Effect of seasonality and pretreatment of the organic fraction of municipal solid waste for black soldier fly larvae production

Abstract This study investigated the potential of using the organic fraction of municipal solid waste (OFMSW) as a rearing substrate for black soldier fly larvae (BSF). Samples of OFSMW were collected in Italy in four different seasons of the year and fed untreated or pulped to the larvae. The larvae successfully grew on OFMSW with minimal impact from either season or pretreatment (pulped vs untreated). Notably, all treatments achieved high larval survival rates (above 89.2%) and a development time within 11 days. Season and pretreatment influenced the chemical composition of the OFMSW (e.g. higher carbohydrates and organic matter in untreated samples). Compared to BSF grown on pulped samples, larvae grown on untreated samples had higher lipid (34.4 vs 28.5% DM), organic matter (90.7 vs 83.6% DM) and apparent metabolizable energy (22.0 vs 15.3 MJ/kg DM) contents. In vitro protein digestibility (%) varied by season, reaching the highest values in autumn (78.6%); moreover, the crude protein digestibily of BSF reared on untreated samples was lower than that on pulped samples (68.8 vs 73.3%). The chitin content was not affected by pretreatment or season (on average 5.45% on DM). Overall, the study demonstrates the feasibility of the use of OFMSW for BSF larvae production. Nevertheless, observed variability in larval nutrient composition highlights the need for process optimization to ensure consistent larval characteristics.