Spirulina in fish immunity development: find the black box

In aquaculture studies, Spirulina can be used to replace fish meal in aquafeed to lower the cost of producing fish feed while adding therapeutic and health benefits. Proteins, carbohydrates, vitamins, minerals, pigments, and fatty acids from Spirulina could enhance the cellular and humoral immunities of a variety of fish species. This review focuses on the functions of various Spirulina components that play a role in haematopoiesis, haemato-biochemical variables, pro-inflammatory and anti-inflammatory cytokine production, stress prevention, disease resistance, and immune responses in a variety of finfish species. Herein, we also presented the overlooked areas on the functionality of Spirulina on the immune response pathway and connected the missing link with the help of a better knowledge of the mammalian system, albeit these must be proved experimentally. This review will inspire the scientific community to investigate the biological role of Spirulina in fish, which is critical to the commercial viability of Spirulina as fish feed.