Effect of waste pretreatments on growth parameters, bioconversion and quality of Black Soldier Fly Hermetia illucens (Diptera: Stratiomyidae)

Abstract Rapid population growth is leading to changes in the global food system. Food insecurity arise because the current production system doesn’t solve the actual food shortage. Yet, the world population generates enormous amounts of waste which could become useful biomass by Black soldier fly larvae transformation. It is obvious that the type of waste has an impact on the development and quality of the black soldier fly larvae. However, the effect of pretreatment of waste on the larvae is poorly known. In this study, Waste were collected from a restaurant in Dschang, Cameroon and were treated diversely: crushed, heated, fermented, and then used to feed 5- day-old larvae of H. illucens. Mature larvae were later harvested from the substrate, then boiled in water at 100°C to take the growth parameters, and were crushed for bromatological analysis. In almost all treatments, larvae reached maturity after 15 days of feeding. Crushing of the organic waste yield the highest mortality rate (11.33%). Fermentation of the waste produced the highest consumption index (3.04) and the lowest bioconversion rate (12.49) conversely, crushing of the waste recorded the lowest consumption index (1.74) and the highest bioconversion rate (20.14). Treatment of substrate influenced Crude protein, organic matter and ash levels. Concerning abiotic parameters of substrate, lowest temperature was recorded in crushing treatment. In conclusion, waste pretreatment by crushing, heating and fermentation positively influences growth parameters, bioconversion of substrate and especially the quality of the larvae. Waste should be treated prior to the larval rearing.