Influence of different growing substrates and processing on the nutrient composition of black soldier fly larvae destined for animal feed

Abstract

Because of the ongoing depletion of fish stocks and thus continuously rising prices for fish meal, substitution possibilities are in demand. However, since alternate protein sources from plants are mostly of lower protein quality, feedstuff produced from the black soldier fly (BSF) larvae, Hermetia illucens, are considered promising alternatives. Hence, this study investigated the influence of different growing substrates on the crude nutrient and mineral composition of BSF larvae. The three tested substrates were a mixture of middlings (control group), dried distillers’ grains with solubles (protein group), and dried sugar beet pulp (fibre group). After a 15 day growing period, the total larvae yield of the control, protein and fibre groups amounted to 2.58, 0.93 and 0.43 kg wet mass, respectively, the crude protein content reached 37.2, 44.6 and 52.3% of dry matter (DM), respectively. Despite a relatively low methionine content of the BSF meal when compared to fish meal, it showed a good overall protein quality. Furthermore, the BSF meal contained about 50% less P than fish meal. Moreover, an accumulation of undesirable substances like heavy metals may occur and should be monitored during production. Because a lower fat content of BSF larvae would simplify further processing, in a second trial larvae yielded from the control group were pressed using 12 different conditions: pressures of 250 or 450 bar and temperatures of 50 or 60 °C, applied over 10, 20 or 30 min. The best fat reduction from 30.8 to 16.6% of DM was achieved by pressing at 250 bar, 50 °C and 30 min. In conclusion, the total yield of BSF larvae and their ingredients were highly influenced by the used growing substrates. Generally, a BSF meal could crucially contribute to substitute fish meal in animal nutrition.

Influence of dietary black soldier fly ( Hermetia illucens Linnaeus) pulp on growth performance, antioxidant capacity and intestinal health of juvenile mirror carp ( Cyprinus carpio var. specularis)

“…The survival rate and feed conversion ratio were not significantly different among all groups ( (Kroeckel et al, 2012;Webster et al, 2016). This discrepancy could be related to differences in life stage of insects and fish species in these studies (Tschirner & Simon, 2015).…”

“…However, other studies on turbot ( Scophthalmus maximus L.) and Nile tilapia ( Oreochromis niloticus L.) indicated that including BSF larvae into their diet significantly reduced their growth performance (Kroeckel et al, ; Webster et al, ). This discrepancy could be related to differences in life stage of insects and fish species in these studies (Tschirner & Simon, ).…”

Effects of dietary protein and carbohydrate on life‐history traits and body protein and fat contents of the black soldier fly Hermetia illucens

“…We find that larval crude protein content is higher when dietary P‐content is lower (P10 and P17). This is in line with the findings of Barragan‐Fonseca et al () and Tschirner & Simon () who report that body crude protein content is higher in larvae fed on the diet with the lowest crude protein content. However, it is also argued that this content has been overestimated so far by approximately 20% as a result of the presence of nonprotein nitrogen in insects (Janssen et al , ).…”

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

“…The total final biomass (larvae + prepupae) and the residual rearing substrate were also weighed. The following parameters were then calculated: larval mortality (LM) growth rate (GR), readapted for this research substituting prepupal body weight (g) with larva body weight (g) substrate reduction (SR) waste reduction index (WRI) …”