Researchers from the Fraunhofer Institute for Molecular Biology and Applied Ecology IME, the Justus Liebig University Giessen, and the LOEWE Centre for Translational Biodiversity Genomics (LOEWE-TBG) published a scientific review highlighting the use of insect flour in the production of crustacean feed, in terms of health and growth benefits, as well as environmental advantages.
Insect-based feed for crustaceans
Crustacean feed consists of 20-50% fish meal, which contains high levels of digestible essential amino acids. Incorporating insect flour is a new approach, although insects are part of the natural diet.
Insects are highly diverse, so there is a wide range of candidates for aquaculture feeds, with different characteristics in terms of nutritional composition.
However, modern industry has focused on few species such as the black soldier fly (Hermetia illucens), the yellow mealworm (Tenebrio molitor), the common housefly (Musca domestica), and the house cricket (Acheta domesticus), all of which can be produced on a large scale.
The black soldier fly, in particular, is the most commercially attractive because it reproduces quickly, grows on a wide range of substrates, and has low potential as a disease vector.
Moreover, the nutritional composition of insects varies depending on the species, life stage, rearing conditions, and diet, and the protein content is generally similar to that of fish meal.
Most studies on the use of insect flour in the feeding of crustaceans have focused on the marine shrimp Litopenaeus vannamei. In this species, fish meal can be completely replaced with T. molitor flour without harmful effects, while high proportions of H. illucens, M. domestica, or Bombyx mori may affect growth and health.
The researchers consider that 100% replacement of fish meal with insects is possible in crustacean aquaculture, if species-specific challenges and processing options are considered.
At low supplementation rates, insects seem to benefit crustaceans as a form of functional food.
Disease and immunity
Insect flour confers a wide range of health benefits by modulating immunity and/or intestinal microbiota to increase disease resistance.
The antioxidant activity of insect chitin can also improve immunity, as chitin and its derivative chitosan support the innate immune response, increase microbiome diversity in the gut, and reduce pathogen abundance in fish. However, chitin digestibility seems to be limited in L. vannamei, and high levels of this compound could be harmful.
Moreover, insects contain antibacterial and anti-inflammatory substances that can contribute positively to health in aquaculture species.
In summary, supplementing aquaculture feeds with insect flour not only satisfies the nutritional needs of crustaceans but also provides functional components to minimize losses caused by dysbiosis and diseases.
Sustainability
Aquaculture feeds represent approximately 90% of the environmental impact of exogenous feed-using aquaculture. The most common protein sources for aquafeeds (fish meal and soybean meal) increase environmental, economic, and social challenges.
Compared to fish meal and soybean meal, insect proteins have the potential to improve the overall sustainability of aquafeeds.
The use of agricultural by-products and the food industry as substrates for mass insect production is also an advantage, and the ability to recover nutrients from organic waste is the biggest contribution to sustainable protein production.
Overall, insect-based feed production can improve the environmental impact of aquaculture feeds, significantly reduce organic waste, provide commercially interesting substances, and therefore facilitate a path towards a circular economy.
Perspectives
Current data indicates that insect meal has a favorable nutritional composition as a replacement for fishmeal in aquafeeds, offering health, environmental sustainability, and economic advantages, but further research is required to identify specific mechanisms. of action.
The insect industry is not yet globally established and may be a potential short-term solution to replace fishmeal and fish oil in the aquaculture feed industry.
The study was funded by the German Ministry of Higher Education and Research, BMBF and the German Academic Exchange Service, DAAD.
Contact
T. Röthig
tillroethig@gmail.com
Reference (open access):
T. Röthig, A. Barth, M. Tschirner, P. Schubert, M. Wenning, A. Billion, T. Wilke, and A. Vilcinskas. 2023. Insect feed in sustainable crustacean aquaculture. In Press. Journal of Insects as Food and Feed 0 0:0, 1-24
