Microbiological load and preantral follicle preservation using different systems for ovarian tissue vitrification in the red-rumped agouti

In vitro culture of red-rumped agouti preantral follicles enclosed in fresh and vitrified ovarian tissues using TCM199 plus different pFSH concentrations

Considering the relevance of establishing biodiversity conservation tools, the study aimed to investigate the TCM199 supplemented with different follicle-stimulating hormone (FSH) concentrations on survival and development of fresh and vitrified preantral follicles enclosed in red-rumped agouti ovarian tissues cultured in vitro. In the first experiment, six pairs of ovaries were fragmented and cultured for 6 days according to groups: 10 ng/mL pFSH (FSH10 group) and 50 ng/mL (FSH50 group). Non-cultured tissues were considered as a control. In the second experiment, vitrified/warmed fragments of four pairs of ovaries were cultured with the best concentration of FSH established (cryopreserved and cultured group). Non-cryopreserved (fresh control group) and cryopreserved but non-cultured (non-cultured group) tissues were used as controls. For both experiments, preantral follicles were evaluated for survival and development using morphological and viability analysis by trypan blue staining. After culturing fresh samples, FSH50 showed a higher percentage of morphologically normal follicles when compared to FSH10 (P < 0.05). This same response was observed for primordial follicles. Regardless of the concentrations of FSH used during in vitro culture, no difference was observed regarding the percentage of viable follicles and diameters (P > 0.05). Thus, the FSH50 group was used for second experiment, in which 76.2 ± 7.2% normal preantral follicles previously vitrified was found after 6-day culture, also presenting the highest values (P < 0.05) for morphology of primordial follicles (95.2 ± 4.7%). Nevertheless, in vitro culture did not affect the viability and diameter of preantral follicles of cryopreserved tissues (P > 0.05). In conclusion, TCM199 supplemented with 50 ng/mL FSH was efficient in maintaining the in vitro survival of fresh and vitrified red-rumped agouti preantral follicles. This was the first study related to the in vitro culture of ovarian preantral follicles in this species, aiming to contribute to its conservation.

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.

Reproductive Technologies Used in Female Neo-Tropical Hystricomorphic Rodents

This is the second of two literature reviews that focuses on the female reproductive anatomy and reproductive technologies used in selected neo-tropical hystricomorphic rodents. The rodents chosen included the agouti (Dasyprocta leporina), the capybara (Hydrochoerus hydrochaeris), and the paca (Cuniculus paca). Over seventy references were used, spanning the years 1919-2021. Knowledge of the reproductive tract is important in understanding any unique features, which may affect the use of reproductive technologies. Some unique characteristics common to these species included the presence of a vaginal closure membrane and a lobulated placenta with a vascular sub-placenta. The capybara had hyperpigmentation of the vagina that was unique to each individual, while the agouti and paca had accessory corpora lutea, in addition to the main one. Some reproductive technologies have been used, with attempts at estrous induction and synchronization taking place within the past five years. Even though most work has been done over the past twenty years, there is still a dearth of information.