PhD defence about possibilities of using black soldier fly in fish feed

Fish farming is to some extent reliant on fishmeal and fish oil sourced from capture fisheries as dietary protein and lipid sources. Due to their scarcity and high prices, alternative feed ingredients are required. Insects, e.g., the black soldier fly, are alternative sources that have recently received much attention. 

Black soldier fly can convert biodegradable side streams, e.g., brewer’s spent grain or shrimp waste, into biomass high in protein and lipid. Furthermore, this species has a short life cycle, which makes it suitable for large-scale production. Nevertheless, there are still several challenges to overcome before black soldier fly can be applied globally as a fish feed ingredient. Kylian Manon Eggink from DTU Aqua has addressed some of these challenges in her PhD project, and she will now defend the thesis "Modification of the nutritional composition of black soldier fly (Hermetia illucens) for fish feed applications”. 

One challenge is the low production volumes compared to commonly used fish feed ingredients. Here, Kylian Manon Eggink demonstrates that harvest yield can be enhanced by harvesting early stage prepupae and by rearing the fly larvae on substrates with adjusted protein content and protein to carbohydrate ratio. 

Other challenges are related to the nutritional profile of the black soldier fly meal compared to the requirements of the fish. Kylian Manon Eggink’s experiments show that the fatty acid profile of the fly larvae can be modified through the rearing substrate. On the other hand, the amino acid composition can only be limitedly modified through changes in rearing conditions and remains limited in certain essential amino acids for fish, requiring for example amino acid supplementation to fish feed. 

The last challenge, which Kylian Manon Eggink has investigated in her PhD project, is the presence of chitin, which is a component in insects’ exoskeleton. Her experimental work shows that chitin has negative effects on nutrient digestibility in rainbow trout and Nile tilapia. However, the thesis also demonstrates that it is possible to reduce the content of chitin in the larval meal by harvesting in early life stages or through the separation of chitin from the meal, e.g. via sieving.

About the PhD defence

Kylian Manon Eggink will defend her PhD thesis "Modification of the nutritional composition of black soldier fly (Hermetia illucens) for fish feed applications” on Tuesday 4 April 2023, 11:00 on Zoom and at DTU, Willemoesvej 2, 9850 Hirtshals.

Supervisors

• Principal supervisor: Senior Researcher Anne Johanne Tang Dalsgaard, DTU Aqua
• Co-supervisor: Senior Researcher Ivar Lund, DTU Aqua

Examiners

• Associate Professor Peter Vilhelm Skov, DTU Aqua
• Associate Professor Niels Thomas Eriksen, Aalborg University
• Adjunct Professor and Research Group Leader Erik-Jan Robert Lock, University of Bergen and Institute of Marine Research, Norway

Chairperson at defence

• Senior Researcher Manuel Gesto, DTU Aqua

Learn more

A copy of the thesis is available by e-mail on request. Please contact PhD secretary Karin Stubgaard, stub@aqua.dtu.dk