Life traits and chemical composition of the black soldier fly on by-products

The black soldier fly (BSF) Hermetia illucens is able to growth on a wide variety of organic matter, from animal waste and municipal garbage to fruits and vegetables, and market waste. Larvae are able to transform high percentage of this mass into high protein biomass. Thus, BSF was identified as a promising candidate for the protein production for aquaculture, poultry and livestock. The following by-products were tested: maize distiller grains, okara (soy pulp) and brewer’s spent grain mixed with trub (from brewing process). Hen diet was used as control. Effects of different feeds on larval survival, larval weight, and duration of larval period were recorded. Prepupae obtained from each substrate were analysed for their nutritional value. BSF larvae grew and developed on all substrates. Survival rate was high on all diets, except on maize distiller where a higher percentage of larvae dead. Larvae fed with brewer’s spent grain took more days to reach prepupal stage. Differences were observed also on the final larval weight: larval growth on maize distiller was similar to the control, while the final larval weight on the other substrates was lighter. BSF Larvae were characterized by a high ether extract content (% on DM): 25.1 (control), brewers and trub (23.2), maize distiller grains (29.9), and 31.3 (okara). Crude protein content was on average 52.9% on DM. The tested by-products can be considered valid substrates for BSF rearing for animal feed, but need more research to be used in mass rearing production.