Regional Protein Sources in a Circular System for New Approaches in Fish Feeding

The ReProtein project takes a resource-efficient approach that utilizes previously evaluated plant-based byproducts to produce sustainable protein sources, specifically from mealworm larvae and duckweed, for fish feed. The goal is to strengthen regional production cycles in aquaculture and increase the resilience of the local feed supply. Initial investigations from a previous project yielded promising results: feed mixtures based on mealworm larvae and duckweed resulted in a characteristic green coloration in brook trout. In ongoing long-term studies with catfish, the suitability of these mixtures is now being further evaluated under practical conditions. In parallel, research is being conducted to determine how heavy metal accumulation in duckweed production can be specifically minimized. Another focus is on optimizing mealworm larvae as a protein source. These are characterized by a favourable fatty acid composition, which can be further improved through targeted feeding strategies, such as the use of linseed, particularly with regard to the content of n-3 fatty acids. Here, too, long-term trials are intended to validate the performance of corresponding feed mixtures in catfish. The project part of BOKU University focuses on the parameters of feed production and the assessment of fillet quality. Overall, the project aims to develop sustainable, locally available alternatives to fishmeal, which currently accounts for about 75% of fish feed. The production of duckweed and mealworm larvae in integrated recirculating systems offers significant potential for providing high-quality protein sources from regional raw materials. This can both strengthen regional value creation and reduce dependence on global supply chains. A key environmental benefit lies in the significant reduction of CO₂ emissions due to short transport distances and the use of regionally available by-products. ReProtein thus serves as a model project for a circular bioeconomy and demonstrates how sustainability, technological innovation, and regional economic development can be effectively linked.