Embracing nanotechnology for selenium application in aquafeeds

Selenium (Se) is an important micronutrient that has been used in aquafeeds for the normal growth, welfare and health of aquatic animals. Through nanotechnology, Se can be converted into nanoparticles that are more bioavailable, utilized and absorbed by aquatic animals. However, this is still a new and emerging area of research in aquafeeds. This paper aims to review the effect of Se and Se nanoparticles (Se-NPs) application in aquafeeds on aquatic animals. Specifically, different compounds of Se, requirement levels by different species, effects on animal growth, physiology, antioxidant capacity and immune response have been highlighted. The review shows that the application of Se in aquafeeds could improve the growth performance, physiology, antioxidant enzymes, immunity and disease resistance in aquatic animals. However, the effectiveness could be highly influenced by the source of Se, aquaculture species and administration quantity. Through nanotechnology, the utilization and absorption of Se could be improved while reducing its toxicity. Therefore, Se-NPs present an efficient way to utilize nutrients in aquafeeds. Important gaps, however, exist in the current knowledge, particularly with regard to the response of shrimps and crustaceans to dietary supplementation of Se and Se-NPs as most of the existing studies have focused on fish species. Also, some species of economic importance and life stages have not been investigated, which hinders the embracement of nanotechnology in aquafeeds production.