EVALUATION OF A TRIVALENT VACCINE FOR Aeromonas hydrophila, Flavobacterium columnare AND Edwardsiella ictaluri USING IN-POND RACEWAY SYSTEMS IN WEST ALABAMA

Commercial catfish farming in the state of Alabama has been hit hard in recent years with significant losses due to bacterial disease outbreaks. Since 2015 Auburn University and the Alabama Fish Farming Center in west Alabama have been conducting trials on a commercial farm in Hale county to investigate different methods for controlling disease outbreaks. In 2017, an experimental trial is being carried out to examine three different administration methods (injection, immersion, immersion with adjuvant) for a trivalent vaccine that targets Aeromonas hydrophila (vAh), Flavobacterium columnare, and Edwardsiella ictaluri. These three bacteria account for a $12.3 million-dollar annual loss for producers in Alabama. Three in pond raceway systems (IPRS) on three different ponds are being used to culture fish for this trial. Each IPRS unit consists of 16 individual 256 ft³ cells (4 replicates per treatment) with air lifts that supply flow and aeration via a regenerative blower (1.5 HP). Channel catfish that were vaccinated at Auburn University were transported to west Alabama and stocked into the IPRS units at 1000 fish per cell in early June and will be cultured until harvest this fall. Water quality (dissolved oxygen, temperature on a daily basis; ammonia, nitrite twice weekly; alkalinity, hardness, and pH biweekly) is being closely monitored along with removal and counting of mortalities in each cell. All disease outbreaks within the cells are monitored and diagnosed by the Alabama Fish Farming Center's diagnostics lab. Throughout the trial catfish are being fed (32% protein commercial feed) twice daily according to established feeding protocols. At the end of the trial catfish in each raceway cell will be harvested, counted, and group weighed. Survival (%), average weight, and feed conversion ratio will be determined. The results for each vaccine administration method will be analyzed to determine which is most effective.