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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #405060

Research Project: Enhancing the Production of Hybrid Striped Bass Through Improved Genetics, Nutrition, Production Management, and Fish Health

Location: Harry K. Dupree Stuttgart National Aquaculture Research Cntr

Title: The use of kaolin as a prophylactic treatment to prevent columnaris disease (Flavobacterium covae) in commercial baitfish and sportfish species

item KELLY, ANITA - Auburn University
item RENUKDAS, NILIMA - University Of Arkansas At Pine Bluff
item Barnett, Louis - Matt
item Beck, Benjamin
item ABDELRAHMAN, HISHAM - Auburn University
item ROY, LUKE - Auburn University

Submitted to: Veterinary Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2023
Publication Date: 7/6/2023
Citation: Kelly, A.M., Renukdas, N., Barnett, L.M., Beck, B.H., Abdelrahman, H.A., Roy, L.A. 2023. The use of kaolin as a prophylactic treatment to prevent columnaris disease (Flavobacterium covae) in commercial baitfish and sportfish species. Veterinary Sciences. 10(7):441.

Interpretive Summary: The aquaculture industry suffers large financial losses every year to a bacteria disease known as columnaris. Columnaris can be treated with antibiotics in the feed, but this is expensive and can lead to antibiotic resistance. Therefore, we tested a kaolinic clay as a preventive to columnaris. This clay is added to the water and has been shown to bind to columnaris bacteria in laboratory studies. When added to the water as a prophylactic treatment, the kaolin clay in fish holding vats on farms bound to columnaris. The kaolin clay did not damage the organs of the fish, nor did it cause mortalities. We have shown that kaolin clay is safe to use as a prophylactic treatment in several freshwater fish species raised in Arkansas, USA.

Technical Abstract: Aquaculture farms in Arkansas, USA routinely battle columnaris disease caused by Flavobacterium covae. Columnaris is prevalent during stressful events such as feed training and when fish are stocked at high densities in holding vats before sale. Kaolin clay was effective in laboratory trials as a treatment for columnaris in catfish. As a result, fish farmers are interested in applying kaolin products but were hesitant as they feared high doses of kaolin clay in vats might negatively affect the gills and overall health of fish. Therefore, we evaluated potential clay concentrations that might be used to prophylactically treat fish in vats. The effects of low to excessively high doses (0, 1, 2, 4, and 8 g/L) of kaolin clay (AkuaProTM) were evaluated using a 72-h bioassay conducted in static tanks using Micropterus salmoides, Pomoxis nigromaculatus, Lepomis macrochirus, Ictalurus punctatus, Notemigonus crysoleucas, and Pimephales promelas. Results of these trials revealed 100% survival across all six fish species exposed to kaolin clay at concentrations up to 8 g/L for 48 h (followed by a 24-h recovery period in clean water) with no adverse effects to eyes, skin, gastro-intestinal tract, or liver histology noted at any treatment. In addition, Micropterus salmoides ana-lyzed for heavy metals due to exposure to the clay indicated concentrations did not differ from control fish.