Study tests black soldier fly larvae meal against soybean in broilers

Black soldier fly larvae meal is getting another close look as poultry nutritionists search for alternatives to soybean meal, and a new study adds a measured answer: partial replacement may be feasible, but higher inclusion rates still raise questions. In a paper published March 18, 2026, in Veterinary Sciences, researchers from Prairie View A&M University evaluated black soldier fly larvae meal in broiler diets across four replacement levels and assessed performance, carcass traits, meat quality, and blood biochemical indicators. (mdpi.com)

The interest is easy to understand. Soybean meal remains a core poultry protein source, but it carries price volatility, supply-chain exposure, and environmental baggage tied to land use and deforestation. Black soldier fly larvae, by contrast, are being studied as a circular-economy ingredient that can convert organic side streams into protein and fat. Reviews published over the past two years have framed BSFL as one of the most credible insect candidates for poultry feeding, though they also note that results vary widely depending on processing, substrate, inclusion rate, and diet formulation. (mdpi.com)

In the new trial, 160 ten-day-old Ross 708 chicks were assigned to diets replacing soybean meal with BSFL meal at 0%, 20%, 40%, or 60%. According to the study summary, the team evaluated birds through starter, grower, and finisher phases and looked beyond weight gain alone to carcass traits, meat quality, and blood responses. That broader design matters, because previous broiler work has shown that insect meal can preserve many health-related blood markers even when production performance shifts. In a 2018 broiler study, partially defatted Hermetia illucens meal did not adversely affect measured blood parameters or histopathology, but higher inclusion levels were linked with less favorable intestinal morphology and poorer feed conversion later in growth. (mdpi.com)

That pattern shows up elsewhere in the literature. A 2023 Animals study examining fish and black soldier fly meals as partial soybean replacements reported that low insect meal inclusion, around 3% to 5%, may be a practical alternative with potential animal production and health benefits. Another Animals broiler study using full-fat Hermetia illucens and Tenebrio molitor meals at 2% and 4% found no adverse effects on growth performance, feed intake, feed conversion, mortality, blood parameters, or overall carcass quality, and breast yield was higher in insect-fed birds than in controls. But it also showed that not all “low inclusion” outcomes are neutral: the higher black soldier fly treatment reduced breast meat pH and increased cooking loss within acceptable ranges, thigh fat deposition rose with insect inclusion, and T. molitor affected ileal length. Other papers have been less encouraging when soybean meal replacement becomes extensive. A 2022 Poultry Science report found that complete replacement of soybean meal with BSFL meal reduced growth performance and altered organ morphology, while another 2022 study reported changes in growth performance, cecal short-chain fatty acids, and excreta metabolomics when soybean meal was partially or completely replaced. A separate 2022 MDPI paper similarly concluded that complete replacement reduced available energy and nutrient digestibility, with chitin among the suspected factors. (mdpi.com)

There is also a useful reminder here that changing soybean meal itself can have consequences, even before insect meal enters the picture. In one broiler study, a diet with soybean meal reduced by 10% increased mortality and feed intake during the later growth phase and lowered ether extract availability. Adding graded raffinose to that low-soybean diet partly shifted cecal microbiota, including reversing increases in Campylobacterota and Helicobacter, but it also reduced gross energy and dry matter utilization. The practical point is that protein-source reformulation can ripple through nutrient use, gut function, and microbial ecology in ways that are not captured by crude protein numbers alone.

Industry and regulatory context is also shifting. AAFCO meeting materials published in early 2025 show black soldier fly larvae ingredients moving into official ingredient definitions for use in finfish, poultry, and swine feed, provided the larvae are raised on feed-grade materials and meet labeling and compositional requirements. That doesn’t settle questions about economics or formulation, but it does reduce one barrier to broader commercial adoption in the U.S. feed sector. At the same time, outside commentary remains cautious on cost. Recent analysis has argued that insect-based livestock feeds still face steep pricing and scale challenges, even where nutritional and sustainability arguments are strong. (aafco.org)

Work outside broilers also supports the idea that inclusion thresholds matter. In grey mullet, partially defatted BSF meal did not significantly impair growth, but the highest replacement levels worsened intestinal condition and produced dose-related spleen changes, while a lower inclusion level appeared to support gut morphology and innate immune activity. In piglets, daily live Tenebrio molitor larvae supplementation improved early feed efficiency, growth, and health indicators under post-weaning conditions, even allowing a moderately lower crude-protein diet without obvious penalties. Those are different species and different feeding strategies, so they should not be overread for broilers, but they reinforce a broader feed-nutrition theme: insect ingredients may offer functional benefits, yet those benefits depend heavily on dose, form, and production context.

Why it matters: For veterinarians, poultry nutrition consultants, and technical teams advising integrators, the message isn’t that soybean meal is about to disappear. It’s that alternative proteins are moving from concept to formulation reality, and they’ll need to be judged on bird performance, gut health, litter quality, carcass outcomes, meat quality, and economics, not just sustainability claims. If black soldier fly larvae meal is used, inclusion level appears to be the key variable. Lower levels may fit more easily into commercial diets, and some studies suggest they can maintain growth while even improving traits like breast yield, but higher substitution rates still seem more likely to expose issues around digestibility, energy density, amino acid balance, gut morphology, and chitin load. (jasbsci.biomedcentral.com)

For pet parents, none of this changes chicken meat in the clinic today. But for veterinary professionals working with food-animal systems, it’s part of a bigger shift in how feed ingredients are sourced, regulated, and evaluated. If insect meal adoption expands, veterinary oversight will likely intersect more often with feed safety, substrate quality, nutrient consistency, flock health monitoring, and the less visible downstream effects on meat quality and intestinal health. (aafco.org)

What to watch: The next important signals will be commercial-scale broiler trials, cost comparisons against soybean meal under real market conditions, and studies testing whether processing changes or enzyme strategies can improve nutrient availability enough to support higher BSFL inclusion without compromising performance. It will also be worth watching for more work on carcass yield, meat quality, intestinal morphometry, and microbiome responses, since some low-inclusion insect diets look acceptable on standard growth metrics while still shifting those secondary outcomes in ways that matter commercially. (mdpi.com)