Comparative sensitivity of carp, Cyprinus carpio L. and rainbow trout, Salmo gairdneri Richardson, to Renibacterium salmoninarum.
All carp injected with 4.8 × 108 cells/fish or 4.8 × 107 cell/fish survived for 38 days. R. salmoninarum was isolated from all moribund fish, but not from the kidney of surviving fish, although R. salmoninarum antigen was detected in several of these fish by dot blot assay. On the other hand, mortality in rainbow trout was 95% in the fish injected with 4.8 × 108 cells/fish, and 15% in those given 4.8 × 107 cells/fish. R. salmoninarum antigen was detected by dot blot assay in all surviving trout. The number of R. salmoninarum cells was immediately decreased by carp or rainbow trout serum, and the serum bactericidal activity of carp was higher than that of rainbow trout. Carp blood leukocytes had higher phagocytic activity than those of rainbow trout.