Researchers tested whether adding chestnut tannin extract to chicken feed could improve how well the birds digest their food and use fat for energy. They fed laying hens four different diets—some with chestnut extract and some without—and measured how well the chickens absorbed nutrients. The results were interesting: the chestnut extract helped chickens digest fat better when they ate a diet with soy oil, but didn’t help as much with a different type of fat. The extract also seemed to change how the chickens’ bodies processed fat at a cellular level. This suggests that chestnut extract might be useful in animal feed, but its benefits depend on what other ingredients are in the diet.

The Quick Take

  • What they studied: Whether adding chestnut tannin extract to chicken feed would help the birds digest nutrients better and change how their bodies use fat for energy.
  • Who participated: 36 laying hens (female chickens that produce eggs) divided into four groups. Each group ate a different diet: some with chestnut extract added and some without. The diets also differed in their fat sources—one used soy oil and the other used palm oil.
  • Key finding: Chestnut extract improved fat digestion in chickens eating soy oil-based feed, but this benefit didn’t happen with palm oil-based feed. The extract also appeared to change how the chickens’ bodies broke down and used fat at the cellular level.
  • What it means for you: While this research is about chickens, it suggests that chestnut extract might be a natural way to improve how animals digest food. However, the benefits seem to depend heavily on what other ingredients are in the diet, so it’s not a one-size-fits-all solution. More research is needed before this could be used in real farm settings.

The Research Details

Scientists created four different chicken feed recipes to test their hypothesis. Two base diets were made: one using corn, soybean meal, and soy oil (easier to digest), and another using wheat, rapeseed meal, and palm oil (harder to digest). Each base diet was then made in two versions—one with chestnut extract added and one without. This gave them four total feed types to test.

They fed these diets to 36 laying hens, with 9 hens eating each type of feed. The researchers then carefully measured how much of each nutrient the chickens absorbed, collected blood samples to check for changes in fat and antioxidant levels, and analyzed the chickens’ bile (digestive fluid) to see if the chestnut extract changed how their bodies processed fat.

By testing two different base diets, the researchers could see whether chestnut extract works the same way regardless of what else is in the feed. This is important because it helps explain why some natural supplements work well in some situations but not others. Understanding these interactions helps farmers and nutritionists make better decisions about what to feed animals.

This was a controlled experiment where researchers carefully managed all variables except the ones they were testing. The sample size of 36 hens is reasonable for this type of study. The researchers measured multiple outcomes (digestion, blood markers, bile composition, and cellular fat processing), which gives a more complete picture. However, this was a short-term study in a controlled setting, so results might differ in real farm conditions. The findings are preliminary and suggest areas for future research rather than providing definitive answers.

What the Results Show

When chestnut extract was added to the soy oil-based diet, chickens digested fat significantly better. However, when the same extract was added to the palm oil-based diet, there was no improvement in fat digestion. This shows that the chestnut extract’s effectiveness depends on what type of fat is in the diet.

Interestingly, while fat digestion improved in the soy oil group, the total energy the chickens got from their food actually decreased slightly when chestnut extract was added. This suggests the extract might have some trade-offs—it helps with fat digestion but may affect overall energy availability.

The researchers also found that chestnut extract didn’t change how well chickens digested protein, which is good news because protein is essential for egg production. At the cellular level, the extract appeared to increase how much fat the chickens’ cells were burning for energy, particularly in the soy oil group.

Blood tests showed that chickens eating the soy oil diet with chestnut extract had higher levels of free fatty acids and antioxidants, suggesting their bodies were actively processing more fat. However, this pattern reversed in chickens eating the palm oil diet with the extract. The researchers also found hints that chestnut extract might change the composition of bile salts (digestive chemicals), which could affect how fat is broken down and absorbed. These changes suggest the extract influences the bacteria living in the chicken’s digestive system.

Tannins from plants have long been considered problematic in animal feed because they can bind to proteins and make them harder to digest. However, this research supports a growing body of evidence suggesting that certain types of tannins, in small amounts, might actually be beneficial. The findings align with previous research showing that chestnut tannins have antioxidant and antimicrobial properties. This study adds new information by showing these benefits are diet-dependent and may work through changes in how the body processes fat.

This study was relatively short-term and conducted in a controlled laboratory setting, so results might differ in real farm environments. The sample size, while reasonable, was modest. The study only tested one dose of chestnut extract (500 mg per kilogram of feed), so we don’t know if higher or lower doses would work better. The research was done only in laying hens, so results might not apply to other types of chickens or animals. Finally, while the researchers measured many markers of fat metabolism, they didn’t directly measure egg production or quality, which would be important for practical farm applications.

The Bottom Line

Based on this research, chestnut extract shows promise as a potential feed additive for laying hens, particularly when combined with unsaturated fats like soy oil. However, these findings are preliminary and come from a controlled study. The recommendation level is ‘promising but needs more research.’ Before farmers use this in practice, larger studies in real farm settings are needed to confirm the benefits and determine the best dosage. The diet composition matters significantly—the extract works differently depending on the fat source used.

This research is most relevant to poultry farmers and animal nutritionists looking for natural ways to improve feed efficiency and animal health. Pet owners with backyard chickens might find this interesting but should wait for more practical guidance. People interested in natural animal agriculture and sustainable farming practices should pay attention to this research direction. However, this is not relevant to human nutrition at this stage—the research is specific to chickens.

If chestnut extract were to be used in chicken feed, any benefits to digestion and fat metabolism would likely occur within days to weeks, as these are relatively quick physiological processes. However, effects on egg production and quality would take longer to observe—typically several weeks to months. Any decision to use this in practice should wait for larger, longer-term studies in real farm conditions.

Want to Apply This Research?

  • For farmers or researchers: Track daily feed intake and measure fat digestibility markers weekly. Monitor egg production numbers, egg quality metrics (shell thickness, yolk color), and feed conversion ratios (how much feed produces how many eggs) over 4-8 week periods when testing chestnut extract supplementation.
  • For poultry farmers considering this: Start by testing chestnut extract in a small portion of your flock (10-15% of birds) while keeping detailed records of feed costs, feed consumption, egg production, and egg quality. Compare results between the test group and control group over at least 6-8 weeks before making larger changes.
  • Establish a baseline of current feed efficiency and egg production metrics. If implementing chestnut extract, monitor weekly: total feed consumed, number and weight of eggs produced, feed cost per dozen eggs, and any visible changes in bird health or behavior. Track these metrics for at least 8-12 weeks to see meaningful patterns, as short-term fluctuations can be misleading.

This research is preliminary and was conducted in controlled laboratory conditions with laying hens. The findings have not yet been tested in real farm settings or with other animal species. Before making any changes to animal feed or nutrition, consult with a veterinarian or animal nutritionist. This research is not applicable to human nutrition or health. The study was published in a peer-reviewed journal but represents early-stage research that requires further validation. Individual results may vary based on specific farm conditions, climate, management practices, and other variables not controlled in this study.