Development of immunological tools for monitoring the immune response of Nile tilapia
Aquaculture is the fastest growing animal food production sector globally. Fish are an import source of protein and as such aquaculture has great potential to play a key role in future food security programmes. Because of their rapid growth and high protein content, tilapia is an attractive species for aquaculture, reaching harvest size after only 6-7 months; tilapia are now in fact the second most farmed species after carp. They are farmed in many low and middle-income countries (LMIC) and provide an important source of revenue for many low income families. Disease in tilapia culture is associated with intensification of the farming system, and both bacterial and viral diseases are severely impacting on the expansion of tilapia farming; in particular Streptococcus spp. There is increasing concern about the use of antibiotics to control disease outbreaks and attention is focusing on the use of vaccination for disease control. Vaccination exposes fish to a non-infectious dose of the pathogen, so when they come into contact with the pathogen at a later date, memory cells of their immune system stimulate a response to combat the disease. We need a better understanding of how tilapia respond to infection and vaccination to be able to develop and formulate effective vaccine products for tilapia. We currently have few reagents available for investigating the immune response of tilapia. Through a collaboration of scientists in Vietnam, Canada and the UK, we plan to develop and apply novel tools (synthetic antibodies) for studying the immune response of this important aquaculture species, using Streptococcus agalactiae as our infection model. Synthetic antibodies are made in the laboratory, unlike conventional antibodies which are produce in animals, thus eliminating the need to use animals to make these reagents. This work will ultimately lead to the development of more effective strategies for managing disease in tilapia aquaculture systems.