Submitted to: American Fisheries Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 29, 2008
Publication Date: July 13, 2008
Citation: Xu, D., Klesius, P.H., Shoemaker, C.A. 2008. Immune response and host protection of Nile tilapia against parasite Ichthyophthirius multifiliis. In: Proceedings of the American Fisheries Society Fish Health Section, July 14-12, 2008, Charlottetown, Prince Edward Island, Canada, p. 154. Technical Abstract: Ichthyophthirius multifiliis (Ich) is one of the virulent ciliated parasites and causes heavy economic loss in freshwater fish. Two immunization trials were conducted to evaluate host protection of Nile tilapia, Oreochromis niloticus against Ich. Immunizations were done with live theronts or sonicated trophonts by bath immersion and intraperitoneal (IP) injection. The immunized fish were challenged with theronts 21 days post immunization in trial I and 180 days post immunization in trial II. The serum anti-Ich antibody was evaluated after immunization and cumulative mortalities of tilapia determined after theront challenge. Serum anti-Ich antibody was significantly higher (p<0.05) in tilapia immunized with live theronts by immersion or IP injection or with sonicated trophonts administered by IP injection than tilapia immunized with sonicated trophonts by immersion, with bovine serum albumin by IP injecton, or non-immunized controls. Host protection was acquired in fish immunized with live theronts by immersion or IP injection. Tilapia immunized with sonicated trophonts by IP injection were partially protected with a 57% - 77% survival in both trials.