Captive Stock Research Articles

Genetic Characterization of Endangered Sterlet (Acipenser ruthenus, Linnaeus 1758) Gene Bank Broodstock, Natural and Cultured Populations in Hungary

The sterlet (Acipenser ruthenus) is the smallest-bodied endangered species among the six native sturgeon species of the Danube River, and self-sustaining populations still inhabit the Hungarian section of the Danube River and its largest tributary, the Tisza River. Their populations are drastically decreasing; however, they still have natural reproduction in these habitats. For the genetic conservation of the species, an ex situ gene bank is maintained in Hungary. The present study aimed to analyze the genetic resources of a gene bank with a near 40-year history and to compare it with natural populations and farmed stocks. Twelve microsatellites were used for population genetics analyses and individual genotyping of 268 specimens from two natural habitats (Danube and Tisza Rivers) and three captive stocks (a gene bank broodstock and two farms). Microsatellites revealed similar patterns among wild populations and gene bank stocks and did not show genetic differentiation (FST: 0.016–0.017) among them. These results confirmed that the gene bank broodstock properly represents the genetic background of the Danube and Tisza populations and is suitable as a source of breeding materials for the restocking programs. Negative trends were detected in the farmed stocks, reflected in reduced polymorphism at a few loci. The results of the principal component analyses indicate the farm stocks’ separation from the wild and gene bank stocks. The present genetic characterization study reveals a valuable captive stock of the endangered sterlet populations and provides unique information about the genetic similarities and differences among farms and wild stocks in Hungary. Our results provide information that contributes to preserving the genetic structure and variability in sterlet populations and supports the management of gene bank broodstock—avoiding inbreeding and preserving the unique genetic background of the Carpathian basin.

Wildlife farming: Balancing economic and conservation interests in the face of illegal wildlife trade

Abstract Demand for wildlife and their products continues to grow, often despite increasingly militarised regulation and consumer awareness campaigns. We review the sustainability, legality and feasibility of wildlife farming of animals, as a potential conservation tool to ensure the development of an equitable and sustainable trade model. While there are some positive examples of well‐managed wildlife farming in trade, we identify common themes of misuse including the intentional mislabelling of wild‐caught specimens in global trade and the use of wild‐caught individuals to supplement captive stocks. We also highlight the frequent failure to incorporate biological data into management strategies, resulting in the widespread use of species with potentially unfavourable life history traits, which constrain the economic and biological sustainability of wildlife farming programmes. We develop a structured decision framework to aid the examination of when wildlife farming may most benefit or hinder species conservation. Synthesis and applications. Key opportunities include developing species suitability assessments and removing barriers to legitimate participation with wildlife farming among poor, rural communities. In the absence of management strategies that address the issues of species suitability and accessibility, wildlife farming will continue to place significant strain on wild populations while failing to provide conservation value and sustainable economic returns. Read the free Plain Language Summary for this article on the Journal blog.

A new sex-specific genetic marker (fshr 1834G>T) for flathead grey mullet, Mugil cephalus, in Queensland, Australia

In this study, genetic sex marker candidates from northern hemisphere Mugil cephalus were tested to see if they could be used to sex a population originating from south-east Queensland, Australia. As such, a region of the follicle stimulating hormone receptor (fshr) gene was sequenced but did not contain previously published single nucleotide polymorphisms (SNPs). However, further screening of the sequenced fshr region revealed a promising sex marker candidate for Queensland M. cephalus, fshr 1834 G>T, which was accurate in 100% of fish tested (excluding intersex fish, which had the female genotype). While all females tested were homozygous G/G, males presented as either G/T (common) or T/T (lower frequency). Subsequently, a real-time high-resolution melt was developed to facilitate rapid and accurate genotyping of M. cephalus based on the fshr 1834 G>T SNP. Initial results suggest that fshr 1834 G>T is a useful SNP that can reduce the need for more invasive sampling techniques such as gonadal biopsy, provide information relating to the sex of captive stock prior to gonadal maturation, and may prove useful in wild population surveys and stock assessment.

Effect of Different Levels of Dietary Lipids on Reproductive Performance of Captive Broodstock of <i>Macrobrachium rosenbergii</i>

The present paper reports the results of a laboratory experiment to study the effect of different levels of dietary lipids on reproductive performance of captive broodstock of giant freshwater prawn Macrobrachium rosenbergii. Three formulated pellet diets were prepared containing 2% (D1), 4% (D2) and 6% (D3) lipid and fed to adult females of M. rosenbergii (Av. body weight - 28 g) at 5% of the biomass per day for 60 days. Prawns fed D3 showed significantly higher (P<0.05) weight gain (221.16±6.48 mg/day) compared to those fed D1 and D2. Similarly, significantly higher (P<0.05) reproductive parameters like fecundity (eggs/ g body weight) (1153.6±174.25), egg clutch weight (g) (4.9±0.25) and gonado-somatic index (6.82±0.27) were also found in prawns fed D3. Reproductive effort (g eggs/ female x100), post–hatch fecundity (nos. of larvae/ g female) and mid gut gland somatic index (%) also showed a similar trend. The present results clearly indicated that dietary lipid level of 6% significantly enhances reproductive performance of captive stock of M. rosenbergii compared to 2% and 4% lipid levels.

Assessment of population structure and genetic diversity of wild and captive populations of Ammotragus lervia provide insights for conservation management

The aoudad (Ammotragus lervia) is a Vulnerable bovid endemic of North Africa. Although legally protected in almost every country of its native distribution, the aoudad continues to be hunted for meat and trophy in both North Africa and the countries where it has been introduced. The species was subject to past translocations planned irrespectively of the genetic diversity and local adaptations of source and receiving populations, and no management or conservation units have ever been designed. We aim to provide here important insights on the taxonomy of the aoudad subspecies and the genetic diversity of most of its wild and captive populations. We collected 127 invasive and non-invasive samples from five of the six subspecies of aoudad recognized to date. We could successfully retrieve genetic data for 74 samples. Of those, 36 provided both nuclear (11 microsatellites) and mitochondrial (Cyt-b) data, 31 just nuclear data, and six just mitochondrial data. We implement Bayesian approaches to infer the population structure and phylogenetic relationships between the different populations/subspecies and backtrack the maternal lineages of introduced individuals in European populations. Our results support the presence of four genetically different wild populations, corresponding to three distinct mitochondrial lineages plus a fourth group restricted to Egypt identified by the nuclear markers. We also provide genetic evidence on the affiliation of some introduced European populations with respect to the native ones. The genetic diversity instead of variation within all wild populations was low. This might be a consequence of small effective population size and/or high inbreeding degree, probably related to hunting, decline in habitat availability and quality (i.e. overgrazing, and frequent drought), and high inbreeding degree. Our results provide important information for the aoudad conservation, including reintroductions and reinforcement actions of wild populations, and the exchange of individuals among captive stocks.

Genetic Assessment of Remnant Sub-Populations of Sterlet (Acipenser ruthenus Linnaeus, 1758) in the Upper Danube

While the potamodromous sterlet was common in the past throughout the Upper Danube in Germany and Austria, it nearly vanished in the second half of the 20th century. Until recently, only one small and isolated reproductive sub-population is known from the German–Austrian border. However, isolated remnants in another section downstream of Vienna, near the Austrian–Slovakian border, were discovered in 2014. An assessment of the population size is one of the most important prerequisites for conservation management. This study aims to assess the population sizes at both sites, using genetic pedigrees and comparison to mark–recapture data. A total of 193 samples collected from these populations between 2011 and 2021 have been investigated. In addition, 59 samples from captive stocks, 38 wild fish from downstream, and 247 genetic profiles from previous studies were used for comparison. Results show close relationships and intermittent reproduction on one site. Estimated populations based upon genetic pedigree are very small, and are consistent with mark–recapture results. Small population sizes of remnant populations have only limited, sporadic reproduction, as well as continual losses to outmigration support conservation actions for sturgeons in the Upper Danube, including the restoration of functional migration corridors.

Different Chromosome Segregation Patterns Coexist in the Tetraploid Adriatic Sturgeon Acipenser naccarii

The Adriatic sturgeon, Acipenser naccarii (Bonaparte, 1836), is a critically endangered tetraploid endemism of the Adriatic region; it has been targeted, over the last 20 years, by different conservation programs based on controlled reproduction of captive breeders followed by the release of their juvenile offspring; its preservation would greatly benefit from the correct and coordinated management of the residual genetic variability available in the different captive stocks. In this sense, the setup of an efficient parental allocation procedure would allow identifying familiar groups and establishing informed breeding plans, effectively preserving genetic variation. However, being the species tetraploid, the analyses often deal with complex genome architecture and a preliminary evaluation of allele segregation patterns at different chromosomes is necessary to assess whether the species can be considered a pure tetraploid, as previously observed at some loci, or if a more complex situation is present. Here we study the segregation at 14 microsatellites loci in 12 familiar groups. Results support in different families the tetrasomic segregation pattern at 11 markers and the disomic segregation at three markers. The Adriatic sturgeon thus shows a mixed inheritance modality. In this species, and likely in other sturgeons, accurate knowledge of the loci used for paternity analysis is therefore required.

Red Junglefowl Resource Management Guide: Bioresource Reintroduction for Sustainable Food Security in Thailand

The domestication of wild animals represents a major milestone for human civilization. Chicken is the largest domesticated livestock species and used for both eggs and meat. Chicken originate from the red junglefowl (Gallus gallus). Its adaptability to diverse environments and ease of selective breeding provides a unique genetic resource to address the challenges of food security in a world impacted by climatic change and human population growth. Habitat loss has caused population declines of red junglefowl in Thailand. However, genetic diversity is likely to remain in captive stocks. We determine the genetic diversity using microsatellite genotyping and the mitochondrial D-loop sequencing of wild red junglefowl. We identified potential distribution areas in Thailand using maximum entropy models. Protected areas in the central and upper southern regions of Thailand are highly suitable habitats. The Bayesian clustering analysis of the microsatellite markers revealed high genetic diversity in red junglefowl populations in Thailand. Our model predicted that forest ranges are a highly suitable habitat that has enabled the persistence of a large gene pool with a nationwide natural distribution. Understanding the red junglefowl allows us to implement improved resource management, species reintroduction, and sustainable development to support food security objectives for local people.

Genetic diversity and relatedness inferred from microsatellite loci as a tool for broodstock management of fine flounder Paralichthys adspersus

Paralichthys adspersus is a native species from the Pacific coast of South America that is of great economic importance for Peruvian aquaculture. Even though establishing sustainable farming depends on avoiding irreversible damage to the population gene pool due to processes such as inbreeding, studies focusing on genetically characterizing farmed stocks are yet to be documented. By using ten microsatellite loci on captive and wild individuals of P. adspersus, we successfully characterized the only commercial broodstock of this species in Peru by means of determining the genetic diversity and inferring relatedness. Although most microsatellite loci showed deviations from Hardy-Weinberg equilibrium, the genetic diversity levels in the commercial broodstock were considered healthy compared to those obtained for a wild population, with an average number of alleles of 17.40, an effective number of alleles of 9.14, and an observed and expected heterozygosity of 0.49 and 0.87. No significant differences between the broodstock and the wild population in terms of genetic diversity were observed. The fixation index and analysis of molecular variance also indicated a low rate of differentiation between both populations. In relatedness estimation, the analysis based on five method-of-moment estimators and a maximum-likelihood estimator showed the category “unrelated” as being the most probable relationship among the individuals within the commercial broodstock. Our findings reveal the conservation of genetic diversity in this population and outline potential breeding strategies that hatchery managers could use to minimize the loss of genetic diversity and long-term inbreeding. This could help establish proper genetic management in captive populations of P. adspersus and should apply to other captive stocks where pedigree information is lacking.

Breeding ecology of the Quailfinch (Ortygospiza atricollis) in the Limpopo Province, South Africa

The Quailfinch (Ortygospiza atricollis) is a widespread African estrildid that features in specialist avicultural collections. However, the species is poorly known and has proven difficult to maintain in captivity, and as such, most captive stock represent wild-caught specimens. Here we report on the breeding ecology of a population of wild Quailfinches as observed at 62 nests in the 2012–2013 and 2013–2014 breeding seasons. Although Quailfinch bred during the wet season, incidental observations suggest rainfall patterns and the availability of suitable habitat for nesting, specifically habitat structure, may influence the onset of the breeding season at a local scale. Both sexes participated in all aspects of nest construction, including collection of material, construction, and maintenance. Nests were occupied for extensive periods prior to the commencement of laying, fulfilling a possible nest guarding or pair bonding function. Mean clutch size was 4.8 eggs (SD 0.2) and there were no significant seasonal differences in clutch size. Both sexes incubated and the incubation period lasted 14 d (SD 0.8). In common with many other estrildid species, there was considerable variation in the onset of incubation. Mean nest attendance during incubation was 83% and was similar between the sexes. The mean nestling period lasted 16.8 d (SD 0.8) and both sexes brooded and provisioned the nestlings with seeds and occasionally invertebrates. Growth was unusually rapid for estrildids, but within the range expected for ground-nesting passerines. The overall breeding success was 12% with predation being the main cause of nest failure.

Hostile Interactions of Punjab Urial (Ovis vignei punjabiensis) towards Indian Gazelle (Gazella bennettii) during Feeding Sessions in Captive Breeding Settings.

Simple SummaryMultiple factors, both natural and anthropogenic, are driving most of the wild species to the verge of extinction across the globe. In order to conserve these threatened species, various conservation interventions and strategies are adopted, among which is re-introduction of captive stocks of species into the wild habitats where they vanished from. Captive breeding is one of the promising tools for endangered species preservation. Providing social enrichment to the captive stocks is an important step in the management, in particular for stocks, which are aimed for re-introduction. The subject species of this study, i.e., Punjab urial (Ovis vignei punjabiensis) and Indian gazelle (Gazella bennettii) are being reared in captivity with the aim of re-introduction. As there is scarcity of information regarding the behavioral aspects of captive species, especially ungulates, this study aimed at understanding the dynamics of their interactions. The current study reported that Punjab urial, being the dominant species, exerts itself on the submissive and subordinate species, the Indian gazelle. This negative interference can possibly lead to negative ramifications in the form of stress and injuries in the short term, while negative effects on population growth in the long term. Thus, this study recommends separate rearing of these species to eliminate the hazardous competition between them.Natural wildlife habitats are regularly subjected to anthropogenic pressures for different purposes, which are heading the biodiversity towards drastic decline. Several endangered wild species are raised in captivity with the aim of re-introduction. In some instances, mixed herds’ rearing approach in captivity is adopted for providing social enrichment to captive stocks; however, the impacts of species on each other are least documented. We tested our prediction that keeping mixed herds of captive wild sheep and antelopes provides adequate social enrichment to the captive stocks: if interspecific interactions are balanced. In the current study, we studied the interspecific competition between mixed herds of captive Punjab urial (Ovis vignei punjabiensis) and Indian gazelle (Gazella bennettii) at Manglot Wildlife Park, Nowshera District, Khyber Pakhtunkhwa Province, Pakistan. We documented the negative effects of behavioural interference by Punjab urial on the feeding behaviour of Indian gazelle. The outcome of the current study revealed that Punjab urial are highly intolerant towards Indian gazelle, with high interference during feeding. Out of the total aggressive events, 77% (N = 1259) of events ended up with win/loss, in which Punjab urial dominated the Indian gazelle 3.5 times. Moreover, lopsided dominance by Punjab urial resulted in increased intraspecific competition among Indian gazelle (p < 0.001). Current study divulged Indian gazelle to be the subordinate species, with less intake of food. Instead of providing social enrichment by heterospecifics, the Punjab urial is negatively affecting the Indian gazelle, therefore, the results of our study discourage the practice of admix captive breeding for wild sheep and antelopes.

Amyloodinium sp. (Brown, 1931) (Dinoflagellida) infestation in captive stock of silver moony, Monodactylus argenteus (Linnaeus, 1758)

This study was undertaken to investigate the cause of mortality in the captive stock of silver moony Monodactylus argenteus. The fishes showed severe infection of dinoflagellate protozoan Amyloodinium sp. (Blastodinida, Oodiniaceae) on gills and skin with complete mortality of the stock within a week. Histopathological changes were evident in the gill tissues with severe lamellar epithelial cell hyperplasia and lamellar fusions with the presence of trophonts of Amyloodinium sp. Scanning electron microscopy (SEM) also revealed trophonts of Amyloodinium sp. of varying sizes in groups consisting of 3 to 5 trophonts tightly attached to gill lamellae. Source water contaminated with the tiny infectious form of the parasite (dinospores) favoured by higher salinity and low water temperature in the rearing tank could be the triggering factor for the spurt of infections. Proper quarantine and biosecurity protocols to prevent the potential sources of water-borne infection sources are likely to be far more effective than treatment.

Fifty Years of Research on European Mink Mustela lutreola L., 1761 Genetics: Where Are We Now in Studies on One of the Most Endangered Mammals?

The purpose of this review is to present the current state of knowledge about the genetics of European mink Mustela lutreola L., 1761, which is one of the most endangered mammalian species in the world. This article provides a comprehensive description of the studies undertaken over the last 50 years in terms of cytogenetics, molecular genetics, genomics (including mitogenomics), population genetics of wild populations and captive stocks, phylogenetics, phylogeography, and applied genetics (including identification by genetic methods, molecular ecology, and conservation genetics). An extensive and up-to-date review and critical analysis of the available specialist literature on the topic is provided, with special reference to conservation genetics. Unresolved issues are also described, such as the standard karyotype, systematic position, and whole-genome sequencing, and hotly debated issues are addressed, like the origin of the Southwestern population of the European mink and management approaches of the most distinct populations of the species. Finally, the most urgent directions of future research, based on the research questions arising from completed studies and the implementation of conservation measures to save and restore M. lutreola populations, are outlined. The importance of the popularization of research topics related to European mink genetics among scientists is highlighted.

Ontogeny and Dynamics of the Gonadal Development, Embryogenesis, and Gestation in Xenotoca eiseni (Cyprinodontiformes, Goodeidae)

We characterized the ontogeny and dynamics of gonadal development, embryogenesis, and gestation in captive stocks of the viviparous redtail splitfin, Xenotoca eiseni. Using histology, we showed that gonads were fully differentiated at the time of birth with a male:female sex ratio of 1:1 in the captive stock. External secondary sex features included a modified anal fin and a distinctive orange tail coloration. These features first appeared at 4 weeks after birth and were discriminative for males thereafter. There was no sex-related dichotomy in body size, and X. eiseni reached sexual maturity at approximately 12 weeks of age. We found no evidence for sperm storage in females. Gestation normally took 6 weeks, and there was a positive correlation between female body size and the number of offspring produced, with up to 27 offspring for a single pregnancy. Yolk is the main food source for developing embryos for the period up to 2 weeks, and thereafter, trophotaeniae in embryos act as nutrient exchange surfaces in the ovarian lumen, which subsequently undergo complete regression within 2 weeks of birth. In our final analysis, we discuss the great potential of X. eiseni as a model for studying the effects of chemicals on sexual development.

Genetic diversity and demographic history of introduced sika deer on the Delmarva Peninsula.

The introduction of non‐native species can have long‐term effects on native plant and animal communities. Introduced populations are occasionally not well understood and offer opportunities to evaluate changes in genetic structure through time and major population changes such as bottleneck and or founder events. Invasive species can often evolve rapidly in new and novel environments, which could be essential to their long‐term success. Sika deer are native to East Asia, and their introduction and establishment to the Delmarva Peninsula, USA, is poorly documented, but probably involved ≥1 founder and/or bottleneck events. We quantified neutral genetic diversity in the introduced population and compared genetic differentiation and diversity to the presumed source population from Yakushima Island, Japan, and a captive population of sika deer in Harrington, Delaware, USA. Based on the data from 10 microsatellite DNA loci, we observed reduced genetic variation attributable to founder events, support for historic hybridization events, and evidence that the population did originate from Yakushima Island stocks. Estimates of population structure through Bayesian clustering and demographic history derived from approximate Bayesian computation (ABC), were consistent with the hypothesized founder history of the introduced population in both timing and effective population size (approximately five effective breeding individuals, an estimated 36 generations ago). Our ABC results further supported a single introduction into the wild happening before sika deer spread throughout the Delmarva. We conclude that free‐ranging sika deer on Delmarva are descended from ca. five individuals introduced about 100 years ago from captive stocks of deer maintained in the United Kingdom. Free‐ranging sika deer on Delmarva have lost neutral diversity due to founder and bottleneck events, yet populations have expanded in recent decades and show no evidence of abnormalities associated with inbreeding. We suggest management practices including increasing harvest areas and specifically managing sika deer outside of Maryland.

Isolation and Characterization of 27 Novel Microsatellite Loci in Critically Endangered Wyoming Toad

Abstract Wyoming toad Anaxyrus baxteri is a federally endangered amphibian endemic to the Laramie basin in southwestern Wyoming, USA. A captive breeding program propagates A. baxteri, and the monitoring of genetic diversity in the captive stock can assist in guiding conservation measures of this species. Illumina paired-end sequencing lead to 27 species-specific polymorphic microsatellite genetic markers being developed. Across 24 samples, A. baxteri exhibited two to eight alleles per locus, and observed and expected heterozygosities per locus ranged from 0.292 to 0.958 and from 0.344 to 0.787, respectively. Tests for Hardy–Weinberg equilibrium were nonsignificant except for Abax_13 and Abax_39. These microsatellite markers will be useful for genetic monitoring to aid recovery efforts of A. baxteri captive and wild populations as well as other amphibians in the family Bufonidae.

Endoscopy and Cannulation as Non-Invasive Tools to Identify Sex and Monitor Reproductive Development in Arapaima gigas

The lack of tools for sex identification and assessment of gonadal development are hindering our ability to study the reproductive dysfunction of Arapaima gigas in captivity. This study initially aimed to validate a non-surgical endoscopy procedure to identify sex in juveniles and assess stage of ovary development in female broodstock under field operational conditions. Cannulation, assisted through the description of the genital anatomy, made ovarian biopsy possible to describe oocyte development from primary growth to pre-ovulation, providing a first classification scheme for oogenesis in the species including description of the micropyle morphology using scanning electron microscopy. Cannulation was also successfully performed without endoscopic guidance, which allowed monitoring of ovarian development along the reproductive season together with profiling of plasma sex steroids (17β-estradiol [E2] and 11-ketotestosterone [11-KT] in females and males, respectively). The monitoring of our study population showed females paired with males in earthen ponds sexually matured and reached oocyte maturation during the spawning season. However, since no spawning was recorded, eggs had either been resorbed or released and not fertilized by the male. Plasma E2 levels remained high in females, as expected in an asynchronous species during the spawning season with multiple batches of oocytes being recruited. Plasma 11-KT showed a tendency to decrease, suggesting a male reproductive dysfunction or the end of the reproductive season with a lack of synchronization between sexes. In conclusion, endoscopy and cannulation are tools that can be promptly applied to aid sex identification, assessment of reproductive function, and overall broodstock management in wild and captive stocks. These tools will greatly help future studies looking at the effects of environmental, social, and hormonal cues on reproductive development with the aim of developing a spawning induction protocol for the species.

How many came home? Evaluating ex situ conservation of green turtles in the Cayman Islands.

Ex situ management is an important conservation tool that allows the preservation of biological diversity outside natural habitats while supporting survival in the wild. Captive breeding followed by re-introduction is a possible approach for endangered species conservation and preservation of genetic variability. The Cayman Turtle Centre Ltd was established in 1968 to market green turtle (Chelonia mydas) meat and other products and replenish wild populations, thought to be locally extirpated, through captive breeding. We evaluated the effects of this re-introduction programmme using molecular markers (13 microsatellites, 800-bp D-loop and simple tandem repeat mitochondrial DNA sequences) from captive breeders (N=257) and wild nesting females (N=57) (sampling period: 2013-2015). We divided the captive breeders into three groups: founders (from the original stock), and then two subdivisions of F1 individuals corresponding to two different management strategies, cohort 1995 ("C1995") and multicohort F1 ("MCF1"). Loss of genetic variability and increased relatedness was observed in the captive stock over time. We found no significant differences in diversity among captive and wild groups, and similar or higher levels of haplotype variability when compared to other natural populations. Using parentage and sibship assignment, we determined that 90% of the wild individuals were related to the captive stock. Our results suggest a strong impact of the re-introduction programmme on the present recovery of the wild green turtle population nesting in the Cayman Islands. Moreover, genetic relatedness analyses of captive populations are necessary to improve future management actions to maintain genetic diversity in the long term and avoid inbreeding depression.

Transferability of heterologous microsatellite primers in Brycon gouldingi

ABSTRACT: Brycon gouldingi is a species of neotropical fish of socioeconomic and environmental importance in the Tocantins-Araguaia Basin. Genetic studies on this species are still limited, making it difficult to evaluate the population structure and genetic diversity in natural and captive stocks. Here, we aimed to evaluate the transferability of heterologous microsatellite primers in B. gouldingi. A total of 30 primers for eight species were evaluated: Brycon hilarii, Brycon opalinus, Brycon cephalus, Brycon orbignyanus, Prochilodus lineatus, Prochilodus argenteus, Piaractus mesopotamicus, and Colossoma macropomum. The primers that showed the best amplification patterns were applied to 20 specimens of B. gouldingi, and their genetic parameters were assessed. Among the 30 primers, seven showed satisfactory transferability, six of which belonged to the genus Brycon: Bh13 (B. hilarii), BoM5, BoM13 (B. opalinus), Borg9, Borg13, and Borg59 (B. orbignyanus), and one belonged to P. argenteus (Par80). The primers for the other species tested showed non-specificity or monomorphism; and were therefore, excluded from the analyses. The number of alleles ranged between two (Borg13 and Borg59) and three (Bh13, BoM5, BoM13, Borg9 and Par80), with sizes varying between 103 bp (BoM5) and 430 bp (Borg9). Four primers showed evidence of null alleles (BoM13, Borg9, Borg13, and Par80), which could probably be attributed to the respective Hardy-Weinberg deviation. Thus, seven primers were validated for cross-amplification in B. gouldingi, which may be used in future studies involving this species.

Captivity-Induced Changes in the Skin Microbial Communities of Hellbenders (Cryptobranchus alleganiensis).

Variation in environmental conditions can result in disparate associations between hosts and microbial symbionts. As such, it is imperative to evaluate how environmental variables (e.g., habitat quality) can influence host-associated microbiome composition. Within wildlife conservation programs, captive conditions can negatively influence the establishment and maintenance of "wild-type" microbiotas within a host. Alternative microbial communities can result in the proliferation of disease among captive stock or upon reintroduction. Hellbenders (Cryptobranchus alleganiensis) are a threatened salamander for which extensive captive management is currently employed. Using metabarcoding, we characterized the skin microbiota of wild and captive hellbenders from two subspecies in the state of Missouri, the eastern (C. a. alleganiensis) and the Ozark hellbender (C. a. bishopi). Both subspecies in our study included wild adults and captive juveniles that were collected from the wild as eggs. Our objectives were to investigate differences in the skin microbial communities' richness/diversity, composition, and functional profiles of microbes between wild and captive individuals. Captive eastern hellbenders possessed richer communities than wild cohorts, whereas the opposite pattern was observed within the Ozark subspecies. We found significant microbial community structure between wild and captive populations of both subspecies. Microbiota structure translated into differences in the predicted metagenome of wild and captive individuals as well. As such, we can expect captive hellbenders to experience alternative microbial structure and function upon reintroduction into the wild. Our study provides a baseline for the effect of captivity on the skin microbial communities of hellbenders, and highlights the need to incorporate microbiota management in current captive-rearing programs.