African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5210

Full Length Research Paper

Highly virulent Photobacterium damselae subsp. piscicida isolated from Taiwan paradise fish, Macropodus opercularis (L.), in Taiwan

Pan-Chen Liu, Shao-Wen Hung, Ming-Hui Chen, Ching-Fu Cheng, Cheng-Chung Lin,Chen-Hsuan Chang, Shiun-Long Lin, Ching-Yu Tu, Yu-Hsing Lin and Way-Shyan Wang
1Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung City 402, Taiwan. 2Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan. 3Graduate Institute of Veterinary Pathology, College of Veterinary Medicine, National Chung Hsing University, Taichung City 402, Taiwan. 4Residue Control Division, Taiwan Agricultural Chemicals and Toxic Substances Research Institute, Council of Agriculture, Executive Yuan, Taiwan. 5The Livestock Disease Control Center of Taichung City, Taichung 402, Taiwan. 6Nursing Department of Yuanpei University, Hsinchu 300, Taiwan
Email: [email protected]

  •  Accepted: 15 July 2011
  •  Published: 04 August 2011


In Taiwan, a fish conservation farm had about 6,250 Taiwan paradise fishes, Macropodus opercularis (L.), which were separately cultivated in an outdoor tank containing 3,250 fishes, and an indoor tank containing the rest. The water supplying both tanks was the same running water source from the adjacent hills. Following a change in the fish feed (the commercial aquaculture feed became eel’s feed) to all fishes in May 2010, rotten body surfaces were only found in diseased and dead fishes in the outdoor tank. Interestingly, no sick fishes were found in the indoor tank. The clinical findings of the diseased fishes were bleeding at basal fins, peripheral site of genital pore, and bilateral surface of the abdomen. Additionally, we discovered whitish-mucus gills, edema of the intestines, and multi-focal white tubercles in infected fishes during gross examination. The results of the histopathology study showed that there were numerous multi-focal granulomas in the spleen, posterior kidney, and liver. Furthermore, Photobacterium damselae subsp. piscicida was isolated from lesions of the ailing fishes. We conducted an experimental animal virulence test, and our data revealed that P. damselae subsp.piscicida was a highly virulent pathogen. Fortunately, P. damselae subsp. piscicidaappeared to be susceptible to most commonly used antimicrobial agents, according to the results of the antibiotic sensitivity study. We recommended a treatment with oxolinic acid (20 mg/kg/day) in the feed for 7 days for all Taiwan paradise fishes. The fishes’ condition significantly improved and the disease appeared to be controlled.


Key words: Conservation, photobacteriosis, Taiwan paradise fish, virulence.