Nowadays we are aware that the gut microbiota is fundamental not only to our health, but also to the health of our pets. The gut plays a crucial role, being responsible for around 70% of the immune system. The intestinal mucosa acts as a barrier, preventing the entry of many bacteria that are harmful to the body and allowing nutrients from food to be absorbed. These foods are essential for the beneficial bacteria that make up the intestinal microbiota of dogs and cats, contributing to their metabolism. This microbiota, in turn, facilitates the digestion and absorption of nutrients and the production of compounds that influence animal health [7].
In addition to bacteria, the intestinal microbiome includes viruses and other eukaryotic organisms that live in the gastrointestinal tract in harmony with the host. For example, bacteria produce short-chain fatty acids that nourish the intestinal epithelium, while the epithelium, in turn, produces mucus that feeds these beneficial bacteria and protects the intestine. The intestinal microbiota fulfills various metabolic functions, helps protect against pathogens and modulates the immune system, directly or indirectly affecting many of the body's functions. To give you an idea, most serotonin, known as the "happiness hormone", is produced in the gut, which gave rise to the concept of the gut-brain axis [5].
When the intestinal microbiota becomes unbalanced, this can be associated with gastrointestinal problems. Inflammation in the gut, whether chronic or acute, is usually linked to significant changes in the composition of this microbiota. We call it intestinal dysbiosis when this imbalance leads to inflammation of the gut. Once inflamed, the intestinal mucosa becomes more permeable, allowing toxins, viruses, harmful bacteria and even fragments of undigested food to enter the bloodstream. When this happens, the immune system reacts, triggering a series of inflammatory processes that can lead to chronic, autoimmune diseases and allergies [7].
The main causes of intestinal dysbiosis include excessive use of antibiotics and anti-inflammatory drugs, prolonged periods of stress [7], low levels of vitamin D[1] and malnutrition [4]. As a result, inflammation can occur in the intestines and throughout the body, increasing ammonia levels, causing liver and kidney overload, increasing itching, digestive problems, malabsorption of nutrients and changes in the immune and neurological systems [8].
Since an imbalance in the microbiota can cause inflammation and affect the immune system, strategies to modulate it can be very useful in the treatment and prevention of various diseases.
Since an imbalance in the microbiota can cause inflammation and affect the immune system, strategies to modulate it can be very useful in the treatment and prevention of various diseases. There are various nutraceuticals and practices that help keep the gut healthy, starting with a balanced diet. In addition, probiotics, prebiotics and postbiotics play an important role in maintaining intestinal health. Today, we're going to talk a little about these three elements.
Probiotics are live microorganisms that, when administered in the correct quantities, bring health benefits. They act both in the lumen and on the intestinal mucosa, interacting with immune cells, enterocytes and other cells via cell receptors and other communication pathways. Probiotics help to strengthen immunity by increasing IgA production and improving the response to vaccines.
They are also important in modulating immunity, treating autoimmune diseases and allergies, as well as acting on the epithelial barrier and stimulating mucus production. They can help restore the epithelial barrier, protecting intestinal cells during inflammation, reducing permeability and decreasing the translocation of bacteria, as well as improving the digestion of nutrients [9].
Prebiotics, on the other hand, are non-digestible carbohydrates, mainly oligosaccharides, obtained from plant raw materials [6], which bring health benefits to the host. They are broken down by the intestinal microbiota, serving as food for beneficial bacteria. The products of this degradation are short-chain fatty acids, which enter the bloodstream and can benefit not only the gastrointestinal tract, but also other organs. The use of prebiotics offers several benefits, such as improving the composition of the intestinal microbiota, reducing toxic substances in the gut and optimizing the production of short-chain fatty acids [2].
In order to be effective, prebiotics need to resist digestion and reach the colon, where they selectively stimulate the growth and activity of microbial species that benefit the host. In addition, the effects of prebiotics can be enhanced when combined with specific probiotic strains, forming what we call symbiotics [6].
Another interesting concept is postbiotics, which are metabolites or components produced by the microbiota that have a positive impact on health. When prebiotics are ingested, they and fermented by gut bacteria and the bioactive postbiotics are the by-products of this fermentation process. Although many studies have already shown the advantages of postbiotics, we are still trying to understand exactly how they are produced and how they impact on health as a whole. Some examples include nutrients such as vitamin B12, vitamin K, folate and various amino acids produced by intestinal bacteria. Other examples are lipopolysaccharides, enzymes, short-chain fatty acids and bacterial lysates. Although the precise mechanisms are still being clarified, in vitro research indicates that have antibacterial, anti-inflammatory, immunomodulatory, antiproliferative and antioxidant properties [10].
In conclusion, the use of prebiotic, probiotic and postbiotic substances is an effective strategy for modulating the intestinal microbiota, improving intestinal health, immune function and, consequently, the general health of our pets.
REFERENCES:
1) CANTORNA, M.T. et al. Vitamin A and vitamin D regulate the microbial complexity, barrier function and the mucosal immune responses to insure intestinal homeostasis. Crit Rev Biochem Mol Biol. April, 2019; 54(2): 184–192. doi:10.1080/10409238.2019.1611734.
2) DAVANI-DAVARI, D. et al. Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications. Foods 2019, 8, 92; doi:10.3390/foods8030092.
3) HAWRELAK, J. A.; MYERS, S. The Causes of Intestinal Dysbiosis: A Review. Alternative Medicine Review, Volume 9, Number 2, 2004.
4) KUMAR, M. Gut Microbiota Dysbiosis is Associated with Malnutrition and Reduced Plasma Amino Acid Levels: Lessons from Genome-Scale Metabolic Modeling. Metab Eng. 2018 September ; 49: 128–142. doi:10.1016/j.ymben.2018.07.018.
5) PILLA, R.; SUCHODOLSKI, J.S. The Role of Canine Gut Microbiome and Metabolome in Health and Gastrointestinal Disease. Frontiers in Veterinary Science. V. 6, n. 498, Jan, 2020.
6) PINNA, C.; BIAGGI, G. The Utilisation of Prebiotics and Synbiotics in Dogs. Italian Journal of Animal Science, 13:1, 3107 (2014) DOI: 10.4081/ijas.2014.3107
7) WERNIMONT, S.M. et al. The Effects of Nutrition on the Gastrointestinal Microbiome of Cats and Dogs: Impact on Health and Disease. Front Microbiol. June, 2020; 11: 1266. doi: 10.3389/fmicb.2020.01266
8) WEISS, G. A.; HENNET, T. Mechanisms and consequences of intestinal dysbiosis. Cellular and Molecular Life Sciences (2017) 4(16):2959-2977. DOI: https://doi.org/10.1007/s00018-017-2509-x
9) WYNN, S. Probiotics in veterinary practice. Vet Med Today: Timely Topics in Nutrition JAVMA, Vol 234, No. 5, March 1, 2009.
10) THORAKKATTU, P. et al. Postbiotics: Current Trends in Food and Pharmaceutical Industry. Foods 2022, 11, 3094. https://doi.org/10.3390/foods11193094
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