Behavioral changes resulting from microbiome restoration

The potential of Microbiome Restorative Therapy (MBRT) to positively affect behavior in companion animals. 

Evidence supporting the critical role of a well-functioning microbiome in the health of veterinary patients continues to grow. Research indicates that significant components
of the immune response originate in the gut,1-6 supporting the claim that disease conditions may arise from damage to the gut’s microbiome.7-13 Exposure to antibiotics and other medications, as well as environmental toxins and poor diets can alter the microbiome, weakening the immune system and setting the stage for gastrointestinal illness (GI) and allergies.14-18 The widespread use of hand sanitizers, bleaches, antimicrobials and chemicals such as pesticides, herbicides and preservatives, could contribute to the depleted numbers of microbes being found in human infants and pets.19-24 There is now growing evidence that such damage may be ameliorated by fecal transplantation, and this therapy, while still in its infancy, is increasingly being utilized in both human and animal medicine.25-34 Microbiome Restorative Therapy (MBRT) is a term this author coined in 2012 (as opposed to the customary term Fecal Microbiota Transplantation or FMT) to better describe what this therapy actually does — restore the microbiome.

Microbiome inoculation and rationale for MBRT

Mammalian transit through the birth canal at parturition results in microbial inoculation. This “vaginal gulp” occurs as the fetus emerges, bathed in vaginal fluid containing lactobacillus and other microbes. Recent research suggests that even prior to birth, fetuses ingest amniotic fluid, the individual’s first “meal” of microbes.35 Further microbial exposure takes place as the newborn nurses and later explores its environment. In the wild, baby animals crawl around in a dirt den while the mother regurgitates the food she has eaten to feed them or offers recently killed prey. This initial inoculation of the microbiome is the beginning of the individual’s immune system.

Individuals not receiving these microbiome inoculations as well as other healthy, normally-occurring environmental bacteria may lose immune strength due to deficient exposure.1-7 In humans, full-term C-section babies who do not get their initial inoculation from the birth canal benefit from an oral transfusion of their mother’s microbiome.36

In the case of animals, coprophagia may be a natural way for them to try to replenish their microbiomes. Giving them a healthy, balanced microbiome by transplantation can reset the gut flora and stop the coprophagia and eating of other undesirable things.37,38 Animals in the wild often eat particular plants and other substances that provide certain nutrients as well as diverse bacteria, an additional way to balance the microbiome.

Behavioral effects of MBRT

This author and her clinical colleagues have observed through years of working with MBRT that this therapy is beneficial not only for its physical healing qualities, but also for its effects on behavior, adding to the possible positive outcomes of fecal transplants in companion animals. We have witnessed in our veterinary clinic, or through client feedback, distinct behavioral and even personality changes in MBRT recipients. While we do not know why these behavioral changes occur, we posit that microbiome restoration appears to be at least partially responsible for this effect.

We have observed an added dimension of mental health and behavioral improvements within just a few hours or days of this novel treatment, and appreciate this as a significantly different consequence from the typical positive outcomes of other holistic treatments. A better understanding of the role the gut plays in emotional and psychological well-being is timely and necessary, and can inform the possibility of incorporating fecal transplants into behavioral therapeutic approaches for animals as well as humans.

A “One Health” approach

The “One Health” concept is a relevant paradigm from which to approach this issue. Published scientific and subjective accounts describe how some organ transplant recipients seem to suddenly take on emotions and characteristics unlike their own, but very similar to those of their donors.39-44 This effect has been documented in heart, lung, kidney, liver and other organ and body part transplant patients (although the most dramatic and long-lasting effects seem to occur with heart transplants)45,46

This intriguing side effect of organ transplants raises interesting questions regarding the nature and mechanisms of some kind of cellular memory that would generate such changes. Likewise, when we hear compelling subjective accounts of similar personality changes after fecal transplants in humans, this raises questions regarding the possible emotional and behavioral effects of MBRT in our animal patients. It is this author’s opinion that providing information on behavioral effects in humans as a result of fecal and organ
transplantation is an important segue to any discussion of analogous responses in other mammals who cannot explain in words what they are experiencing.

MBRT case studies

The following are brief observational accounts of behavior and personality changes in some of our patients, as well as a report from a client who experienced MBRT through her own medical team. Please note that in addition to MBRT treatments, each animal was provided with an overall integrative therapy approach that included several other holistic treatments. These combined treatment modalities appear to provide significant healing synergistic effects, so are deemed crucial in our treatment protocols. But it was only after receiving MBRT in particular that animals showed a marked change in their behaviors, usually occurring within hours to one or two days. 

1. An 11-year-old spayed calico cat, thin and fragile on physical examination, suffered from constant diarrhea for over 18 months, producing ten to 20 stools per day, following years of intermittent diarrhea treated with metronidazole. She frequently hid in the basement of her home, and was fearful of the family’s dog. Previous evaluations included extensive ultrasounds, blood work and fecal examinations.

Less than two days after MBRT, her stools were normal, and she could be found sitting confidently on the couch and playing with the dog. To have such a complete change in both her stool consistency and behavior after years of illness — and in less than 48 hours  following therapy — is very unusual, even in an animal treated with standard holistic care for inflammatory bowel disease. This cat continues to do well, has gained weight, and has had no further episodes of diarrhea.

2. An 18-month-old black Labrador had been raised and trained as an assistance animal. Unfortunately, as a puppy and even after extensive training that he otherwise responded favorably to, he was coprophagic and exhibited some anxiety. His behavior as an assistance animal was excellent, but eating his stool as soon as it dropped to the ground was unacceptable to the organization, so they sold the dog to a caring family. For over six months, his new family still could not break his habit of eating stools, and his anxiety remained. After a single MBRT treatment, his coprophagia ceased and his anxiety was no longer an issue.

3. A seven-year-old neutered Maine coon cat presented with a mangy coat from years of atopic dermatitis, previously treated with multiple courses of antibiotics, cyclosporine, antihistamines and steroids. Following MBRT from a oneyear-old Siamese male donor who had just been neutered, he not only started healing from his dermatitis but showed a much happier demeanor than before treatment. After subsequent MBRT treatments from the same donor, he started showing sexual behaviors not seen before. This case raises questions about the effects of fecal transplants from hormonally-charged donors.

4. A 35-year-old woman, a client of this author, suffered from an autoimmune disease with gut complications, and received three fecal transplants, each from a different donor, over a period of several weeks. The only identifying factors she knew about the donors were their ages and genders: an 11-year-old girl, a 25-year-old woman, and a healthy young man. With the young girl, she reported a dramatic change, feeling healthy, balanced and blissful. With the young woman, while she was physically improved, she felt no emotional changes. With the third, she reported sweating copiously with the strong body odor of a man, which she intensely disliked. She was also up all night feeling much stress, anxiety and upset. Upon inquiring, she learned that that the male donor was a bodybuilder who had just broken up with his girlfriend and was quite upset. Was the transplant responsible for these intense physical and emotional effects?

More questions than answers

At this stage in medical science, study of the microbiome creates more questions than answers. There are more than 100 trillion microbes in a healthy human being — microbes which originated about 3,000 million years ago. A large percentage of microbes are in the gut; however there are microbes in every organ system. Medical science does not currently understand the full significance of each of the microbiomes throughout the body. Is it the organ that runs the system, or the microbiome within the organ that directs the individual’s health?

What we do know from direct observation is that in the majority of our fecal transplant cases, the animals are livelier and happier and exhibit more vitality following MBRT. Researchers continue to appreciate the value of the microbiome and how it can influence neurotransmitters, serotonin growth factors, and many other aspects of cellular communication and survival.41 Research illuminating the connection between the gut and brain is finding that precursors to many enzymes and neurotransmitters are within the microbiome.35,47-49 How this brain/gut association is connected to actual behavioral outcomes following MBRT is an area for much-needed research. Through further observation as well as scientific research, we will uncover a better understanding of this primordial creation that is basic to all life.

For information on using MBRT in your practice, see IVC Journal (Fall 2014) or visit

Acknowledgements: Many thanks to Carvel Tiekert, DVM, Odette Suter, DVM, PJ Broadfoot, DVM, and Deborah Moore, PhD for their critiques and comments on an earlier version of this paper. Thanks also to my clients and their beloved pets for seeing the possible benefits of these procedures, and much appreciation to my own dogs and cat for their microbiome donations to others.


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