Black soldier fly meal shows promise, limits in broiler diets

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Black soldier fly larvae meal is getting another look as a soybean meal substitute in broiler diets, and a new Veterinary Sciences paper suggests the answer is nuanced rather than all-or-nothing. In the study, researchers evaluated incremental replacement of soybean meal with black soldier fly larvae meal in Ross 708 broilers and found that partial replacement, particularly at 20%, maintained performance reasonably well, while higher replacement levels came with weaker growth and feed efficiency. (mdpi.com)

The backdrop is familiar to anyone in poultry nutrition: soybean meal remains a cornerstone protein source, but its price, supply chain exposure, and environmental footprint keep alternative proteins on the table. Black soldier fly larvae has drawn sustained interest because it delivers protein and fat, can be produced on side streams, and fits a broader push toward circular feed systems. Prior broiler studies have pointed in the same general direction as this new paper, showing that low or moderate inclusion levels can work, but complete or near-complete replacement of soybean meal often depresses growth unless formulations are carefully adjusted. That pattern is also consistent with a broader principle seen outside broilers: in grey mullet, for example, partially defatted black soldier fly meal maintained growth across diets, but the best intestinal and immune findings were seen at a moderate 10% inclusion, while higher levels showed worsening intestinal condition and dose-related spleen effects. (mdpi.com)

In the new trial, 160 ten-day-old birds were assigned to four diets with 0%, 20%, 40%, or 60% soybean meal replacement by black soldier fly larvae meal. According to the study summary, the investigators tracked growth performance, carcass traits, meat quality, and blood biochemical responses across starter, grower, and finisher phases. The topline finding was that lower inclusion levels were tolerated better, with higher replacement levels associated with poorer weight gain and feed conversion. That pattern aligns closely with a 2023 Poultry Science study in which broilers fed 12.5% black soldier fly larvae meal performed similarly to controls by day 35, while birds on 100% replacement had lower body weight and higher cumulative feed conversion ratios. (mdpi.com)

Other poultry studies help fill in what “tolerated better” can look like in practice. In an Animals trial of 1,750 Ross 308 broilers, adding 2% or 4% full-fat Hermetia illucens or Tenebrio molitor meal did not affect feed intake, feed conversion, growth, or mortality. Breast yield was higher in insect-fed birds than in controls, while most carcass and health measures remained acceptable. There were, however, ingredient-specific differences: birds on 4% H. illucens had lower breast pH and higher cooking loss, suggesting some reduction in water-holding capacity within acceptable limits; thigh meat showed dose-dependent lipid accumulation; and T. molitor increased serum total cholesterol through higher HDL rather than LDL and was associated with shorter ileal length. The practical takeaway is that low inclusion can be safe and productive, but “insect meal” is not one uniform ingredient class. (mdpi.com)

That consistency matters because it suggests the issue is not whether insect meal can be used in broilers, but how much, in what form, and with what formulation adjustments. Another 2023 broiler study in Animals reported that black soldier fly larvae meal at 3% in the starter phase and 5% in the grower-finisher phase did not negatively affect growth performance, blood traits, or nutrient excretion, and may support gut microbial health. Reviews published in the past two years have also described black soldier fly larvae as a promising ingredient, while emphasizing that outcomes vary with larval processing, fat content, chitin level, amino acid balance, and inclusion rate. (mdpi.com)

The soybean side of the equation also deserves attention. A recent Animals study testing a low-soybean-meal broiler diet found that simply reducing soybean meal by 10% increased mortality and feed intake during days 22–42 and reduced ether extract availability. It also shifted the cecal microbiota toward greater abundance of Campylobacterota and Helicobacter. Adding graded raffinose to that low-soy diet partly modulated the microbial changes and showed a trend toward lower mortality, but it also reduced gross energy and dry matter utilization and downregulated duodenal SLC5A1 expression. For clinicians and nutrition advisors, that is a useful reminder that reducing soybean meal is not automatically benign; the replacement strategy has to preserve both nutrient delivery and gut ecology. (mdpi.com)

Direct outside commentary on this specific paper was limited at the time of writing, but the broader industry and regulatory context is moving. In the U.S., AAFCO’s 2025 Official Publication includes a definition for dried black soldier fly larvae for use in finfish, poultry, swine feed, and adult dog food, signaling a more mature regulatory footing for commercial feed use. Internationally, the EU expanded authorization for processed insect protein in poultry and pig feed in 2021, which has helped move insect meal from pilot-stage curiosity toward a regulated feed ingredient in more markets. The interest is not limited to broilers: a recent Frontiers in Veterinary Science study in post-weaning piglets found that daily live Tenebrio molitor larvae supplementation improved early feed efficiency and growth, reduced diarrhea and respiratory disorders, and helped piglets on a lower-protein diet perform comparably to controls on a standard-protein diet, without adverse effects on digestibility or serum metabolic markers by day 42. (aafco.org)

Why it matters: For veterinarians, poultry nutritionists, and technical service teams, this study is useful because it reinforces a practical message: insect protein may be a viable partial tool, but not a drop-in replacement for soybean meal at high levels. Flock performance, carcass outcomes, and health indicators can hold up at lower inclusion rates, yet overreaching on replacement risks undoing those gains. The broader literature also suggests that low-level insect inclusion may sometimes improve specific endpoints such as breast yield or early resilience, while still introducing subtle shifts in meat quality, lipid metabolism, or gut morphology that deserve attention. In practice, that means any move toward black soldier fly meal will likely depend on formulation precision, digestibility data, ingredient consistency, and economics, not sustainability claims alone. (mdpi.com)

There’s also a client-facing angle. As feed companies and integrators explore alternative proteins, veterinary professionals may increasingly be asked whether insect-based ingredients are safe, effective, and commercially realistic. The current evidence base supports cautious optimism, especially for partial inclusion, but it also shows that performance can slip when replacement levels climb too high or when nutrient balance is not fully corrected. And while this article is about protein substitution, adjacent feed-additive research shows how many levers can influence final product quality: for example, Stevia rebaudiana extract has been studied in yellow-feathered broilers as a phytogenic additive that altered several meat-quality traits, underscoring that diet changes can affect more than growth alone. (mdpi.com)

What to watch: The next wave of research will likely focus on standardized commercial products, digestible amino acid formulation, cost-per-ton comparisons with soybean meal, and whether black soldier fly meal can deliver consistent results at scale across different broiler strains and production systems. Just as important will be defining threshold effects more clearly: where inclusion supports performance and gut health, where carcass or meat-quality changes begin to appear, and how those cutoffs differ by insect species, processing method, and host species. (mdpi.com)