Submitted to: Aquaculture Miscellaneous Publications
Publication Type: Review Article
Publication Acceptance Date: July 30, 2007
Publication Date: October 1, 2007
Citation: Shoemaker, C.A., Klesius, P.H., Lim, C.E. 2007. Feed deprivation increases the susceptiblity of channel catfish to columnaris disease. Schering Plough Animal Health Aqua Focus 65: 1-4. Technical Abstract: Columnaris disease caused by Flavobacterium columnare is a major disease in warm and cold water species of fish. In the U.S. channel catfish industry, it is considered among the top two bacterial pathogens, along with enteric septicemia of catfish (ESC). Often times, columnaris and ESC, which is caused by Edwardsiella ictaluri, are seen concurrently on the same farm. Two studies in channel catfish were conducted to evaluate the effect of withholding feed and its influence on columnaris disease, which is caused by F. columnare. After exposure to F. columnare, mortality was significantly higher in fish that were not fed for 7 or more days compared to fish that were fed. Results of these studies suggest that channel catfish that are not fed for 7 days or more in an environment where natural food is absent have an altered innate resistance to F. columnare, characterized by increased mortality upon exposure to this pathogen. It is generally believed that poor nutrition results in decreased health and immunity. In catfish and other animals, immune cell (macrophage) function becomes impaired following periods of restricted feeding. Starvation has been characterized as a form of chronic stress that may lead to immunosuppression. Although we did not measure stress parameters in our studies, fish that were not fed were shown to be highly susceptible to disease. This may indicate that one or more nutrients essential for maintenance of optimum immune function is lacking in feed-deprived catfish. Our study results also suggest that juvenile channel catfish should be fed to apparent satiation at lease once every other day to maintain weight, normal physiological parameters, proper immune function and to improve resistance to columnaris disease.