Protection of channel catfish Ictalurus punctatus following natural exposure to Edwardsiella ictaluri and effects of feeding antigen on antibody titer

S Vinitnantharat, JA Plumb
1993 Diseases of Aquatic Organisms  
Channel catf~sh Ictalurus punctatus that s u m v e d a natural infect~on of Edwardslella lctalun demonstrated a strong relahonsh~p between E ictaluri aggluhnahon a n t~b o d y tlter and degree of protechon upon challenge Intrapentoneal injection of 2 0 X lo7 cells fish-' killed 100 % of f~s h with ant~body titers of 0 and 128 (low) 77 8 % of fish with bters from 256 to 512 (medium) and 57 7 % of the fish with hters of >l024 (high) A second challenge tnal usmg 5 1 x 105 cells f~s h -' produced
more » ... f~s h -' produced 72 2 % mortahty in fish with no detectable antibody titers 51 3 % In low a n t~b o d y titer flsh 25 0 % in m e d~u m antibody tlter fish and 6 5 % in h~g h a n t~b o d y titer fish These results demonstrate that channel catfish have protective antibodies after they are exposed to E lctalun but that a titer of over 256 1s necessary to ensure detectable protect~on against an ~njected challenge If fish are challenged with large numbers of pathogen this protechve immunity can be overcome Administration of E ictalun cell extract impregnated feed every 5 or 10 d to fish vaccinated by inlection resulted in the fish malntainmg theu anbbody titer, whereas the antibody titers of fish receiving no oral vaccine continued to dechne O Inter-Research 1993
doi:10.3354/dao015031 fatcat:lfpg7y63j5b55itudh6g4gsgzi