Aquafeed formulations often rely on lipid sources that supply n-3 fatty acids but are vulnerable to oxidation, highlighting the need for ingredients that clarify how n-3 delivery and oxidative stability interact. Biomass from Dunaliella tertiolecta and Tetraselmis chuii were chemically characterized to examine this relationship using fatty acid profiles, lipid quality indices, and antioxidant activity. Dunaliella contained α-linolenic acid as its main n-3 fatty acid (27.19% of total FA), whereas Tetraselmis contained eicosapentaenoic acid (5.94%) and minor docosahexaenoic acid (0.77%). These differences produced distinct peroxidizability index values: 82.5 in Dunaliella and 101.4 in Tetraselmis, reflecting the contrasting susceptibilities of their lipid fractions to oxidation. Antioxidant measurements also diverged; Dunaliella showed higher reducing activity (FRAP: 200.33 mg TE g−1 db), while Tetraselmis exhibited greater DPPH activity (69.62 mg TE g−1 db) and flavonoid content (25.73 mg EEPC g−1 db). The combination of high EPA with higher PI in Tetraselmis and lower PI with stronger reducing capacity in Dunaliella highlights the conditions under which each biomass may influence n-3 availability and oxidative stability in formulated feeds. These results establish a functional decision framework for selecting and combining microalgal ingredients based on trade-offs between HUFA delivery and oxidative stability in aquafeed formulation.
Serrano-Espinosa et al. (Mon,) studied this question.