This study investigated the feasibility of replacing fishmeal and fish oil in tilapia feed with a blend of two commercially available microalgae: *Nannochloropsis oculata* (protein-rich defatted biomass) and *Schizochytrium* sp. (DHA-rich whole cells). Results showed significantly better growth, weight gain, and specific growth rate in tilapia fed the fish-free diet compared to a control diet. The fish-free feed also yielded higher fillet lipid, DHA, and protein content, and exhibited higher in-vitro protein hydrolysis and digestibility. The economic conversion ratio of the fish-free feed was slightly lower than the control diet, suggesting cost competitiveness. This research presents a viable alternative to fishmeal and fish oil in tilapia aquaculture, enhancing both sustainability and nutritional quality.

Pallab K. Sarker, Anne R. Kapuscinski, Brandi McKuin, Devin S. Fitzgerald, Hannah M. Nash, Connor Greenwood