Polysaccharide Degradation in the Rumen and Large Intestine

Forsberg, Cecil W.; Cheng, K.-J.; White, Bryan A.

doi:10.1007/978-1-4615-4111-0_10

Cited by 90 publications

(85 citation statements)

References 249 publications

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“…So, we propose that whereas the previous evidence suggested that the most important organisms and gene sets for efficient hydrolysis of plant cell walls were associated with the fiber portion of the rumen digesta (15), there appears to be a dynamic process with initial colonization by one subset of organisms, which is probably later replaced by another subset of organisms that degrade the main chains of cellulose and xylan. Furthermore, when compared with the termite hindgut microbiome, there are fundamental differences in the GH content that appear to be diet driven for either the bovine rumen (forages and legumes) or the termite hindgut (wood).…”

Section: This Ismentioning

confidence: 71%

“…However, the complex chemical processes required to break down the plant cell wall are rarely carried out by a single species. Evidence also suggests that the most important organisms and gene sets involved in the most efficient hydrolysis of plant cell walls are associated with the fiber portion of the rumen digesta (15). Because we continue to investigate the community structure of the rumen, it is also clear that the system is not fully characterized with respect to the metabolic potential, especially as the system relates to plant cell wall degradation.…”

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confidence: 99%

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Gene-centric metagenomics of the fiber-adherent bovine rumen microbiome reveals forage specific glycoside hydrolases

Brulc

Antonopoulos

Miller

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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638

554

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The complex microbiome of the rumen functions as an effective system for the conversion of plant cell wall biomass to microbial protein, short chain fatty acids, and gases. As such, it provides a unique genetic resource for plant cell wall degrading microbial enzymes that could be used in the production of biofuels. The rumen and gastrointestinal tract harbor a dense and complex microbiome. To gain a greater understanding of the ecology and metabolic potential of this microbiome, we used comparative metagenomics (phylotype analysis and SEED subsystems-based annotations) to examine randomly sampled pyrosequence data from 3 fiber-adherent microbiomes and 1 pooled liquid sample (a mixture of the liquid microbiome fractions from the same bovine rumens). Even though the 3 animals were fed the same diet, the community structure, predicted phylotype, and metabolic potentials in the rumen were markedly different with respect to nutrient utilization. A comparison of the glycoside hydrolase and cellulosome functional genes revealed that in the rumen microbiome, initial colonization of fiber appears to be by organisms possessing enzymes that attack the easily available side chains of complex plant polysaccharides and not the more recalcitrant main chains, especially cellulose. Furthermore, when compared with the termite hindgut microbiome, there are fundamental differences in the glycoside hydrolase content that appear to be diet driven for either the bovine rumen (forages and legumes) or the termite hindgut (wood).CAZymes ͉ cellulases ͉ plant cell wall ͉ pyrosequencing H erbivores carry out a foregut fermentation that digests plant cell wall materials by a complex and efficient microbial process. The microbiome inhabiting the rumen is characterized by its high population density, wide diversity, and complexity of interactions. Bacteria predominate the rumen, with a variety of anaerobic protozoa and fungi (1), and the associated occurrence of bacteriophage is well documented (2). The use of small subunit (SSU) rRNA sequence analysis has allowed for a more complete description of the rumen microbiome and these inventories have demonstrated that a large microbial component remains uncultured (3)(4)(5)(6)(7)(8)(9)(10)(11)(12) and that a high proportion of the fibrolytic population has not been thoroughly described (7,8,13,14). The rumen habitat contains a consortium of microbes that harbor the complex lignocellulosic degradation system for the microbial attachment and digestion of plant biomass. However, the complex chemical processes required to break down the plant cell wall are rarely carried out by a single species. Evidence also suggests that the most important organisms and gene sets involved in the most efficient hydrolysis of plant cell walls are associated with the fiber portion of the rumen digesta (15). Because we continue to investigate the community structure of the rumen, it is also clear that the system is not fully characterized with respect to the metabolic potential, especially as the system relates to plant...

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Section: This Ismentioning

confidence: 71%

mentioning

confidence: 99%

Gene-centric metagenomics of the fiber-adherent bovine rumen microbiome reveals forage specific glycoside hydrolases

Brulc

Antonopoulos

Miller

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

638

554

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“…Addition of DF in vivo may stimulate the use of hydrogen during fermentation, and decrease the negative feed-back effect of hydrogen on microbes, which in turn improves the growth of fiber-degrading microorganisms. F. succinogenes, R. flavefaciens and R. albus are the representative cellulolytic species in the rumen (Forsberg et al, 1997). Moreover, several of them also might reduce fumarate.…”

Section: Discussionmentioning

confidence: 99%

Effects of disodium fumarate on ruminal fermentation and microbial communities in sheep fed on high-forage diets

Zhou

McSweeney

Wang

et al. 2012

Animal

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This study was conducted to investigate effects of disodium fumarate (DF) on fermentation characteristics and microbial populations in the rumen of Hu sheep fed on high-forage diets. Two complementary feeding trials were conducted. In Trial 1, six Hu sheep fitted with ruminal cannulae were randomly allocated to a 2 3 2 cross-over design involving dietary treatments of either 0 or 20 g DF daily. Total DNA was extracted from the fluid-and solid-associated rumen microbes, respectively. Numbers of 16S rDNA gene copies associated with rumen methanogens and bacteria, and 18S rDNA gene copies associated with rumen protozoa and fungi were measured using real-time PCR, and expressed as proportion of total rumen bacteria 16S rDNA. Ruminal pH decreased in the DF group compared with the control (P , 0.05). Total volatile fatty acids increased (P , 0.001), but butyrate decreased (P , 0.01). Addition of DF inhibited the growth of methanogens, protozoa, fungi and Ruminococcus flavefaciens in fluid samples. Both Ruminococcus albus and Butyrivibrio fibrisolvens populations increased (P , 0.001) in particle-associated samples. Trial 2 was conducted to investigate the adaptive response of rumen microbes to DF. Three cannulated sheep were fed on basal diet for 2 weeks and continuously for 4 weeks with supplementation of DF at a level of 20 g/day. Ruminal samples were collected every week to analyze fermentation parameters and microbial populations. No effects of DF were observed on pH, acetate and butyrate (P . 0.05). Populations of methanogens and R. flavefaciens decreased in the fluid samples (P , 0.001), whereas addition of DF stimulated the population of solid-associated Fibrobacter succinogenes. Population of R. albus increased in the 2nd to 4th week in fluid-associated samples and was threefold higher in the 4th week than control week in solid samples. Analysis of denaturing gradient gel electrophoresis fingerprints revealed that there were significant changes in rumen microbiota after adding DF. Ten of 15 clone sequences from cut-out bands appearing in both the 2nd and the 4th week were 94% to 100% similar to Prevotella-like bacteria, and four sequences showed 95% to 98% similarity to Selenomonas dianae. Another 15 sequences were obtained from bands, which appeared in the 4th week only. Thirteen of these 15 sequences showed 95% to 99% similarity to Clostridium sp., and the other two showed 95% and 100% similarity to Ruminococcus sp. In summary, the microorganisms positively responding to DF addition were the cellulolytic bacteria, R. albus, F. succinogenes and B. fibrisolvens as well as proteolytic bacteria, B. fibrisolvens, P. ruminicola and Clostridium sp.

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“…Eventually, other fumaratereducing bacteria also might have been stimulated by DF under the high-forage diet. F. succinogenes, Ruminococus albus and R. flavefaciens have been recognized as the major fibrolytic bacterial species in the rumen (Forsberg et al, 1997), and the increase in cellulolytic bacteria abundance may lead to an improvement in fiber digestion in ruminants. The present study through quantitative PCR assays showed that the abundance of R. flavefaciens and F. succinogenes was not affected by 15.4 g/kg DM DF supplementation.…”

Section: Discussionmentioning

confidence: 99%

Effect of disodium fumarate on microbial abundance, ruminal fermentation and methane emission in goats under different forage : concentrate ratios

Yang

Mao

Long

et al. 2012

Animal

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This study investigated the effects of disodium fumarate (DF) on methane emission, ruminal fermentation and microbial abundance in goats under different forage (F) : concentrate (C) ratios and fed according to maintenance requirements. Four ruminally fistulated, castrated male goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments and the main factors being the F : C ratios (41 : 59 or 58 : 42) and DF supplementation (0 or 10 g/day). DF reduced methane production (P< 0.05) on average by 11.9%, irrespective of the F : C ratio. The concentrations of total volatile fatty acids, acetate and propionate were greater in the rumen of goats supplemented with DF (P< 0.05), whereas the abundance of methanogens was lower (P< 0.05). In high-forage diets, the abundance ofSelenomonas ruminantium, a fumarate-reducing bacterium, was greater in the rumen of goats supplemented with DF. The abundance of fungi, protozoa,Ruminococus flavefaciensandFibrobacter succinogeneswere not affected by the addition of DF. Variable F : C ratios affected the abundance of methanogens, fungi andR.flavefaciens(P< 0.05), but did not affect methane emission. The result implied that DF had a beneficial effect on thein vivorumen fermentation of the goats fed diets with different F : C ratios and that this effect were not a direct action on anaerobic fungi, protozoa and fibrolytic bacteria, the generally recognized fiber-degrading and hydrogen-producing microorganisms, but due to the stimulation of fumarate-reducing bacteria and the depression of methanogens.

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Polysaccharide Degradation in the Rumen and Large Intestine

Cited by 90 publications

References 249 publications

Gene-centric metagenomics of the fiber-adherent bovine rumen microbiome reveals forage specific glycoside hydrolases

Gene-centric metagenomics of the fiber-adherent bovine rumen microbiome reveals forage specific glycoside hydrolases

Effects of disodium fumarate on ruminal fermentation and microbial communities in sheep fed on high-forage diets

Effect of disodium fumarate on microbial abundance, ruminal fermentation and methane emission in goats under different forage : concentrate ratios

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