Rattanachaikunsopon P, Phumkhachorn P.
Department of Biological Science, Faculty of Science, Ubon Ratchathani
University, Warin Chamrap, Ubon Ratchathani 34190, Thailand.
rattanachaikunsopon@yahoo.com
To develop antibiotic-free and chemical-free aquaculture, it is
necessary to have natural substances to control diseases of aquatic
animals. The aim of this study was to find an herb having therapeutic
effect against columnaris, a fish disease caused by the bacterium
Flavobacterium columnare. Of all tested herbs (including kalmegh
Andrographis paniculata, candle bush Cassia alata, Asiatic pennywort
Centella asiatica, mangosteen Garcinia mangostana, pomegranate Punica
granatum, and guava Psidium guajava), the aqueous extract of Asiatic
pennywort exhibited the strongest antimicrobial activity against F.
columnare; the minimal inhibitory concentration was 31.25 lg/mL. It
was also found to have a bactericidal effect on F. columnare. When
experimental bath exposures of Nile tilapia Oreochromis niloticus to
F. columnare were performed, the median lethal dose was determined to
be 2.37 x 10(5) colony forming units/mL. For in vivo trials, six
different concentrations (0, 20, 40, 60, 80, and 100 mg/L) of Asiatic
pennywort aqueous extract were used as bath treatments to control
experimentally induced columnaris in Nile tilapia. The decrease in
fish mortality was dose dependent, and at a concentration of 100 mg/L
no mortality or adverse effects were noted in the infected fish. This
study suggests that Asiatic pennywort aqueous extract has the
potential to control disease caused by F. columnare.
PMID: 20575361 [PubMed - in process]
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