COMMERCIAL DEMONSTRATION OF KAOLINITIC CLAY FOR PROTECTION OF Flavobacterium columnaris IN SPORTFISH

Nilima Renukdas*, Luke A. Roy, Anita M. Kelly, L. Matthew Barnett, Ben H Beck, David Heikes, Robert P. Glennon, Phil Jones
 
Aquaculture/Fisheries Center
University of Arkansas at Pine Bluff, Pine Bluff, AR
 renukdasn@uapb.edu

Sportfish farms in Arkansas routinely battle Columnaris disease, which is caused by Flavobacterium columnare. Columnaris is especially prevalent during the feed training of centrarchids such as largemouth bass and immediately following harvest of crappie, redear sunfish, and bluegill while they are being held in load out sheds prior to being sold. Largemouth bass fingerlings are brought in from the pond and held indoors for several weeks in vats during the feed training process. A commercial research demonstration trial was devised with two commercial sportfish farms in Arkansas to test the efficacy of kaolin clay to prevent outbreaks of Columnaris.  Kaolinitic clay was utilized as a prophylactic treatment for largemouth bass, crappie, bluegill, and redear sunfish.  Participating producers treated vats of fish with 1 ppt kaolin and 0 ppt kaolin (control) as a prophylactic treatment and also during active Columnaris infections.  Vats were treated on commercial farms and then samples of fish were brought to the UAPB Lonoke Fish Disease Diagnostic Laboratory. Gills, fins, and tissues of treated and non-treated fish were examined visually for the presence of columnaris both before and after prophylactic treatment.  Fish tissue samples were also sampled to confirm the presence/absence of Columnaris in fish receiving 0 or 1 ppt kaolinitic clay. The demonstration is currently ongoing, however, preliminary data suggests that fish treated with kaolinitic clay while being feed trained and during holding periods prior to sale are having less incidences of Columnaris.