Probiotics are a class of active microorganisms that colonize the human body, altering the bacterial composition in a particular location for the host's benefit. Modulating the host mucosa's interaction with systemic immunity or balancing gut microbiota promotes nutrient absorption. It maintains gut health, generating beneficial effects through a single microorganism or a clearly defined mixed microbe.

Characteristics:
* Adhering to the epithelial cells of the host's intestinal mucosa.
* The ability to remove or reduce the adhesion of pathogenic bacteria.
* Capable of inhibiting pathogenic bacteria.
* Safety, without pathogenicity.

Category:
* Yeast: Current research has revealed that yeast possesses beneficial probiotic characteristics. It is commonly employed as a feed additive in livestock farming. Of the yeasts studied extensively, there are the Saccharomyces cerevisiae species (used in brewing), Debreuomyces thermophilus (found in hot springs), Candida glabrata (commonly found in the gut), Wickerhamomyces anomalous (responsible for some wine spoilage), Pichia brasilensis (used in biofuel production), Blastocystis hongkongensis (an intestinal parasite), Schizosaccharomyces pombe (found in fruit), Rhodotorula rubra (known for its red color), Zymomonas mobilis (involved in biohydrogen production), and Candida utilise (employed in bioremediation).

* Clostridium butyricum: Butyric acid bacteria is an anaerobic Gram-positive spore-forming bacterium isolated from the intestines of healthy animals and humans. Current research has found that Clostridium butyricum has beneficial properties such as enhancing immune function, producing nutrients, preventing and treating enteritis, and maintaining intestinal flora balance.

* Lactic acid bacteria refers to a group of non-spore-forming, Gram-positive bacteria that produce lactic acid as the major sugar fermentation product.

* Bifidobacterium: a type of beneficial bacteria that exists in the human body, and it is the most important and researched one among the probiotics in the human body, closely related to human health.

Function:
Probiotics can stimulate the secretion of digestive enzymes in the animal body, participate in the digestion of nutrients in the intestines, reduce the depth of intestinal crypts, increase villus height, promote the absorption of intestinal nutrients, and increase the surface area of the small intestine.

* The structure of probiotics themselves, such as lipoteichoic acid, peptidoglycan, and other components, can act as antigens to directly activate the immune system or stimulate the host immune system through the secretion of immunostimulants, thereby enhancing the animal's immunity. This can activate dendritic cells, stimulate the production of cytokines in the body, and stimulate B cells to secrete antibodies and strengthen the activity of innate immune cells and natural killer cells.

* Maintaining the balance of gut microbiota structure:

* Improving meat quality:
Probiotics can affect fatty acid metabolism and improve muscle tenderness. They can also enhance muscle brightness by inhibiting lipid peroxidation and delaying the formation of high-iron hemoglobin.

* In the body, oxidants such as oxygen free radicals and hydroxyl free radicals contain unpaired electrons, prone to undergo oxidation-reduction reactions. When there is an excess of oxidants in the body, it can lead to oxidative damage. The body has antioxidant systems that continuously remove the oxidants produced, maintaining a dynamic balance of oxidants.

* Probiotics can release intestinal mucosal permeability, thus protecting the integrity of the intestinal mucosal barrier.

* Aquaculture water quality regulation:
Probiotics participate in various cycling processes in water, consume organic matter in water through their metabolism, and reduce the concentrations of nitrite nitrogen and ammonia nitrogen in water, improving and maintaining good water quality.

Target Audience:
1. Infants who are artificially fed and have low immunity are more susceptible to fevers and intestinal diseases: premature infants, low birth weight infants, and infants born by cesarean section.
2. Patients with intestinal inflammation.
3. As intestinal function gradually declines in middle-aged and older adults, probiotics such as bifidobacteria in the intestines decrease with age. Supplementing probiotics appropriately is an essential health measure.
4. Individuals with congenital lactase deficiency may experience bloating and diarrhea when lactose is not broken down due to the lack of lactase. Supplementing with probiotics can be beneficial in such cases.
5. Cancer patients undergoing chemotherapy or radiation therapy may experience imbalances in their gut microbiota due to the susceptibility of probiotics to chemotherapy drugs. Therefore, patients receiving chemotherapy or radiation therapy should actively supplement probiotics.
6. For patients with peritonitis and cirrhosis, it can inhibit the putrefactive bacteria in the intestine, lower the acidity in the intestine, and reduce the content of endotoxins in the blood.

Notice:
1. Only scientifically and reasonably using probiotics can it truly benefit the balance of the human microbiota, promote human health, and enhance immune function.
2. Research shows that an adult human body contains approximately 1.5 kilograms of bacteria. Among these bacteria, the majority are 'peaceful' bacteria that do not impact the human body. Only a few are pathogenic bacteria, while another consists of beneficial 'probiotic' bacteria.The human microbiota should be maintained in a balanced state, so more probiotics are not necessarily better.
3. Excessive intake and supplementation of probiotics may not only have positive effects on the human body but may also lead to excessive burden on the organs, resulting in serious adverse effects and severely disrupting the intestinal environment.
4. When it comes to probiotic supplementation, people should focus on consuming foods that contain probiotics in moderation, rather than relying too much on probiotic supplements.