Rumen microbes produce cellular protein inefficiently partly because they do not direct all ATP toward growth. They direct some ATP toward maintenance functions, as long-recognized, but they also direct ATP toward reserve carbohydrate synthesis and energy spilling (futile cycles that dissipate heat). Rumen microbes expend ATP by vacillating between (1) accumulation of reserve carbohydrate after feeding (during carbohydrate excess) and (2) mobilization of that carbohydrate thereafter (during carbohydrate limitation). Protozoa account for most accumulation of reserve carbohydrate, and in competition experiments, protozoa accumulated nearly 35-fold more reserve carbohydrate than bacteria. Some pure cultures of bacteria spill energy, but only recently have mixed rumen communities been recognized as capable of the same. When these communities were dosed glucose in vitro, energy spilling could account for nearly 40% of heat production. We suspect that cycling of glycogen (a major reserve carbohydrate) is a major mechanism of spilling; such cycling has already been observed in single-species cultures of protozoa and bacteria. Interconversions of short-chain fatty acids (SCFA) may also expend ATP and depress efficiency of microbial pro...Continue Reading
Factors affecting the uptake and metabolism of soluble carbohydrates by the rumen ciliate Dasytricha ruminantium isolated from ovine rumen contents by filtration
Bioenergetic aspects of aerobic growth of Klebsiella aerogenes NCTC 418 in carbon-limited and carbon-sufficient chemostat culture
Frothy feedlot bloat in cattle: production of extracellular polysaccharides and development of viscosity in cultures of Streptococcus bovis
Glucose toxicity and inability of Bacteroides ruminicola to regulate glucose transport and utilization
Interaction of ruminal bacteria in the production and utilization of maltooligosaccharides from starch
Futile cycling of glycogen in Fibrobacter succinogenes as shown by in situ 1H-NMR and 13C-NMR investigation
Futile cycling of ammonium ions via the high affinity potassium uptake system (Kdp) of Escherichia coli
Metabolic responses of Saccharomyces cerevisiae CBS 8066 and Candida utilis CBS 621 upon transition from glucose limitation to glucose excess
Heat production by ruminal bacteria in continuous culture and its relationship to maintenance energy
Effect of reducing-equivalent disposal and NADH/NAD on deamination of amino acids by intact rumen microorganisms and their cell extracts
Carbohydrate metabolism in the ruminant. Bacterial carbohydrates formed in the rumen and their contribution to digesta entering the duodenum
Methane production and soluble carbohydrates in the rumen of sheep in relation to the time of feeding and the effects of short-term intraruminal infusions of unsaturated fatty acids
Metabolic and energetic aspects of the growth of Klebsiella aerogenes NCTC 418 on glucose in anaerobic chemostat culture
The nutritive value of rumen micro-organisms in ruminants. 2. The apparent digestibility and net utilization of microbial N for growing lambs
Diurnal variations in bacterial numbers and fluid parameters in ruminal contents of animals fed low- or high-forage diets
Cellodextrin efflux by the cellulolytic ruminal bacterium Fibrobacter succinogenes and its potential role in the growth of nonadherent bacteria
Activities and regulation of the enzymes involved in the first and the third steps of the aspartate biosynthetic pathway in Enterococcus faecium
Energy-spilling reactions of Streptococcus bovis and resistance of its membrane to proton conductance
Digestion in the rumen and total tract of forage-based diets with starch or dextrose supplements fed to Holstein heifers
Variations in the uptake and metabolism of peptides and amino acids by mixed ruminal bacteria in vitro
Effect of amino acids on the heat production and growth efficiency of Streptococcus bovis: balance of anabolic and catabolic rates
Growth and metabolism of Saccharomyces cerevisiae in chemostat cultures under carbon-, nitrogen-, or carbon- and nitrogen-limiting conditions
Role of phosphorolytic cleavage in cellobiose and cellodextrin metabolism by the ruminal bacterium Prevotella ruminicola
The effect of amino nitrogen on the energetics of ruminal bacteria and its impact on energy spilling
Hydrogen regulation of growth, growth yields, and methane gene transcription in Methanobacterium thermoautotrophicum deltaH
Competition for cellobiose among three predominant ruminal cellulolytic bacteria under substrate-excess and substrate-limited conditions
Formation of formate and hydrogen, and flux of reducing equivalents and carbon in Ruminococcus flavefaciens FD-1
The endogenous polysaccharide utilization rate of mixed ruminal bacteria and the effect of energy starvation on ruminal fermentation rates
Relationship between intracellular phosphate, proton motive force, and rate of nongrowth energy dissipation (energy spilling) in Streptococcus bovis JB1
Alternative schemes of butyrate production in Butyrivibrio fibrisolvens and their relationship to acetate utilization, lactate production, and phylogeny
Compartmental modeling with nitrogen-15 to determine effects of degree of fat saturation on intraruminal N recycling
Fibrobacter succinogenes S85 ferments ball-milled cellulose as fast as cellobiose until cellulose surface area is limiting
Concurrent maltodextrin and cellodextrin synthesis by Fibrobacter succinogenes S85 as identified by 2D NMR spectroscopy
Biosynthesis of methionine from homocysteine, cystathionine and homoserine plus cysteine by mixed rumen microorganisms in vitro
13C and 1H nuclear magnetic resonance study of glycogen futile cycling in strains of the genus Fibrobacter
Molecular characterization and expression of pyruvate formate-lyase-activating enzyme in a ruminal bacterium, Streptococcus bovis
Stimulatory and inhibitory effects of protein amino acids on growth rate and efficiency of mixed ruminal bacteria
Acetate utilization and butyryl coenzyme A (CoA):acetate-CoA transferase in butyrate-producing bacteria from the human large intestine
Serine acetyltransferase of Escherichia coli: substrate specificity and feedback control by cysteine
Some serological and chemical studies on materials extracted from an amylolytic streptococcus from the rumen of the sheep
A quantitative study of the production of dextran from sucrose by rumen strains of Streptococcus bovis
Transglucosidase activity of rumen strains of Streptococcus bovis. 2. Isolation and properties of dextransucrase
The structure of Escherichia coli ATP-phosphoribosyltransferase: identification of substrate binding sites and mode of AMP inhibition
Use of stable isotopes to measure de novo synthesis and turnover of amino acid-C and -N in mixed micro-organisms from the sheep rumen in vitro
A mathematical model for the branched chain amino acid biosynthetic pathways of Escherichia coli K12.
Structure-function relationships of glucansucrase and fructansucrase enzymes from lactic acid bacteria
A Role for Fructose 1,6-Diphosphate in the ATPase-Mediated Energy-Spilling Reaction of Streptococcus bovis
Studies of the extracellular glycocalyx of the anaerobic cellulolytic bacterium Ruminococcus albus 7
Cross-feeding between Bifidobacterium longum BB536 and acetate-converting, butyrate-producing colon bacteria during growth on oligofructose
Relation between phylogenetic position, lipid metabolism and butyrate production by different Butyrivibrio-like bacteria from the rumen
Board-invited review: Recent advances in biohydrogenation of unsaturated fatty acids within the rumen microbial ecosystem
Diversity, metabolism and microbial ecology of butyrate-producing bacteria from the human large intestine
Investigating unsaturated fat, monensin, or bromoethanesulfonate in continuous cultures retaining ruminal protozoa. I. Fermentation, biohydrogenation, and microbial protein synthesis
Toxicity of unsaturated fatty acids to the biohydrogenating ruminal bacterium, Butyrivibrio fibrisolvens
The complete genome sequence of Fibrobacter succinogenes S85 reveals a cellulolytic and metabolic specialist
Quantitative analysis of growth and volatile fatty acid production by the anaerobic ruminal bacterium Megasphaera elsdenii T81
Some are more equal than others: the role of "keystone" species in the degradation of recalcitrant substrates
The effect of saturated fatty acids on methanogenesis and cell viability of Methanobrevibacter ruminantium
Special topics--Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options
Metagenomic insights into the carbohydrate-active enzymes carried by the microorganisms adhering to solid digesta in the rumen of cows
Analysis of the bovine rumen microbiome reveals a diversity of Sus-like polysaccharide utilization loci from the bacterial phylum Bacteroidetes
Eukaryotic inhibitors or activators elicit responses to chemosensory compounds by ruminal isotrichid and entodiniomorphid protozoa
Kinetics of microbial methionine metabolism in continuous cultures administered different methionine sources
RUMINANT NUTRITION SYMPOSIUM: How to use data on the rumen microbiome to improve our understanding of ruminant nutrition
Simultaneous quantification of purine and pyrimidine bases, nucleosides and their degradation products in bovine blood plasma by high performance liquid chromatography tandem mass spectrometry
Effects of chestnut tannins and coconut oil on growth performance, methane emission, ruminal fermentation, and microbial populations in sheep
Feeding value of whole raw soya beans as a protein supplement for beef cattle consuming low-quality forages
Effects of High Forage/Concentrate Diet on Volatile Fatty Acid Production and the Microorganisms Involved in VFA Production in Cow Rumen
Administration of Streptococcus bovis isolated from sheep rumen digesta on rumen function and physiology as evaluated in a rumen simulation technique system
Between-cow variation in digestion and rumen fermentation variables associated with methane production
Evaluation of the National Research Council (2001) dairy model and derivation of new prediction equations. 2. Rumen degradable and undegradable protein
Comparison of milk production, intake, and total-tract nutrient digestion in lactating dairy cattle fed diets containing either wheat middlings and urea, commercial fermentation by-product, or rumen-protected soybean meal
Copper sulfate and sodium selenite lipid-microencapsulation modifies ruminal microbial fermentation in a dual-flow continuous-culture system
Investigation of ammonium lactate supplementation on fermentation end products and bacterial assimilation of nitrogen in dual-flow continuous culture
A route to decreasing N pollution from livestock: Use of Festulolium hybrids improves efficiency of N flows in rumen simulation fermenters
Alterations in fermentation parameters during and after induction of a subacute rumen acidosis in the rumen simulation technique
Nutrient digestibility and endogenous protein losses in the foregut and small intestine of weaned dairy calves fed calf starters with conventional or enzyme-treated soybean meal.
Effects of diet fermentability and supplementation of 2-hydroxy-4-(methylthio)-butanoic acid and isoacids on milk fat depression: 2. Ruminal fermentation, fatty acid, and bacterial community structure.
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Feed intake, digestibility, and energy contents in growing bull fed pineapple crop waste silage in different planes of nutrition.
Effects of Increasing Doses of Condensed Tannins Extract from Cistus ladanifer L. on In Vitro Ruminal Fermentation and Biohydrogenation.
Diet Transition from High-Forage to High-Concentrate Alters Rumen Bacterial Community Composition, Epithelial Transcriptomes and Ruminal Fermentation Parameters in Dairy Cows.
Short-Term Variations of C18:1 Trans Fatty Acids in Plasma Lipoproteins and Ruminal Fermentation Parameters of Non-Lactating Cows Subjected to Ruminal Pulses of Oils.
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