Use of pigmented fungi as additives in aquaculture

Abstract Lately, the need for a shift towards more sustainable aquaculture practices has become essential to ensure the industry’s long-term viability. While the cost of raw materials remains high, policymakers also highlight the need to reduce aquaculture’s environmental footprint. Thus, a way to overcome this is to replace marine-derived aquafeed ingredients with more economical and environmentally friendly alternatives. Pigment-producing yeasts and fungi emerge as potential nutritional solutions with multiple possibilities for enhancing fish pigmentation, growth, and overall health simultaneously. Existing studies have dealt with aspects of pigmented yeasts and fungi applications in aquaculture. However, further research is needed to fully understand their exact routes of action on fish health, production efficiency, and immune function. This review addresses the underexplored potential of pigmented yeasts and fungi in aquaculture. It delves into their benefits, mechanisms of pigment synthesis, and their effects on various aspects of fish physiology, including growth parameters, lipid metabolism, reproduction capacity, pigmentation (colouration), blood biochemical parameters, antioxidant activity, and immunological responses. Finally, the review will address the need to optimize the production processes yield of pigmented yeasts and fungi for effective use in aquafeeds. Still, it will also deal with possible limitations related to their use as additives in aquafeeds.