Immunochemotherapy with doxycycline and CpG-ODN 1668 for treatment of scuticociliatosis in olive flounder (Paralichthys olivaceus)

Abstract

Abstract Immunotherapy along with chemotherapy can be a way to enhance therapeutic efficacy and to reduce amount of chemotherapeutics. So, in the present study, we adopted an immunochemotherapy (CpG-ODN 1668 plus doxycycline) to reduce doxycycline dose to be used while at the same time to get the same treatment efficacy against scuticociliatosis in olive flounder ( Paralichthys olivaceus ). The survival rates of fish administered with doxycycline 100 mg/kg plus 10 μg of CpG-ODN 1668 were higher than those of fish administered with doxycycline alone at a dose of 200 mg/kg of fish weight, suggesting that coadministration of CpG-ODN 1668 can reduce doxycycline to half the dose. Furthermore, reduction of CpG-ODN 1668 to 5 μg/fish plus doxycycline 100 mg/kg led to high survival rates that were comparable to doxycycline 200 mg/kg, suggesting that the used amount of both immunotherapeutics and chemotherapeutics can be reduced through coadministration. There have been no reports on the treatment of scuticociliatosis by combining chemotherapy and immunotherapy. In the present study, we demonstrated that a combination of chemotherapy (doxycycline) and immunotherapy (CpG-ODN 1668) was effective against scuticociliatosis in olive flounder fingerlings.