Current Challenges of Vaccination in Fish Health Management

TL;DR

This paper reviews the importance of vaccination in fish health management, highlighting the economic impact of fish diseases and the need for effective vaccines.

Contribution

The paper emphasizes the role of modern biotechnological approaches in developing novel fish vaccines to combat emerging diseases.

Findings

Fish vaccination is crucial for reducing losses due to infectious diseases in aquaculture.

Modern technologies like plant-derived vaccines and DNA vaccines are being explored for fish health.

Effective adjuvants and administration routes remain key challenges in fish vaccine development.

Abstract

About a 4% decline in fish production was recorded in 2020 in comparison to 2018 in inland aquaculture sectors. In 2014, about 10% of aquatic cultured animals were lost (costing global annual losses > USD 10 billion) due to infectious diseases. Contagious diseases generate several stresses, including oxidative stress in fishes that hampers their reproduction, growth, and production value. Aquaculture management needs to employ preventive measures against various contagious diseases for maintenance. Therefore, vaccination in fish, especially in broodstocks, is one of the most important measures to curb such fish losses. Here, we reviewed the current status of fish vaccines and the modern technology used to produce (alternative) fish vaccines, such as plant-derived vaccines for fish health management. Reliable aquaculture vaccines to increase economic productivity in aquaculture sectors are needed. Emerging contagious diseases in different fish species demand novel vaccines to be produced by adapting biotechnological approaches. Vaccination in broodstocks is important, and the fish vaccines are produced with whole-killed pathogens; subunits of a protein, peptide, or a recombinant protein; DNA vaccines; or live attenuated vaccines via different modes of administration. The use of adjuvants in fish vaccines needs to be researched.

Vaccination is an essential method of immunological preventive care required for the health management of all animals, including fish. More particularly, immunization is necessary for in-land aquaculture to manage diseases in fish broodstocks and healthy seed production. According to the latest statistics in 2020, 90.3 million tons of capture fishery production was achieved from the aquaculture sector. Out of the above, 78.8 million tons were from marine water aquaculture sectors, and 11.5 million tons were from inland water aquaculture sectors. About a 4% decline in fish production was achieved in 2020 in comparison to 2018 from inland aquaculture sectors. On the other hand, the digestive protein content, healthy fats, and nutritional values of fish products are comparatively more affordable than in other meat sources. In 2014, about 10% of aquatic cultured animals were lost (costing global annual losses > USD 10 billion) due to infectious diseases. Therefore, vaccination in fish, especially in broodstocks, is one of the essential approaches to stop such losses in the aquaculture sector. Fish vaccines consist of whole-killed pathogens, protein subunits, recombinant proteins, DNA, or live-attenuated vaccines. Challenges persist in the adaption of vaccination in the aquaculture sector, the route of administration, the use of effective adjuvants, and, most importantly, the lack of effective results. The use of autogenous vaccines; vaccination via intramuscular, intraperitoneal, or oral routes; and, most importantly, adding vaccines in feed using top dressing methods or as a constituent in fish feed are now emerging. These methods will lower the risk of using antibiotics in cultured water by reducing environmental contamination.

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