Immunisation of tilapia broodstock as a strategy to prevent vertical transmission of tilapia lake virus (TiLV)
Aquaculture is the fastest growing food-production sector globally, with over 1 billion people relying on fish as their major protein source. Within low and middle income countries (LMIC), aquaculture has an important role in improving food security, as well as the economic and social development of the country. Tilapia (particularly Oreochromis spp.) is the world’s second most predominant aquaculture species after carp. Reaching harvest size in just 6 months, it provides 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 expansion of tilapia farming. Tilapia fry are actively traded for aquaculture purposes, globally. There is a huge risk of widespread disease resulting from the movement of live fish without appropriate control measures in place e.g. tilapia lake virus (TiLV) in tilapia, white spot virus in shrimp, etc. Thus, production of specific pathogen-free, immunised fry is considered an ideal approach for disease control and preventing the spread of disease worldwide. Maternal antibody transfer from female broodstock to offspring has been confirmed to occur in several finfish species, and has been shown to protect early embryos and fry from infection. However, little is known about maternal antibody transfer in tilapia. TiLV has recently emerged as a new viral disease problem in tilapia culture, and its rapid spread has raised global concern for the tilapia aquaculture industry. Vaccinating broodstock maybe a novel disease control strategy in tilapia, but it requires vaccinated tilapia broodstock to be able to pass specific antibodies to their embryos, and for these antibodies to prevent vertical transmission. We intend to test these hypotheses in this project using TiLV as our model pathogen.