The search for sustainable and cost-effective protein sources in aquaculture nutrition has intensified due to the rising cost and environmental concerns of fishmeal use. Brewery spent yeast (BSY), a by-product of the brewing industry, has emerged as a promising alternative due to its favorable biochemical composition and potential functional benefits. This study aimed to characterize the nutritional profile of BSY, assessing it proximate composition, fatty acid profile, amino acid composition and mineral profile.
Figures 1 and 2 present the proximate composition and amino acid profile of BSY. The spent yeast demonstrated strong oxidative stability (TBARS: 13.63 mg MDA/kg). Mineral analysis revealed high levels of potassium (67.3%), sodium (2.2%), calcium (2.4%), magnesium (2.5%), and phosphorus (1.3%), along with appreciable amounts of zinc (0.35 g/100g dw), iron (0.13 g/100g dw), manganese (0.02 g/100g dw), copper (0.008 g/100g dw), and trace selenium . Furthemore t he replacement score value was determined by evaluating the amino acid profile and total protein content of BSY relative to an ingredient regarded as nutritionally ideal, such as fishmeal in aquaculture diets.
BSY’s compositional qualities show promise as a sustainable alternative protein in aquaculture, potentially supporting fish health and welfare. Moreover, its production from food waste by-products offers a significant environmental advantage by promoting a circular economy