In vitro nutrient digestibility values of black soldier fly as a swine feed ingredient can be estimated by nitrogen concentrations

Abstract

Abstract The objectives were to determine effects of growth stages (experiment 1) of black soldier fly (BSF; Hermetia illucens) and processing methods (experiment 2) on in vitro nutrient digestibility of BSF for pigs and to develop prediction equations for estimating in vitro nutrient utilization in BSF. In experiment 1, in vitro ileal disappearance (IVID) and in vitro total tract disappearance (IVTTD) of dry matter (DM) and nitrogen in BSF larva (15 d of age), BSF prepupa (d 17), and BSF adults (d 34) were determined. The IVID of DM and nitrogen in BSF larva was higher () than that in BSF prepupa and BSF adults. The IVTTD of DM in BSF larva and BSF prepupa was higher () than that in BSF adults. In experiment 2, the BSF larva employed in experiment 1 was processed using 4 different methods to obtain dried larva press liquid, dried larva press cake, partially defatted larvae meal (PDLM), and fully defatted larvae meal. The IVID of DM and nitrogen in PDLM was higher () than that in other 3 ingredients. The IVTTD of DM in dried larva press liquid and PDLM was higher () than that in dried larva press cake or fully defatted larvae meal. Based on the feed ingredients employed in experiments 1 and 2, quadratic and linear prediction equations were developed for IVID of DM (; ) and IVTTD of DM (; ), respectively, in BSF-derived ingredients using nitrogen as an independent variable. Overall, the nutrients in BSF larva at 15 d of age were better utilized compared with older growth stages, and the nutrients in PDLM were better utilized compared with other processing methods. Equations for IVID and IVTTD of DM were developed using nitrogen concentrations as an independent variable in BSF-derived ingredients for pigs.