Application and Research Progress of Probiotics in Companion Animals, Thesis of Public Health

Download Application and Research Progress of Probiotics in Companion Animals and more Thesis Public Health in PDF only on Docsity! 1 Application and research progress of probiotics in companion animals Clinical abuse of antibiotics in pets and unreasonable addition of antibiotics in diets will lead to drug resistance in pets, damage the structure of intestinal flora，and reduce body's immunity.Probiotics have functions of regulating intestinal health, improving body immunity, improving growth performance of young pets，enhancing the antioxidant capacity of body and so on.The paper reviews the application status and research progress of pet probiotics,in order to provide evidence for clinical application of probiotics in pets. The role of antibiotics in the treatment of pet diseases is obvious, but long-term and large- scale use of antibiotics will lead to drug resistance in pets, causing adverse reactions and toxic effects. Therefore, it is necessary to find safer and more efficient products to replace antibiotics in the prevention and treatment of pet diseases. Probiotics are a class of active microorganisms that can colonize animals, maintain a relative balance of flora in the gut, regulate the gut health of animals, and promote nutrient absorption. Probiotic products are excellent feed additives and are widely used in pet food and livestock and poultry feed. Probiotics are easy to obtain and have good palatability, and can be used as a substitute product for the treatment and prevention of various diseases. At present, the mechanism of action of pet probiotics in improving body health is not clear. This article reviews the types, mechanisms of action and applications of probiotics, and provides a reference for the application of probiotics in pet breeding. 1 Overview of probiotics At present, there are more than 90 kinds of common probiotics, including Bacillus, yeast and lactic acid bacteria, which have been widely used in the pet industry. 1.1 Bacillus Bacillus Bacillus is widely distributed and exists in water, air, soil and animal intestines, and has the characteristics of high temperature resistance, high pressure resistance, and rapid resurrection. In pet clinics, Bacillus subtilis, Bacillus cereus, Bacillus licheniformis and Bacillus megaterium are widely used. Bacillus can maintain intestinal balance, produce metabolites that nourish somatic cells, and inhibit the growth of harmful bacteria. Studies have shown that the addition of Bacillus subtilis C-3102 to dog food at a dose of 3.47x 108CFU/d can significantly improve the apparent digestibility of crude fat and nitrogen-free extracts in adult hunting dogs. Coagulobacter can promote the absorption of nutrients in dogs and maintain intestinal health. Studies have shown that Bacillus compound can significantly improve the apparent digestibility of dry matter and crude protein in adult Ragdoll cats, and reduce the rate of soft stools. 1.2 Lactic acid bacteria Lactic acid bacteria is a general term for bacteria that can use fermentable carbohydrates to produce a large amount of lactic acid, including Lactobacillus and Bifidobacterium. Studies have found that lactobacillus protease can decompose macromolecular proteins in food into some small molecular peptides and essential amino acids, which can be used by animals, thereby improving the digestibility of animals. Studies have shown that lactic acid bacteria can effectively improve the anti-stress ability of livestock and poultry, and prevent some diseases. Because of its immune modification, it can be made into a live vector vaccine to improve the immunity of animals. In a rabbit fracture surgery model, lactic acid bacteria can prevent infection after fracture surgery. 1.3 Yeast 2 Yeast is a simple and fast cultivation method. It is a single-celled fungus with tenacious vitality and can be used as a feed additive instead of antibiotics. Yeast enter the intestines of animals and can multiply rapidly and become the dominant population. Studies have found that yeast can significantly improve animal growth performance and effectively improve digestibility. Escherichia coli is the main cause of canine urinary tract infections, and yeast contains beta-glucan, which can reduce the number of Escherichia coli. 2. The mechanism of probiotics regulating intestinal flora 2.1 The theory of biological oxygen capture The intestinal tract of animals is sterile at birth, and various microorganisms colonize the intestinal tract several hours later. The intestinal flora is colonized sequentially by aerobic bacteria, facultative anaerobic bacteria and anaerobic bacteria on demand. Most of the former two are pathogenic microorganisms. When aerobic pathogenic microorganisms colonize and multiply in the intestinal tract, the oxygen in the intestinal tract is gradually exhausted, and anaerobic bacteria begin to grow and colonize, and the environment of the intestinal tract is gradually favorable for the growth of anaerobic bacteria. After the probiotics enter the intestinal tract, they quickly colonize, bringing the surrounding environment to a level suitable for the growth of anaerobic bacteria, the oxygen disappears, and the pathogenic microorganisms cannot reproduce, thereby promoting the restoration of the intestinal flora balance. 2.2 The theory of mucosal barrier immunity The intestinal mucosal barrier mainly includes physical barrier, chemical barrier, immune barrier and microbial barrier, which can resist the invasion of pathogenic microorganisms and is an important defense barrier for the body. After entering the intestinal tract of animals, probiotics compete with pathogenic microorganisms for the adhesion sites of intestinal epithelial cells, providing probiotics with a competitive advantage. Beneficial bacteria form a dense biofilm in the gut, form a microbial barrier, competitively reject pathogens, and maintain the balance of gut microecology. After adding 1.0 g/(kg BW·d) compound probiotics to the dog’s diet, it was found that the content of canine motilin and interleukin-10 (IL-10) were significantly increased, and the levels of tumor necrosis factor-α (TNF-α) were significantly increased. -α) levels are reduced, and the body’s inflammatory response is reduced. Studies have shown that probiotics can act on multi-protein structures, regulate intestinal epithelial goblet cells, Paneth cells and enteroendocrine cells, relieve animal stress, and maintain the immune function of animal bodies. 2.3 The Dominant Population Theory Under the condition of a healthy body, the beneficial and harmful flora in the intestinal tract of animals are in a state of relative balance. The increase of harmful flora can lead to increased permeability of intestinal endothelial cells, accompanied by bacterial translocation, and trigger a series of gastrointestinal diseases. After colonization of the intestine, probiotics can promote the increase in the number of beneficial bacteria, inhibit the reproduction of pathogenic microorganisms such as Escherichia coli, Salmonella, etc., and restore the intestinal balance. Bacillus produces acetic acid, propionic acid and other substances in the intestinal tract, which reduces the pH value of the intestinal tract, forms an acidic environment conducive to the growth and reproduction of beneficial bacteria, and maintains the balance of the intestinal tract. 3 Application progress of probiotics in pets