Comparative Gut Microflora, Metabolic Challenges, and Potential Opportunities
Open Access
- 1 July 2005
- journal article
- research article
- Published by Elsevier BV in Journal of Applied Poultry Research
- Vol. 14 (2), 444-453
- https://doi.org/10.1093/japr/14.2.444
Abstract
Bacteria colonize practically every habitat in the nature. Bacterial community of the gastrointestinal tract (GIT) is one of the major metabolic tissues of animals. Still, its species composition is not known, because methods that have been previously used for bacterial analysis do not capture the species present. The bacterial community within the GIT not only has intracommunity interactions, but it also interacts with the host tissues. For the host, it is essential to tolerate commensal bacteria and to recognize and fight intestinal pathogens. In addition to recognized pathogens, there are many functional bacterial groups, which produce metabolites considered harmful for the host. Such functional bacterial groups include protein-fermenting bacteria that produce toxic end products in their amino acid metabolism, which is why a high-protein diet is often considered unhealthy. Carbohydrates are preferred substrates for gastrointestinal bacteria, but in the distal colon, they may become depleted, and putrefaction becomes the dominating type of fermentation. This largely accounts for the health effects of slowly fermenting dietary fibers. Microbial communities in the GIT of different animals have developed hand-in-hand with their digestion strategy. In monogastric animals, bacterial fermentation has concentrated in the lower GIT, whereas in ruminants bacteria are responsible for the initial digestion of the diet. Rumen-like sites with intense bacterial fermentation are found in most animals, but no other group of animals totally depends on bacteria. The response of rumen bacteria to feed components can be evaluated by an in vitro rumen simulation, which measures relevant fermentation parameters, such as the yield of bacterial biomass (protein) and volatile fatty acids (energy). In monogastric animals, it is essential that the host has measures to prevent bacterial competition for substrates in regions in which absorption takes place; the use of prophylactic antibiotics for production animals has aided this. Availability of good methods for monitoring the total bacterial communities and their metabolism is a prerequisite for informative studies in the future.Keywords
This publication has 25 references indexed in Scilit:
- Characteristics of the gastrointestinal microbial communities, with special reference to the chickenWorld's Poultry Science Journal, 2004
- Human milk is a source of lactic acid bacteria for the infant gutThe Journal of Pediatrics, 2003
- Diversity and Succession of the Intestinal Bacterial Community of the Maturing Broiler ChickenApplied and Environmental Microbiology, 2003
- Molecular Pathogenesis ofSalmonella entericaSerotype Typhimurium-Induced DiarrheaInfection and Immunity, 2003
- Culture-Independent Microbial Community Analysis Reveals that Inulin in the Diet Primarily Affects Previously Unknown Bacteria in the Mouse CecumApplied and Environmental Microbiology, 2002
- Percent G+C Profiling Accurately Reveals Diet-Related Differences in the Gastrointestinal Microbial Community of Broiler ChickensApplied and Environmental Microbiology, 2001
- Regulatory effects of bifidobacteria on the growth of other colonic bacteriaJournal of Applied Bacteriology, 1994
- Hatchery-Acquired Salmonellae in Broiler ChicksPoultry Science, 1994
- The control and consequences of bacterial fermentation in the human colonJournal of Applied Bacteriology, 1991
- The intestinal flora of the chicken in the period 2 to 6 weeks of age, with particular reference to the anaerobic bacteriaBritish Poultry Science, 1972