Biobanks, offspring fitness and the influence of developmental plasticity in conservation biology

Mitigation of the widely known threats to the world's biodiversity is difficult, despite the strategies and actions proposed by international agreements such as the United Nations Framework Convention on Climate Change (UNFCCC) and the Convention on Biological Diversity (CBD). Nevertheless, many scientists devote their time and effort to finding and implementing various solutions to the problem. One potential way forward that is gaining popularity involves the establishment of biobank programs aimed at preserving and storing germplasm from threatened species, and then using it to support the future viability and health of threatened populations. This involves developing and using assisted reproductive technologies to achieve their goals. Despite considerable advances in the effectiveness of reproductive technologies, differences between the reproductive behavior and physiology of widely differing taxonomic groups mean that this approach cannot be applied with equal success to many species. Moreover, evidence that epigenetic influences and developmental plasticity, whereby it is now understood that embryonic development, and subsequent health in later life, can be affected by peri-conceptional environmental conditions, is raising the possibility that cryopreservation methods themselves may have to be reviewed and revised when planning the biobanks. Here, I describe the benefits and problems associated with germplasm biobanking across various species, but also offer some realistic assessments of current progress and applications.(AU)

Cryopreservation of jaguar (Panthera onca) sperm cells using different cryoprotectants and different thawing temperatures

The cryopreservation of jaguar semen must be improved to produce high-quality biobanking doses. Until now, the rare studies of semen freezing in the species have only evaluated glycerol, always with a significant reduction in sperm quality in thawed semen. The purpose of this study was to assess the efficacy of three cryoprotectants, dimethylsulfoxide (DMSO), glycerol (GLY), and methanol (MET), in the cryopreservation of jaguar semen in an LDL-based extender, as well as the effect of thawing temperature on dosage quality. Five mature males with a history of reproduction were used. On the males, an infrared thermal image (IRT) was captured, the spicules and testes were analyzed, and the CASA system was used to evaluate the quality of fresh and thawed sperm. The superficial IRT was 4.6 ± 1.2 °C cooler than the anal sphincter, and the semen measured between 27.3 and 28.7 °C shortly after exiting the urethra. The total motility of fresh sperm was 55.3 ± 22.6%, and progressive motility was 36.3 ± 18%. The total motility of thawed sperm was 5.28 ± 2.51%, 4.49 ± %2.49, and 0.51 ± 0.62% for DMSO, GLY, and MET, respectively. DMSO and GLY performed better than MET, and there was no difference in thawing temperature (37°C 30 s vs. 50°C 12 s). All animals exhibit a considerable level of morphological changes in sperm. Low amounts of total and progressive motility were found in the thawed sperm. Males with a high level of sperm morphological changes were found to be fertile, but the lone male with normospermia was infertile. Thus, we contest the applicability of the commonly used morphological classification for bovines to felid species.(AU)

Biobanking and use of gonadal tissues - a promising strategy for conserving wildlife from the Caatinga biome

Biological Resource Banks (BRB) or Genetic Resource Banks (GRB) are critical tools for the conservation of animal biodiversity. According to the International Union for Conservation of Nature, more than 38,500 species are threatened with extinction, out of a total of 138,300 surveyed species. These banks are repositories of biological samples and data recovered and preserved for the long term by zoos, universities, research centers and other conservation organizations. In recent years, BRB have increasingly included ovarian and testicular tissues as additional options to rescue and propagate wild species, especially those at risk of extinction. After in vitro culture or grafting, gonadal tissues are potential sources of matured gametes that can be used for Assisted Reproduction Technologies while informing about gametogenesis or mechanisms involved in infertility. It therefore is crucial to properly recover, cryopreserve, and culture these tissues using species-specific protocols. Developing BRBs is currently one of the strategies to preserve species from the Caatinga biome - an exclusively Brazilian biome with a rich wild fauna that suffers from anthropogenic activities. Among wild species from this biome, studies have been primarily conducted in collared peccaries, agoutis, cavies, and armadillos to preserve their ovarian and testicular tissues. Additionally, domestic species such as the domestic cat and donkeys have been proposed as models for wild species that are phylogenetically close. This review addresses the main technical aspects involved in obtaining BRB derived from gonadal tissues in some wild species of the Caatinga biome. It reports recent advances and perspectives to use these biological materials for wildlife conservation.(AU)

Advances and Challenges in Understanding and Assisting Reproduction of Wild Animal Species / Avanços e desafíos na compreensão e reprodução assistida de espécies selvagens

Studying reproduction in wild animals is complex as there are as many biological traits as there are species. What we currently know is minimal compared to the large number of species that remain unstudied. In addition to the impressive diversity of natural mechanisms, other complexities limit the progress of wildlife reproductive science - little interest in animal reproduction, difficult access to animals, lack of expertise, hard working conditions, and insufficient funding. Despite those challenges, some species are being saved from extinction with the help of a precise understanding of reproduction, development of assisted reproductive technologies, and creations of cryo-banks. Those advances originate from huge progresses in non-invasive measurements of steroid metabolites in urine or fecal samples to study and monitor reproductive functions and pregnancies. Progresses in cryobiology also have been impactful in animal conservation. Importantly, emerging technologies (transcriptomics, microfluidics) and additional research areas (reproductive aging, microbiomes) could lead to more successes and address current challenges in the reproduction of rare and endangered species. However, while some emerging approaches like stem cell technologies may sound promising, it is necessary to design holistic strategies considering all available tools to optimize investments, time, and efforts in conservation.

Biobanking and fertility preservation for rare and endangered species

For more than 25 years, systematic gatheringand cryo-storage of biomaterials from diverse wildspecies have been ongoing to save gene diversity andimprove captive (ex situ) and wild (in situ) animalmanagement. Cryo-storage of biomaterials offers broadopportunities - from helping understand the fundamentalbiology of unstudied species to enhanced conservationbreeding, genomics and veterinary medicine. Whilepromoted for decades, the banking of germplasm, tissue,blood and DNA from wildlife species only recently hasbeen considered by some to be a core function of animalconservation programs. Importantly, reproductivebiotechnologies and fertility preservation are criticaltools for saving and maintaining endangered species andare tightly related to biobanking. Some successes havebeen reported with the use and integration of artificialinsemination (with fresh or frozen-thawed semen) inconservation programs. However, not a single wildspecies is currently managed through oocyte freezing orembryo-based technologies. This is primarily due to thelack of knowledge of species biology, as well asinadequate facilities, space, expertise, and fundingneeded for their successful application. Morefundamental studies on animal reproductive biology aswell as more fertility preservation options are neededwith all parties involved (reproductive technologists,zoo biologists and conservationists) adopting parallelefforts to sustain wild populations and habitats.

Biobanking and fertility preservation for rare and endangered species

For more than 25 years, systematic gatheringand cryo-storage of biomaterials from diverse wildspecies have been ongoing to save gene diversity andimprove captive (ex situ) and wild (in situ) animalmanagement. Cryo-storage of biomaterials offers broadopportunities - from helping understand the fundamentalbiology of unstudied species to enhanced conservationbreeding, genomics and veterinary medicine. Whilepromoted for decades, the banking of germplasm, tissue,blood and DNA from wildlife species only recently hasbeen considered by some to be a core function of animalconservation programs. Importantly, reproductivebiotechnologies and fertility preservation are criticaltools for saving and maintaining endangered species andare tightly related to biobanking. Some successes havebeen reported with the use and integration of artificialinsemination (with fresh or frozen-thawed semen) inconservation programs. However, not a single wildspecies is currently managed through oocyte freezing orembryo-based technologies. This is primarily due to thelack of knowledge of species biology, as well asinadequate facilities, space, expertise, and fundingneeded for their successful application. Morefundamental studies on animal reproductive biology aswell as more fertility preservation options are neededwith all parties involved (reproductive technologists,zoo biologists and conservationists) adopting parallelefforts to sustain wild populations and habitats.(AU)

EFEITO DA PROTEÍNA MORFOGENÉTICA ÓSSEA 15 (BMP15) NO CULTIVO IN SITU DE TECIDO OVARIANO DE CATETOS (Pecari tajacu LINNAEUS, 1958)

Os catetos são animais silvestres que possuem grande importância ecológica e potencial econômico. Assim, a fim de aumentar o potencial reprodutivo desta espécie, biotécnicas como cultivo in vitro de folículos pré-antrais vem sendo estudadas. Sabe-se que a foliculogênese pré-antral é regulada por fatores autócrinos e parácrinos em um mecanismo orquestrado que define o curso de desenvolvimento ou morte folicular. Entre esses fatores está a proteína morfogenética óssea 15 (BMP15), que atua na ativação, sobrevivência e desenvolvimento folicular em diferentes espécies. O objetivo do presente estudo foi avaliar o efeito de diferentes concentrações de BMP15 sobre a sobrevivência, ativação, crescimento e proliferação das células da granulosa de folículos pré-antrais de catetos cultivados in vitro por 6 dias. Para tanto, 5 pares de ovários foram coletados de fêmeas de cateto e de cada par foram retirados fragmentos do córtex, dos quais, um foi utilizado como controle fresco, e os demais foram cultivados in vitro por 1 ou 6 dias nos diferentes tratamentos: 0, 1, 25 e 50 ng/mL de BMP15. Os fragmentos do controle fresco e pós-cultivo foram fixados, processados para histologia clássica (hematoxilina/eosina e AgNOR) para a confecção das lâminas. Os folículos ovarianos foram avaliados quanto à morfologia, sendo classificados em normais ou degenerados e quanto ao grau de evolução, sendo classificados em primordiais ou em desenvolvimento (primários e secundários). Este último parâmetro foi utilizado para o estudo da ativação folicular, levando em consideração a razão entre o percentual de folículos primordiais e em desenvolvimento ao longo do cultivo. Além disso, os folículos e oócitos foram mensurados antes e após o cultivo para registrar o crescimento folicular e oocitário. A proliferação celular dos folículos ovarianos durante o cultivo foi avaliada pela contagem das regiões organizadoras nucleolares (NORs) pela técnica de AgNOR. O controle fresco apresentou altas taxas de folículos com morfologia normal (92.68% ± 1,09) e, após o cultivo, a adição de BMP15 (25 ng/mL) ao meio resultou numa maior percentagem de folículos normais (79,67% ± 0,69) quando comparada aos demais tratamentos (P<0,05), exceto 1 ng/mL BMP15 (74,00% ± 1,90) (P> 0,05). Além disso, as concentrações mais elevadas de BMP15 (25 ng/ml e 50 ng/ml) estimularam a ativação dos foliculos primordiais em relação ao controle cultivado (P<0,05). No entanto, esta substância não demonstrou efeitos no crescimento oocitário e folicular. Todas as concentrações de BMP15 utilizadas aumentaram o número de NORs após 1 dia de cultivo em relação ao controle fresco e cultivado (P<0,05), e após 6 dias de cultivo, o número de NORs nos fragmentos cultivados em todos os tratamentos foi maior do que a observada no controle fresco (P<0,05). Em conclusão, a adição de 25 ng/ml de BMP15 ao meio de cultivo de folículos pré-antrais de catetos mantém um elevado número de folículos morfologicamente saudáveis e estimula a ativação de folículos primordiais após 6 dias de cultivo.

Collared peccaries are wild animals that have a great ecological importance and economic potential. Thus, in order to increase reproductive potential this species, biotechniques such as in vitro culture of preantral follicles have been studied. It is known preantral folliculogenesis is regulated by autocrine and paracrine factors in an orchestrated mechanism that defines the course of development or death. Among these factors is bone morphogenetic protein 15 (BMP15), which acts on activation, survival and follicular development in different species. Nevertheless, the roles of BMP15 in the regulation of primordial follicle development in collared peccaries remains unknown. The aims of present study were to investigate the effects of BMP15 on in vitro culture of collared peccaries preantral follicles using histological studies. To this end, fragments of collared peccaries (Pecari tajacu) ovarian cortex were cultured for 1 or 6 days, at 38.5 °C in an atmosphere containing 5% CO2, in TCM199+ (control medium) supplemented with different concentrations of recombinant human BMP15 (rhBMP15, R&D Systems, Minneapolis, MN, USA) (1, 25 and 50 ng/mL). The fresh control and cultured fragments were fixed, processed for classical histology (hematoxylin/eosin and AgNOR), and the ovarian follicles were evaluated for morphology, classified as normal or degenerate, and classified as primordial or developing (primary and secondary). The latter parameter was used for study of follicular activation, taking into account the ratio between percentage of primordial and developing follicles throughout the culture. In addition, follicles and oocytes were measured before and after culture to record follicular and oocyte growth. The cell proliferation of ovarian follicles during experiment was evaluated by counting the nucleolar organizing regions (NORs) by the AgNOR technique. The fresh control showed high rates of follicles with normal morphology (92.68% ± 1.09) and, after culturing, addition of BMP15 (25 ng/mL) to medium resulted in a higher percentage of normal follicles (79.67 ± 0.69) compared to the other treatments (P<0.05), except for 1 ng/mL BMP15 (74.00% ± 1.90) (P>0.05). In addition, higher concentrations of BMP15 (25 ng/ml and 50 ng/ml) stimulated the activation of primordial follicles in relation to cultured control (P<0.05). However, this substance did not demonstrate effects on oocyte and follicular growth. All concentrations of BMP15 used increased the number of NORs after 1 day of cultivation relative to fresh and cultivated control (P<0.05), and, after 6 days, number of NORs in fragments cultured in all treatments was higher than that observed in fresh control (P <0.05). In conclusion, the addition of 25 ng/ml of BMP15 to culture medium of preantral follicles of peccaries maintains a high number of morphologically healthy follicles and stimulates activation of primordial follicles after 6 days of culture.

DESCRIÇÃO ULTRAESTRUTURAL DE ESPERMATOZOIDES A FRESCO E CRIOPRESERVADOS DE CATETOS (Pecari tajacu Linnaeus, 1758)

A presente dissertação teve por objetivo descrever a ultraestrutura de espermatozoides frescos e criopreservados de catetos por meio das microscopias eletrônicas de varredura (MEV) e transmissão (MET). Para tanto, três catetos machos adultos foram submetidos à eletroejaculação e o sêmen obtido foi imediatamente avaliado quanto à motilidade, integridade e funcionalidade da membrana, integridade da cromatina e morfologia por meio da microscopia de luz. Posteriormente, as amostras foram criopreservadas em diluente Tris acrescido de gema de ovo (20%) e glicerol (6%), descongeladas após uma semana e avaliadas. Amostras de sêmen fresco e descongelado foram combinadas em pools distintos de espermatozoides que foram processados para MEV e MET, sendo microfotografadas e avaliadas. Após a descongelação, observou-se um declínio na motilidade espermática, integridade e funcionalidade da membrana (P < 0,05), porém a morfologia espermática e a integridade da cromatina avaliadas pela microscopia de luz não foram significativamente afetadas. Por meio da MEV, identificou-se que os espermatozoides de catetos apresentam cabeça achatada em forma de pá, medindo 6,1 ± 0,1 m de comprimento e 3,8 ± 0,1 m de largura, com um vasto acrossomo (4,3 ± 0,1 m) apresentando uma clara demarcação entre a região pós-acrossomal, sendo delimitada por uma borda distendida, denominada de espessamento marginal. As caudas normais mediram 38,1 m, sendo formadas por uma extensa peça intermediária de 15,5 m de comprimento. Nas amostras descongeladas, tanto a MEV quanto a MET forneceram informações sobre crioinjúrias não detectadas através da microscopia de luz como a presença de vesículas no acrossomo, membrana plasmática frouxa, mitocôndrias vacuolizadas, fibras densas desorganizadas e cromatina descondensada. Em conclusão, o presente estudo fornece a primeira descrição da ultraestrutura dos espermatozoides de catetos. Além disso, a MEV e a MET contribuíram na identificação de alguns danos nanométricos provocados pelo processo de criopreservação, fornecendo informações valiosas para o aprimoramento de importantes protocolos usados para a formação de biobancos.

The objective of the present work was to describe the ultrastructure of fresh and cryopreserved spermatozoa from collared peccaries by scanning (SEM) and transmission electron microscopy (TEM). Three adult males were submitted to electroejaculation and semen was immediately evaluated for motility, membrane integrity and functionality, chromatin integrity and morphology. Subsequently, the samples were cryopreserved in Tris extender plus egg yolk (20%) and glycerol (6%), thawed after one week and evaluated. Samples of fresh and frozen-thawed semen were combined in distinct pools that were processed for SEM and TEM,. After thawing, there was a decline in sperm motility, membrane integrity and functionality (P < 0.05), sperm morphology and chromatin integrity assessed by light microscopy were not significantly affected. Analysis by SEM revealed that collared peccaries sperm presents a flattened head in a paddle format, measuring 6.1 ± 0.1 m in length and 3.8 ± 0.1 m in width. Collared peccaries sperm had a long acrosome (4.3 ± 0.1 m), presenting a clear demarcation across the post-acrosomal region, being delimited by a distended border, called the marginal thickening. Normal tails measured 38.1 m, formed by an extensive midpiece with 15.5 m in length. In frozen-thawed analysis by SEM and TEM detected presence of vesicles in the acrosome, loose plasma membrane, vacuolized mitochondria, dense fibers disorganized, and decondensed chromatin. In conclusion, we provide the first description of the ultrasctruture on sperm from collared peccaries. Moreover, SEM and TEM help us to identify some nanometric damage caused by freezing-thawing procedures, thus providing valuable information for the improvement of protocols used for biobanking formation.