A supplement made from microalgae and yeast helped fish stay healthier when eating plant-based diets, according to a 2026 research study. Fish receiving the supplement showed better liver function, more balanced immune responses, and better-preserved intestinal structure compared to fish on plant-based diets without it. The supplement activated genes related to energy production and helped prevent excessive inflammation, suggesting it could support sustainable aquaculture by enabling fish to thrive on plant-based feeds while maintaining strong health and welfare.
Researchers tested a new supplement made from algae and yeast on fish fed plant-based diets to see if it could help them stay healthy when their immune systems were challenged. According to Gram Research analysis, the supplement helped fish maintain better liver health, balance their immune responses, and preserve their gut structure compared to fish without the supplement. The findings suggest that adding this nutraceutical to plant-based fish feed could improve fish health and welfare while supporting sustainable aquaculture practices that use fewer ocean resources.
Key Statistics
A 2026 research study found that fish fed a plant-based diet supplemented with LB-IMMUNOboost showed restored or maintained metabolic parameters and improved hepatic integrity compared to unsupplemented plant-based diets, with activation of energy-related genes including sirt1, sirt7, cpt1ab, nd1, nd2, and cox1.
According to research reviewed by Gram, the microalgae and yeast supplement promoted a balanced immune response in fish by regulating both pro-inflammatory and anti-inflammatory responses, supporting immune defense without causing excessive inflammation that could damage tissues.
The 2026 study demonstrated that LB-IMMUNOboost supplementation helped preserve intestinal architecture in plant-fed fish, including partial recovery of goblet cell numbers and improved absorptive surface features compared to unsupplemented plant-based diets.
The Quick Take
- What they studied: Whether a supplement made from microalgae and yeast could help fish stay healthy and fight inflammation when eating plant-based diets instead of traditional fish-based feed
- Who participated: Young sea bream fish (Sparus aurata) divided into three groups: one eating traditional fish-based feed, one eating plant-based feed without the supplement, and one eating plant-based feed with the new supplement. All fish were given an immune challenge to simulate stress
- Key finding: Fish that received the supplement showed better liver health, more balanced immune responses, and better-preserved gut structure compared to fish on plant-based diets without the supplement
- What it means for you: This research could lead to more sustainable fish farming that uses fewer ocean resources while keeping farmed fish healthier. If you eat farmed fish, this means producers may soon have better tools to raise fish on plant-based diets without compromising their health or nutritional quality
The Research Details
Scientists divided young sea bream fish into three feeding groups for 90 days. The first group ate traditional feed with fish meal and fish oil. The second group ate a plant-based diet with much less fish content. The third group ate the same plant-based diet but with added LB-IMMUNOboost supplement made from algae and yeast. After 90 days, all fish received an immune challenge (an injection designed to trigger an inflammatory response) to test how well their bodies could handle stress. Researchers then examined the fish’s livers, intestines, and immune organs to measure health markers and gene activity.
The study measured multiple health indicators including liver size, liver cell structure, intestinal tissue appearance, and the activity of genes related to energy production and immune function. Scientists looked at tissue samples from the liver, intestines, head kidney, and spleen to understand how the supplement affected different body systems. This comprehensive approach allowed researchers to see whether the supplement worked throughout the fish’s body or in specific areas.
This research design is important because it tests whether a supplement can help fish thrive on sustainable plant-based diets while still maintaining strong health and immune function. The study mimics real-world conditions where farmed fish face multiple stressors simultaneously, including dietary changes and immune challenges. By measuring both molecular changes (gene activity) and physical changes (tissue structure), the researchers could confirm that the supplement’s benefits were real and not just temporary
The study used multiple measurement methods to verify results, including gene expression analysis, tissue examination, and physical measurements. The researchers examined multiple organs and tissues to understand how the supplement affected the whole body. However, the study used an artificial immune challenge rather than a real infection, which may not perfectly reflect how fish respond to natural pathogens. The sample size was not specified in the available information, which limits our ability to assess statistical power
What the Results Show
Fish receiving the supplement showed significantly better liver health compared to those on plant-based diets without it. The supplement appeared to activate genes related to energy production and mitochondrial function, suggesting the fish’s bodies were better equipped to handle the stress of both dietary change and immune challenge. This activation of energy-related genes indicates the supplement helped fish maintain metabolic balance during difficult conditions.
At the immune level, the supplement promoted what researchers call a ‘balanced immune response.’ This means the fish’s bodies produced appropriate levels of inflammation-fighting molecules without going overboard and causing excessive inflammation that could damage their own tissues. This balance is crucial because too much inflammation can harm the fish just as much as too little immune response.
The supplement also helped preserve the fish’s intestinal structure, which is the barrier that controls what gets absorbed into the body. Fish receiving the supplement showed better-maintained intestinal tissue, including more mucus-producing cells (goblet cells) that protect the gut lining. The intestinal surface features that help with nutrient absorption were also better preserved in the supplement group compared to fish on plant-based diets alone.
The supplement showed tissue-specific effects, meaning it worked differently in different parts of the fish’s body. In the head kidney and spleen (immune organs), the supplement activated genes related to both immune function and energy production. However, in the intestines, the supplement appeared to reduce excessive immune activation, suggesting it helped prevent unnecessary inflammation in the gut. This tissue-specific pattern suggests the supplement works intelligently, boosting immune function where needed while preventing overreaction in the digestive system
This research builds on growing evidence that plant-based diets can work for farmed fish when properly supplemented. Previous studies have shown that fish can adapt to plant-based feeds, but they often struggle with immune function and gut health. This study advances the field by demonstrating that targeted nutraceutical supplementation can address these specific challenges. The findings align with broader research showing that microalgae and yeast-derived products can support immune and digestive health in various animal species
The study used an artificial immune challenge (an injection of incomplete Freund’s adjuvant) rather than exposing fish to real pathogens, so results may not perfectly reflect how the supplement works against actual infections. The researchers noted that they only measured gene activity at specific time points, so they may have missed important changes that occurred at other times. The study did not include functional tests to confirm that the changes in gene activity actually translated to improved immune function. Additionally, the exact sample size was not clearly specified, making it difficult to assess how reliable the results are. The supplement’s effects also varied across different regions of the intestine, suggesting the benefits may be inconsistent throughout the digestive system
The Bottom Line
Based on this research, the LB-IMMUNOboost supplement shows promise for supporting fish health on plant-based diets, with moderate to strong evidence for benefits to liver function, immune balance, and gut structure. For fish farmers considering plant-based feeds, this supplement appears worth testing as part of a comprehensive nutrition strategy. However, more research with real pathogenic challenges and larger sample sizes would strengthen these recommendations. Confidence level: Moderate, as this is a single study with some methodological limitations
Fish farmers and aquaculture producers should pay attention to this research, as it offers a practical tool for transitioning to more sustainable, plant-based fish feeds without sacrificing fish health. Consumers who care about sustainable seafood production should care, as this could lead to more environmentally responsible fish farming. Nutritionists and veterinarians working in aquaculture should consider these findings when advising on feed formulations. People with general interest in sustainable food production and animal welfare should find this relevant. However, home aquarium owners may not need to apply these findings, as this research focuses on commercial farming of specific fish species
If fish farmers implement this supplement, they should expect to see improvements in fish health markers within 90 days, based on this study’s timeline. However, benefits to immune function during actual disease challenges might take longer to fully develop. Long-term effects beyond 90 days are unknown and would require additional research
Frequently Asked Questions
Can fish be raised on plant-based diets without losing health?
Fish can adapt to plant-based diets when properly supplemented, according to 2026 research. Fish receiving a microalgae and yeast supplement showed better liver function, balanced immune responses, and preserved gut structure compared to unsupplemented plant-based diets, suggesting targeted supplementation can address nutritional gaps
What does a microalgae and yeast supplement do for fish health?
The supplement activates genes related to energy production and immune function while promoting balanced inflammation responses. It helps maintain liver integrity, preserves intestinal tissue structure, and supports immune defense without causing excessive inflammation that damages tissues
How long does it take for fish to show health improvements from this supplement?
Based on the 2026 study, fish showed measurable improvements in liver health, immune markers, and intestinal structure within 90 days of receiving the supplemented diet. However, the timeline for benefits during actual disease challenges may differ and requires further research
Is this supplement safe for farmed fish?
The 2026 research found no adverse effects from the microalgae and yeast supplement in fish fed plant-based diets. The supplement promoted balanced immune responses and improved tissue health, suggesting it works safely alongside dietary changes, though long-term safety data beyond 90 days would strengthen this conclusion
Why does sustainable fish farming matter?
Plant-based fish feeds reduce pressure on wild fish populations and ocean ecosystems. This supplement enables fish to thrive on plant-based diets without health compromise, making sustainable aquaculture more practical and allowing consumers to choose seafood with lower environmental impact
Want to Apply This Research?
- For aquaculture producers using the app: Track weekly measurements of fish liver health indicators (hepatosomatic index), feed conversion efficiency, and any signs of inflammation or disease. Record gene expression markers if laboratory testing is available, or use proxy measurements like growth rate and feed consumption as indicators of metabolic health
- Implement a gradual transition to plant-based feed supplemented with LB-IMMUNOboost over 2 to 4 weeks, monitoring fish behavior and health markers daily. Log any changes in fish activity, appetite, or visible health signs. Compare these observations to baseline measurements taken before the dietary change
- Establish a 90-day monitoring protocol measuring fish growth, feed efficiency, disease resistance, and tissue health markers at 30-day intervals. Create alerts for any decline in these metrics that would indicate the supplement needs adjustment. After 90 days, reassess whether the plant-based diet with supplementation is meeting production and health goals
This research was conducted on young sea bream fish (Sparus aurata) in controlled laboratory conditions using an artificial immune challenge. Results may not directly apply to other fish species, wild fish populations, or human consumption. This study does not constitute medical or nutritional advice for humans. The supplement tested (LB-IMMUNOboost) is a research product and may not be commercially available. Aquaculture producers should consult with fish nutrition specialists and veterinarians before implementing dietary changes based on this research. Consumers should note that this research focuses on fish farming practices and does not directly address the nutritional or health benefits of consuming fish raised on plant-based diets. Always consult qualified professionals before making significant changes to fish farming practices or dietary decisions
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.