Researchers studied whether special foods containing helpful bacteria could reduce depression-like symptoms in young chickens. They found that chicks eating a diet with prebiotics and probiotics (special foods that feed good gut bacteria) showed fewer signs of depression when stressed. However, when these chicks were also given ketamine, a powerful depression medication, the results were confusing—the medication didn’t work the same way. This suggests that taking gut-health supplements while using ketamine might not be a good combination, and doctors need to study this more carefully before recommending them together.

The Quick Take

  • What they studied: Whether eating foods with prebiotics and probiotics (good bacteria and their food) could help reduce depression-like behaviors, and how these foods might interact with ketamine, a strong depression medication
  • Who participated: Young Black Australorp chickens (a type of farm chicken) that were raised together socially, split into groups eating either regular food or special food with prebiotics and probiotics
  • Key finding: Chickens eating the special prebiotic and probiotic diet showed fewer signs of depression when stressed compared to chickens eating regular food. However, when given ketamine, the medication worked differently in chickens on the special diet—it actually reduced the depression-like behavior instead of increasing it like in the regular diet group
  • What it means for you: If you’re considering taking prebiotic or probiotic supplements while using ketamine for depression, talk to your doctor first. This early research suggests they might interfere with each other, though much more research in humans is needed before we know for sure

The Research Details

Scientists used young chickens as a model to study depression because chickens show stress responses similar to humans. They divided the chickens into two groups: one ate regular chicken feed, and the other ate feed mixed with prebiotics (food for good bacteria) and probiotics (actual good bacteria). After one week, they separated the chicks from their group for 90 minutes, which causes them to make distress calls—a sign of stress and depression-like behavior. The researchers recorded how many distress calls each chick made during this stressful time.

Some chicks also received ketamine, a medication sometimes used to treat severe depression in humans, while others received a salt-water solution (placebo) as a control. The researchers gave the chicks different doses of ketamine to see how it affected their stress response. They measured the distress calls during two phases: an early panic-like phase and a later depression-like phase.

Using animals to study depression helps scientists understand how the gut bacteria might affect mood and how medications work before testing in humans. Chickens are useful because their stress responses have similarities to human depression. This approach allows researchers to control conditions carefully and test combinations that might be risky to test in people first.

This is an early-stage animal study, which means the findings are preliminary and shouldn’t be directly applied to humans yet. The sample size was small (about 24 chicks total), which means the results might not be as reliable as larger studies. The study was well-designed with clear measurements (counting distress calls) and proper control groups, which strengthens the findings. However, animal studies don’t always translate directly to how humans would respond, so human research is needed to confirm these results.

What the Results Show

Chicks that ate the special prebiotic and probiotic diet showed significantly fewer distress calls during the depression-like phase compared to chicks eating regular food. This suggests the special diet had an antidepressant-like effect, meaning it helped reduce depression-like behavior.

When chicks on regular food received ketamine at the higher dose (10 mg/kg), they made more distress calls during the depression-like phase, which is the opposite of what you’d expect from an antidepressant. However, in chicks eating the special prebiotic and probiotic diet, both doses of ketamine actually reduced distress calls during the depression-like phase—the opposite of what happened in the regular diet group.

This unexpected difference suggests that the prebiotic and probiotic diet may interfere with how ketamine works in the body. The special diet seemed to produce antidepressant-like effects on its own, but when combined with ketamine, the results were contradictory and confusing.

The study didn’t report major secondary findings, but the researchers noted that the interaction between the synbiotic diet and ketamine was particularly surprising and warrants further investigation. The fact that ketamine’s effects were reversed in the synbiotic diet group suggests a real biological interaction rather than a chance finding.

Previous research has shown that prebiotics and probiotics can help reduce anxiety and depression-like symptoms in various animal models. This study confirms those findings but adds important new information: the combination of these gut-health supplements with ketamine may not work well together. Most previous studies looked at prebiotics and probiotics alone or with other medications, so this is one of the first to examine their interaction with ketamine specifically.

The biggest limitation is that this study used chickens, not humans, so we can’t be sure the results would be the same in people. The sample size was small, which means the findings might not be as reliable as larger studies. The study only lasted one week of diet treatment, so we don’t know if longer-term use would produce different results. The researchers didn’t measure actual gut bacteria changes, so we don’t know if the diet actually changed the chickens’ microbiota as intended. Finally, this is a single study, so the findings need to be repeated by other researchers before we can be confident in the results.

The Bottom Line

Based on this preliminary animal research, people currently taking or considering ketamine for depression should consult with their doctor before starting prebiotic or probiotic supplements. The evidence suggests a possible negative interaction, though human studies are needed to confirm this. If you’re interested in gut health, discuss with your healthcare provider which supplements are safe to use with your current medications. Confidence level: Low to Moderate (this is early-stage animal research)

This research is most relevant to people with treatment-resistant depression who are considering or currently using ketamine therapy. It’s also important for healthcare providers prescribing ketamine to be aware of potential interactions with gut-health supplements. People interested in using prebiotics and probiotics for general health should discuss any medications they’re taking with their doctor, but this research doesn’t suggest they need to avoid these supplements entirely—just be cautious about combining them with ketamine specifically

In this animal study, the prebiotic and probiotic diet showed effects after just one week of use. However, in humans, gut bacteria changes typically take 2-4 weeks to develop, and mood changes may take even longer. If you were to try this approach (with doctor approval), you’d likely need to wait at least 4-6 weeks to see any potential benefits. The interaction with ketamine, if it occurs in humans, might be noticeable more quickly, but this is unknown

Want to Apply This Research?

  • If working with a healthcare provider, track daily mood scores (1-10 scale) and any depression or anxiety symptoms for at least 4-6 weeks while monitoring prebiotic/probiotic use separately from any ketamine therapy. Note any changes in energy, sleep quality, and overall well-being
  • Users should log any prebiotic or probiotic supplements they’re taking, including the type, dose, and timing. If they’re also using ketamine or other depression medications, they should create a separate log for those medications and note any changes in how the medication seems to work. This data can help identify patterns and inform conversations with their healthcare provider
  • Establish a baseline of mood and depression symptoms before starting any new supplements or medications. Then track weekly for the first month, then bi-weekly for the next 2-3 months. If combining prebiotics/probiotics with ketamine, pay special attention to whether the medication seems more or less effective than before. Share this tracking data with your healthcare provider at regular check-ins to help guide treatment decisions

This research is preliminary animal-based evidence and should not be used to make decisions about your own mental health treatment without consulting a healthcare provider. If you are currently taking ketamine or considering it for depression, do not start, stop, or change any supplements or medications without first discussing it with your doctor. The findings from this chicken study may not apply to humans, and much more research is needed. This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.