New Vaccines Developed for Farm-Raised Catfish

(Agricultural Research Service/USDA)

Scientists from the USDA’s Agricultural Research Service (ARS) are developing vaccines to help protect against common diseases faced by healthy farm-raised catfish. Biologists and aqua pathologists from ARS labs in Auburn, Alabama and Chestertown, Maryland are focusing on protections for catfish against against the bacteria Streptococcus (S.) iniae, S. agalactiae, and other pathogens.

The scientists create fish vaccines by modifying the genetic makeup of pathogens to make them nonvirulent, and then develop vaccines that expose fish to low doses of the modified forms of the pathogens. For now, fish are vaccinated by immersing them in water that contains the modified pathogen.

This fish-vaccine project builds on earlier ARS work. The team has have developed a modified live S. iniae vaccine that appears to be superior to inactivated or killed vaccines. The live modified vaccine has enough similarity with the pathogen to create a lifelong immunity in fish.

An earlier vaccine trial of a catfish vaccine by Mississippi State University researchers against the bacteria Edwardsiella ictaluri that causes enteric septicemia showed a 12 percent increase in the survival rate of fish that were given the vaccine, and a substantial increase in returns for producers who used the vaccine in their ponds.