** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** THE CATFISH INDUSTRY, COMPRISED OF CHANNEL AND HYBRID CATFISH, IS THE LARGEST SECTOR OF US AQUACULTURE ($421 MILLION IN FOOD SIZE CATFISH 2021). COLUMNARIS DISEASE IS A LEADING CAUSE OF MORTALITY IN CHANNEL CATFISH, AND THERE ARE CURRENTLY NO VACCINES AVAILABLE TO FARMERS. THIS DISEASE ALONE LEADS TO APPROXIMATELY $30 MILLION IN YEARLY LOSSES IN THE UNITED STATES.AS CHANNEL CATFISH PRODUCTION CONTINUES TO RISE IN THE US, ALTERNATIVE MEANS OF DISEASE PREVENTION WILL BE NECESSARY. ONE OF THE AGENTS OF COLUMNARIS, FLAVOBACTERIUM COVAE, HAS SHOWN TO BE HIGHLY PREVALENTIN CHANNEL CATFISH COMPARED TO OTHER COLUMNARIS-CAUSING BACTERIA AND CAUSES SEVERE DISEASE. COLLABORATIVE RESEARCH BETWEEN SCIENTISTS AT AUBURN UNIVERSITY AND THE USDA ARS AQUATIC ANIMAL HEALTH RESEARCH UNIT FOCUSES ON DEVELOPING METHODS FOR COLUMNARIS DISEASE CONTROL, INCLUDING VACCINE DESIGN AND PROBIOTIC SELECTION. THIS PROPOSED RESEARCH WILL DEVELOP A MULTI-PROTEIN SUBUNIT VACCINE AND INCLUDE A DIETARY PROBIOTIC SUPPLEMENT AS A COMBINATION THERAPY AGAINST FLAVOBACTERIUM COVAE. FROM THIS RESEARCH, WE AIM TO IDENTIFY NEW PROTEINS TO USE IN A VACCINE FORMULATION THAT WILL PROTECT CHANNEL CATFISH AGAINSTF. COVAEINFECTION AND GENERATE PROTECTIVE ANTIBODIES AGAINST F. COVAE. NEXT, WE WANT TO EVALUATE THE BEST METHOD TO ADMINISTER THE VACCINE THAT'S EFFECTIVE IN PROTECTING CHANNEL CATFISHWHILE STILL PRACTICAL FOR AQUACULTURE FARMERS. WE WILL COMPARE VACCINATING FISH BY A BATH IMMERSION OF THE VACCINE OR COATING FEED WITH THE FORMULATION FOR A 7-DAY LONG FEEDING. LASTLY, WE WANT TO EVALUATE THE USE OF A DIETARY PROBIOTIC,BACILLUS VELEZENSISAP193, FOR PROTECTING FISH FROM DISEASE, WHETHER DIRECTLY INHIBITING F. COVAEOR STIMULATING THE CATFISH IMMUNE SYSTEM. THE RESULTS FROM THIS RESEARCH WILL ADVANCE OUR KNOWLEDGE CONCERNING THE EFFICACY OF AMULTI-PROTEIN SUBUNIT VACCINEIN PROVIDING PROTECTION FOR CHANNEL CATFISH AGAINST F. COVAE INFECTION, AND WHETHER THERE IS ADDITIONAL DISEASE PROTECTION THAT CAN BE AFFORDED BY A COMBINED PROBIOTIC AND VACCINE ADMINISTRATION.