Title: There must be something in the water (for F. columnare pathogenesis) Authors
Submitted to: Annual Eastern Fish Health Workshop
Publication Type: Abstract Only
Publication Acceptance Date: March 28, 2014
Publication Date: April 28, 2014
Citation: Straus, D.L., Farmer, B.D., Beck, B.H., Bosworth, B.G., Torrans, E.L., Tucker, C.S. 2014. There must be something in the water (for F. columnare pathogenesis) [abstract}. Annual Eastern Fish Health Workshop. p.21. Technical Abstract: Why can we routinely produce columnaris infections in our lab, while the lab on the other side of the ditch can't? Anecdotal reports suggest that tannins may inhibit F. columnare. Do tannins in their water prevent this, or are other water chemistry parameters involved? In the first experiment, two waters were used: unfiltered well waters from the Stuttgart National Aquaculture Research Center (SNARC) and from the Warmwater Aquaculture Research Unit (WARU). Fingerling channel catfish (Ictalurus punctatus) were exposed to an F. columnare suspension in aquaria for 4 days; each aquarium contained 10 L of water and half was replaced daily. No fish died in the WARU water, but 100% of the fish died in SNARC water. Using qPCR, we found that there were approximately 1900 times more F. columnare attached to the gills of the fish in SNARC water (P = 0.0001). In the second experiment, four waters were used: the above waters, WARU water filtered through a carbon bed to remove tannins and SNARC water filtered through a water softener to remove hardness. No fish died in the WARU or filtered waters, but 17% of the fish died in SNARC water. Again using qPCR, we found that there were approximately 1600 times more F. columnare attached to the gills of the fish in SNARC water (P = 0.0001). Filtered SNARC water had less F. columnare than unfiltered SNARC water (P = 0.0809) and filtered WARU water had more F. columnare than unfiltered WARU water (P = 0.6191). Results suggest tannins have minimal involvement, and water analyses suggest that calcium and hardness are two parameters influencing bacterial attachment and ultimately pathogenesis.