“Barley as a production platform for oral vaccines in sustainable fish aquaculture (7370)”

Barley as a production platform for oral vaccines in sustainable fish aquaculture

Fish health remains a major bottleneck in carp aquaculture. Beyond water quality, which can considerably weaken their immunity, carp are highly susceptible to viral, bacterial, fungal, and parasitic infections. Because these pathogens persist in pond systems, total eradication is unrealistic, and recent reductions in inflow water make it increasingly difficult to maintain optimal pond conditions. Alongside general preventive measures, species-specific vaccines could substantially improve fish survival. Yet no carp vaccine is currently registered in the European Union, even though many groups are pursuing its development.

An oral vaccine would be the best solution for practical use in farms, as its administration would not require excessive handling of the fish or special technical equipment. However, oral vaccines face a notable limitation due to insufficient stimulation of the complex gut-associated lymphoid tissue caused by factors such as vaccine degradation and poor absorption. Plant cells enable targeted storage of recombinant vaccines in specific cell organelles to ensure superior protection and contain natural compounds acting as adjuvants, which could lead to more efficient immune system activation.

Here we evaluate barley (Hordeum vulgare) as a production platform for an oral subunit vaccine against the envelope glycoprotein of spring viraemia of carp virus (SVCV). Lyophilised plant material was delivered to common carp (Cyprinus carpio) by intubation, and fish were sampled at 3, 7, 14, 21 and 28 days post-immunisation (dpi) to asses the induced immune responses on both cellular and molecular levels using a combination of flow cytometry and transcriptional analyses.

The results suggest a potent capacity of the plant material in inducing immune responses, manifested by an early influx of inflammatory myeloid cells to the intestinal tissue, accompanied by a progressive, 3—to 8-fold up-regulation of immunoglobulin genes across mucosal and systemic tissues. Collectively, these findings demonstrate that barley-based recombinant antigens can successfully prime carp immunity, highlighting the potential of plant-based vaccines for aquaculture.

1. KORYTAR, TOMAS, BIOLOGY CENTRE CAS, Presenter
2. Mičůchová, A., Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Author
3. Frébort, I., Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Author
4. Sebastian, A., Faculty of Fisheries and Protection of Waters, University of South Bohemia in České Budějovice, Author
5. Adamek, M., Fish Disease Research Unit, Institute of Parasitology, University of Veterinary Medicine Hannover, Author
6. Kyslík, J., Biology Centre CAS, Institute of Parasitology, Author
7. Piačková, V., 1Faculty of Fisheries and Protection of Waters, University of South Bohemia, Author