Compounds with Inhibitory Activity against the Channel Catfish Pathogens Edwardsiella ictaluri and Flavobacterium columnare

Abstract Enteric septicemia of catfish (ESC) and columnaris, the most common diseases in channel catfish Ictalurus punctatus in the southeastern United States, are caused by the bacteria Edwardsiella ictaluri and Flavobacterium columnare , respectively. Although producers may rely on antibiotics and certain therapeutants to help manage these diseases, the discovery of new compounds that are environmentally safe and efficacious alternatives to current antibiotics and therapeutants would benefit the channel catfish aquaculture industry. A rapid bioassay was used to evaluate compounds as the first step in the discovery process. Tannic acid was highly toxic to E. ictaluri and F. columnare , and it is promising for future efficacy testing against ESC and columnaris. Sodium percarbonate, an environmentally safe compound, is promising for future efficacy testing to determine its potential use in managing and preventing F. columnare outbreaks in small‐scale systems used for channel catfish culture or during transport.