Utilization of Agro-Derived Bioactive in Aquafeed: Impact on Nutritional Response, Immunity, and Aquaponics System Efficiency: A Review

Aquaculture, integrated with hydroponic systems, forms the foundation of aquaponics —a closedloop method for sustainable food production that enables effective resource utilization and nutrient cycling. Excessive reliance on commercial fish feeds, often made from fishmeal and fish oil, presents significant economic and ecological challenges, including high costs and environmental degradation. This review assesses the potential of agriculturally derived bioactive compounds, generated from agricultural by-products such as fruit peels, oilseed cakes, and vegetable waste, as functional and alternative feed ingredients for aquaculture and aquaponic systems. These agrarian wastes are not only abundant and inexpensive but also rich in proteins (6–45%), fibers (10–45%), and bioactive components such as flavonoids and polyphenols, which possess antibacterial, immunomodulatory, and antioxidant properties. SDG 2 (Zero Hunger), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action) are three of the Sustainable Development Goals (SDGs) of the United Nations Development Program (UNDP) that sustainable feeds directly support by reducing reliance on imported feed ingredients and repurposing agricultural by-products. To promote low-impact aquaponic systems and the principles of the circular bioeconomy, this paper summarizes the current state of knowledge regarding the composition, processing, and species-specific responses to feed inputs.