ANIHWA call2: Sustainable management of aquaculture fish health through the development of low cost plant-derived vaccines

The aquaculture industry is the fastest growing food-producing sector worldwide. To achieve a sustainable aquaculture food-fish production and manage the aquaculture fish health, vaccination has been found to be an effective method for increasing economic output and improving animal welfare. It has also permitted the development of more sustainable fish farming with reduced use of antibiotics and chemicals. Since viral diseases pose a serious threat to aquacultures worldwide, this lack of preventive measures has extensive negative consequences. For instance, pancreas disease (PD), a viral fish disease caused by the Salmonid alphavirus (SAV) has a significant impact on Norwegian salmonid aquaculture as well as in other European countries e.g. UK. Another fish viral disease, viral haemorrhagic septicaemia (VHS), which can affect most species of salmonid fish reared in fresh water or sea water, is caused by the VHS virus. The economic loss caused by VHSV on farmed rainbow trout is a challenging task in Finnish aquaculture. Outbreaks of VHS
have also occurred in Norway and the UK. VHSV has been detected in marine fish, and is known to have high mutation rate and adaptability. Thus, there is an urgent need to develop low-cost fish vaccines to assist sustainable aquaculture production in Europe. Thus, we three Europeans partners (Norway, UK and Finland) aim to advance our existing plant-based recombinant protein production technologies to establish a transnational plant-based low cost vaccine production platform to facilitate the future production of fish vaccines in large quantity at low cost. We have selected PD and VHS as two cases for proof-of-principle and will test our three different tobacco-production technologies (i.e. transient expression by producing virus like particles, chloroplast genetic engineering and tobacco BY-2 cell line platform). By comparing the three systems in terms of total production costs, scaling-up potential and timeline by the end of the project period, the PlantVac project can provide a technology-based plant production platform for future production of PD and VHS vaccines as well as other fish vaccines. The PlantVac consortium consists of experienced scientists with the required expertise on three of the proposed plant production systems, fish health, veterinary immunology and economics.

The aquaculture industry is the fastest growing food-producing sector worldwide. The global aquaculture
production of food fish reached 66.5 million tonnes in 2012. To meet the challenges, the fish industry depends on stable production and good management of fish health. The demand for effective vaccines and vaccination methods is increasing in parallel with the growth of fish production. In Norway, the aquaculture industry is one of the most important industries after oil and gas. Today's sale of fish vaccines amounts to nearly 500 million NOK in Norway. In Finland the value of aquaculture in 2012 was approximately 65 million Euros. To date, there are nomore than 30 commercial vaccines for the prevention of a wide range of fish diseases, with a few more under development. The economic, environmental and animal welfare benefits have been recognised as a result of the widespread use of vaccines in the aquaculture industry. For example in Norway, the total annual vaccinemarket represents about 475 million NOK (approx. 431 million doses). Plant production systems
offer several advantages including economic aspects as plants can be grown on a larger scale than other systems. Low cost is one of the most important issues in the future development of fish vaccines. Plants also possess the ability to carry out post-translational modifications similar to that of other eukaryotic systems. The plant-based systems bypass the safety concerns inherent in live virus vaccines. To date, three main plant-based
techniques have been used for the expression of a large number of vaccine antigens. These are (i) stable
expression of transgenes in the nuclear genome of transgenic plants or cell lines (ii) stable expression of transgenes in the plastid genome of plants by plastid genetic engineering and (iii) transient expression of transgenes in plants. In the current project, we will evaluate all three technologies for producing PD and VHS vaccines in tobacco.

This is a "science-led" project which will utilise recent developments in the production of VLPs via transient expression in plants at JIC to create a new generation of vaccines top protect fish against viral diseases. The aquaculture industry is the fastest growing food-producing sector worldwide. To achieve a sustainable aquaculture food-fish production and manage aquaculture fish health, vaccination has been found to be an effective method for increasing economic output and improving animal welfare. It has also permitted the development of more sustainable fish farming with reduced use of antibiotics and chemicals. Since viral diseases pose a serious threat to aquacultures worldwide, this lack of preventive measures has extensive negative consequences. For instance, pancreas disease (PD), a viral fish disease caused by Salmonid alphavirus (SAV) has a significant impact on Norwegian salmonid aquaculture as well as in other European countries e.g. UK. Another fish viral disease, viral haemorrhagic septicaemia (VHS), which can affect most species of salmonid fish reared in fresh water or sea water, is caused by the VHS virus. The economic loss caused by VHSV on farmed rainbow trout is a challenging task in Finnish aquaculture. Outbreaks of VHS have also occurred in Norway and the UK. VHSV has been detected in marine fish, and is known to have high mutation rate and adaptability. Thus, there is an urgent need to develop low-cost fish vaccines to assist sustainable aquaculture production in Europe.

The introduction of lower-cost plant produced vaccines is expected to effectively promote economic sustainability in aquaculture farming by also ensuring the health safety of the fish stocks. Furthermore, it is anticipated that the risk of any disease spreading from hatcheries to the fishes in open sea, will be drastically reduced. This is of high importance for the good ecological of the aquatic ecosystems and the sustenance of the fishery activities in open seas. The economic and environmental abatement costs arising from the plant produced vaccines will be compared through a cost-effectiveness analysis with the traditional mammalian-based vaccines. Also, the preferences of fish farm representatives towards the potential commercialization of plant production vaccines will be explored.