Submitted to: Aquaculture Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/23/2005
Publication Date: 6/1/2005
Citation: Shoemaker, C.A., Xu, D., Shelby, R.A., Klesius, P.H. 2005. Detection of cutaneous antibodies against flavobacterium columnare in channel catfish, ictalurus punctatus, (rafinesque). Aquaculture Research 36(8): 813-818. Interpretive Summary: Flavobacterium columnare (a Gram negative bacteria) is responsible for columnaris disease in the cultured channel catfish industry. Presently, columnaris disease is as important as enteric septicemia of catfish and together, they account for over 70 % of the disease losses. Little information is available concerning the immune response of catfish to this important pathogen. Our study was designed to determine if antibody (a protective protein made by the catfish against foreign agents) was present in the fish's skin after exposure to Flavobacterium columnare. We found that antibody against F. columnare was present in the fish skin. Further studies are planned to study the role of this antibody in protection against columnaris disease in channel catfish.
Technical Abstract: This study was conducted to determine if antibodies against Flavobacterium columnare were present in excised skin explants of channel catfish, Ictalurus punctatus (Rafinesque) following experimental infection. An indirect ELISA was used to determine cutaneous antibody titers at 16, 32 and 60 days post infection from excised skin explants cultured in vitro. Cutaneous antibodies against F. columnare were detected in the skin explants from intraperitoneally (IP) injected channel catfish. Titers ranged from 16 to 128 (mean 44 ± standard error (SE) 12.5; N=12) from infected fish and were significantly higher (P < 0.003) than non-infected fish (mean 2.0 ± 0.0; N=12) at day 16-post immunization. A second group of fish was IP injected and boosted by bath immersion at day 16. Titers ranged from 4 to 16 (mean 7.6 ± 1.5; N=10) and were significantly higher (P < 0.04) than titers detected in the control fish (mean 2.0 ± 0.0; N=5) at 32 days post boost. A third group of fish were injected and boosted by IP injection at day 32 with titers being determined at day 60. Titers ranged from 4 to 32 (mean 12.0 ± 3.7; N=9) and were significantly higher (P < 0.01) than titers detected in the control fish (mean 2.0 ± 0.0; N=9). To our knowledge, this is the first description of cutaneous antibodies against F. columnare in channel catfish.