Nutrient digestibility in black soldier fly larva was greater than in adults for pigs and could be estimated using fiber.

The objectives of the present study were to determine the nutrient digestibility of fish meal, defatted black soldier fly larvae (BSFL), and adult flies and to develop equations for estimating nutrient digestibility of BSFL for pigs. digestion procedures were employed to mimic the digestion and absorption of nutrients in the pig intestine. Correlation coefficients between chemical composition and nutrient digestibility of BSFL were calculated. In Exp. 1, ileal digestibility (IVID) of dry matter (DM) and crude protein (CP) and total tract digestibility (IVTTD) of DM and organic matter in defatted BSFL meal were less ( < 0.05) than those in fish meal but were greater ( < 0.05) than those in adult flies. In Exp. 2, CP concentrations in BSFL were negatively correlated with ether extract ( = -0.91) concentration but positively correlated with acid detergent fiber (ADF; = 0.98) and chitin ( = 0.95) concentrations. ADF and chitin concentrations in BSFL were negatively correlated with IVID of DM ( = -0.98 and -0.88) and IVTTD of DM ( = -1.00 and -0.94) and organic matter ( = -0.99 and -0.98). Prediction equations for nutrient digestibility of BSFL were developed: IVID of CP (%) = -0.95 × ADF (% DM) + 95 ( = 0.75 and = 0.058) and IVTTD of DM (%) = -2.09 × ADF + 113 ( = 0.99 and < 0.001). The present experiments suggest that defatted BSFL meal was less digestible than fish meal but was more digestible than adult flies, and nutrient digestibility of BSFL can be predicted using ADF as an independent variable.