Can Additives Ameliorate Oxidative Stress and Improve Development of Greenshell™ Mussel (Perna Canaliculus) Oocytes During Cryopreservation?

BACKGROUND: Cryopreservation of P. canaliculus oocytes has not yet been achieved. OBJECTIVE: The present study is to investigate whether the incorporation of: DMSO (0.09%), α-tocopherol (0.1mM) plus taurine (1mM) and ethylenediaminetetraacetic acid (EDTA; 0.1mM), is beneficial during cryopreservation. METHODS: These three additives were incorporated to both the cryoprotectant (CPA) and recovery media, and evaluated in terms of development and oxidative stress at three key stages of cryopreservation: 1) cryoprotectant addition [10% v/v ethylene glycol plus 0.2M trehalose; final concentration], 2) cooling to –6°C, and 3) cooling to –35°C and liquid nitrogen immersion. RESULTS: Over all treatments (including controls) progressive cryopreservation steps resulted in a decrease in fertilization and development to D-larvae, an increase in macromolecular oxidative damage markers (protein carbonyls, lipid hydroperoxides and oxidized DNA), and a decrease in enzymatic (superoxide dismutase, catalase, glutathione S-transferase and glutathione reductase) and non-enzymatic antioxidants. CONCLUSION: Whilst results varied, the major effects of the additives were the improved percentage fertilization and a decrease in macromolecular damage.