Metabolism of lactic acid isomers in the rumen of silage-fed sheep

Gill, M.; Siddons, R. C.; Beever, D. E.; Rowe, JB

doi:10.1079/bjn19860046

Cited by 37 publications

(26 citation statements)

References 24 publications

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“…Lactic acid absorption parameters related to lactic acid concentration and pH were set based on the in vivo data of Williams & Mackenzie (1964) and the in vitro results from Møller et al (1997). Fermentation of lactic acid to VFA is calculated using a constant stoichiometry taken from sheep in the radioisotope study of Gill et al (1986). Where one mole of lactate fermented yields 0·95 mol VFA (Baldwin, 1995), the stoichiometric coefficients are 0·571 acetate, 0·333 propionate and 0·0487 butyrate.…”

Section: Model Constructionmentioning

confidence: 99%

The role of dynamic modelling in understanding the microbial contribution to rumen function

Dijkstra

Mills

France

2002

NRR

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Mechanistic models of microbial metabolism in the rumen aim at an improved understanding and integration for research purposes or at an improved prediction for practical purposes. The standard way of representing such models is the rate : state formalism. The system is defined by a number of state variables and a set of differential equations describe the change of the state variables with time. Three different types of solution to these dynamic models are distinguished, and examples of these solutions are described to illustrate the applications and contributions of dynamic modelling in the study of the rumen microbial ecosystem. Type I solutions are obtained when the system is in steady state and the differential equations are solved by setting the differentials to zero. An application of the type I solution is the indirect approach to quantifying the fibrolytic anaerobic fungi in the rumen. The solutions of the model describing the alternate life cycle of rumen fungi, with its free-swimming dispersal and particle-attached stages, appear to be consistent with ruminal and faecal observations. Type II solutions are obtained when the system is not in steady state but the differential equations can be integrated analytically. An application of this type of solution is the quantification of the growth and growth yield in batch cultures. Such models help to quantify the degradation of substrates in the rumen and to elucidate the interactions between groups of rumen micro-organisms. Type III solutions are obtained when the system is not in steady state and when the differential equations have to be solved numerically. Applications of the type III solutions are the rumen simulation models that describe substrate degradation, endproduct formation and microbial metabolism in an integrated manner. To illustrate this type III solution, a model of lactic acid metabolism in the rumen is defined, and its contribution to understanding of the paths and rates of lactic acid disappearance described. It is essential that the models are based Nutrition Research Reviews (2002), 15, 67-90

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Section: Model Constructionmentioning

confidence: 99%

The role of dynamic modelling in understanding the microbial contribution to rumen function

Dijkstra

Mills

France

2002

NRR

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“…Lactate-producing bacteria are particularly stimulated by high-starch feeds. Although some starch promotes efficiency of the rumen fermentation, large amounts of starch are detrimental to an unadapted animal, because the poorly controlled starch fermentation causes a decrease in rumen pH, which can lead to acidosis and even death of the animal (15,16).…”

Section: Introductionmentioning

confidence: 99%

Fermentation of Cottonseed and Other Feedstuffs in Cattle Rumen Fluid

Schneider

Ames

Rasmussen

et al. 2002

J. Agric. Food Chem.

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Bovine rumen fluid was fermented anaerobically over 48 h with cottonseed, corn, alfalfa, or a mixture of these substrates in anaerobic mineral buffer. Samples taken at different incubation times were derivatized with nbutanol and subjected to gas chromatography and mass spectroscopy. No unusual fermentation end-products from the cottonseed substrate were detected. Cottonseed supported rumen fermentation at levels comparable to those of the other substrates. Major components were usually found in the decreasing order of acetate, propionate, butyrate, and valerate, although acetate and propionate concentrations decreased late in the alfalfa and mixed-feed fermentations, eventually allowing butyrate concentrations to exceed those of propionate. As expected, lactate was produced in high concentrations when corn was fermented. The minor components 2-methylpropionate, 2-and 3-methylbutyrate, phenylacetate, phenylpropionate, and caproate also accumulated, with their relative concentrations varying with the substrate. Succinate was produced in substantial amounts only when corn and alfalfa were fermented; it did not accumulate when cottonseed was the substrate. Samples containing cottonseed were derivatized and subjected to reversed-phase highperformance liquid chromatography, revealing that gossypol concentrations did not change during fermentation. Disciplines Biochemical and Biomolecular Engineering | Biological Engineering | Bioresource and Agricultural Engineering | Chemical Engineering CommentsPosted with permission from Journal of Agricultural and Food Chemistry, 50, no. 8 (2002) Bovine rumen fluid was fermented anaerobically over 48 h with cottonseed, corn, alfalfa, or a mixture of these substrates in anaerobic mineral buffer. Samples taken at different incubation times were derivatized with n-butanol and subjected to gas chromatography and mass spectroscopy. No unusual fermentation end-products from the cottonseed substrate were detected. Cottonseed supported rumen fermentation at levels comparable to those of the other substrates. Major components were usually found in the decreasing order of acetate, propionate, butyrate, and valerate, although acetate and propionate concentrations decreased late in the alfalfa and mixed-feed fermentations, eventually allowing butyrate concentrations to exceed those of propionate. As expected, lactate was produced in high concentrations when corn was fermented. The minor components 2-methylpropionate, 2-and 3-methylbutyrate, phenylacetate, phenylpropionate, and caproate also accumulated, with their relative concentrations varying with the substrate. Succinate was produced in substantial amounts only when corn and alfalfa were fermented; it did not accumulate when cottonseed was the substrate. Samples containing cottonseed were derivatized and subjected to reversed-phase high-performance liquid chromatography, revealing that gossypol concentrations did not change during fermentation.

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“…After SBM administration, thirst increased slightly until H 4-6 and H [6][7][8] , in experiments 1 and 2, respectively. After SBM administration, hay ingestion was stopped until H [6][7][8] and H 30 and then increased progressively to return to the initial amount (5.0 kg) after H 24 and H 72 for experiments 1 and 2, respectively.…”

Section: Clinical Signsmentioning

confidence: 99%

Experimental Soybean Meal Intoxication in Cattle

Raboisson

Ferrières

Nicot

et al. 2012

Veterinary Internal Medicne

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Background: Cattle are commonly fed soybean meal (SBM) and accidental intoxication sometimes occurs. Objectives: To describe the biologic and clinical features of SBM intoxication. Animals: Four steers with ruminal cannula. Methods: Controlled experimental trial. SBM was administered once at 1 and 2% of body weight (BW) via cannula at 2-month intervals.Results: This study showed a 2-phase pathogenic course for 2% BW SBM intoxication. The 1st phase (until 10 hours post-administration) is restricted to ruminal modification with volatile fatty acid overproduction and moderate ruminal ammonia concentration. In the 2nd phase (12-22 hours post-administration), ruminal pH returned to initial values and marked ammonia accumulation occurred in blood, inducing severe metabolic alkalosis with hyperglycemia, hyperinsulinemia, and delayed aciduria (30-40 hours post-administration). Among the clinical signs, nervous signs were only observed during the period with increased plasma ammonia concentration. At 1% BW, ruminal and blood modifications were less pronounced than at 2% BW, and clinical signs were not observed.Conclusions and Clinical Relevance: Ammonia accumulation in blood during the second phase is the consequence of continued ammonia production, decreased carbohydrate fermentation, and overwhelming of hepatic detoxifying capacity. Because ammonia accumulation is associated with the clinical signs, treatment of SBM intoxication could be similar to treatment of urea intoxication, including rumenotomy, oral administration of cold water and vinegar, and measurement of ruminal pH.

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Metabolism of lactic acid isomers in the rumen of silage-fed sheep

Cited by 37 publications

References 24 publications

The role of dynamic modelling in understanding the microbial contribution to rumen function

The role of dynamic modelling in understanding the microbial contribution to rumen function

Fermentation of Cottonseed and Other Feedstuffs in Cattle Rumen Fluid

Experimental Soybean Meal Intoxication in Cattle

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