Fishmeal and fish oil, used in production of aquaculture feeds are widely recognized as limited resources, due to strategic efforts in conservation and management of the species that are the source of these ingredients. In order to significantly and sustainably advance the growth of domestic aquaculture, viable alternatives for fishmeal and fish oil are needed. Aquaculture is the largest growing food production sector globally, providing a key role in meeting the protein demand of a rising global population. Insects are an underexplored alternative for sustainable aquaculture and aquafeeds in the US, that could help grow the domestic aquaculture industry, and increase the environmental sustainability of aquaculture. Our study looked at the use of insects, specifically mealworms Tenebrio molitor, as a potential alternative for fishmeal and fish oil. Insects such as mealworms are sustainably cultured; they can be grown from organic by-products and have good nutritional profiles making them a well-suited protein alternative ingredient. Three experimental diets were prepared with varying degree of fishmeal and fish oil replacement by whole dried mealworms. In addition, a reference group of fish were fed a commercial salmon feed that was high in fishmeal and fish oil. Diets were fed to apparent satiation to juvenile sablefish Anoplopoma fimbria, a cold-water marine fish, for 10 weeks to evaluate any differences in feed and growth performance.
Comparable growth across treatments was observed, demonstrating the ability of mealworms to fully replace fishmeal and fish oil in sablefish feeds (Figure 1). Proximate analyses conducted on whole fish collected at the end of the study showed no significant differences in total protein and crude fat in between each treatment.These results show that mealworms show promise as an alternative ingredient in marine fish feeds, however more detailed examination is needed to determine how fish produced from mealworm diets nutritionally compare to wild fish and fish produced from conventional fishmeal diets.