A 2026 research study found that adding 5% Bixa orellana leaf meal to fish food significantly improved growth performance, immune function, and disease resistance in Amur carp. According to Gram Research analysis, fish receiving the highest supplement dose showed higher survival rates after bacterial infection, stronger blood health markers including increased red and white blood cells, and less tissue damage compared to unsupplemented fish. The supplement reduced mortality following Edwardsiella tarda bacterial challenge, suggesting natural plant additives may enhance fish health in aquaculture settings.
Researchers tested whether a natural plant supplement called Bixa orellana leaf meal could help Amur carp fish grow better and resist disease. Over 90 days, fish fed increasing amounts of this plant supplement (up to 5%) showed better growth, stronger immune systems, and higher survival rates when exposed to a harmful bacteria called Edwardsiella tarda. According to Gram Research analysis, the fish receiving the highest dose of the supplement had the best health markers and lowest mortality rates after infection. This finding suggests natural plant supplements may boost fish health in aquaculture, though more research is needed to understand exactly how it works.
Key Statistics
A 2026 research study of 180 Amur carp found that fish receiving 5% Bixa orellana leaf meal supplementation showed significantly higher survival rates and improved growth performance compared to unsupplemented control fish following Edwardsiella tarda bacterial infection.
Fish receiving 5% Bixa orellana leaf meal had higher red blood cell counts, white blood cell counts, hemoglobin levels, and hematocrit values compared to control fish, indicating stronger immune function and better oxygen-carrying capacity.
Fish in the control group (no supplement) had the highest glucose and cortisol stress markers, while supplemented fish showed lower stress indicators and higher protective blood proteins including albumin and globulin.
Histopathological examination revealed that fish receiving Bixa orellana leaf meal supplementation experienced significantly less tissue damage to gills, liver, and intestines following bacterial challenge compared to unsupplemented fish.
The Quick Take
- What they studied: Whether adding a natural plant powder called Bixa orellana leaf meal to fish food could help Amur carp grow better and fight off bacterial infections
- Who participated: 180 young Amur carp fish (a type of carp used in fish farming) were divided into four groups and fed different amounts of the plant supplement for 90 days, then exposed to a harmful bacteria
- Key finding: Fish that received 5% Bixa orellana leaf meal in their food grew faster, had stronger immune systems, and survived better when infected with bacteria compared to fish that received no supplement
- What it means for you: This research suggests that natural plant supplements could help farmed fish stay healthier and grow better, potentially reducing the need for antibiotics in fish farming. However, this study was done in fish, so results may not apply to humans or other animals
The Research Details
Scientists divided 180 young Amur carp fish into four equal groups. One group received regular fish food with no supplement (the control group), while the other three groups received fish food mixed with increasing amounts of Bixa orellana leaf meal: 1%, 3%, and 5%. All fish ate this food for 90 days. After the feeding period, the researchers injected all fish with a harmful bacteria called Edwardsiella tarda to see how well each group could fight the infection. They then measured how many fish survived, checked their blood health markers, and examined tissue damage under a microscope.
This research design is important because it tests whether a natural supplement can improve both normal growth and disease resistance in fish. By measuring multiple health markers (growth, blood counts, protein levels, and tissue damage), the researchers could see exactly how the supplement affected fish health at different levels. This approach helps determine if the supplement is truly beneficial and at what dose it works best
The study used a clear control group for comparison, tested multiple dose levels to find the best amount, measured many different health markers, and examined tissue damage directly under a microscope. These are all signs of careful research. However, the study was conducted only in fish, so results may not apply to other animals or humans. The researchers did not mention whether they repeated the study or tested it in different conditions
What the Results Show
Fish that received the highest dose of Bixa orellana leaf meal (5%) showed the best results across almost all measurements. These fish gained more weight, grew faster, and had better feed conversion ratios, meaning they turned their food into body weight more efficiently. The survival rate was significantly higher in the treatment groups compared to the control group, with the 5% group showing the best survival after bacterial infection. Blood tests showed that fish receiving the supplement had higher counts of red and white blood cells, more hemoglobin (the protein that carries oxygen), and higher hematocrit levels (the percentage of blood that is red blood cells). These are all signs of a stronger immune system and better overall health.
Fish receiving the supplement also had higher levels of protective proteins in their blood, including total protein, globulin, and albumin. These proteins help fight infections and maintain body functions. Interestingly, fish in the control group (no supplement) had the highest glucose and cortisol levels, which are stress markers. High cortisol indicates the fish were under stress, while high glucose suggests their bodies were working harder to manage the infection. When researchers examined fish tissues under a microscope, they found that fish receiving the supplement had less damage to their gills, liver, and intestines after bacterial infection, showing that the supplement protected their organs
This study builds on earlier research showing that natural plant supplements can boost immune function in farmed fish. Previous studies have shown that various plant-based additives can improve growth and disease resistance, but this is one of the first to specifically test Bixa orellana leaf meal in Amur carp. The results are consistent with other research showing that natural supplements can reduce the need for antibiotics in fish farming while improving health outcomes
This study was conducted only in fish, so the results may not apply to humans or other animals. The researchers did not test whether the supplement works in different water temperatures or conditions, which could affect results in real fish farms. The study lasted only 90 days, so we do not know if the benefits continue over longer periods. The researchers did not explain the exact mechanisms of how the supplement works, only that it does. Additionally, the study did not compare this supplement to other treatments or antibiotics that are currently used in fish farming
The Bottom Line
Based on this research, fish farmers may consider adding 5% Bixa orellana leaf meal to fish food to improve growth and disease resistance. This recommendation has moderate confidence because the study showed clear benefits, but more research in different conditions and fish species would strengthen the evidence. Fish farmers should consult with aquaculture specialists before making changes to feeding programs
Fish farmers and aquaculture companies should pay attention to this research as a potential way to improve fish health and reduce antibiotic use. Pet fish owners may also be interested, though this supplement was tested in farmed fish, not ornamental fish. Consumers who care about how farmed fish are raised may appreciate research into natural alternatives to antibiotics. This research does not directly apply to human nutrition or health
Based on this study, improvements in fish growth and immune function appeared within the 90-day feeding period. Fish showed better survival rates within 14 days of bacterial exposure. In a real fish farm, farmers would likely see benefits within 2 to 3 months of adding the supplement to feed
Frequently Asked Questions
Can Bixa orellana leaf meal help farmed fish grow faster and stay healthier?
Research shows that 5% Bixa orellana leaf meal supplementation improved growth performance, increased survival rates by 14 days post-infection, and strengthened immune markers in Amur carp. The supplement reduced tissue damage and stress indicators, suggesting it enhances both growth and disease resistance in farmed fish.
What are the health benefits of this plant supplement for fish?
The supplement increased red and white blood cell counts, hemoglobin levels, and protective blood proteins in fish. It also reduced stress hormones and glucose levels, indicating better overall health. Fish receiving the supplement had less organ damage when exposed to harmful bacteria.
Is 5% the best dose of Bixa orellana leaf meal for fish?
The 2026 study tested doses of 1%, 3%, and 5%, with 5% showing the best results across growth, immune function, and survival metrics. However, the optimal dose may vary depending on fish species, water conditions, and farm management practices.
Could this supplement reduce the need for antibiotics in fish farming?
The research suggests potential, as supplemented fish showed better disease resistance and lower mortality rates following bacterial infection. However, this study did not directly compare the supplement to antibiotics, so more research is needed to determine if it can fully replace antibiotic treatments.
How long does it take to see benefits from this supplement?
The study showed improved growth within the 90-day feeding period and better survival rates within 14 days of bacterial exposure. Fish farmers would likely observe benefits within 2 to 3 months of adding the supplement to regular feed.
Want to Apply This Research?
- For aquaculture professionals using a farm management app, track weekly weight gain, feed conversion ratio, and mortality rates for each fish group receiving different supplement doses. Record these metrics alongside water quality parameters and feeding dates to identify patterns
- Fish farm managers could implement a gradual transition to 5% Bixa orellana leaf meal supplementation over 2 weeks, monitoring fish behavior and appetite daily. Use the app to log any changes in feeding response, water clarity, or fish appearance to ensure the supplement integrates well with current farming practices
- Establish a baseline of current growth and mortality rates, then track these metrics weekly after introducing the supplement. Use the app to compare performance between control and treatment groups over 90 days. Record blood health markers (if testing is available) and tissue condition observations monthly to validate the supplement’s effectiveness in your specific farming conditions
This research was conducted in farmed fish and may not apply to humans, pets, or other animal species. The study tested one specific plant supplement in one fish species under controlled laboratory conditions. Results may differ in commercial fish farms with different water conditions, temperatures, or fish strains. Fish farmers should consult with aquaculture specialists and veterinarians before changing feeding programs. This information is for educational purposes and should not replace professional agricultural or veterinary advice. Always follow local regulations regarding fish farming practices and feed additives.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.