A 2026 research study found that Atlantic salmon fed a diet containing 10% black soldier fly meal developed significantly stronger immune responses and thicker protective mucus barriers in their gills, intestines, and skin compared to salmon eating traditional fish meal. According to Gram Research analysis, immune cells increased, protective mucus genes were activated, and tissue structure improved in the black soldier fly group, suggesting insect-based feed could be a sustainable alternative to fish meal while potentially enhancing fish health in aquaculture.
Researchers tested whether insect-based meals could replace traditional fish meal in salmon diets while keeping the fish healthy. They fed Atlantic salmon five different diets over 74 days: one with standard fish meal and four with varying amounts of black soldier fly or yellow mealworm meals. The salmon eating the highest amount of black soldier fly meal showed stronger immune responses, thicker protective mucus layers in their gills and intestines, and more immune cells throughout their bodies. According to Gram Research analysis, this suggests insect meals could be a sustainable alternative to fish meal while potentially improving fish health in aquaculture.
Key Statistics
A 2026 research study of Atlantic salmon found that those fed 10% black soldier fly meal showed significantly increased mucous cell area and barrier integrity in their intestines, skin, and gills compared to salmon fed traditional fish meal.
Salmon fed 10% black soldier fly meal demonstrated elevated expression of immune-related genes including muc2, muc5b, and cath1 across intestinal, skin, and gill tissues, indicating stronger natural immune defenses than control groups.
In a 74-day feeding trial, Atlantic salmon fed black soldier fly meal showed higher counts of immune cells including rodlet-like cells and lymphocytes in their intestines and skin compared to fish fed traditional fish meal or yellow mealworm meal.
Research on Atlantic salmon revealed that skin health markers showed a significant positive correlation (p = 0.034) with overall fish body condition when fed black soldier fly meal, suggesting tissue improvements reflect genuine health benefits.
The Quick Take
- What they studied: Whether meals made from insects (black soldier flies and mealworms) could replace fish meal in salmon feed and how this affects the fish’s immune system and protective barriers in their gills, skin, and intestines.
- Who participated: Atlantic salmon were divided into five groups and fed different diets for 74 days. One group ate traditional fish meal, while four groups ate diets containing varying amounts of black soldier fly or yellow mealworm meal.
- Key finding: Salmon fed the highest amount of black soldier fly meal (10% of their diet) developed stronger immune responses, thicker protective mucus layers, and more immune cells compared to salmon eating traditional fish meal or mealworm-based diets.
- What it means for you: This research suggests that fish farms could switch to insect-based feed, which is more sustainable and environmentally friendly, while potentially keeping farmed salmon healthier. However, this is early-stage research in controlled conditions, so more testing is needed before widespread adoption.
The Research Details
Scientists created five different salmon diets and tested them over 74 days. The control diet used traditional fish meal, fish oil, and plant-based ingredients. The four experimental diets replaced some of these ingredients with black soldier fly meal (at two different amounts: 5% and 10%) or yellow mealworm meal (at two different amounts: 15% and 30%). Each diet group had multiple tanks of salmon to ensure reliable results.
After the feeding period, researchers examined tissue samples from the salmon’s intestines, skin, and gills under microscopes. They looked at the structure of these tissues, measured how well they protected the fish from harmful bacteria, and analyzed which immune genes were turned on or off. They also counted different types of immune cells in each tissue type.
This approach allowed researchers to see not just whether the fish survived on insect meal, but whether their immune systems and protective barriers actually improved compared to fish eating traditional feed.
The aquaculture industry needs sustainable alternatives to fish meal because fishing for wild fish to feed farmed fish is not environmentally sustainable. Insect meals offer a renewable protein source, but scientists needed to confirm they don’t harm fish health. This study goes beyond just measuring growth and survival, examining the actual immune system and protective barriers that keep fish healthy.
This study was published in a peer-reviewed scientific journal focused on fish and shellfish health. The researchers used multiple measurement techniques (tissue structure analysis, immune cell counting, and gene expression testing) to confirm their findings. They tested multiple diet variations and used proper statistical analysis. However, the study doesn’t specify the exact number of salmon used, which would help readers understand how reliable the results are. The controlled laboratory setting means results may differ in real-world fish farm conditions.
What the Results Show
The salmon fed 10% black soldier fly meal showed the most dramatic improvements. Their intestinal, skin, and gill tissues had noticeably different structures compared to other groups, suggesting these tissues were healthier and more developed. The protective mucus layer, which acts like a shield against harmful bacteria and parasites, was thicker in these fish.
Immune cell counts increased significantly in the black soldier fly group. The researchers found more rodlet-like cells (which fight infections) and lymphocyte cells (white blood cells) in the intestines and skin. The salmon also showed more cell growth and division in their intestinal tissues, indicating active tissue repair and strengthening.
Gene expression analysis revealed that immune-related genes were activated across all insect meal diets, but the 10% black soldier fly group showed the strongest activation. Specifically, genes responsible for producing protective mucus (muc2, muc5b) and antimicrobial peptides (natural antibiotics produced by the fish) were significantly elevated. These genes help the fish fight off infections naturally.
Interestingly, salmon fed yellow mealworm meal showed similar results to the control group eating traditional fish meal, suggesting that black soldier fly meal has unique immune-boosting properties that mealworm doesn’t provide.
The researchers found a positive correlation between fish body condition and intestinal, skin, and gill health markers. This means healthier tissues were associated with better overall fish condition. The skin health marker showed a statistically significant relationship with body condition, suggesting that skin tissue changes were a reliable indicator of overall fish wellness. Cell size and percentage of lymphocytes and macrophages (immune cells) were also higher in the black soldier fly group, indicating a more robust immune response.
Previous research suggested that insect meals could provide good nutrition for fish, but this study is among the first to demonstrate that they can actually enhance immune function and mucosal barrier health. The findings align with earlier observations that chitin (a compound in insect exoskeletons) has immune-stimulating properties. However, this is the first detailed examination of how different insect species and amounts affect salmon’s protective tissues and immune gene activation.
The study doesn’t report the exact number of salmon used in each group, making it difficult to assess statistical power. The research was conducted in controlled laboratory conditions, so results may differ in commercial fish farms with different water conditions, stocking densities, or environmental stressors. The study only tested Atlantic salmon, so results may not apply to other fish species. The 74-day feeding period is relatively short, so long-term effects remain unknown. The study didn’t measure whether these immune improvements actually prevent disease in real-world conditions.
The Bottom Line
Based on this research, aquaculture facilities could consider replacing up to 10% of traditional fish meal with black soldier fly meal as a sustainable alternative. The evidence is strong that this change improves immune markers and tissue health in controlled settings. However, facilities should conduct their own pilot trials before switching all their feed, as real-world conditions may produce different results. Yellow mealworm meal did not show the same benefits, so black soldier fly appears to be the better choice if switching to insect-based feed.
Fish farmers and aquaculture companies should care about this research because it offers a more sustainable feed option that may improve fish health. Environmental advocates should care because reducing wild fish harvesting for feed is better for ocean ecosystems. Consumers of farmed salmon may eventually benefit from healthier, more sustainably raised fish. However, home aquarium owners with small fish tanks shouldn’t make changes based on this research, as it’s specific to commercial salmon farming.
The immune and tissue changes observed in this study occurred within 74 days of feeding. Fish farmers could expect to see similar improvements within 2 to 3 months of switching to black soldier fly meal. However, disease prevention benefits would take longer to measure and would require monitoring fish health over an entire production cycle (typically 18 to 24 months for salmon).
Frequently Asked Questions
Can insect meal replace fish meal in salmon farming?
Black soldier fly meal can replace up to 10% of traditional fish meal while improving immune health and protective barriers in Atlantic salmon. Yellow mealworm meal showed no advantage over fish meal. More research is needed to determine if higher percentages work in real-world farm conditions.
What makes black soldier fly meal better for fish than mealworm?
Black soldier fly meal contains chitin and other compounds that activate immune genes more strongly than mealworm meal. Salmon fed black soldier fly developed thicker protective mucus layers, more immune cells, and stronger antimicrobial defenses within 74 days.
How long does it take to see health improvements from insect-based fish feed?
Immune and tissue improvements appeared within 74 days in this study. Fish farmers could expect to observe changes in gill color, skin condition, and immune markers within 2 to 3 months of switching to black soldier fly meal.
Is farmed salmon fed insect meal safe to eat?
This study focused on fish health, not food safety. Insect meal is already approved as fish feed in many countries. The immune improvements suggest healthier fish, which could mean safer, higher-quality farmed salmon, but additional food safety testing would be needed to confirm.
Why is switching from fish meal to insect meal important?
Using insect meal reduces pressure on wild fish populations used for fish meal production, making aquaculture more sustainable. This study shows the switch doesn’t harm fish health and may actually improve it, making it an environmentally friendly alternative.
Want to Apply This Research?
- For aquaculture operations using this research, track the percentage of black soldier fly meal in feed formulations and monitor fish health markers weekly, including gill color, skin condition, and feeding behavior. Record any disease outbreaks or health issues to compare against baseline data from traditional fish meal feeding.
- If managing a fish farm, gradually introduce black soldier fly meal into feed formulations, starting with 5% replacement and increasing to 10% over 2 to 3 weeks. Monitor fish response during this transition period. Document feed costs, fish growth rates, and any visible health changes to evaluate whether the switch is beneficial for your specific operation.
- Establish a long-term tracking system that compares health metrics between fish fed traditional fish meal and those fed black soldier fly meal. Track survival rates, growth rates, feed conversion efficiency, and disease incidence over a full production cycle. Periodically sample fish tissues to verify that immune improvements observed in this study are replicated in your facility.
This research describes laboratory findings in controlled conditions and has not yet been tested in commercial fish farming operations. Results may differ in real-world aquaculture settings. Fish farmers should consult with aquaculture nutritionists and conduct pilot trials before making large-scale feed changes. This study was conducted on Atlantic salmon and may not apply to other fish species. The long-term health and disease prevention benefits of insect-based feed in commercial settings remain to be determined. Always follow local regulations regarding aquaculture feed ingredients.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.