IntroductionThe diet of ruminants is rich in fiber (it is made up of polymers, for example cellulose) and low in proteins. Nearly all animals and mammals lack the enzymes to metabolize cellulose. Only microorganisms possess enzymes that help ferment cellulose and other polysaccharides consumed by ruminants. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Microorganisms are in a symbiotic relationship with the host. Habitat of the rumenThe rumen, a special digestive organ that is home to billions of microorganisms including bacteria, protozoa and fungi that coexist. This habitat presents some conditions that favor the permanence of these microbes. Anatomy of the Rumen The characteristics of the rumen that maintain microorganisms are: A large rumen Anaerobic fermenter Warm, constant temperature (39℃) Narrow pH range (5.5 to 7.0 depends on diet and saliva production) Digestive system of ruminants is made up of 4 compartments:RumenReticulumOmasAbomasumDigestive mechanism: food passes through first from the esophagus to the reticulum and rumen then to the omasum and finally to the acidic abomasum. Among these compartments, the rumen is considered the main fermentation reservoir containing microorganisms. Rumen microbiota. Microorganisms are in a symbiotic relationship in the anoxic rumen. The microbiota is composed of bacteria, protozoa and fungi, at concentrations of 1010, 106 and 104 cells/ml respectively. . It is evident that the bacterial population is more abundant and any physicochemical changes are vulnerable to them. Rumen Bacteria The rumen contains a diverse general bacterium. Since ruminants are herbivores, cellulose is a major component of their diet, so the need to degrade cellulose is critical. Therefore, the presence of cellulose-degrading bacteria such as Fibrobacter succinogenes and Butyrivibrio fibrisolvens help break the β 1,4 glycosidic bonds of cellulose providing nutrition to the host. The ruminant intestine also contains amylolytic bacteria such as S. bovis that help break down starch. component of the host's diet. Furthermore, the rumen also contains important degrading bacteria such as lactate-degrading bacteria, pectin-degrading bacteria, etc. Total rumen bacteria help produce volatile fatty acids which are fermentation products that help maintain the biochemical pathways present in the rumen. his intestines. These abundant bacteria are digested in the acidic abomasum providing vital proteins and vitamins to the host. The abundance of ruminant bacteria depends on the diet followed by the ruminant. Ingested forage proteins and polysaccharides are degraded by proteolytic bacteria – Bacteroides amylophilus, Bacteroides rutminicola and Butyrivibrio fibrisolvens Lipids are converted to saturated fatty acids in the rumen by lipolytic bacteria. Examples: Megasphaera elsdenii, B. fibrisolvens. In addition to rumen bacteria, archaea or methanogens are also present. Carbon dioxide and hydrogen formed during fermentation are converted into methane by methanogens such as motile methanomicrobium, methanobrevibacter ruminantium, furthermore these microorganisms can degrade substrates containing methyl (CH3-) or acetyl (CH3OO-) groups, such as methanol and acetate. In addition to prokaryotes, there are protozoa and fungi (table 2). Both play a role in the metabolism of ingested food. Consequences All microorganisms in the rumen are interdependent on each other. The product of its own fermentation is metabolized by others. The composition or proportion of these microbes depends on the ruminant's diet. For example, if a ruminant is fed pectin-rich food from the previous food.