Combination treatment against scuticociliatosis by reducing the inhibitor effect of mucus in olive flounder, Paralichthys olivaceus.
The olive flounder, Paralichthys olivaceus, is an economically important food fish in Japan and Korea. Scuticociliatosis is a major parasitic disease, and fatal infection with scuticociliates, or mixed infections with scuticociliates and other pathogenic agents (e.g., Vibrio spp.) cause severe mortalities in farmed olive flounders. To date, however, effective chemotherapeutic treatment of scuticociliatosis has only been reported at the in vitro level. In this study, we employed combination treatment, using benzalkonium chloride (to remove excess mucus from the body surface) and bronopol (to kill the parasites), to overcome the protective effect of mucus by some medicine to the scuticociliates. In the presence of the mucus mixture, the higher dose of bronopol (156 ppm) yielded morphologies and motilities similar to those of ciliates treated with the lower dose of bronopol (80 ppm) in the absence of mucus. We also investigated the in vivo effects of this treatment in field trials involving a total of 15,025 naturally infected flounders. We observed that short-term bath treatments with benzalkonium chloride (50 ppm) followed by bronopol (500 ppm) were effective, assessed by the relative percentage mortality (RPS) value. Thus, this study provides a notable therapeutic strategy by removing the mucus to treat scuticociliatosis in olive flounders at the aquaculture field level.
Lab. of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Gyeongnam, South Korea.
Seong Bin
SB
Park
Lab. of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Gyeongnam, South Korea.
Ho Bin
HB
Jang
Lab. of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Gyeongnam, South Korea.
Fernand F
FF
Fagutao
Lab. of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Gyeongnam, South Korea.
Young Kyu
YK
Kim
Lab. of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Gyeongnam, South Korea.
Seong Won
SW
Nho
Lab. of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Gyeongnam, South Korea.
In Seok
IS
Cha
Lab. of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Gyeongnam, South Korea.
Jong Earn
JE
Yu
Lab. of Aquatic Animal Diseases, Research Institute of Life Science, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Gyeongnam, South Korea. Electronic address: jungts@gnu.ac.kr.
Tae Sung
TS
Jung
D000818:Animals; D000977:Antiparasitic Agents / Q000494:pharmacology*; D017756:Aquaculture; D001548:Benzalkonium Compounds / Q000494:pharmacology*; D016798:Ciliophora / Q000187:drug effects*; D016770:Ciliophora Infections / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D004359:Drug Therapy, Combination; D005393:Fish Diseases / Q000188:drug therapy* / Q000469:parasitology; D005412:Flatfishes; D009093:Mucus / Q000187:drug effects; D011409:Propylene Glycols / Q000494:pharmacology*; D056910:Republic of Korea
D000977:Antiparasitic Agents; D001548:Benzalkonium Compounds; D011409:Propylene Glycols; C006827:bronopol
Benzalkonium chloride; Bronopol; Combination treatment; Olive flounder; Scuticociliatosis