How Does Stress Impact the Animal Microbiome?

The Thanksgiving holiday is just around the corner, bringing travel plans, family gatherings, delicious meals, and plenty of excitement. Maybe you’re heading out of town and arranging care for your pet, or perhaps you’re hosting guests at home. The change in routine and busy holiday atmosphere can sometimes cause extra stress for the animals we love.

“Stress is defined as a disruption in homeostasis that elicits an adaptive physiological and behavioral response to restore” (1). Every person and animal experiences stress in life but not all stress is bad. Stressors can derive from physical, social, and/or environmental causes. In the veterinary setting, we see patients with separation anxiety, thunderstorm/noise phobia, and travel phobias to name a few. While these examples may not evoke a strong stress response for humans, they can certainly impact our pets.  

Change = Stress

The Thanksgiving season can be a busy time, filled with travel, visiting family and friends, and lively gatherings, all of which can elicit stress in animals not well adapted to it. Some clinical signs associated with stress include hiding and self-isolation, over-grooming, urinating outside of the litter box, pacing and panting, changes in appetite, and gastrointestinal issues. In veterinary medicine, we use a variety of different methods to attempt to manage stress in our patients. Establishing a routine and allowing our pets to have a “safe” space in the house to retreat to can be helpful. Depending on the situation, anxiety medications and some natural supplements are the best options for helping to reduce anxiety and promote calmness. For chronic situations, it can be beneficial to consult with a trainer to develop a behavioral modification plan for the desensitization of certain triggers. 

The Gut Brain Axis

Did you know there is research growing in the field of gastrointestinal health which is finding that stress can modulate the microbiome?

The gut-brain axis, while not well understood, is bi-directional communication between the nervous, endocrine, and immune systems. Research supports evidence that the microbiota is a key component in this axis and can also affect stress responses in animals. Stress can modulate the microbiome community, contribute to dysbiosis, and cause stress-related behaviors such as anxiety and depression (2). A study in mice examined the effects of psychological distress on the microbiota by exposing the mice to chronic social defeat stress which caused a change in behavior, a reduction in the richness of the microbiome, and alterations to the nervous and immune systems (3)

There are several studies examining the benefits of supplements such as omega fatty acids, prebiotics, and probiotics on the gut-brain axis. A study in rats revealed that supplementation with the probiotic Lactobacillus helveticus N58 reduced levels of the stress hormone corticosterone and improved stress-associated behaviors (2). A recent pilot study assessed the effects of a nutraceutical supplement which included probiotics, prebiotics, natural anti-inflammatories, and L-theanine administered to dogs who displayed anxiety and stress-related behaviors. While it was a small study, it determined that the microbiome of the healthy control group and treatment group were significantly different at the beginning of the trial. While diet was not taken into consideration in this study, this finding does raise the question of whether the treatment group, the stress and anxiety group, had a different microbiota makeup due to the levels of stress. Dogs that received the supplement experienced changes in their microbiome compared to the control group as well as a reduction in stress-induced behaviors at the end of the trial.

As we prepare for the excitement of the Thanksgiving holiday, it’s important to also consider our pets and how the added activity, guests, and travel plans might affect them. Perhaps supplementation with a probiotic may benefit their overall gastrointestinal and immune health as well as their ability to adapt to stressors.