Submitted to: World Aquaculture Society Meeting
Publication Type: Abstract Only
Publication Acceptance Date: January 18, 2006
Publication Date: May 9, 2006
Citation: Klesius, P.H., Evans, J.J., Shoemaker, C.A. 2006. Benefits of the use of attenuated vaccines in aquaculture. Aqua 2006: including World Aquaculture 2006 and Aquaculture Europe 2006. May 9-13, 2006. Florence, Italy. p.468. Technical Abstract: The prevention of diseases is becoming more dependent on the use of vaccines in aquaculture. An important consideration in whether to vaccinate is cost effectiveness to producers compared to other means of disease control. The risks of not using a vaccine may be a more significant factor when faced with the total loss of profits even when minor-moderate disease outbreaks occur. The choice of the vaccine needs to be compatible with production system and growth life cycle of the fish species. Also, the choice needs to be compatible with method of administration and the duration of protection. In the aquaculture, the best type of vaccine is one that is cost-effectively administered to large numbers (i.e. mass vaccination) of the youngest life-stage of fish with no or minimal stress. Attenuated vaccines fulfill these needs for the aquaculture. Attenuated vaccines against Gram-negative pathogens meet or exceed the vaccinology requirements of the catfish aquaculture. Attenuated vaccines against Edwardsiella ictaluri and Flavobacterium columnare are fully licensed for use in 7-10 day post-hatched catfish fry by immersion exposure. The USDA, Agricultural Research Service vaccines were licensed to Intervet and marketed under the trade name AQUAVAC-ESC® and AQUAVAC-COL® for protection against enteric septicemia of catfish (ESC) and columnaris (COL), respectively. AQUAVAC-ESC® and AQUAVAC-COL® vaccines enhance fish survival (Table 1). The immunization duration is 1 to 2 years. Moreover, Intervet estimated that economic benefit of the AQUAVAC-ESC® to the producer is $1,706 per acre over non-vaccinated catfish. Attenuated vaccines are safe and they have been effectively used in the livestock and poultry industries. Attenuated fish vaccines are generally used where the pathogen(s) is endemic in the cultured fish and the aquatic environment. Thus, attenuated vaccines offer a number of advantages over the less efficacious and cost-ineffective killed vaccines for the aquaculture industry. Table 1. Protection against ESC and columnaris disease after immersion vaccination 10-14 day post hatch channel catfish. Treatment % Mortality (SEM) RPS ESC-1 X 107 2.37±1.6a 94.7 COL-1 X 107 4.97±2.0a 83.0 Control-ESC 92.0 ±1.0b ---- Control-COL 29.34±1.5b ---- Control 0.00±0.0a non-challenged) Bath immersed in vaccine for 2 minutes and challenged with E. ictaluri (ESC) or F. columnare (COL) at 30 days post-immunization. Percent cumulative mortality and RPS at 14 days post challenge.