Optimizing Black Soldier Fly (Hermetia illucens) production: effects of substrate variation on biomass, nutritional quality, hatchability, fecundity, and frass quality

Introduction Insects such as the Black Soldier Fly (Hermetia illucens, BSF) are increasingly recognized for their potential to convert organic waste into high-quality protein and fertilizer inputs, contributing to circular bioeconomy models. However, the type of substrate used significantly affects BSF production performance. Methods This study investigated the influence of five organic waste substrates—market vegetable/fruit waste, brewery waste, fish processing waste, poultry manure, and a mixed organic waste blend—on the production performance indicators of Hermetia illucens (Black Soldier Fly, BSF). The BSF larvae were evaluated under controlled conditions for hatchability, survival, growth, nutrient composition, reproductive output, and frass quality. Results Substrate type significantly affected BSF performance, with the mixed organic waste yielding the highest hatchability (98.7 ± 1.1%) and survival (98.2 ± 1.3%) and the shortest hatching time (3.1 ± 0.6 days). The Survival Activity Index (SAI) peaked in mixed organic waste (88.4 ± 6.8%), indicating superior larval resilience. Larvae reared on mixed waste also recorded the highest specific growth rate (SGR: 28.0 ± 1.5%) and the most efficient feed conversion ratio (FCR: 1.1 ± 0.1). Nutritionally, the fish waste produced protein-rich larvae (53.5 ± 2.1%), while brewery waste generated the highest fat content (35.6 ± 3.1%). Mixed waste achieved a balanced profile (protein: 45.9 ± 3.3%, fat: 32.3 ± 1.4%) and elevated mineral content (Ca: 10,500 mg/kg, K: 11,500 mg/kg). Reproductively, mixed organic waste supported the highest fecundity (1408.9 ± 65.4 eggs/female), egg clutch size (679.4 ± 40.3), and oviposition preference (95.9 ± 6%). Frass quality mirrored substrate composition: vegetable waste produced the highest organic matter (75.4 ± 3.9%), while poultry and fish waste frass showed superior nitrogen and phosphorus content, with low C:N ratios (16.9–17.8) favorable for composting. Discussion The mixed organic waste emerged as the most effective substrate, optimizing BSF biomass production, nutritional value, reproductive output, and fertilizer potential. These findings highlight the importance of substrate blending in insect farming and its role in advancing circular bioeconomy models for sustainable aquafeed production. The results offer actionable insights for large-scale BSF rearing and waste valorization systems.