susceptible species, Alytes obstetricans, was treated with a variety of temperature and microbial conditions to test the effects of probiotic therapies and environmental conditions on mucosome function. We found that antifungal function of the amphibian skin mucosome predicts the prevalence of infection with the fungal pathogen in natural populations, and is linked to survival in laboratory exposure experiments. When altered by probiotic therapy, the mucosome increased antifungal capacity, while previous exposure to the pathogen was suppressive. In culture, antifungal properties of probiotics depended strongly on immunological and environmental context including temperature, competition, and pathogen presence. Functional changes in microbiota with shifts in temperature provide an alternative mechanistic explanation for patterns of disease susceptibility related to climate beyond direct impact on host or pathogen. This nonlethal management tool can be used to optimize and quickly assess the relative benefits of probiotic therapies under different climatic, microbial, or host conditions.


Assuntos
Anfíbios/imunologia , Anfíbios/microbiologia , Quitridiomicetos/fisiologia , Interações Hospedeiro-Patógeno , Probióticos/uso terapêutico , Anfíbios/fisiologia , Animais , Quitridiomicetos/imunologia , Mucosa/imunologia , Mucosa/microbiologia , Mucosa/fisiologia , Pele/imunologia , Pele/microbiologia , Simbiose
8.
Infect Genet Evol ; 12(8): 1854-64, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22940461

RESUMO

Heterogeneity in immune defense effectors can benefit hosts encountering a variety of parasites and pathogens. Antimicrobial peptides (AMPs) are a diverse set of immune defense effectors in many amphibians, and are secreted from dermal granular glands to protect the skin from infection. Over 50 different skin peptides have been reported from the European water frog hybridogenic complex (Pelophylax esculentus complex), consisting of the hybrid P. esculentus, and the parent species Pelophylax lessonae and Pelophylax ridibundus. In central Europe the hybrid is sympatric with only P. lessonae, while in other areas all three species can co-occur. Amphibian immune defenses are likely under selective pressure from emerging pathogens such as the chytrid fungus Batrachochytrium dendrobatidis (Bd). To assess if hybridization affects immune defenses against Bd, we compared skin peptides of the three species in terms of (i) quantity, (ii) activity against Bd, (iii) repertoire, and (iv) stability. Hybrids secreted AMPs at higher quantities and with greater fungicidal activity compared to cohabiting P. lessonae. Compared to P. ridibundus, AMPs from hybrids were of similar quantity but slightly greater antifungal activity. Mass spectrometric analyses (MALDI-TOF) revealed that of all three species P. esculentus has the greatest peptide diversity, a repertoire inclusive of peptides occurring in either one or the other parent species. Measurements of degradation dynamics indicate that peptides remain relatively stable on the skin of all species for over an hour after induction of skin gland secretions. Our data demonstrate that the hybrid has more effective peptide defenses against Bd and a richer peptide repertoire than either parent species. Hybrid advantage in environments hosting virulent pathogens may contribute to disassortative mating preferences, and we suggest that AMP diversity may be analogous to major histocompatibility complex (MHC) heterozygosity by benefiting hosts encountering multiple parasites.


Assuntos
Peptídeos Catiônicos Antimicrobianos/imunologia , Ranidae/imunologia , Pele/imunologia , Sequência de Aminoácidos , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Quitridiomicetos/efeitos dos fármacos , Biologia Computacional , Dados de Sequência Molecular , Norepinefrina , Ranidae/genética , Ranidae/metabolismo , Pele/química , Pele/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
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