Black soldier fly meal shows promise, with limits, in broilers

A new broiler nutrition study is adding nuance to one of feed’s most closely watched alternative protein stories. In Veterinary Sciences, Ahmed A. A. Abdel-Wareth and colleagues evaluated black soldier fly larvae meal as a replacement for soybean meal in Ross 708 broilers and found a familiar tradeoff: modest inclusion looked workable, but pushing replacement higher hurt performance. The study tested 0%, 20%, 40%, and 60% soybean meal replacement and assessed growth, carcass traits, meat quality, and blood biochemical markers. (mdpi.com)

The backdrop is easy to understand. Soybean meal remains a core protein source in poultry diets, but cost pressure, supply volatility, land-use concerns, and interest in circular feed systems have all pushed insect proteins higher on the industry agenda. Black soldier fly larvae, in particular, have attracted attention because their amino acid profile can compare favorably with conventional proteins, and because they can be produced on side streams under controlled conditions. But the science has been mixed, especially when inclusion rates climb or when products differ in fat content, chitin content, and digestibility. (mdpi.com)

That’s why this paper matters. According to the study summary, the researchers used whole dried black soldier fly larvae rather than a defatted or highly processed ingredient, aiming to reflect practical feed production conditions. Their results align with prior reports that low to moderate use can be tolerated, while heavier substitution can reduce weight gain and worsen feed conversion. A 2023 Poultry Science paper from Agriculture and Agri-Food Canada similarly found that replacing soybean meal with up to 12.5% to 25% black soldier fly larvae meal could maintain performance in some phases, but 100% replacement lowered body weight and feed intake and increased cumulative feed conversion ratio. (mdpi.com)

The broader evidence base points in the same direction. A meta-analysis published in Animal Production Science concluded that black soldier fly larvae meal was generally safe up to about 10% inclusion, with effectiveness influenced by feeding duration and formulation. Other recent broiler work helps define what “low inclusion” can look like in practice. In an Animals study of 1,750 Ross 308 broilers, adding 2% or 4% full-fat Hermetia illucens or Tenebrio molitor meal did not affect growth performance, feed intake, feed conversion, or mortality. Insect-fed birds had higher breast yield than controls, although the highest H. illucens inclusion was associated with slightly lower breast pH and higher cooking loss, and thigh meat showed dose-dependent lipid accumulation. Tenebrio diets also shifted serum cholesterol fractions and were linked to shorter ileal length. Overall, though, that study supports the idea that low-level full-fat insect meal can be used without obvious harm to broiler growth or health, even if carcass and meat-quality details still need attention. In other words, the question is shifting from whether black soldier fly can be used at all to where its practical limit sits in commercial diets, and what processing methods make it most reliable. (publish.csiro.au)

There is also a useful caution from the soybean side of the equation. In an Animals study of low-soybean-meal broiler diets, a 10% reduction in dietary soybean meal increased mortality and feed intake during days 22–42 and reduced ether extract availability, while also altering cecal microbiota, including higher relative abundance of Campylobacterota and Helicobacter. Raffinose supplementation partly modulated some of those microbial changes and showed a tendency to reduce mortality, but it also reduced some measures of nutrient utilization. The practical takeaway is that reducing soybean meal is not nutritionally neutral; whether the replacement ingredient is insect-derived or not, formulation changes can ripple through digestibility, gut ecology, and flock outcomes.

Industry and regulatory context also matters here. The Poultry Science Association has highlighted that AAFCO updated its ingredient definition for dried black soldier fly larvae to include poultry feed, alongside salmonid and swine feeds, with the important condition that larvae be raised on feed-grade materials. AAFCO meeting materials in 2025 also show continued movement on insect-derived ingredients, underscoring that regulators and feed officials are treating this as a growing, not fringe, category. That doesn’t erase practical hurdles around ingredient consistency, nutrient variability, or cost, but it does make commercial trials and formulation work more realistic in the U.S. market. (poultryscience.org)

Why it matters: For veterinarians working with poultry operations, the takeaway is pragmatic. Black soldier fly ingredients may help reduce dependence on soybean meal, but they’re not a simple one-for-one swap. Diet formulation still has to account for amino acid balance, energy density, fat level, mineral load, and the effects of chitin on digestibility. Health-related signals, including blood biochemistry and gut outcomes, remain promising in some studies, but performance remains the commercial gatekeeper. If birds lose ground on weight gain or feed efficiency, sustainability arguments alone won’t carry the ingredient. (mdpi.com)

There’s also a systems-level point for the profession. As more novel feed ingredients move from experimental diets into field use, veterinary oversight will increasingly intersect with nutrition, flock health, ingredient sourcing, and food safety. Insect-derived proteins could become a useful tool, especially where pet parents and consumers are pushing for more sustainable animal agriculture, but the operational details will determine whether they stay niche or scale. And the broader animal-feeding literature suggests insect ingredients may offer more than just protein replacement in some settings: a recent Frontiers in Veterinary Science study found that live Tenebrio molitor larvae improved early feed efficiency, growth, and health indicators in post-weaning piglets, with lower diarrhea and respiratory disorder rates and good acceptance even in a reduced-protein diet. That does not translate directly to broilers, but it reinforces the idea that insect-based ingredients may have functional effects worth separating from their crude nutrient contribution alone. The current evidence in poultry, however, still suggests black soldier fly larvae meal is best viewed as a targeted partial replacement, not a universal soybean meal substitute. (publish.csiro.au)

What to watch: The next wave of research will likely focus on digestibility-adjusted formulation, defatted versus full-fat products, cost per unit of usable protein, and whether specific inclusion windows can preserve performance while improving sustainability metrics. Processing will be a big part of that. In aquaculture, for example, partially defatted black soldier fly meal in grey mullet did not significantly impair growth, but histology suggested a threshold effect: the 10% inclusion diet appeared optimal, while higher levels were associated with worsening intestinal condition and dose-related spleen changes. That kind of threshold finding is likely relevant to poultry as well. Watch, too, for work on companion additives and quality modifiers. Phytogenic strategies such as Stevia rebaudiana extract are also being studied for broiler meat-quality effects, a reminder that if insect meals alter carcass or sensory traits, producers may eventually look at multi-ingredient approaches rather than expecting one novel protein to solve every formulation goal at once. Commercial validation studies and more U.S. feed guidance will be important next steps as the category moves beyond controlled trials into production settings. (tandfonline.com)