PSXV-18 - Effects of Drying Methods for Black Soldier Fly Larva Meals on in vitro Nutrient Disappearance

Abstract: The objective was to determine the effects of different drying methods on nutrient utilization of black soldier fly (BSF; Hermetia illucens) larva meals using in vitro assays. Two-step and 3-step in vitro assays were employed to simulate the gastrointestinal tract of pigs. Four methods were used to obtain BSF larva meal sources: 1) microwave-drying for 32 min, 2) hot-air drying at 60°C for 17 h, 3) water blanching for 5 min and hot-air drying for 17 h, and 4) 2% citric acid solution blanching for 5 min and hot-air drying for 17 h. After the drying process, each BSF larva was defatted and ground to obtain BSF larva meals. The crude protein (CP) concentration in the test ingredients ranged from 54.7 to 60.4% on dry matter (DM) basis and ether extract ranged from 7.1 to 11.8% DM. Hot-air-dried BSF larva meal had greater in vitro ileal disappearance (IVID) of CP compared with microwave-dried BSF larva meal (86.7% vs. 84.4%; P < 0.05). However, blanching BSF larva in water or 2% citric acid solution before hot-air drying resulted in less IVID of CP (81.3 or 82.5%; P < 0.05) compared with microwave-dried or hot-air-dried BSF larva meal. Blanching BSF larva in water or 2% citric acid solution before hot-air drying resulted in less in vitro total tract disappearance of DM (85.0% or 84.5% vs. 90.4% or 89.6%; SEM = 0.3, P < 0.05) and OM (80.6% or 81.5% vs. 85.7% or 86.6%; SEM = 0.1, P < 0.05) compared with microwave-dried or hot-air-dried BSF larva meal. In conclusion, hot-air-dried BSF larva meal had greater nutrient utilization compared with microwave-dried BSF larva meal. However, blanching BSF larva in water or citric acid solution negatively affected nutrient digestibility based on in vitro assays.