Mycoprotein for circular and sustainable aquaculture growth

Aquaculture is steadily emerging as a key pillar in meeting the global demand for high-quality animal protein; however, its sustainability remains constrained by continued dependence on conventional feed ingredients such as fishmeal and plant-based oil cakes. These resources are associated with ecological pressure, supply volatility, and rising costs, highlighting the urgent need for circular and resource-efficient alternatives. This review provides new integrative insights into mycoprotein as a next-generation aquafeed ingredient by systematically comparing fungal species (e.g., Fusarium , Aspergillus , Rhizopus ), substrate sources (agro-industrial residues, lignocellulosic by-products, and food-processing wastes), and fermentation strategies (submerged versus solid-state fermentation) relevant to aquaculture applications. The article critically evaluates how substrate selection and fermentation optimization influence protein quality, amino acid balance, cell wall composition, and functional bioactivity, thereby affecting growth performance, gut health, immune modulation, and feed efficiency across finfish and crustacean species. Novel synthesis of recent feeding trials demonstrates that mycoprotein can partially or fully replace fishmeal without compromising growth, feed conversion ratio, or physiological resilience, while significantly reducing land use, freshwater demand, and greenhouse gas emissions. The review further highlights emerging processing and pretreatment strategies (enzymatic hydrolysis, thermal treatment, and cell wall modification) aimed at improving digestibility and nutrient bioavailability. By integrating biological performance data with circular bioeconomy metrics, this work offers a framework for selecting fungal strains, substrates, and fermentation systems tailored to sustainable aquaculture feeds. Overall, the review positions mycoprotein as a scientifically robust and environmentally responsible protein source, while identifying critical research gaps and technological priorities needed to enable its large-scale adoption in circular aquaculture systems.