A review on insect meals in aquaculture: the immunomodulatory and physiological effects

The depletion of global fishery stock has posted significant effects to the world capture fishery industry. Constant environmental issues and fluctuation of fish meal (FM) costs have pushed the aquafeed industry to seek for alternative protein sources to sustain the huge demand of feed in aquaculture production. Insect meal (IM) has already started to gain global attention as an alternative for FM replacement. Substantial feeding trials have revealed its promising application not only beneficial as in protein replacement but also playing a vital role as a functional ingredient that boosting immunostimulatory effects in a wide range of aquatic animals. Here, we compiled and categorized several major groups of insects, for example black soldier fly, yellow mealworm, housefly, silkworm, alongside a minor group of insect species widely used as the alternative diet in aquaculture. Critically, we discuss the functional properties of the IMs, their immunomodulatory, and physiological effects in aquatic species. Biological parameters include oxidative stress, serum biochemical, hematological parameters, and immune-related genes are also further discussed in this review. In short, we suggest that low levels of IM supplementation could improve survival, immunity, and feed conversion efficiency of targeted aquaculture species. Chitin and its derivatives alongside active substances in insect exoskeleton, such as antimicrobial peptides (AMPs) play an essential role in the immunomodulation of aquatic organisms. Knowledge of this area is still in infancy. Therefore, it is a critical need to further address the mechanism of immunomodulation focusing on the isolated components from IMs.