Behavior
Gut-Brain Axis (GBA)
The gut has been called "the second brain". Research reveals that the enteric nervous system (ENS), a branch of the autonomic nervous system that is found in the GI tract, can communicate with, and function independently of the brain. The enteric nervous system of the gut is comprised of millions of neurons. The enteric nervous system can "think", "remember" and "learn" on its own accord.
Many researchers suggest that the enteric neurons have an important role to play in regulating behavior. We know that the enteric nervous system communicates with the brain via the vagus nerve. We also know that strains of intestinal bacteria have a powerful regulatory effect on the enteric neurons with hundreds of studies showing probiotics’ effect on behavior. These same bacterial colonies can induce behavior-modifying effects. This section will explore these studies in canine and other animal-relevant animal models.
How Training, Nutrition, and Environment affect Behavior.
We are learning that behavior is intricately dependent on a variety of aspects that affect the microbiome. We now know that there is a bidirectional relationship between the gut and brain via the vagus nerve. A stressful event can damage the diversity of the microbiome similar to a 2-week course of antibiotics. Nutrient deficiencies can create anxiety and behavior disorders and toxins, such as polysorbate 80 can increase aggression. Here we explore the many ways our dog’s behavior can be altered.
There is strong evidence for the gut-brain axis via the vagus nerve across animal models and human studies. We are just recently seeing evidence to support what many us of have known through working with rescue dogs and controlling nutrition. Our rescue has seen incredible results in dramatic behavior changes in reactive dogs by focusing on the microbiome. While there are specific bacteria associated with behavior issues, we focus on creating a diverse microbiome through a balanced, diverse, and rotated local diet and access to the natural regional species pool while minimizing microbiome monsters, such as antibiotics, pesticides, processed foods, and other microbiome disrupters.
Diverse microbiome: http://bit.ly/DiverseMicro
Canine Microbiome: http://bit.ly/dogbiome
Antibiotics: http://bit.ly/AntibioticsV
Dirt: http://bit.ly/DirtMV
"The findings, published today in PeerJ, stop short of saying the composition of a dog’s gut microbiome causes aggressiveness, or vice-versa – only that there are statistical associations between how an animal acts and the microbes it hosts."
https://today.oregonstate.edu/.../sample-rescued-dogs...
Kirchoff, Nicole S., Monique AR Udell, and Thomas J. Sharpton. "The gut microbiome correlates with conspecific aggression in a small population of rescued dogs (Canis familiaris)." PeerJ Preprints 6 (2018): e26990v1
Unfortunately, these are nutrients that are quite often deficient in unbalanced raw diets. Here, nutrients are shown to mediate behavior in dogs.
Niyyat, Marzieh Rahimi, Mohammad Azizzadeh, and Javad Khoshnegah. "Effect of Supplementation With Omega-3 Fatty Acids, Magnesium, and Zinc on Canine Behavioral Disorders: Results of a Pilot Study." Topics in companion animal medicine 33.4 (2018): 150-155.
From the article:
"In total, 48 dogs including 6 dogs without any behavior disorder (control group) and 42 dogs with at least one common behavioral disorder, namely excessive activity, inappropriate elimination, fearfulness, destructiveness and aggression towards unfamiliar people and dogs (test group), were given daily oral dose of gelatin capsules of fish oil supplements containing 330 mg EPA (eicosapentaenoic acid) and 480 mg DHA (docosahexaenoic acid). Moreover, all dogs received 12-15 mg/kg of magnesium citrate and 5 mg/kg of zinc sulfate. Data were obtained using a questionnaire that dog owners were invited to fill out two times before (Days 0 and 42) and two times after the supplement treatment period (Days 84 and 126). "
Gut-Brain Axis: Animal study shows that common food additives in human processed food and kibble may be linked to disrupted gut bacteria and increased anxiety. "Dietary emulsifiers carboxylmethylcellulose (CMC) and polysorbate 80 (P80) alter the composition of the intestinal microbiota and induce chronic low-grade inflammation, ultimately leading to metabolic dysregulations in mice (1). " Both P80 and CMC are acceptable emulsifiers found in many kibbles and processed treat products for companion animals. "[W]e know that inflammation triggers local immune cells to produce signaling molecules that can affect tissues in other places, including the brain. The gut also contains branches of the vagus nerve, which forms a direct information pathway to the brain (2)." -Prof. Geert de Vries
(1) https://www.nature.com/articles/s41598-018-36890-3
(2) https://www.medicalnewstoday.com/articles/324232.php?fbclid=IwAR384S3nyl_nURR_kFNabSFwRGxRPiZTzFOSNeDyh1e2mLXE75Oi4C80L_U
figure 3b
(2) of https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6591269/ "The Gut-Brain Axis in Neurodegenerative Diseases and Relevance of the Canine Model: A Review."
While this article is focused on using the canine model for human nuerodegenerative disease, it also shows a plethora of research supporting the Gut-Brain Axis (GBA), such as Canine Cognitive Dysfunction (CCD) and Alzheimer’s Disease (AD)
No doubt the interplay of bacteria within the terrain of the organism may have an influence on results beyond the isolated bacteria. Preliminary studies are interesting. See how we have been using l. reuteri in our CAD cases for years in a comment below.
Referenced Study:
Sgritta, Martina, et al. "Mechanisms Underlying Microbial-Mediated Changes in Social Behavior in Mouse Models of Autism Spectrum Disorder." Neuron (2018).
Poutahidis, Theofilos, et al. "Microbial symbionts accelerate wound healing via the neuropeptide hormone oxytocin." PloS one 8.10 (2013): e78898. A side note. We have been using L. Reuteri with canine atopic dermatitis (primarily females) due to health benefits that include accelerated fur regrowth. Levkovich, Tatiana, et al. "Probiotic bacteria induce a ‘glow of health’." PloS one 8.1 (2013): e53867.
Effects of a ketogenic diet on ADHD-like behavior in dogs with idiopathic epilepsy.
"These data support the supposition that dogs with IE may exhibit behaviors that resemble ADHD symptoms seen in humans and rodent models of epilepsy and that a MCTD [ketogenic medium-chain triglyceride diet] may be able to improve some of these behaviors, along with potentially anxiolytic effects."
Packer, Rowena MA, et al. "Effects of a ketogenic diet on ADHD-like behavior in dogs with idiopathic epilepsy." Epilepsy & Behavior 55 (2016): 62-68.
Original Research:
Closed access “Identification and characterization of a novel anti-inflammatory lipid isolated from Mycobacterium vaccae, a soil-derived bacterium with immunoregulatory and stress resilience properties”. David G. Smith, Roberta Martinelli, Gurdyal S. Besra, Petr A. Illarionov, Istvan Szatmari, Peter Brazda, Mary A. Allen, Wenqing Xu, Xiang Wang, László Nagy, Robin D. Dowell, Graham A. W. Rook, Laura Rosa Brunet, Christopher A. Lowry. Psychopharmacology. doi:10.1007/s00213-019-05253-9
https://neurosciencenews.com/dirt-fat-anxiety-14108/?fbclid=IwAR3bSDQEdijGnkAhTRHVLQSNgZZFOSLBdKP8Xu3wITmULUCtJIwudvEMG90
While probiotics alleviate anxiety symptoms, a diverse diet was found to be even more significant.
"Overall, 11 of the 21 studies showed a positive effect on anxiety symptoms by regulating intestinal microbiota, meaning that more than half (52%) of the studies showed this approach to be effective, although some studies that had used this approach did not find it worked.
Of the 14 studies that had used probiotics as the intervention, more than a third (36%) found them to be effective in reducing anxiety symptoms, while six of the remaining seven studies that had used non-probiotics as interventions found those to be effective -- a 86% rate of effectiveness."
Reference: Beibei Yang, Jinbao Wei, Peijun Ju, Jinghong Chen. Effects of regulating intestinal microbiota on anxiety symptoms: A systematic review. General Psychiatry, 2019; 32: e100056 DOI: 10. 1136/gpsych-2019-100056
Curcumin as effective as Prozac for Depression
In a randomized control human trial, curcumin is found to be as effective as Prozac in treating depression but without all the negative side effects. Side effects in dogs include diarrhea, nausea, panting, insomnia, shaking, weakness, even increased aggression and seizures.
“Curcumin is the main active component in the spice turmeric that has been used for centuries in Ayurvedic medicine to treat a variety of conditions, including anxiety and depressive disorders.”
Fluoxetine (generic Prozac) is often used in canines with anxiety and aggression disorders. Curcumin has also been shown to reduce anxiety symptoms. Of course, taking a systems biology approach that assesses the entire animal and its environment will bear more significant results in managing depressive and anxiety symptoms.
Mechanisms of action (MOA) of curcumin:
Increase Brain-derived neurotropic factor (BDNF): increases the protein that helps neurons make new nerve connections. Brain disorders are linked with low BDNF.
Increases dopamine: learning, memory, and motor system functions.
Increases serotonin: helps regulate mood, sleep learning ability, and memory
References:
https://pubmed.ncbi.nlm.nih.gov/23832433/
https://pubmed.ncbi.nlm.nih.gov/31185140/
https://link.springer.com/article/10.1007/s00213-008-1300-y
https://www.frontiersin.org/articles/10.3389/fpsyt.2020.572533/full
"Glyphosate-based- herbicide exposure affects gut microbiota, anxiety and depression-like behaviors in mice" Adding to our GBA (gut-brain axis) series, a 2018 study showed that glyphosate (GBH) the active ingredient in Monsanto's Round-up, can create anxiety behaviors in mice by altering the makeup of the microbiome. Diet is an integral part of our rescue's wellness program that goes well beyond meeting the minimal nutrient requirements for dogs set forth by accepted governing bodies that have little or no consideration to the paradigm shift brought about by the complex relationships within the microbiome. Both kibble and raw are subject to GBH contamination. See resources below on how to identify if your pet food is contaminated with glyphosate.
Original study: https://www.ncbi.nlm.nih.gov/pubmed/29635013
Excerpts from the study: "In the present study, repeated exposures to GBH affected the microbiota composition in exposed groups, which express at the same time anxiety and depression phenotype, with the absence of the Lactobacillus and Bacteroidetes bacteria. This result is consistent with previous work demonstrating that Lactobacillus phylum has shown psychoactive and neuroactive properties, by reducing anxiety and depression-like behaviors in healthy mice via the vagus nerve (Bravo et al., 2011)."
"Glyphosate, patented as an antimicrobial (Monsanto Technology LLC, 2010) has been shown to disrupt gut bacteria in animals, preferentially killing beneficial forms and causing an overgrowth of pathogens (Shehata et al., 2013). Nevertheless, it is important to highlight that a large array of crucial molecules with neuroactive functions are produced by microbes (Cryan and Dinan, 2012). Indeed, several neurotransmitters such as GABA, serotonin, catecholamines, and acetylcholine are produced by bacteria (Cenit et al., 2017).
Collectively, these data suggest that GBH-induced perturbation of gut microbiota might disturb the normal metabolism of neurotransmitters or related peripheral precursors in the gut, which could further interfere with normal gut-brain interactions."
"In this study, an exacerbation of anxiety and depression-like behaviors and significant perturbations in relative abundance and phylogenic diversity of gut microbiota in mice was induced by GBH exposure. Our findings may provide novel insights into the mechanism underlying GBH-induced health risk, particularly mood disorders."
Resources to glyphosate exposure in dog food:
https://www.facebook.com/PawsitivelyPrimal/photos/a.1263110090450459/2012982482129879/?type=3&theater https://petsandgmos.com/herbicide-glyphosate-found-in-pet-foods/ How to read prepackaged pet food: https://youtu.be/BbgBnGXJSgw https://petsandgmos.com/non-gmo-pet-foods-all-brands-2/
