Asymptotic estimated digestibility, a new indicator of black soldier fly (<i>Hermetia illucens</i>) conversion efficiency in relation to larval density

Black soldier fly larvae (BSFL) are highly efficient at converting organic substrates into insect biomass suitable for livestock nutrition. BSFL conversion efficiency depends on the nature of their feed, and formulation approaches use macronutrient contents to reach a targeted performance. However, digestibility varies between ingredients data is lacking due methods unsuitable insects living in feed. This study proposes work under range larval densities total ingestion defines Estimated Digestibility (ED) as difference distributed feed frass weight, divided by weight Using same amount chicken feeding time 0 29 larvae/cm 2 , ED dry mass (DM), starch, nitrogen, ether extract (EE), neutral detergent fibre, acid lignin, ash energy were evaluated, along with survival rate, ratio (FCR) individual gain fresh basis. DM, EE increased density following an asymptotic trend. 11.4 larvae/cm2 but decreased higher densities. logistic model, DM (80.3±1.3%), starch (99.0±2.3%), nitrogen (78.6±1.1%), (95.3±1.5%), (58.4±1.0%) (80.6±1.2%) determined. No effect areal fibre fractions was detected. Survival rate peaked below 5 FCR (dry fresh) improved increasing density, while dry) optimised . Asymptotic new indicator corresponding maximal fraction macronutrients potentially digestible BSFL. It should be used develop diet approach based rather than crude contents. Further studies focus evaluating different ingredients.