Spent Brewer’s Yeast as an Alternative Ingredient in Aquafeed

Aquaculture is a rapidly expanding industry which contributes significantly to meeting global protein demand. As the world population continues to increase, the aquaculture industry is expected to grow and adapt. To reduce feed input costs and environmental impacts, alternative feed ingredients can replace or supplement increasingly expensive and unsustainable fish meal and fish oil components. A promising yet underutilized replacement for fish meal may be found with spent brewer’s yeast (SBY) which is a major by-product of beer production and typically contains high protein content (40–60% of dry mass) which is beneficial for some fish production. The use of SBY as a protein supplement has been extensively examined and applied in terrestrial livestock, however it is difficult to implement due to high water content and logistical challenges. Limited foundational studies have investigated the use of SBY in aquacultural applications. Analysis of amino acid profiles, potential antinutritional capacities, and economic factors indicate that the use of SBY as a protein supplement may be more suitable for aquaculture compared to terrestrial livestock raising. SBY caters well to the nutritional requirements of aquatic species, which could significantly contribute to the growth of the industry. Many criteria exist which influence the practicality of adopting a novel ingredient in aquafeed. Therefore, this review provides an overview of the nutritional profile, potential benefits, and feasibility in aquaculture production, as well as the drawbacks for the use of SBY in aquaculture.