The State-of-the-Art of Aquafeed Extrusion: Mechanisms, Challenges and Opportunities

Abstract

To sustain the expanding volume of aquaculture production, there is significant demand for an affordable supply of energy and nutrients to aquatic species. High-quality feed is essential to ensure the productivity, sustainability and economic viability of aquaculture systems. Over the past 30–40 years, extrusion technology has emerged as an efficient method to produce high-quality feed with enhanced functional attributes, such as digestibility, palatability, buoyancy and water stability. This review provides a comprehensive overview of the current state-of-the-art in aquafeed extrusion, highlighting the mechanisms underpinning extrusion technology, challenges for industrial production and future opportunities in this field. Through bibliometric analysis, we examine the evolution of aquaculture feeding techniques and their impact on feed quality and fish growth performance. Comparisons between pelletised and extruded feeds highlight advancements in extrusion methods, which offer superior nutrient retention and feed conversion efficiency. We elucidate the scientific principles of feed extrusion, including the effects of temperature, moisture and mechanical energy on feed properties. Despite significant progress, key challenges remain for the production of extruded feed, such as ingredient variability, operational complexity, diverse product requirements and waste management. Conversely, we explore opportunities for extrusion technology, emphasising predictive characterisation, extrusion modelling, and AI-driven quality control. The review concludes with a perspective of the industrial context, discussing the commercial drivers for aquafeed milling, insights from industry stakeholders and future directions for commercial research and development. This review offers researchers, technologists and industry stakeholders a comprehensive understanding of the current landscape, challenges and future prospects for extruded aquafeed production.