Citric Acid Metabolism in the Bovine Rumen

Wright, D. E.

doi:10.1128/aem.21.2.165-168.1971

Cited by 11 publications

(11 citation statements)

References 3 publications

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“…Later, rumen microflora populations probably adjust to the new diet and decompose the organic acids. An exception to this conditioning occurs in the presence of high K levels, which are known to decrease the rate at which rumen microorganisms can utilize citric acid (14).…”

Section: Resultsmentioning

confidence: 99%

Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany¹

Maryland¹,

Gruñes²,

Waggoner³

et al. 1975

Agronomy Journal

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Nitrogen fertilization of forage is often accompanied by an increased incidence of grass tetany. A field experiment was established on two calcareous soils to evaluate the effects of N fertilizer on forage quality indices of grass tetany. Nitrogen, as NH4NO3, was applied at 0 and 150 kg N/ha in each of 2 years to separate plots. The crested wheatgrass [Agropyron desertorum (Fisch.) Schult] forage was harvested at regular intervals in the Spring tetany period during 1968 through 1971. Forage was analyzed for inorganic cations, N, total water‐soluble carbohydrates (TWSC), aconitic acid, higher fatty acids (HFA), dry matter, and ash alkalinity — a measure of total organic acids. Nitrogen fertilizer increased the concentrations (equiv. basis) of forage Mg and Ca more than the increase in K, thus slightly reducing the K/(Ca + Mg) values when compared to the unfertilized forage. However, forage K/(Ca + Mg) values were usually less than the 2.2 value above which the incidence of grass tetany increases rapidly. The potential dietary benefits from the higher Mg concentrations may have been offset by increased concentrations of K, N, HFA, N/TWSC, and aconitic acid, since these parameters are associated with decreased Mg availability to cattle. Low values for hypothetical blood serum Mg (calculated from forage N, Mg, and K concentrations) coincided with the occurrence of grass tetany in the field. The calculated serum Mg values were lower in the N‐fertilized forage than in the control. The aforementioned effects of N fertilization should not deter the judicious use of N for optimizing forage yields on semiarid ranges, since other research workers have found that grass tetany losses can be reduced by supplementing animals with Mg.

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Section: Resultsmentioning

confidence: 99%

Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany¹

Maryland¹,

Gruñes²,

Waggoner³

et al. 1975

Agronomy Journal

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“…Wright (18) and Kennedy (11) observed that citrate and aconitate, respectively, were rapidly metabolized by rumen bacteria, and they questioned the importance of these organic acids in hypomagnesemia. In our experiments, citrate and aconitate were, likewise, fermented at a rapid rate, and it seemed unlikely that they would be present in the rumen for a long enough time to decrease the availability of dietary magnesium.…”

Section: Discussionmentioning

confidence: 99%

In vitro ruminal fermentation of organic acids common in forage

Russell¹,

Soest²

1984

Appl Environ Microbiol

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Mixed rumen bacteria from cows fed either timothy hay or a 60% concentrate were incubated with 7.5 mM citrate, trans-aconitate, malate, malonate, quinate, and shikimate. Citrate, trans-aconitate, and malate were fermented at faster rates than malonate, quinate, and shikimate. Acetate was the primary fermentation product for all six acids. Quinate and shikimate fermentations gave rise to butyrate, whereas malate and malonate produced significant amounts of propionic acid. High-pressure liquid chromatography of fermentation products from trans-aconitate incubations revealed a compound that was subsequently identified as tricarballylate. As much as 40% of the trans-aconitate acid was converted to tricarballylate, and tricarballylate was fermented slowly. The slow rate of tricarballylate metabolism by mixed rumen bacteria and its potential as a magnesium chelator suggest that tricarballylate formation could be an important factor in the hypomagnesemia that leads to grass tetany.

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“…Scotto et al (1971) noted a positive relation between dietary KCl treatment and citrate absorption, but we did not observe a significant effect of KCl on tricarballylate absorption. Citrate is rapidly fermented by rumen microorganisms (Wright, 1971 ;Russell & Van Soest, 1984); however, KCl may have increased rumen fluid dilution rate and washed citrate out of the rumen before it could be fermented. During the experimental period, sheep given KCl consumed twice as much water but aconitate was never detected in the blood.…”

Section: Fs C U S Si Onmentioning

confidence: 99%

Production of tricarballylic acid by rumen microorganisms and its potential toxicity in ruminant tissue metabolism

Russell

Forsberg

1986

Br J Nutr

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1. Rumen microorganisms convert trans-aconitate to tricarballylate. The following experiments describe factors affecting the yield of tricarballylate, its absorption from the rumen into blood and its effect on mammalian citric acid cycle activity in vitro.2. When mixed rumen microorganisms were incubated in vitro with Timothy hay (Phleum praiense L.) and 6.7 mM-trans-aconitate, 64 % of the trans-aconitate was converted to tricarballylate. Chloroform and nirate treatments inhibited methane production and increased the yield of tricarballylate to 82 and 75% respectively. 3. Sheep given gelatin capsules filled with 20 g trans-aconitate absorbed tricarballylate and the plasma concentration ranged from 0.3 to 0.5 mM 9 h after administration. Feeding an additional 40 g potassium chloride had little effect on plasma tricarballylate concentrations. Between 9 and 36 h there was a nearly linear decline in plasma tricarballylate.4. Tricarballylate was a competitive inhibitor of the enzyme, aconitate hydratase (aconitase; EC 4.2.1 .3), and the inhibitor constant, K I , was 0.52 mM. This KI value was similar to the Michaelis-Menten constant (K,) of the enzyme for citrate.5. When liver slices from sheep were incubated with increasing concentrations of tricarballylate, [I4C]acetate oxidation decreased. However, even at relatively high concentrations (8 mM), oxidation was still greater than 80% of the maximum. Oxidation of [I4C]acetate by isolated rat liver cells was inhibited to a greater extent by tricarballylate. Concentrations as low as 0.5 mM caused a 30% inhibition of citric acid cycle activity.

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Citric Acid Metabolism in the Bovine Rumen

Cited by 11 publications

References 3 publications

Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany¹

Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany¹

In vitro ruminal fermentation of organic acids common in forage

Production of tricarballylic acid by rumen microorganisms and its potential toxicity in ruminant tissue metabolism

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Citric Acid Metabolism in the Bovine Rumen

Cited by 11 publications

References 3 publications

Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany1

Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany1

In vitro ruminal fermentation of organic acids common in forage

Production of tricarballylic acid by rumen microorganisms and its potential toxicity in ruminant tissue metabolism

Contact Info

Product

Resources

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Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany¹

Nitrogen Effects on Crested Wheatgrass as Related to Forage Quality Indices of Grass Tetany¹