Captive Breeding Research Articles

Melhor aproveitamento da carcaça do jacaré e caracterização físico-química da carne separada mecanicamente

ABSTRACT: The captive breeding of the Pantanal caiman (Caiman yacare) offers great potential for the full use of all the component parts of the animal. The meat is an option for human consumption with good sensory acceptance, the skin is valued on the international market and the carcass can be used for obtaining mechanically separated caiman meat (MSCM). This research evaluated the physical chemical parameters of mechanically separated meat obtained from caiman yacare carcass to improve its yield. The proximate composition, lipid oxidation, pH, total volatile bases (TVB) and color during storage under freezing at -18 °C for 90 days were all evaluated. The MSCM presented low lipid content, high protein content and good stability during storage under freezing for 90 days. These results demonstrated that MSCM can be used in the development of caiman meat products.

Genomic data reveal strong differentiation and reduced genetic diversity in island golden eagle populations

Abstract Understanding population structure and the extent and distribution of genetic diversity are recognized as central issues in endangered species research, with broad implications for effective conservation management. Advances in whole genome sequencing techniques provide greater resolution of genome-wide genetic diversity and inbreeding. Subspecies of golden eagles (Aquila chrysaetos) in Scotland (A. c. chrysaetos) and Japan (A. c. japonica) are endangered; it is therefore important to understand genetic diversity and inbreeding of these small island populations to increase the chances of conservation success. We investigated this using whole genome sequencing data from golden eagles in Scotland, continental Europe, Japan, and the USA. Following determination of population genetic structure, analysis of heterozygosity and nucleotide diversity revealed reduced levels of genetic diversity together with runs of homozygosity, suggesting evidence of inbreeding attributable to recent shared parental ancestry in the island populations. These results highlight the need to consider genetic reinforcement of small isolated golden eagle populations from neighbouring outbred populations, alongside existing efforts to boost population size through within-island conservation translocations and captive breeding programmes.

Protective Measures for Dalian Spotted Seal Reserve

Dalian Spotted Seal Reserve is one of the eight harbor seal breeding areas in the world. Leopard seals in the Liaodong Bay breeding area lack genetic gene exchange with other breeding areas in the world, and there is a phenomenon of reproductive isolation. They belong to a branch of the world's independently evolved leopard seals and have their own unique genetics, so are of high conservation value in this regard. This paper highlights the benefits that aquaculture and captive breeding bring to protected areas. The focus of aquatic products is mainly on the bottom-sown varieties. There is a foundation for artificial breeding, and what people need to do is to continue to expand the number and scope when there is sufficient funding. At the same time, this paper will clarify the relationship between them, and explain the measures and development of seal protection from the biological and economic perspectives. Both focus studies could help further protect seals.

Patrones de cambios cromáticos en juveniles y adultos de la castañeta Nexilosus latifrons (Cichliformes: Pomacentridae)

Patterns of temporal chromatic and shape variations of live specimens of Nexilosus latifrons were studied. Observations were made on specimens captured in intertidal pools in the coastal area of Arica, northern Chile, which were kept in captivity for 16 months. Five developmental stages, in which there were noticeable changes in shape and colouration, were described. Findings obtained primarily to improve species identification are discussed, as well as to prevent removal of juvenile specimens from the environment and improve captive breeding practices.

Genetic distinctiveness of an endangered falcon: Implications for conservation in Europe.

In the Falconidae, the genus Falco comprises species of large birds of prey with wide distribution worldwide. However, the European lanner falcon Falco biarmicus feldeggii is rapidly heading for global extinction following a dramatic decline caused by anthropogenic interference. Conservation projects are currently underway with the main purpose of increasing its population size in the Mediterranean basin through captive breeding and release of birds into the wild. To support the projects, and strengthen the legitimacy of conservation efforts consistently with the Evolutionary Significant Unit concept, we explored the possibility of characterising the gene pool of the European lanner and reliably distinguishing it from other falcon taxa inhabiting the Mediterranean area, which show morphological and genetic similarities. To address the issue, we examined genetic variability at the nuclear level through the analysis of 12 neutral Short Tandem Repeat loci, and, for the first time in these taxa, two single-copy functional genes, coding for the brain-derived neurotrophic factor precursor and the oocyte maturation factor, respectively. The second exon of the major histocompatibility complex class II B gene was also investigated. Additionally, to frame our data with previously published data, we assess variation at the mitochondrial level by sequencing portions of the cytochrome b, 12S rRNA gene, and the control region. Our results showed that the European lanner is highly distinct from other falcon taxa, as revealed by nuclear, but not by mitochondrial DNA. We discuss our findings focusing on their implications for the preservation of this highly endangered European bird, and highlighted the critical role of genetic information in planning and monitoring concrete interventions.

A review of conservation status of freshwater fish diversity in China.

China harbors a high species diversity of freshwater fishes not shared with any of its neighboring nations. Freshwater fish diversity in the country has been under severe threat from human activities over the past decades, thus conservation freshwater fishes and ecosystems is urgently needed. To accumulate baseline data for guiding protection actions, the third red list assessment of Chinese freshwater fishes was carried out. Among Chinese freshwater fishes assessed, there are 355 at-risk species (22.3% of the total), including 69 ranked as Critically Endangered, 97 as Endangered, and 189 as Vulnerable. Two species are classified as Extinct and one as Regionally Extinct. China's threat level seems to be lower than the known average level found in the IUCN's global assessment of freshwater fishes, but this is an artifact of a high rate of species classified as Data Deficient. Conservation of freshwater fishes is presently facing a grim situation in China. Imperilment of Chinese freshwater fishes is primarily attributed to habitat loss and degradation arising from human perturbations, particularly river damming. Despite the adoption of protected areas setting up, captive breeding and release, and a fishing moratorium, conservation efforts for freshwater fishes are compromised by disproportional attention in China's biodiversity conservation, baseline data deficiency, insufficiently designed protection networks, and inefficient or inadequate implementation of conservation strategies. To achieve the objectives of Chinese freshwater fish conservation, it is proposed to conduct a national-scale survey of fish diversity and reassess their at-risk status, develop systematic conservation planning of freshwater fish diversity and ecosystems, prioritize strategies for protected areas development, perform genetic-based captive breeding for releasing in concert with other protection actions, and implement flexible fishing moratorium strategies in different water bodies.

Genetic insights to assist management of the Critically Endangered hangul Cervus hanglu hanglu in the Kashmir Himalaya

AbstractThe hangul Cervus hanglu hanglu, a Critically Endangered mountain ungulate of Jammu and Kashmir, India, faces the imminent threat of population loss and extinction. Effective management of its largest viable population in Dachigam National Park in the Kashmir Himalaya requires reliable demographic information. Using 14 microsatellite markers we identified 293 individuals (208 females and 85 males) through faecal analysis, and generated data on the genetic status and population size of the hangul in its winter habitat. The mean expected and observed heterozygosities of 0.62 and 0.59 are comparable to those of several red deer Cervus elaphus populations elsewhere. The effective population sizes were 46.3 and 93.7 when the frequencies of rare alleles were considered to be 0.050 and 0.010, respectively. The average mean kinship of the population was 0.34, and there was no evidence of a recent bottleneck event. In genetic mark–recapture analysis the best model included an effect of sex on both detection and recapture probabilities. Detection of males was highest in November, coinciding with the hangul breeding season, whereas detection of females was highest in December. Our estimate of the hangul population using genetic mark–recapture with bootstrapping was 394 individuals. To our knowledge, this is the first study to use genetic data to estimate the population of the hangul. It will guide future studies of this subspecies and also serve as an impetus for identifying founder animals for captive breeding, and for connecting the population in Dachigam National Park with the other small, isolated populations to ensure the long-term survival of this subspecies.

Impacts of Diet on Reproductive Performance of Captive American Alligators (Alligator mississippiensis).

Historically, there has been little success with the captive breeding of American alligators (Alligator mississippiensis) for both commercial and conservative purposes. This study, conducted at Golden Ranch in Gheens, LA, between 2016 and 2022, utilized a newly formulated commercial feed and practical dietary supplementation (crawfish waste products) to enhance egg production, fertility, and hatch rates. The primary focus of this study was to compare the outcome of this captive breeding program at Golden Ranch with a program conducted at Rockefeller Refuge (RR) between 1979 and 1984. Notable success was achieved in terms of reproductive performance in comparison to the captive breeding program conducted at Rockefeller Refuge. In this study, 16.1 hatchlings were produced per nest on Golden Ranch from captive breeders. Additionally, when wild nests from Golden Ranch were incubated in the same controlled environmental chambers, they produced an average of 16.3 hatchlings per nest. This comparison emphasizes the similarity in egg production between captive-bred A. mississippiensis and their wild counterparts. The findings of this study suggest that a closed farming system for A. mississippiensis can be established by employing captive breeders derived from artificially incubated wild eggs. Furthermore, American alligators raised in controlled environmental chambers during their initial three years of life demonstrated adaptability to captive conditions and tolerated stocking rates associated with farming conditions and served as breeding stock.

The Early Allometric Growth and Osteological Ontogeny of Pot-Bellied Seahorse (Hippocampus abdominalis, L. 1827) under Mass-Scale Captive Breeding Conditions in North China

Seahorses are valuable species for their use in traditional Chinese medicine, as well as for the aquarium trade as ornamentals and curiosities. To balance market demand and reduce pressure on wild populations, many countries have undertaken commercial seahorse cultivation. Skeletal development plays a crucial role in fish fry culture, affecting external morphology, feeding, and movement. This study investigated the ontogeny allometry, timing, and progression of skeletal development in H. abdominalis from DAB (day after birth) 1 to DAB 100 under mass-scale captive breeding conditions in north China. The results of this study revealed the growth rate was significantly increased between DAB 30 and DAB 54. Allometry analysis revealed that in the early stage, the head, trunk, and tail demonstrated almost isometric growth. However, in the later stage, the head and trunk exhibited negative isometric growth, whereas the tail displayed positive isometric growth. Skeletal staining results showed that newborn seahorses do not have ossified bones until DAB 11 (SL 28.14 ± 2.94 mm). Ossification was primarily observed in the jaw region and the tubular nasal structure of the cranium, which indicated the importance of the early development of feeding organs. The initial formation of ossified vertebral columns was observed at DAB 13 (SL 26.48 ± 0.63 mm), with the complete ossification of all vertebrae occurring by DAB 45 (SL 54.87 ± 4.70 mm). Furthermore, the cranium, rings, and plates were all fully ossified by DAB 30. Ossification of the fins began at DAB 23 (SL 31.27 ± 4.05 mm). However, neither of them were fully ossified by DAB 100. The pelvic fin and the complete structure of the caudal fin were not observed, possibly because of caudal fin ray structure degeneration within the pouch. In addition, no skeletal deformities were observed in all the tested samples. The results of this study provide valuable information on the developmental biology of H. abdominalis, enriching our understanding of their growth and offering insights for optimizing fish fry breeding technologies.

A community‐driven captive‐breeding and reintroduction program maintains genetic diversity in a threatened freshwater fish

AbstractCollaborative approaches to conservation management are critical to respond to the ongoing biodiversity crisis. However, local community involvement in many conservation actions is lacking, especially within translocation and reintroduction programs. Similarly, rapid integration of genetic information into collaborative programs with local communities is rarely conducted. Here, we describe a community‐based and collaborative reintroduction program for a threatened Australian freshwater fish, the southern pygmy perch (Nannoperca australis). We integrate on‐the‐ground translocation efforts by volunteers from local communities, captive breeding by a private aquarium business, and genetic analyses done by a research institution to provide a holistic framework for the reintroduction of southern pygmy perch. We evaluated genetic diversity, population structure, relatedness, and inbreeding across the duration of the reintroduction program using data from neutral and adaptive genomic markers. This allowed us to assess the ability of such a program to minimize inbreeding and retain genomic variation, and to promote adaptive potential of the reintroduced population. While genetic variation for the source populations was very low, we found no decrease in genetic diversity or increase in inbreeding across the program. These genetic findings support the efforts made by local communities and will further inform future reintroductions as part of a collaborative conservation framework. We expand on our empirical case study by describing a theoretical framework for integrating conservation genomics research with community‐led conservation management programs and identifying the benefits of such a collaboration. Our study highlights the importance of multifaceted and integrated conservation management approaches to effectively protect and manage threatened species.

Conflict between cultural development and wildlife conservation: A potential threat to Reeves's pheasant (Syrmaticus reevesii)

AbstractReeves's pheasant feathers are used to make headgears for the Chinese opera—Xiqu; however, this posed a considerable threat to the bird's population before it was banned from hunting/trade. It is unclear whether Xiqu‐troupes currently use feathers from wild or captive breeding; therefore, we investigated their source and scale of feather utilization. Through interviews, we clarified the current status of feather‐use by state‐run troupes. We conducted a cluster analysis and established a “random forest” model using stable isotopes as variables to distinguish sources of feathers from Xiqu‐troupes. Annual demand for feathers in China was estimated as 1159.4 pairs. Isotope analysis revealed that feathers used by Xiqu‐troupes are likely derived from wild sources. We suggest strengthening the supervision of acquisition of Reeves's pheasant feathers and harvesting feathers through captive breeding. Stable isotope analysis can be an effective method for identifying the source of tail feathers, which will support law enforcement efforts.

Gonad and Germ Cell Development and Maturation Characteristics of the Pot-Bellied Seahorse (Hippocampus abdominalis) under Captive Breeding Conditions in Northern China

Ovoviviparity and male pregnancy represent distinctive reproductive strategies in seahorses. However, the detailed process of gonadal development in seahorses, particularly in the pot-bellied seahorse (Hippocampus abdominalis), remains largely unknown. In this study, we investigated the complete gonadal development process of the pot-bellied seahorse under captive breeding conditions (18 ± 1 °C). Immediately after birth, primordial germ cells (PGCs) were found within the genital ridge, enclosed by a single layer of somatic cells. Around 7–9 days after birth (DAB), the ovary begins to differentiate. By 30 DAB, two germinal ridges had formed along the edge of the follicular lamina in the ovary. The primary oocytes, resulting from this differentiation process, gradually migrated from the dorsal sides to the mid-ventral area of the ovary, eventually maturing into eggs. In the testis, the primary and secondary spermatocytes appeared at 15 and 30 DAB, respectively, preceding the formation of the testicular lumen (50 DAB). The testis was observed to consist of a single large germinal compartment. Under captive breeding conditions in Northern China, the pot-bellied seahorse demonstrated year-round breeding capability, with each male producing approximately 100–150 larvae. The findings from this study contribute valuable insights into seahorse aquaculture and enhance understanding of the unique reproductive strategy employed by seahorses.

Commensal protists in reptiles display flexible host range and adaptation to ectothermic hosts.

Environmental factors like climate change and captive breeding can impact the gut microbiota and host health. Therefore, conservation efforts for threatened species may benefit from understanding how these factors influence animal microbiomes. Parabasalid protists are members of the mammalian microbiota that can modulate the immune system and impact susceptibility to infections. However, little is known about parabasalids in reptiles. Here, we profile reptile-associated parabasalids in wild and captive reptiles and find that captivity has minimal impact on parabasalid prevalence or diversity. However, because reptiles are cold-blooded (ectothermic), their microbiotas experience wider temperature fluctuation than microbes in warm-blooded animals. To investigate whether extreme weather patterns affect parabasalid-host interactions, we analyzed the gene expression in reptile-associated parabasalids and found that temperature differences significantly alter genes associated with host health. These results expand our understanding of parabasalids in this vulnerable vertebrate group and highlight important factors to be taken into consideration for conservation efforts.

Ongoing harlequin toad declines suggest the amphibian extinction crisis is still an emergency

Biodiversity loss is extreme in amphibians. Despite ongoing conservation action, it is difficult to determine where we stand in overcoming their extinction crisis. Among the most threatened amphibians are the 131 Neotropical harlequin toads. Many of them declined since the 1980s with several considered possibly extinct. Recently, more than 30 species have been rediscovered, raising hope for a reversing trend in the amphibian extinction crisis. We use past and present data available for harlequin toads (Atelopus), to examine whether the amphibian extinction crisis is still in an emergency state. Since 2004 no species has improved its population status, suggesting that recovery efforts have not been successful. Threats include habitat change, pathogen spread and climate change. More mitigation strategies need implementation, especially habitat protection and disease management, combined with captive conservation breeding. With harlequin toads serving as a model, it is clear that the amphibian extinction crisis is still underway.

FELASA Working Group report: Capture and transport of live cephalopods - recommendations for scientific purposes.

On 1 January 2013, research using cephalopod molluscs, from hatchlings to adults, became regulated within Directive 2010/63/EU. There are significant difficulties in captive breeding in the great majority of currently utilised species. Thus, scientific research relies upon the use of wild-caught animals. Furthermore, live cephalopods are shared and transported between different stakeholders and laboratories across Europe and other continents. Despite existing European and national legislation, codes, guidelines and reports from independent organisations, a set of recommendations specifically addressing the requirements for the capture and transport of animals belonging to this taxon are missing. In addition, although training and development of competence for all people involved in the supply chain are essential and aim to ensure that animals do not suffer from pain, distress or lasting harm, the requirements for those capturing and transporting wild cephalopods have not been considered. This Working Group reviewed the current literature to recognise scientific evidence and the best practice, and compiled a set of recommendations to provide guidance on the 'techniques' to be used for the capture and transport of live cephalopods for their use in scientific procedures. In addition, we propose to (a) develop standardised approaches able to assess recommended methods and objectively quantify the impact of these processes on animals' health, welfare and stress response, and (b) design a training programme for people attaining the necessary competence for capture and transportation of live cephalopods, as required by Directive 2010/63/EU.

Optimization Model for Captive Breeding of Lake Sheep Based on Space Utilization

Power Lake sheep have excellent characteristics such as fast early growth, early sexual maturity, four-season estrus and can be kept in captivity, etc. It is of great significance to explore the development of appropriate production plans to improve the space utilization of farms in order to increase the annual turnout of lake sheep. In this paper, under the condition of continuous production, in order to determine the reasonable number of breeding rams and basic ewes in the farm and estimate the range of the annualized number of sheep, we used a set of inequalities to depict the breeding cycle of the lake sheep from the spatial and temporal dimensions, and established a model to analyze the number of annualized number of sheep under the condition of deterministic factors, and based on the analytical model, we solved the gap between the number of standard sheep pens and the number of standard sheep pens in the existing one, under the requirement of the farms to have not less than 1500 sheep pens per year. gap in the number of standard sheep pens. On the basis of the above model, taking into account the influence of uncertain factors such as the success rate of mating, the number of lambs delivered and the mortality rate, an optimization algorithm for fluctuating reproduction of lake sheep was adopted to achieve the optimization of the production plan in order to maximize the economic benefits.

Antifertility effects of EP-1 (quinestrol and levonorgestrel) on Pacific rats (Rattus exulans).

Pest rodents pose a serious threat to island biodiversity. Fertility control could be an alternative approach to control the impact of rodents on these islands. In this study, we examined the antifertility effects of EP-1 baits containing quinestrol (E) and levonorgestrel (P) using a dose of 50 ppm E and P at three different ratios (E:P ratio = 1:2, 1:1, and 2:1) on Pacific rats (Rattus exulans) in the Xisha Islands, Hainan, China. Compared to the control group, all animals in EP-1 treatment groups showed significantly decreased food intake and body weight. In treated males, there were obvious abnormalities in testis structure and a significant decrease of relative seminal vesicle weight, but no significant effect on relative uterine and ovarian weights (gkg-1 body weight), or ovarian structure in females. Adding 8% sucrose to the original 50-ppm baits (E:P ratio = 1:1) significantly increased bait palatability for males and females. This dose induced uterine edema and abnormalities of ovarian structure in females but had no significant negative effect on the relative testis, epididymis, and seminal vesicle weights (gkg-1 body weight) or sperm density in males. In summary, 50-ppm EP-1 (1:1) baits have the potential to disrupt the fertility of females, and 8% sucrose addition to the EP-1 baits (E:P ratio = 1:1) could improve bait palatability. This dose disrupted the testis structure in males. Future studies are needed to improve bait acceptance and assess the antifertility effects of EP-1 (1:1) on Pacific rats in captive breeding trials and under field conditions.

Effect of four eggshell repair materials on weight loss during incubation of white leghorn chicken eggs.

Egg weight loss during incubation is a key indicator used to monitor successful egg development and is closely related to hatchability and chick survival. Artificial incubation is one of the most important captive breeding techniques used in conservation efforts to bolster avian populations. To repair damage to the eggshell and ensure embryonic viability during incubation, a variety of repair coverings can be applied. This study tested the impact of four repair materials (nail polish, synthetic glue, medical dressing, and molten wax film) on egg weight loss during incubation. We found no impact on weight loss for coverings smaller than 35% of the eggshell surface, nor did we find any differences between covering types. The average egg weight loss decreased as the coverage area increased, and the weight loss did not differ when blunt versus sharp-end coverings were compared. Given the relative insensitivity of egg weight loss and survival to the type of patch material used, we concluded that the selection of material for the purpose of weight loss management could be based on practical considerations, such as ease of application and availability.

Comparison of muscle structure and transcriptome analysis reveals the mechanism of growth variation in Yangtze sturgeon (Acipenser dabryanus)

Sturgeons display a slow growth rate and delayed initial sexual maturity, which extends the captive breeding and conservation processes. To date, few studies have revealed the molecular mechanism underlying the growth difference of sturgeons. In the present study, juvenile Yangtze sturgeons (Acipenser dabryanus) with different growth rates were selected from the same cultured pool for muscle structure, enzyme activity and comparative transcriptome analysis. Histological assays showed that the fiber diameter of the fast-growing group was significantly larger than that of the slow-growing group. The activities of four glycometabolism related enzymes, including two key rate-limiting enzymes hexokinase and pyruvate kinase, were significantly higher in fast-growing group. RNA-Seq of muscle tissues identified 7408 differentially expressed genes (DEGs), which consisted of 3637 upregulated genes and 3771 downregulated genes, in the fast-growing group vs. the slow-growing group. In the brain, a total of 12,213 unigenes were differentially expressed (6050 upregulated unigenes and 6163 downregulated unigenes) between the two groups. The expression levels of IGF1 and IGF1-binding proteins (IGFBPs) in muscle were significantly higher in the fast-growing group and might be promising candidate biomarkers for measuring growth performance in Yangtze sturgeon. Two myogenic regulatory factors (myog and myf6) were significantly upregulated, which indicated that the growth variation in juvenile Yangtze sturgeon might be partly due to the difference in the differentiation of muscle cells. In addition, pathway enrichment analysis revealed that the glycolysis and cell cycle pathways were significantly enhanced in the fast-growing groups, suggesting that they might also play important roles in the improved growth performance of A. dabryanus. Furthermore, the WGCNA as well as hub gene network analyses supported that cell cycle and gluconeogenesis might be involved in the differential growth performance of A. dabryanus. The results of this study may contribute to our understanding of the underlying molecular mechanism of growth variation in fish.

Scent detection dogs as a novel method for oestrus detection in an endangered species, the Tasmanian devil (Sarcophilus harrisii).

Captive breeding is a critical tool for conservation of endangered species. Identifying the correct time to pair males and females can be a major challenge for captive breeding programmes, with current methods often being invasive or slow. Detection dogs may provide a non-invasive way to determine female receptivity, but this has not been explored in captive wildlife. This exploratory study investigated the use of detection dogs as a novel method of oestrus detection in the endangered Tasmanian devil (Sarcophilus harrisii). Faecal samples were collected from 11 captive female devils during the breeding seasons of 2020 and 2021. Three dogs with prior detection experience were trained and subsequently assessed (n = 188 searches per dog), on their ability to discriminate between oestrus and non-oestrus devil faecal samples, in a one sample set-up. When assessed on training samples, dogs were able to correctly discriminate oestrus from non-oestrus with a mean sensitivity of 69.1% and mean specificity of 65.7%. When assessed on novel samples, their sensitivity to oestrus dropped (mean sensitivity of 48.6%). However, they were still able to correctly identify non-oestrus samples (mean specificity of 68.1%). This study is the first to explore detection dogs' ability to identify oestrus in a captive breeding programme for endangered wildlife, providing a promising tool for non-invasive monitoring of reproductive status in wildlife.