Microwave-dried black soldier fly larvae enhance growth, intestinal health, and humoral immunity in broiler chickens: A functional feed approach.

Background and aim: The global demand for sustainable animal protein sources has led to the exploration of insects as alternative feed ingredients. Among these, black soldier fly (BSF) larvae (Hermetia illucens) have demonstrated significant nutritional and functional potential. This study investigated the effects of microwave-dried BSF larvae meal (MDBSFM) on growth performance, intestinal morphology, humoral immune response, and insulin-like growth factor-1 (IGF-1) messenger RNA (mRNA) expression in broiler chickens.

Materials and methods: A total of 160 unsexed Lohmann broiler chickens were randomly allocated to five dietary treatments (T0-T4), with MDBSFM supplementation levels of 0%, 0.25%, 0.50%, 0.75%, and 1.00%, respectively. Each treatment consisted of four replicates, each with eight birds. Growth performance metrics, organ weights, intestinal histomorphology, immunoglobulin levels (IgA and IgY), and IGF-1 mRNA expression were measured. Fatty acid composition of MDBSFM was analyzed by gas chromatography.

Results: MDBSFM supplementation significantly improved body weight gain, final body weight, and feed conversion ratio (p < 0.05), with optimal outcomes observed at 0.75% inclusion. Villus height in the ileum was markedly increased in the 0.50% and 0.75% groups (p < 0.01), suggesting enhanced nutrient absorption. IgA and IgY concentrations were significantly elevated in response to MDBSFM (p < 0.05), particularly in the T3 and T4 groups. Although IGF-1 mRNA expression did not differ significantly (p = 0.58), the highest fold change (1.54) was noted in the 1.00% group.

Conclusion: Microwave-dried BSF larvae meal represents a promising functional feed additive capable of improving growth, intestinal health, and humoral immune responses in broilers without adverse effects. The high lauric acid content and bioactive compounds in MDBSFM may contribute to these beneficial effects. While IGF-1 upregulation trends warrant further molecular investigation, MDBSFM offers a viable alternative to antibiotic growth promoters in poultry diets. Future research should focus on microbiota profiling and large-scale commercial validation.