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

Area of Science:

• Marine Biology
• Conservation Science
• Reproductive Biology

Background:

• Gorgonian corals face decline due to human activities and environmental changes.
• Ex-situ conservation methods like cryopreservation are vital for ensuring future reproduction.
• Developing effective cryopreservation protocols is crucial for gorgonian coral survival.

Purpose of the Study:

• To assess vitrification properties of cryoprotectant mixtures for gorgonian coral oocytes.
• To evaluate different cryopreservation methods (cryotop, cryoloop, OPS) for Junceella juncea.
• To determine the optimal vitrification solution (VS) and conditions for gorgonian oocyte cryopreservation.

Main Methods:

• Vitrification property assessment of cryoprotectant (CPT) mixtures using cryotop, cryoloop, and open pulled straw (OPS) methods.
• Investigation of equilibration and vitrification solutions' (ES and VS) effects on oocytes under varying incubation periods.
• Cryopreservation of Junceella juncea oocytes using the cryotop method with a specific VS (VS2) at different temperatures (5°C vs. 26°C).

Main Results:

• The cryotop method demonstrated the highest success rate for vitrification.
• A favorable vitrification solution (VS) comprised propylene glycol (3.5 M), ethylene glycol (1.5 M), and methanol (2 M).
• The cryotop method with VS2 resulted in the least impact on oocytes at 5°C compared to 26°C, achieving 76.6 ± 6.2% viability based on adenosine triphosphate (ATP) levels.

Conclusions:

• The cryotop method is effective for vitrifying gorgonian coral oocytes.
• Specific cryoprotectant concentrations and lower temperatures optimize gorgonian oocyte cryopreservation.
• This study advances vitrification protocols for whip coral conservation, improving ex-situ reproductive strategies.