White spot resistance breakthrough
The disease is one of the most serious affecting farmed shrimp, and there is currently no effective way of combating it. However, the markers can now be used to breed shrimp that are more resistant.
The virus that causes white spot disease (WSSV) is capable of killing all the shrimp in a pond within 10 days of infection. The disease can, on occasions, totally devastate shrimp aquaculture in a complete region. There are currently no treatments available to effectively prevent outbreaks of the disease.
The research has been carried out by Nofima and the Indian CIBA (Central Institute of Brackishwater Aquaculture), and financed by the Research Council of Norway and the Indian Department of Biotechnology. Senior scientist at Nofima, Nicholas Robinson, explains: “Now that these markers have been found in the tiger shrimp, it will be possible to select for higher immunity to the disease in the next generation by implementing what is known as ‘marker-assisted selection’ into an advanced breeding program. Since the generation time of the shrimp is short, we can expect a clear effect within a few years.”
This is the first extensive experiment in which genes markers related to disease have been found in shrimp, while the scientists have also found markers for genes that determine sex. The gene markers for sex could assist hatcheries to produce exclusively female shrimp for distribution. Male shrimp are small and grow slowly, so the discovery of sex-determining markers can enable aquaculture personnel to produce healthier shrimp that grow more rapidly.
The scientists are also now planning to examine whether the same genes affect the resistance to white spot disease in white shrimp. This will be financed by the same sources, and new partners will be involved. White shrimp is also used in aquaculture in India and several Asian countries.
“We are now in the process of starting a project for the white shrimp with the same goals – to discover genetic tools that can reduce a disease that is widespread in shrimp aquaculture,” concludes Robinson.
