Microbial community-based protein enables sustainable fishmeal replacement and improved resilience in Pacific white shrimp (Litopenaeus vannamei)

The growing demand for aquaculture feeds requires sustainable alternatives to fishmeal. Microbial community-based single-cell protein (SCP), produced from soybean-processing wastewater, represents a promising solution aligned with circular bioeconomy principles. Here, we evaluated SCP as a fishmeal replacement in feed for Pacific white shrimp (Litopenaeus vannamei) across four feeding trials of 42-84 days, using shrimp from different hatcheries and SCP produced at two scales (laboratory and pilot). Diets containing 0-100% fishmeal replacement, corresponding to up to 220 g SCP per kg feed, were tested. Survival remained consistently high at all inclusion levels, and growth performance was maintained up to 90% replacement. Tissue proximate and amino acid profiles were unaffected by SCP inclusion. Beyond nutritional adequacy, survival consistently improved with higher SCP inclusion, suggesting functional benefits linked to microbial communities and their postbiotic metabolites that may enhance shrimp resilience. These findings demonstrate that microbial community-based SCP can replace up to 90% of fishmeal in shrimp diets without adverse effects, offering a robust and scalable strategy for valorising food-processing wastewater into sustainable and functional aquafeed ingredients.