Experimental induction of bacterial kidney disease in Chinook salmon by immersion and cohabitation challenges

Abstract

Two challenge methods for inducing bacterial kidney disease (BKD), caused by Renibactenum salmoninarum (Rs), in salmon were evaluated using chinook salmon Oncorhynchus tshawytscha. The first method involved immersing the fish in various concentrations of Rs cells ( 1 0 9 0 106 ml-l) for 15 or 30 min (the immersion method); the second method was based on the enforced cohabitation of uninfected fish with others that had been injected intraperitoneally with various doses (10" 1o5, and 10') of Rs cells (the cohabitation method). Both methods were successful in establishing BKD in the test fish but, as expected with this slow-acting pathogen, the challenges took considerable time to complete.