Advances in the use of dietary β-glucan in aquaculture: Structural insights, immunological benefits, and feed applications

β-glucan, a bioactive polysaccharide derived from fungi, yeast, grains, and algae, has become a versatile element in aquaculture feeding. This review thoroughly examines the structural differences, extraction techniques, and purification methods of β-glucans, correlating these characteristics with their biological effectiveness. Particular attention is given to their antioxidant, immunomodulatory, antibacterial, and hypolipidemic properties, along with their integration into functional diets to enhance aquatic animal performance. β-glucan supplementation has demonstrated effectiveness in enhancing development, augmenting disease resistance, and fortifying stress tolerance in many aquatic species by altering innate immunity, oxidative equilibrium, and metabolic functions. The fundamental mechanisms, encompassing receptor-mediated signaling pathways and dose-dependent responses, are meticulously examined. Furthermore, issues pertaining to delivery techniques, structural integrity, and practical use are examined. This investigation underscores β-glucan as a viable and sustainable substitute for antibiotics in enhancing aquaculture health and productivity.