Functional additives in fishmeal-replaced aquafeeds: precision strategies for sustainable aquaculture

Aquaculture serves as a critical pillar of global food security and human nutrition by providing high-quality protein, essential fatty acids, and efficient feed conversion while minimizing land use. However, its rapid expansion depends heavily on stable supplies of high-quality protein sources, particularly fishmeal (FM), which faces growing instability due to climate change and overfishing. While sustainable alternative protein sources like plant and insect proteins have been explored, high inclusion levels often impair growth and health in aquatic animals, partly due to poor palatability, amino acid (AA) imbalances, low digestibility, and antinutritional factors (ANFs). Precision strategies, especially functional additives, offer a promising solution by targeting these challenges: attractants enhance palatability, crystalline AAs correct AA imbalances, exogenous enzymes improve digestibility, and functional compounds mitigate health impairments. Although research on functional additives for FM replacement lags behind studies on alternative protein sources, theoretical and experimental evidence confirms their potential. Precisely formulated functional additives not only counteract the drawbacks of alternative protein sources or enable higher substitution ratios, underscoring their innovative role in sustainable aquafeed development. This review highlights the targeted use of functional additives to address appetite suppression, AA imbalances, digestive inefficiencies, and health risks, offering actionable insights for researchers, aquaculture nutritionists, and the feed industry to advance both scientific knowledge and practical FM replacement solutions.