Drug Research Information Bulletin - Efficacy of Aquamycin 100® (22.045% Erythromycin Thiocyanate) to Control Mortality in Chinook Salmon Fingerlings Diagnosed with Bacterial Kidney Disease

Chemotherapeutic control of BKD has been relatively ineffective because of the intracellular nature of the pathogen (Fryer and Sanders 1981). Erythromycin has been used with limited success when administered in feed for 28 d to young fish (Munson et al. 2010). Aquamycin 100® (22.045% erythromycin thiocyanate; ET; Bimeda USA, Inc., Oakbrook Terrace, Illinois USA) is the product most commonly used in the U.S. to treat BKD; however, it can only be used under a U.S. Food and Drug Administration (FDA) Investigational New Animal Drug exemption. Treatment efficacy has been inconsistent, and some investigators have noted signs of toxicity. Nevertheless, efforts to obtain FDA approval continue. To that end, we cooperated in a trial to evaluate the efficacy of Aquamycin 100® administered in feed to control mortality in freshwater-reared Chinook salmon (CHS) Oncorhynchus tshawytscha diagnosed with BKD.