Exploiting immunomodulatory properties of β-glucans derived from natural products for improving health and sustainability in aquaculture-farmed organisms: Concise review of existing knowledge, innovation and future opportunities

The global aquaculture industry has surpassed capture fishing to achieve goals of economic and environmental sustainability. This intensification, albeit extremely beneficial, has limitations with regard to the cultured animals, including infections, pollution and stress. This can lead to an increase in disease and mortality rates not experienced in natural habitats. Several drugs and vaccination programs have been proposed to address these issues, with only partial success, and as such, there is an urgent requirement for an alternative approach to these threats. One such potential solution is the administration of β-glucans, natural polysaccharides which can induce nonspecific innate defences, ultimately increasing disease resistance. This review will discuss the benefits of the administration of β-glucans in aquaculture by highlighting key data including enhanced immune responses, anti-inflammatory effects, resistance to infection, stress resistance, physical growth improvement, as well as extension of lifespan. We also highlight the important variables to be considered in incorporating β-glucans in aquaculture.