Submitted to: Aquatic Fish Health International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: July 19, 2002
Publication Date: September 1, 2002
Citation: Xu, D., Klesius, P.H. 2002. Protective effect of cutaneous antibody against ichthyophthirius on channel catfish. Aquatic Fish Health International Symposium. Technical Abstract: Fish recovered from sublethal ichthyophthiriasis acquire protective immunity against Ichthyophthirius (Ich). The objective of this study was to evaluate the protective effect of cutaneous antibody produced by channel catfish immune to Ich on cohabited non-immune catfish after exposure to 15,000 theronts/fish. Non- immune and immune fish controls were separately maintained and infected with theronts. Ich infection was assessed by scoring 0, <50, 50-100 and >100 trophonts/fish at 5 days post-infection. The results of infection showed that cohabited fish at the ratio of 15 non-immune to 2 immune fish had <50 trophonts/fish. Eighty percent of the cohabited fish at the ratio of 10 non-immune to 2 immune fish showed 0 or <50 trophonts/fish. The control non- immune fish had 50-100 trophonts/fish or >100 trophonts/fish. The infection score of the control immune fish was 0 trophonts/fish. Anti-Ich antibody was detected in water samples taken from tanks containing immune fish by ELISA after the water samples were concentrated 40X. Immunoadsorption of these water samples with theronts reduced the level of anti-Ich antibodies. The results of the study suggest that immune fish cohabited with non-immune fish may protect non-immune fish against Ich infection.