![]() |
Inter-Research |
IR Home
DAO Home Editors Forthcoming Information Journals Home MEPS AME CR DAO ESEP ESR Search Subscribe Book Series EE Books Top Books ESEP Books Order EEIU Brochures (pdf format) Discussion Forums Home Research IR Research Institutions International Ecology Institute Eco-Ethics International Union Foundation Otto Kinne Foundation ![]() | ![]() |
![]()
Treatment of columnaris disease of rainbow trout: low pH and salt as possible tools?L.-R. Suomalainen*, M. Tiirola, E. T. ValtonenDepartment of Biological and Environmental Science, University of Jyväskylä, PO Box 35, 40014, Finland![]() ABSTRACT: The impact of salt and low pH on columnaris disease of fish was studied. Survival of Flavobacterium columnare after exposure to either 4% NaCl (pH 7.2) or pH 5.0, pH 4.86 or pH 4.6 for 15 min or 1 h was studied in vitro. All conditions significantly reduced the numbers of viable bacterial cells. The effects of salt (4 and 2%) and acidic baths (pH 4.6) were studied in 2 experiments in vivo with rainbow trout Oncorhynchus mykiss infected with F. columnare. Both salt and acidic baths failed to prevent fish mortality; the overall mortality reached 100% in all groups. However, according to survival analysis, the mortality rate was lower in fish treated with 4% salt baths compared to a control group. The buffering capacity of fish skin mucus against low water pH was also studied. Fish skin mucus was an efficient buffer against decreased water pH and the pH of the skin could be remarkably higher than that of the mucus. This may explain the failure of bath treatments to prevent mortality providing that attached F. columnare are located below the mucus surface. We suggest, however, that salt and acidic bath treatments can be used to disinfect water containing F. columnare cells shed by infected fish and thus prevent the transmission of the disease.
KEY WORDS: Flavobacterium columnare · Treatment · Bathing · pH · NaCl
Published in DAO Vol.
65, No. 2
(2005) on June 30
|
![]() | |
![]() |
Copyright © 2005; Inter-Research
Webmaster: webmaster@int-res.com |