Fraunhofer Research Institution for Individualized Medical Technology and Engineering IMTE
Fraunhofer Research Institution for Individualized Medical Technology and Engineering IMTE

ReLeÖl

ReLeÖl: Combination of Resveratrol, Lecithin and Vegetable Oil for the Complete Replacement of Fish Oil in Aquafeeds

salmon

In the ReLeÖl project, Fraunhofer IMTE, Kiel University, and Marvesa Oils & Fats B.V. investigate how an innovative combination of resveratrol, lecithin, and vegetable oil can be used as a sustainable lipid source in fish feed. The goal is to fully replace fish oil without compromising growth performance, feed intake, or product quality — while simultaneously increasing the content of valuable omega‑3 HUFA (EPA, DHA) in fish.

Research Focus

The work focuses on salmonids and examines how the new compound mixture affects the following areas:

  • Fatty acid profile — particularly the enrichment of EPA and DHA in fish tissues
  • Growth, feed conversion and feed intake — compensating for the limitations observed with resveratrol in the previous project
  • Digestion and energy digestibility — the role of lecithin as an emulsifier and absorption enhancer
  • Molecular mechanisms — in vitro cell culture studies at CAU Kiel to elucidate interactions between the active compounds

Why Alternative Raw Materials Matter

Fish is considered particularly healthy due to its omega‑3 fatty acids. However, the increasing use of vegetable oils in aquaculture feeds has led to modern farmed fish containing less EPA and DHA than in the past.

The ReLeÖl combination addresses this challenge on several levels:

  • Resveratrol has been shown to enhance the endogenous biosynthesis of EPA and DHA
  • Lecithin improves lipid digestion and stabilizes feed intake
  • Vegetable oil (Ahiflower oil) enables a sustainable, fish‑oil‑free lipid supply

Together, this combination has the potential to fully replace fish oil without reducing the nutritional quality of the fish. This can lead to a more sustainable aquaculture production and reduce the usage of marine resources.

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