Intestinal microbiota

The chicken intestinal microbiota is composed principally of Gram-positive bacteria (Gong et al., 2002). The lactobacilli are predominant in the small intestine (with smaller numbers of streptococci and enterobacteria), whereas the caecal flora is composed mainly of anaerobes and fewer numbers of facultative bacteria. Predominant cultured flora of the ileum of chicken include Lactobacillus, Streptococcus, E. coli and Eubacterium, while Eubacterium and Bacteroides dominated the caecum flora. 

Brigidi P, Swennen E, Rizzello F, Bozzolasco M, Matteuzzi D Effect of rifaximin administration on the intestinal microbiota in patients with ulcerative colitis. J Chemother (Florence) 2002 14(3) 290-295. 

Clinical trial Multispecies probiotic supllementation alleviates the symptoms of irritable bowel syndrome and stabilizes intestinal microbiota. Aliment. Pharmacol. Ther. 27(1), 48-57. 

This chapter is focnsed on the influence of breastfeeding on the postnatal development of intestinal microbiota, the possibihties to mimic this fnnction with oligosaccharides of nonmilk origin, and the benefits regarding the postnatal development of the immrme system. 

Before birth, the infant is sterile. During vaginal delivery, the natural colonization of the infant starts with bacteria mainly from the vaginal and intestinal microbiota of the mother. For the further development of the intestinal microbiota of the infant, the diet plays an important role. During breastfeeding, the microbiota change within a short period to a flora dominated by bifidobacteria whereas the intestinal microbiota of infants fed formulas without prebiotics is characterized by a flora of a more adult type (12). 

Because there is a broad consensus that the intestinal microbiota plays an important physiological role for the host, many attempts have been made to influence the intestinal microbiota by dietary interventions. 

Short-chain fatty acids (SCFAs) are of considerable importance to the physiological effect of the intestinal microbiota. They are the fermentation product of bacteria in the colon and are therefore an important characteristic feature of the intestinal microbiota (60). Compared to formula-fed infants, the profile of SCFAs differs considerably from that of breastfed infants. On supplementing an infant formula... 

In summary, the experimental data as well as the results of clinical trials have proven that substances with a structure different from the structure of HMOS are able to influence the intestinal microbiota. The most extensively studied prebiotic... 

Due to the very complex composition of the intestinal microbiota and considering the great variety of structures found in HMOS, it is now plausible that mixtures of different oligosaccharide types and chain lengths, which are composed to meet the different metabolic requirements of the different bacteria, will have a better chance of mimicking the prebiotic effect of breastfeeding than individual compounds. 

V. Effect of Intestinal Microbiota on the Immune System Preclinical Studies... 

There is accumulating evidence that the interaction between the intestinal microbiota and the gut plays an important role for the postnatal development of the immune system. However, the interactions between the intestinal epithehal and immune cells and the different species of the intestinal microbiota are very complex and not fully understood. The complexity of these interactions is based on the fact that on the one hand the human defense system consists of several layers, for example, of mechanical and chemical barriers (first line of defence) as well as innate and adaptive immunity (67) all of which can be influenced by microbiota (68). 

In the same experiments, different classical fiber mixtures in a similar dose to the GOS/lcFOS mixture were tested. There was no effect of these fibers on the measured parameter of the immune system, indicating that different nondigestible carbohydrates react differently with respect to intestinal microbiota and immune function (71). 

In summary, the animal data allow the conclusion that prebiotics, like the mixture of GOS/lcFOS, modulate the immune system and provide a preventive effect with regard to the development of allergic diseases. This effect is mainly mediated by modulation of the intestinal microbiota. 

There is increasing evidence that the interaction between the intestinal microbiota and the intestinal epithelial and immune cells plays a key role in the postnatal development of the immune system. First studies with probiotics (74) and synbio-tics (40) demonstrate effects during infancy, and studies regarding the vaccination response in the elderly (75) indicate that the prebiotics might also influence the immune system. In particular, the animal experiments with prebiotics described above allow the hypothesis that prebiotics that are able to influence the composition of the entire intestinal microbiota toward microbiota found in breastfed infants might support the development of the immune system during infancy. 

Intestinal microbiota was measured using plating techniques. In the plasma samples, subsequently total immune globulins, cow s milk protein (CMP), and DTP-specific immune globuhns were measured. 

Reilly, P., O Doherty, J. V., Pierce, K. M., Callan, J. J., O Sullivan, J. T., and Sweeney, T. (2008). The effects of seaweed extract inclusion on gut morphology, selected intestinal microbiota, nutrient digestibility, volatile fatty acid concentrations and the immune status of... 

Prebiotics and probiotics are an area of growing scientific interest for the development and production of fnnctional foods. " The terms prebiotics and probiotics themselves reveal important implications for hnman health that may result from their use and that are related to the intestinal microbiota. In fact, the target organ of the action of these ingredients is the intestines, but indirectly the whole body is the real beneficiary of their effects. The function of prebiotics and probiotics is to promote the proliferation and the balance of the bacterial composition that constitutes the intestinal ecosystem. The intestinal microbiota is made of hundreds of different bacterial species, whose multiple metabolic activities affect the state of health of the host. 

As defined by Wang, an ingredient can be classified as prebiotic if (1) it is resistant to the digestion in the upper gut tract, (2) it can be fermented by intestinal microbiota, (3) it brings beneficial effects to the host health, (4) it selectively stimulates the activity of probiotics, and (5) it is stable to food processing treatments. 

De Los Reyes-Gavilan, C.G., and Ruas-Madiedo, P. (2015) Exopolysaccharides produced by lactic acid bacteria and bifidobacteria as fermentable substrates by the intestinal microbiota. Crit. Rev. Food Sci. Nutr, 56, 1440-1453. 

Hooper, L.V. and MacPherson, A.J. 2010. Immune Adaptations that Maintain Homeostasis with the Intestinal Microbiota. Nat Rev Immunol, 10 159-169. 

Yaron, S Shachar, D Abramas, L Riskin, A Bader, D Litmanovitz, 1 et al. Effect of High y5-Palmitate Content in Infant Formula on the Intestinal Microbiota of Term Infants. J Pediatr Gastroenterol Nutr, 2013 56(4) 376-81. 

Yaron, S., D. Shachar, L. Abramas, A. Riskin, D. Bader, 1. Litmanovitz, F. Bar-Yoseph, T. Cohen, L. Levi, Y. Lifshitz, R. Shamir and R. Shaoul (2013). "Effect of high beta-palmitate content in infant formula on the intestinal microbiota of term infants." J. Pediatr. Gastroenterol. Nutr. 56(4) 376-381. 

One of the early targets of probiotics has been the improvanent of the composition of the intestinal microbiota. From the above, it is obvious that criteria for improving intestinal microbiota composition are at present not clearly defined. Nevertheless, some options exist for improving intestinal microbiota. Keeping under control potential pathogens such as Clostridium difficile and Helicobacter pylori, which can be present in low numbers in the microbiota of asymptomatic healthy carriers, may be beneficial (see following text). Furthermore, although the composition of a healthy or normal microbiota is not known, it is assumed that the nuCTobiota a... 

In addition to the evidence on the impact on human immunity, evidence has accumulated during the past decade on the capability of the intestinal microbiota to participate in and also influence the metabolism of its human host. The effects of probiotics are still little studied in this area, but considering the global epidemic of obesity and metabolic diseases, this application holds huge possibilities if probiotic efficacy can be scientifically demonstrated and the epidemic of Western diseases ameliorated. 

---