Reassessing the manipulation of protein synthesis by rumen microbes

Broudiscou, Laurent; Jouany, J.P.

doi:10.1051/rnd:19950505

Cited by 19 publications

(11 citation statements)

References 27 publications

(22 reference statements)

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“…The nucleic acid content of a cell also varies with the growth stage. Dormant or starving cells contain much less RNA than growing cells (Nierlich, 1978) and there is discussion about the use of RNA as a marker for microbial biomass (Broudiscou & Jouany, 1995;Robinson et al 1996). However, there are specific advantages of the use of intact ribosomal RNA as a microbial marker.…”

Section: Discussionmentioning

confidence: 99%

Supplementation of barley straw withSesbania pachycarpaleavesin vitro: effects on fermentation variables and rumen microbial population structure quantified by ribosomal RNA-targeted probes

Muetzel

2003

Br J Nutr

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Tropical livestock is often maintained on roughage-based diets deficient in N, and therefore requires supplementation with protein-rich substrates to achieve reasonable production levels. The optimum inclusion rate of a potential supplement is usually determined by in vivo feeding trials or by in vitro incubation of the diet components to estimate the feed value of the complete diet. The present work simulates a supplementation experiment in vitro, by incubating a pure roughage (barley straw), a pure supplement (Sesbania pachycarpa leaves) and mixtures of the two, with increasing inclusion levels of the supplement, in a short-term batch incubation system. Fermentation kinetics were followed by the release of fermentation endproducts (gas and short-chain fatty acids). Microbial biomass was estimated using ribosomal (r) RNA as internal marker for bacteria and eukaryotes separately. Cell-wall-degrading subpopulations were quantified by hybridisation with taxon-specific oligonucleotide probes targeting Chytridiomycetes, Fibrobacter spp., Ruminococcus albus and R. flavefaciens. Carboxymethylcellulase (CMCase) was assayed as an indicator for cell-wall-degrading activity. The addition of S. pachycarpa leaves stimulated fermentation in all cases. Gas production, and especially rRNA concentration, showed clear maxima at 40 % S. pachycarpa inclusion, rates that significantly exceeded the values interpolated from the incubations of the pure substrates. Short-chain fatty acid yield changed only slightly, but in the same way. The analysis of the microbial population structure showed that the positive effects were mainly mediated through enhanced growth of Ruminococcus spp. Increasing proportions of S. pachycarpa leaves in the diet led to a drastic decline in the total eukaryotic population. This points to a defaunation, which may also have added to the positive effects. The eukaryotic subpopulation of the rumen fungi were affected to a lesser degree. Although the cell-wall-degrading organisms showed positive responses to the supplementation, the CMCase activity was not affected significantly by the supplementation. The present work shows that it is possible to predict optimum inclusion levels for a new feed supplement in vitro and thus reduce in vivo experiments. It was also demonstrated that true supplementation effects occur particularly for the microbial biomass production, which is the primary source of amino acids for the ruminant animal. The analysis of microbial population structure in context with conventional metabolic measurements adds valuable information to interpret the observed effects on production-related variables.

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Section: Discussionmentioning

confidence: 99%

Supplementation of barley straw withSesbania pachycarpaleavesin vitro: effects on fermentation variables and rumen microbial population structure quantified by ribosomal RNA-targeted probes

Muetzel

2003

Br J Nutr

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“…Every day of incubation, cellobiose 0.225 mol L −1 , maltose 0.075 mol L −1 , caseine 12.5 g L −1 , (NH 4 ) 2 SO 4 2.36 g L −1 and (NH 4 )H 2 PO 4 19.17 g L −1 were solubilised in artificial saliva24 at pH 6.8. The resulting nutrient solution met the nutritional requirements of rumen micro‐organisms25, 26 by providing 1.2 mmol hexoses, 7 mg N and 1.25 mg S per tube. Fresh contents (300 g per fermenter) were anaerobically taken at 10:30 h from the six dual flow continuous culture fermenters, pooled according to EO exposure and filtered through a 250 µm mesh nylon gauze.…”

Section: Methodsmentioning

confidence: 99%

In vitrodegradation of 10 mono‐ and sesquiterpenes of plant origin by caprine rumen micro‐organisms

2007

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The extent of disappearance of 10 mono-and sesquiterpenes in presence of mixed rumen microorganisms has been measured in 24-h batch cultures. The molecules that were tested are frequently found in the plants consumed by ruminants in highland pastures (limonene, β-myrcene, β-ocimene, α-pinene, sabinene, γ -terpinene and thymol) or are potential markers of the diet (camphene, β-caryophyllene and α-copaene). All terpenes were tested at 2 µL mL −1 , except α-copaene and thymol, which were tested at 0.9 µL mL −1 and 2 mg mL −1 , respectively. Camphene and thymol were not degraded to a significant extent. The disappearance of part of β-caryophyllene, (−)-limonene and γ -terpinene could not be attributed to the direct action of rumen micro-organisms but rather than to an effect of the extracellular medium. In contrast, a third group of one sesquiterpene (α-copaene) and four monoterpenes (myrcene, β-ocimene, α-pinene and sabinene) was extensively degraded by rumen micro-organisms, at rates of 1.6, 4.5, 3.5, 4.8 and 5.4 µmol mL −1 inoculum day −1 , respectively. The preliminary exposure of rumen micro-organisms to a specific blend of essential oils compounds, containing mainly thymol, guajacol and limonene, increased the extent of disappearance of γ -terpinene only.

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“…MBP production in control, water and fat-soluble vitamins were 163 and 140 g/d, respectively thus, indicating B-complex vitamin supplementation improves rumen MBP production. 41 Antimicrobial chemicals: Effect of plant extracts like garlic and ginger extracts were found to have decreased the protozoa population resulting in a reduction of methane emission in the rumen and thus inhibiting methanogenesis and decrease rumen protein production. The other one is essential oils in the rumen which resulted in the reduction of protein and starch degradation, due to selective action on certain rumen microorganisms like Gram-positive bacteria due to the barrier of the cell wall structure not tolerating the inflow of the secondary metabolites.…”

Section: Chemical Factorsmentioning

confidence: 99%

Factors Affecting Rumen Microbial Protein Synthesis: A Review

Harun¹

2019

Vet Med Open J

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There is a diversified microbial ecosystem in the rumen for efficient utilization of diet by providing essential nutrient to their host. But there are different factors affecting rumen microbial protein synthesis which are physical factors, chemical factors, dietary factors, biological factors and endogenous factors. Among the details of factors, dietary factors and ruminal pH are the dominant factors influencing rumen microbial protein production. The effects of some dietary factors, on the amount and efficiency of microbial protein synthesis, are discussed in this review. Specifically, these factors include forage quality diets, level of feed and types of feed. It seemed that diets containing a mixture of forages and concentrates increase the efficiency of microbial protein synthesis because of an improved rumen environment for the growth of more diverse bacterial species. This review describes physical and chemical factors which include: pH and buffer system, oxygen concentration, rumen outflow rate and synchronized release of nitrogen and energy from the diet, a nitrogen compound, energy spilling, vitamins and minerals and antimicrobials chemicals, respectively. Age, species, physiological status, sex, and stress are among endogenous factors that mostly affect microbial protein synthesis of a ruminant. Bacteriophages, protozoa predation and bacterial lysis are biological factors affecting the efficiency of microbial protein synthesis. All these factors have a direct effect on the synthesis of microbial protein in the rumen. Therefore, the cumulative effects of the above factors are resulted in the depopulation of rumen microflora and finally reduction of animal product. So, improvement in quantitative aspect of microbial protein synthesis solves many problems from simple to complex so that, the quantitative aspect of rumen microbial biomass are invaluable for health and productivity of ruminants than qualitative aspect hence, maintain health rumen ecosystem means having healthy ruminant.

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Reassessing the manipulation of protein synthesis by rumen microbes

Cited by 19 publications

References 27 publications

Supplementation of barley straw withSesbania pachycarpaleavesin vitro: effects on fermentation variables and rumen microbial population structure quantified by ribosomal RNA-targeted probes

Supplementation of barley straw withSesbania pachycarpaleavesin vitro: effects on fermentation variables and rumen microbial population structure quantified by ribosomal RNA-targeted probes

In vitrodegradation of 10 mono‐ and sesquiterpenes of plant origin by caprine rumen micro‐organisms

Factors Affecting Rumen Microbial Protein Synthesis: A Review

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