Multi-omics analysis reveals the regulatory effects of black soldier fly larvae (Hermetia illucens L. HI) on rumen metabolism, microbiota, and host immunity in goats

Black soldier fly larvae (Hermetia illucens; HI) are protein-rich, and heat treatment may increase rumen bypass protein, thereby improving ruminant performance. This study evaluated the effects of HI supplementation on growth performance, nutrient digestibility, serum immune status, and rumen microbiota in goats using a multi-omics framework. Thirty Qianbei Ma goats (20.30 +/- 1.09 kg, mean +/- SD) were randomly assigned to three individually housed groups: a control diet supplemented with 10% full-fat soybean (FFS), a diet containing 10% untreated HI (BSF), or a diet containing 10% heat-treated HI (HTBSF). Compared with FFS and BSF, HTBSF significantly increased total-tract apparent neutral detergent fiber digestibility (P < 0.05), while total ruminal volatile fatty acid concentrations did not differ among groups (P > 0.05). Serum immune parameters were higher in FFS and HTBSF than in BSF (P < 0.05). Rumen microbial profiling showed higher Bacteroidota and lower Firmicutes in HTBSF than in FFS and BSF (P < 0.05), and Prevotella abundance increased in both BSF and HTBSF (P < 0.05). Metabolomics and lipidomics indicated that BSF and HTBSF shifted rumen metabolite and lipid profiles relative to FFS, with changes in pathways including arachidonic acid and tryptophan metabolism, fatty acid biosynthesis, vitamin B6 metabolism, glycerolipid metabolism, and glycerophospholipid metabolism. Overall, heat-treated HI produced more favorable effects on fiber digestibility, immune status, and rumen microbial structure, and multi-omics results suggest these benefits are mediated by coordinated remodeling of rumen metabolic and lipid networks.