August 20, 2014
Merck Animal Health develops vaccine against most prevalent tilapia disease
Merck Animal Health (known as MSD Animal Health outside the United States and Canada) introduced a new fish vaccine to help protect tilapia and other fish against the biotype 1 strain of Streptococcus agalactiae, which is the biotype specific to Thailand and other key tilapia-producing regions in Asia, including Malaysia.
"We are pleased to introduce a new fish vaccine to help producers protect their fish from one of the most costly diseases affecting the species," said Norman Lim, regional technical manager for aquaculture in Asia of Merck Animal Health. "The vaccine is backed by Merck Animal Health''s ''Strep Control: Your Tilapia Health'' programme, which provides producers with the support they need to implement an effective vaccination and control programme."
Merck Animal Healthconducted extensive sampling of farms in the world''s most important tilapia-producing regions and found that Streptococcus accounted for 70% of all pathogens collected, making it the most prevalent disease affecting tilapia. Of the two Streptococcus strains that have been identified, S. agalactiae is the most economically damaging, causing widespread mortality and morbidity in larger fish.
The fish vaccine provides specific protection against the biotype 1 strain of S. agalactiae, the main cause of Streptococcosis in tilapia in Thailand. Fish vaccinated with the vaccine are safe for human consumption.
In a laboratory test, fish experienced full onset of immunity one week after vaccination with this vaccine and protection was demonstrated to last for at least 12 weeks. In a large-scale field trial in an environment challenged by S. agalactiae biotype 1, the fish vaccine increased survival by 17%, increased biomass by 11.2%, and improved feed conversion efficiency by 9%. Protection was demonstrated for the entire grow-out period.