Adding 0.1% of an Astragalus and Codonopsis herbal blend to fish feed improved growth, digestion, immunity, and liver health in largemouth bass over 72 days. Higher doses of 0.2% reduced growth and survival, so the study suggests 0.1% works best. These results come from fish, not humans.
According to research reviewed by Gram, adding a small amount of a traditional Chinese herbal blend to fish feed may help farmed fish grow, digest food, and resist disease. In a 72-day study published in 2026 in the journal Aquaculture Nutrition, researchers fed young largemouth bass four levels of an extract made from two herbs used in traditional medicine, Astragalus mongholicus and Codonopsis pilosula. Fish receiving 0.1% of the blend grew faster, digested their food better, and had stronger immune responses. Their livers looked healthier, and they showed less cell damage from oxidation. They also survived better when exposed to a harmful bacterium. Fish given the highest dose, 0.2%, did worse than the others, showing that more is not always better. Because the study was done on fish, it does not directly show benefits for people.
Key Statistics
A 2026 study published in Aquaculture Nutrition found that largemouth bass fed 0.1% of a herbal blend made from Astragalus mongholicus and Codonopsis pilosula for 72 days grew better and digested food more efficiently than fish on a standard diet.
In the same 2026 study, largemouth bass given 0.2% of the herbal blend showed weaker growth and lower survival after a bacterial challenge than fish given 0.1%, suggesting that higher doses may be less effective.
The Quick Take
- What they studied: Scientists wanted to know whether adding a blend of two traditional Chinese herbs to fish feed could improve how young largemouth bass grow, digest food, fight infection, and process fat.
- Who participated: Young largemouth bass, a popular freshwater fish, that started the study weighing about 10.33 grams each. The abstract does not state how many fish took part. The fish were divided into groups fed diets with 0%, 0.05%, 0.1%, or 0.2% of the herbal blend.
- Key finding: Fish fed 0.1% of the herbal blend for 72 days grew better, digested food more efficiently, had stronger immune responses, and survived a bacterial challenge better than fish on a standard diet. Fish given 0.2% did worse on growth and survival than the 0.1% group.
- What it means for you: The results suggest that a small, carefully measured amount of this herbal blend may help farmed fish stay healthy. This study was done on fish only, so it does not show that herbal supplements will help people. Anyone considering herbal supplements for their own health should talk with a doctor first.
The Research Details
The researchers used a controlled feeding experiment. Young largemouth bass were placed into groups and each group ate feed containing a different amount of an herbal extract mixture, called QSY in the study. One group ate standard feed with no herbal blend, which served as the comparison. The other groups received 0.05%, 0.1%, or 0.2% of the blend mixed into their food. The fish were fed this way for 72 days.
During the study, the team tracked how much the fish weighed and grew, how well they turned food into body mass, and how well they digested nutrients. At the end, they looked at the fish’s intestines, which are where food is absorbed. They measured the height and width of the tiny finger-like folds lining the intestine, along with digestive enzyme activity. They also measured signs of immune strength and antioxidant activity in the liver, intestine, and blood. Antioxidants are substances that help protect cells from damage.
To test disease resistance, the researchers exposed the fish to Aeromonas veronii, a bacterium that causes disease in fish, and counted how many survived. They also examined liver tissue and measured how much fat built up in the liver. Using several groups with different doses makes it possible to see whether results change with the amount given, which is a strength of this design.
Comparing several doses against a control group helps show whether the herbal blend itself causes the changes, rather than something else in the environment. Testing growth, gut health, immunity, liver health, and survival in the same experiment gives a broader picture of how the supplement works, not just whether fish got bigger. Measuring the fish’s response to a real bacterial challenge also shows whether the benefits apply in a setting closer to real fish farms.
The study used a comparison group and several dose levels, and it measured many outcomes with laboratory methods, which are useful strengths. It was published in a peer-reviewed journal, meaning other scientists checked the work before publication. However, the abstract does not state how many fish were in each group, so it is hard to judge how strong the statistics are. The study was also done in a single species under controlled laboratory conditions, so results may differ on real farms or in other fish species. Readers should consider this an early, promising result rather than a final answer.
What the Results Show
The main result was that the 0.1% dose improved growth and feed use in young largemouth bass. Compared with fish on the standard diet, these fish grew better and turned their food into body weight more efficiently. They also absorbed nutrients from their food better, which means more of what they ate was put to use by the body.
The 0.1% dose also improved the intestine. The tiny folds lining the gut became taller and wider, and the gut wall was thicker. Taller folds generally mean more surface area for absorbing nutrients. The fish also showed higher activity of trypsin, a digestive enzyme that helps break down protein. Together, these changes suggest that the herbal blend helped the digestive system work better.
The 0.1% dose also appeared to strengthen the immune system. Fish given this amount showed higher activity of immune-related enzymes and produced more anti-inflammatory signals, which help calm excessive inflammation. When these fish were exposed to Aeromonas veronii, a harmful bacterium, more of them survived than fish on the standard diet. This suggests the blend may help fish resist infection.
Finally, the researchers found signs that the herbal blend acted on the body’s natural defense against oxidative stress, which is cell damage caused by unstable molecules. The 0.1% dose appeared to activate a built-in protective pathway called Nrf2-Keap1, which boosted antioxidant enzymes in the liver, intestine, and blood. The fish also had less liver damage and lower levels of lipid peroxidation, a type of fat damage in tissues. The 0.1% dose further reduced fat buildup in the liver by encouraging the burning of fatty acids for energy while slowing the creation of new fat.
The study found that the highest dose, 0.2%, did not work as well as 0.1%. Fish on this dose showed weaker growth and lower survival after the bacterial challenge than fish on the 0.1% dose. This suggests that adding more of the herbal blend does not automatically bring more benefit and may even be counterproductive.
The 0.1% dose also appeared to support liver health more broadly. Reduced liver damage and less fat buildup suggest the blend may help prevent the fatty liver problems that can occur when fish are fed rich diets. Keeping the liver working well is important for fish health and growth, because the liver plays a central role in processing nutrients and fighting stress.
Astragalus and Codonopsis have a long history of use in traditional Chinese medicine, where they are often described as supporting energy, digestion, and immune function. Earlier animal research has explored similar claims, and many studies on herbal additives in fish feed have reported improved growth and immune responses. This study adds to that work by testing a specific blend in largemouth bass and measuring many outcomes together, including gut structure, antioxidant pathways, and survival after infection. Still, findings from one species and one study are not enough to confirm the benefits across all fish farming settings.
The abstract does not state the number of fish used, which makes it harder to judge how reliable the statistical results are. The study lasted 72 days, so it does not show whether benefits last longer or whether there are effects over a full fish-farming cycle. It was conducted on one fish species, young largemouth bass, so results may not apply to adult fish or other species. The fish were kept under controlled laboratory conditions, which may differ from commercial farms with different water quality, stress levels, and feeding practices. The study also did not test whether eating fish raised on this feed affects human health, and it did not examine possible side effects of long-term use.
The Bottom Line
Research shows that 0.1% of this herbal blend improved growth, digestion, immunity, and liver health in largemouth bass over a 72-day feeding period. Confidence in these fish-specific results is moderate, since the findings come from a single study. Confidence that the same benefits apply to humans is low, because no human research was included. Aquaculture professionals may consider testing the 0.1% level on a small scale before using it widely, and should avoid the higher 0.2% dose based on this study.
Fish farmers, aquaculture researchers, and feed companies may find these results useful when deciding whether to test herbal feed additives. Anyone who raises largemouth bass or similar fish may also find the study interesting. People looking for herbal health products for themselves should not apply these findings directly, since the study did not test human outcomes. Those with health conditions or who take medications should speak with a doctor before using any herbal supplement.
In this study, the benefits were measured after 72 days of feeding. Fish farmers may begin to see changes in growth and feed efficiency within a few months of consistent use, based on this timeline. Improvements in disease resistance and liver health would need careful testing on real farms before anyone can predict how quickly they appear. Results could vary depending on fish size, water conditions, and feeding routines.
Frequently Asked Questions
Can herbal additives in fish feed help fish grow faster?
A 2026 study found that largemouth bass fed 0.1% of an Astragalus and Codonopsis herbal blend for 72 days grew better and turned food into body weight more efficiently than fish on standard feed. The findings apply to fish, and the study did not test other species.
What is Astragalus mongholicus used for?
Astragalus mongholicus is a plant used in traditional Chinese medicine, where it is often associated with supporting energy and immune function. In the 2026 fish study, it was combined with Codonopsis pilosula, and the blend was tested in largemouth bass feed rather than in human health research.
Do herbal supplements help fish fight off disease?
In a 2026 study, largemouth bass fed 0.1% of a herbal blend showed stronger immune enzyme activity and better survival after exposure to Aeromonas veronii, a harmful bacterium. Fish given 0.2% did not perform as well, so the study suggests the amount matters.
Is it safe for people to eat fish raised on herbal feed additives?
The 2026 study focused on how the herbal blend affected fish growth, gut health, immunity, and liver function. It did not measure effects on people who eat the fish, so no safety conclusion for human consumption can be drawn from this research alone.
Want to Apply This Research?
- If a user raises fish or uses this research for a fish-keeping project, they could record the amount of herbal additive added to each feeding as a percentage of total feed, along with the fish’s weight every two weeks. Tracking this data over 72 days would allow a direct comparison with the study timeline. Users could also log any signs of illness, such as lethargy or loss of appetite, to see whether changes line up with the supplement.
- Users who keep fish may choose to measure feed carefully and avoid adding more herbal supplement than recommended. Using a kitchen scale to weigh additives can help keep the amount close to 0.1% rather than guessing. For personal health, users should not use this research as a reason to start herbal supplements, and should instead discuss any supplement plans with a healthcare provider.
- A long-term approach would be to record monthly weight, feeding amounts, water quality readings, and any health notes in the app. Users could review these trends every three months to see whether growth and health are improving compared with previous periods. If a user changes the supplement amount, the app could mark the change date so results can be compared before and after. Users should also keep track of any new scientific updates, since this field is still developing.
This article summarizes a study on largemouth bass, a fish species, and does not provide medical or nutritional advice for people. The findings have not been tested for human health effects, and herbal products can interact with medications or health conditions. Consult a qualified healthcare provider before starting any supplement, and consult an aquaculture specialist before changing fish feed.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.