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Percorrer por autor "Magny, Ana"

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  • Development and improvement of gamete (cryo)preservation protocols for elasmobranchs
    Publication . Magny, Ana; Gallego, Víctor; Velez, Zélia
    Elasmobranchs are among the most threatened groups of vertebrates on Earth, and primary threats to their survival are overfishing and habitat destruction. To address this, both in-situ conservation efforts and ex-situ conservation programs are essential. Implementing assisted reproductive technologies, though not widely developed for elasmobranchs, is a crucial aspect of these ex-situ measures. This study aimed to improve the current gamete preservation protocols in elasmobranch using new storage conditions, new cryoprotectants, and new biodegradable vials. These trials used small-spotted catshark (Scyliorhinus canicula) as the model species, with sperm collected on the day of each experiment, and samples showing more than 70% motility were selected for the experiments. For the short-term storage trials, our data showed that the best short term storage method is at 4°C and pH 6.5, maintaining 40% motility for up to 14 days. About the study aimed at improving methods for "sending gamete samples", the best option was to store the sperm sample at room temperature with ice in it without cryoprotectants, achieving motilities close to 40-50% after 1 week. On the other hand, and regarding cryopreservation trials, the best result was obtained with the combination of 5% methanol and 5% DMSO, reaching post thawed motilities of 25-30%. In addition, biodegradable capsules were tested as an ecologic alternative to plastic vials in elasmobranchs, and first attempts showed that traditional vials, such us cryotubes, showed better results (30-35% of post-thawing motility) than biodegradable vials (15-20% after cryopreservation process). This study significantly advances gamete handling, evaluation, and cryopreservation protocols for elasmobranchs. Several objectives have been achieved, both by attempting to adapt and apply several reproductive techniques and tools previously used in other fish species, and by carrying out the current cryopreservation protocols developed on elasmobranch species.
    2024-12-13Dissertação de mestrado Acesso aberto Ver mais