Effect of rearing substrate on growth performance, waste reduction efficiency and chemical composition of black soldier fly (Hermetia illucens) larvae

Abstract BACKGROUND Wastes can be used as rearing substrate by black soldier fly (BSF) larvae, the latter being exploitable as a protein source in animal feed. This research aimed to assess the influence of four rearing substrates (Trial 1 (organic wastes): a mixture of vegetable and fruit (VEGFRU) vs . a mixture of fruits only (FRU); Trial 2 (agro‐industrial by‐products): brewery (BRE) vs . winery (WIN) by‐products) on BSF larvae development, waste reduction efficiency and nutritional composition. RESULTS If respectively compared to FRU and WIN, VEGFRU and BRE larvae needed less time to reach the prepupal stage (22.0, 22.2, 20.2 and 8.0 days of trial, respectively) and had higher protein content (229.7, 257.3, 312.9 and 395.7 g kg −1 dry matter). The waste reduction index ranged from 2.4 (WIN) to 5.3 g d −1 (BRE). BRE larvae showed the lowest saturated and the highest polyunsaturated fatty acid proportions (612.4 and 260.1 g kg −1 total fatty acids, respectively). CONCLUSION Vegetable and fruit wastes and winery by‐products can be used as rearing substrates for BSF larval mass production. Brewery by‐products led to very promising larval performance and nutritional composition. However, given BRE limited availability, low BRE dietary inclusion levels could be used with the purpose of increasing larval performance. © 2018 Society of Chemical Industry