Elena Fako, Haoran Zhao, Muhammad Zeeshan Akram, Tara Grauwet, Nadia Everaert
Abstract BACKGROUND Black soldier fly larva (BSFL) protein has gained attention as a sustainable alternative protein source in poultry nutrition. However, its effects on gut‐related processes remain insufficiently characterized. This study evaluated the in vitro digestibility and fermentability of BSFL protein compared to plant‐based proteins, including wheat gluten, corn distillers' dried grains with solubles (DDGS corn), and peas, using an in vitro digestion, absorption, and fermentation model. Crude protein, degree of protein hydrolysis, and in vitro protein digestibility (IVPD) were assessed, alongside gas production kinetics, ammonia, short‐chain fatty acids (SCFA), branched‐chain fatty acids, and microbiota modulation of a single, pooled broiler cecal inoculum during fermentation. RESULTS An IVPD of 63.5% was observed for BSFL, being lower than for wheat gluten (84.4%) and peas (74.6%), and higher than for DDGS corn (36.9%) ( P < 0.05). Its gas production (92.5 mL g −1 ) and SCFA levels (23.8 mmol L −1 ) are similar to those of other protein ingredients ( P < 0.05). Peas showed the highest total SCFA (45.7 mmol L −1 ) and total gas production (147.3 mL g −1 ). Microbiota analysis revealed distinct communities shaped by protein ingredient. Fermentation of BSFL was associated with a relatively higher abundance of Escherichia‐Shigella , warranting further investigation. In addition, relatively higher abundances of Lactobacillus and Bifidobacterium were associated with BSFL. As no differentially abundant genera were identified by ANCOM‐BC2, these microbiota‐related findings should be considered exploratory. CONCLUSION Overall, BSFL protein appears to be a promising partial replacement for plant‐based proteins in broiler diets, demonstrating similar digestibility, but promoting distinct microbiota‐associated responses. © 2026 Society of Chemical Industry.