The Korea Institute of Ocean Science & Technology (KIOST, President Kim Woong-seo) announced that, after three years of research, it has discovered a new marine source material and validated its effectiveness in boosting the immunity, survival rate, and disease resistance and increasing the hatching rate of fish.

 In 2015, Dr. Kang Do-hyeong and his research team at the KIOST Jeju Marine Research Section successfully extracted “SmP,”^* a new marine source material, which a focus on the antioxidant, immune control, and heavy metal emission functions of spirulina.
 After the discovery, the researchers found that the application of the SmP treatment to zebrafish^** increased the survival rates of both fry and adult fish by increasing the hatching rate and enhancing their immunity and resistance to disease.
 * SmP: microalgae pectin (Spirulina maxima pectin)
 ** Zebrafish: widely used as a model for research on vertebrate-derived genes, due to the ease of observing all stages of development, from egg to embryo and adult, and the fact that their transparent bodies make it possible to see how the drugs work in their bodies with the naked eye.

 As a result of the SmP treatment of fry infected with Edwardsiella piscicida and Aeromonas hydrophila, which cause Edwardsiella tarda,*** the cumulative survival rate of the fry increased by an average of 33 to 67 percent, and the cumulative survival rate of the fry in the early stages of disease increased significantly to 93.3 percent and 60.0 percent, respectively, compared to the fry infected with each virus but not subject to SmP treatment.
 In addition, the SmP treatment of zebrafish resulted in an increase in immune-related genes. In particular, the fry showed a two-fold increase, on average, in active compounds such as antimicrobial enzymes, glycoprotein (mucin), cytokine, and antioxidants.
 *** Edwardsiella tarda: a summer disease found in fry and adult fish that causes fin and abdominal redness, hyperemia, abdominal distention, and hernias.

 Dr. Kang Do-hyeong, the research director, said, “This material is considered to be sufficient for application to reduce high-temperature mortality and improve disease resistance, which are problems with which domestic inland flatfish aquaculture farms struggle to cope. In addition, it is an environmentally friendly and sustainable method, as it uses biodegradable natural products rather than general chemicals and antibiotics.” Dr. Kang also said that he would continue conducting follow-up research using related source material technology in the future.

 This study, which was carried out as part of KIOST’s “Marine Bioresource-based Clean, Functional, and Industrial Material Mass Production Technology Development” project, was published in the September 2019 online edition of Fish and Shellfish Immunology, a renowned journal in the field of marine fisheries.