Influence of Photoperiod and Dietary Substrate Composition on Growth Performance and Biochemical Profile of Hermetia illucens Larvae

Abstract

This study investigates the effects of photoperiod and dietary substrate composition on the growth performance, developmental rate, and biochemical composition of Hermetia illucens (black soldier fly; BSF) larvae. Larvae reared under a 12 h light: 12 h dark cycle exhibited the highest growth performance, attaining an average length of 2.9 cm by the sixth instar and completing development more rapidly than larvae maintained under continuous darkness. Dietary substrate composition significantly influenced larval growth and biomass accumulation. Larvae fed a mixed organic substrate containing both plant- and animal-derived waste (Group 3) showed superior growth, achieving the highest mean body weight (98 mg by day 30), followed by larvae reared on animal-based and plant-based diets. Biochemical analysis revealed significant differences among dietary treatments. Larvae reared on the mixed substrate exhibited the highest protein (60.3±0.2 mg/100 mg fresh weight) and lipid (51.6±0.3 mg/100 mg fresh weight) contents, along with moderate carbohydrate levels, indicating improved biomass quality. In contrast, larvae reared on single-source diets displayed comparatively lower macronutrient accumulation. Overall, the findings demonstrate that a 12-hour light–dark photoperiod combined with a nutrient-rich mixed organic substrate provides optimal conditions for enhancing BSF larval growth, development, and biomass quality. These results highlight the importance of optimizing both environmental and nutritional factors in black soldier fly rearing systems and support the application of H.illucens larvae in sustainable protein production and organic waste valorization