Development of Cryopreservation Techniques for Gorgonian (Junceella juncea) Oocytes through Vitrification

Gorgonian corals are slowly declining due to human interaction and environmental impacts. Cryopreservation of gorgonian corals is an ex-situ method of conservation, ensuring future reproduction. The present study assessed the vitrification properties of cryoprotectant (CPT) mixtures using the cryotop, cryoloop and open pulled straw (OPS) cryopereservation methods prior to experimentation on gorgonian (Junceella juncea) oocytes. Investigations of the equilibration and vitrification solutions' (ES and VS) effect on oocytes throughout different incubation periods were conducted. The cryotop method was found to be the most successful in ensuring vitrification. The most favourable VS was composed of propylene glycol (PG), ethylene glycol (EG) and methanol with concentrations of 3.5 M, 1.5 M and 2 M respectively. Experiments were performed using the cryotop method to cryopreserve Junceella juncea oocytes using VS2, the solution had the least impact on oocytes at 5°C rather than at 26°C. The success of the vitrification procedures was determined by adenosine triphosphate (ATP) levels in cooled-thaw oocytes and the highest viability obtained from the present study was 76.6 ± 6.2%. This study provides information regarding gorgonian corals' tolerance and viability throughout vitrification to further advance the vitrification protocol on whip corals.