Submitted to: Fisheries Forum Asian Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 30, 2008
Publication Date: September 26, 2008
Citation: Xu, D., Klesius, P.H., Shoemaker, C.A., Shelby, R.A. 2008. Prevention of Ichthyophthirius multifiliis in Fish Using Vaccination. 2008 Forum on Fishery Science and Technology. p. 166-170. Technical Abstract: Ichthyophthirius multifiliis (Ich) is a severe fish parasite that causes high mortality in many cultured fish. Ich infection is difficult to control with chemical treatments after the parasite penetrates into the fish skin and gills. Chemical treatment is also expensive and may actually harm the fish. Vaccination is an alternative way to prevent Ich mortality. Two immunization trials were conducted to evaluate immune responses and host protection of channel catfish Ictalurus punctatus and Nile tilapia, Oreochromis niloticus against Ich using live theronts and sonicated trophonts. Immunizations with live theronts or sonicated trophonts were done by both bath immersion and intraperitoneal (IP) injection. Cutaneous and serum anti-Ich antibodies were measured 12 and 21 days post immunization for catfish and 12, 25 and 180 days post immunization of tilapia. The survivals of catfish and tilapia were determined after theront challenge. Anti-Ich antibodies titers were significantly higher (p<0.05) in catfish and tilapia immunized with live theronts by immersion or IP injection or with sonicated trophonts administed by IP injection. In contrast, fish immunized with sonicated trophonts by immersion and with bovine serum albumin (control) by IP injection had significantly lower antibody titers. Immunity was noted only in fish immunized with live theronts by immersion or IP injection or with sonicated trophonts by IP injection. There was a positive correlation between higher levels of anti-Ich antibodies and host survival in the immunized fish. The results of this study show the vaccination against Ich is an excellent alternative to chemical treatments.