**Background:** The poultry industry faces increasing pressure to find sustainable alternatives to traditional feed sources like soybean meal, which accounts for 65–75% of total production costs. Since 2005, plant-based protein sources have become scarce due to limited agricultural land, deforestation, and biofuel production demands. Insects represent a promising solution as they require less water and space, can be grown on organic side streams, release fewer greenhouse gases than traditional livestock, and have high feed conversion efficiency. The European Commission's 2020 circular economy action plan, part of the European Green Deal, supports insect-based feed as part of sustainable agricultural practices. With over 2000 edible insect species identified globally, the insect feed industry is projected to generate over EUR 2 billion annually by the end of the decade.
**Methods:** This is a narrative review that synthesizes findings from multiple studies on insect composition, nutritional value, and application in poultry feed. The review covers six main insect types used in poultry nutrition: black soldier fly (Hermetia illucens), mealworm (Tenebrio molitor), housefly (Musca domestica), grasshopper/locust (Orthoptera), silkworm (Bombyx mori), and termite (Macrotermes spp.). The authors examined studies on growth performance, egg production, meat quality, gut health, immunity, and safety considerations. They also reviewed regulatory frameworks across different countries including the EU, US, Canada, South Korea, China, Japan, Australia, and Nigeria.
**Key Results:** The chemical composition of insects varies significantly by species. Black soldier fly larvae (BSFL) contain 42.3% protein and 33.5% fat; housefly meal contains 52% protein and 18% fat; mealworm contains 45% protein and 30% fat; locusts contain 57.3% protein and 8.5% fat; silkworm contains 54% protein and 12% fat; and grasshopper contains 47.71% protein and 12.21% fat. Compared to soybean meal (44% protein, 0.9% fat), insects generally provide higher methionine and lysine content. For broiler performance, BSFL at 10% inclusion enhanced performance traits in multiple studies. Mealworm at 2.5–5% improved body weight and reduced harmful intestinal bacteria. Housefly meal at 4–10% improved growth performance, carcass traits, and meat quality. Grasshopper meal at 5–10% as fish meal replacement improved broiler development. For layers, BSFL at 3% improved performance and blood biochemistry in Hy-Line Brown hens, while 5–7.5% BSFL improved performance and egg quality in White Leghorn hens. Bioactive components including chitin demonstrate antibacterial activity against Gram-negative bacteria such as E. coli, Vibrio cholerae, Shigella dysenteriae, and Bacteroides fragilis. Antimicrobial peptides from insects show activity against both Gram-positive and Gram-negative bacteria without promoting bacterial resistance. Safety concerns include microbiological risks (aerobic bacteria exceeding 6 log CFU/g and Enterobacteriaceae exceeding 3 log CFU/g in over half of tested freeze-dried insects), chemical contamination (heavy metal accumulation, with T. molitor larvae cadmium concentration reaching 2 mg/kg dw when substrate contained 0.13 mg/kg), and potential allergens (tropomyosin and arginine kinase implicated in cross-reactivity). The EU has authorized seven insect species for poultry, pig, and aquaculture feed: H. illucens, M. domestica, T. molitor, A. diaperinus, A. domesticus, G. sigillatus, and G. assimilis. Current market prices for insect-derived protein in EU nations range from EUR 2.0 to 10.0/kg, though projections suggest parity with fishmeal by 2023.
**Clinical Implications:** Insect products demonstrate potential as sustainable nutraceuticals in poultry production, with evidence showing improved broiler growth (>3%) and layer egg production (>5%). The bioactive compounds in insects—particularly chitin, antimicrobial peptides, and lauric acid—may reduce reliance on antibiotics in poultry production, addressing concerns about antimicrobial resistance. However, the review emphasizes that insects should only partially replace conventional protein sources to ensure proper bird growth and production. Regulatory barriers, particularly in Western nations, currently limit commercial adoption. The authors recommend further research in histomorphology, histochemistry, immunohistochemistry, and molecular biology to confirm safety and efficacy. Cost-benefit assessments are needed to determine financial effects of incorporating insects into animal diets. Consumer education is essential to overcome neophobia and misconceptions about insect-based feed, as studies show that increasing knowledge significantly increases willingness to accept insect-derived products.