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.

Influence of antibiotics on bacterial load and sperm parameters during short-term preservation of collared peccary semen

Abstract Studies on semen and sperm cells are critical to develop assisted reproductive technologies for the conservation of the collared peccary. The objective of the study was to compare the effect of different antibiotics on the bacterial load and sperm quality during short-term storage of peccary semen. Fresh semen samples from 10 males were extended in Tris-egg yolk or Tris-Aloe vera supplemented with streptomycin-penicillin (SP; 1 mg/mL - 1000 IU/mL or 2 mg/mL - 2000 IU/mL) or gentamicin (30 µg/mL or 70 µg/mL) before storage at 5°C. Bacterial load and sperm motility, membrane integrity and function, mitochondrial activity, and morphology, were evaluated at different time points for 36 h. The SP and gentamicin treatments concentration inhibited (p < 0.05) bacterial growth for 36 h regardless of the extender. Compared to the other treatments, Tris-egg yolk plus 70 µg/mL gentamicin maintained the sperm parameters for longer, including total motility (41.9 ± 6.1%) at 24 h, and membrane integrity (58.3 ± 2.1%) at 36 h. In contrast, the highest SP concentration in both extenders impaired sperm membrane integrity at 36 h (p < 0.05). For the liquid storage of collared peccary semen, it therefore is recommended to use Tris extender supplemented with egg yolk and gentamicin (70 µg/mL).

Influence of antibiotics on bacterial load and sperm parameters during short-term preservation of collared peccary semen

Studies on semen and sperm cells are critical to develop assisted reproductive technologies for the conservation of the collared peccary. The objective of the study was to compare the effect of different antibiotics on the bacterial load and sperm quality during short-term storage of peccary semen. Fresh semen samples from 10 males were extended in Tris-egg yolk or Tris-Aloe vera supplemented with streptomycin-penicillin (SP; 1 mg/mL - 1000 IU/mL or 2 mg/mL - 2000 IU/mL) or gentamicin (30 µg/mL or 70 µg/mL) before storage at 5°C. Bacterial load and sperm motility, membrane integrity and function, mitochondrial activity, and morphology, were evaluated at different time points for 36 h. The SP and gentamicin treatments concentration inhibited (p < 0.05) bacterial growth for 36 h regardless of the extender. Compared to the other treatments, Tris-egg yolk plus 70 µg/mL gentamicin maintained the sperm parameters for longer, including total motility (41.9 ± 6.1%) at 24 h, and membrane integrity (58.3 ± 2.1%) at 36 h. In contrast, the highest SP concentration in both extenders impaired sperm membrane integrity at 36 h (p < 0.05). For the liquid storage of collared peccary semen, it therefore is recommended to use Tris extender supplemented with egg yolk and gentamicin (70 µg/mL).(AU)

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)