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PubMedDate not supplied

[The dynamics of the content of ammonia and volatile fatty acids in the rumen fluid during the use of dry feed rations in the cow].

The development of the pH-value, the molar quota of volatile fatty acids and of the NH3 content in the change from silage rations to dried rations on the basis of pelleted feed and in dependence on the time after the beginning of feeding was tested in studies of the rumen fluid of four cows in order to explain the causes of the very low NH3 content of the rumen fluid in feeding experiments with rations based on pelleted straw-concentrate mixtures. An influence of the ration type and the time after the beginning of feeding on the molar quota of the individual volatile fatty acids and the NH3 content was ascertained. The ration type tested can cause an NH3 content in the rumen fluid below 1 mmol/l.

Ammonia↗
PubMedDate not supplied

Identification of Flavobacterium strains by gas liquid chromatographic analysis of volatile fatty acids produced in culture.

The classification previously established for 74 Flavobacterium strains by gas liquid chromatographic (GLC) analysis of volatile fatty acids (VFA) produced in culture allowed the recovery of 9 groups (J. gen. Microbiol., 1986, 132, 2723-2732). Since graphic representation of the strains based on the first 3 factors obtained by principal component analysis (PCA) clearly separated these groups, we tried to identify 80 new strains by comparing their positions with those of the 9 groups, on the basis of both hierarchical classification and PCA methods. Of the 153 strains studied, only 12 were not allocated to a group corresponding to their original biochemical identification. Thus, on the whole, this characterization method by GLC analysis seemed satisfactory, although it could not be established whether the method was adequate for routine identification, or would serve merely as a complement.

Chromatography, Gas↗
PubMed2000

Net portal appearance of volatile fatty acids in sheep intraruminally infused with mixtures of acetate, propionate, isobutyrate, butyrate, and valerate.

The net portal appearance of volatile fatty acids (VFA) was investigated in four ruminally fistulated and multicatheterized sheep. During the experiments, the sheep were fed once every hour for 14 h and intraruminally infused with mixtures of VFA for the 12 h commencing 2 h after the initiation of the hourly feeding protocol. Paired arterial and portal blood samples were obtained hourly during the last 6 h of the experiments. In the control treatment (1), only water was infused intraruminally. In Treatments 2 through 4, the intraruminal infusion rates of propionate (40 mmol/h), isobutyrate (5 mmol/h), and valerate (5 mmol/h) were unchanged. In Treatments 2, 3, and 4, the acetate infusion rate was 100, 60, and 20 mmol/h, respectively, and the butyrate infusion rate was 10, 30, and 50 mmol/h, respectively. Thus, the infusion rate of VFA carbon was constant across Treatments 2 through 4. Portal recovery estimated from the increased net portal appearance in Treatments 2 through 4 compared to the control treatment was 85% for propionate and 60% for isobutyrate, and these recoveries were unaffected by treatment. The portal recovery of butyrate increased (from 21 to 32%) with increasing infusion rate of butyrate and decreasing infusion rate of acetate, as did the portal recovery of valerate (from 14 to 31%). The portal recovery of acetate was 55%, when measured as net portal appearance. Thus, it seems that the capacity for beta-oxidation in ruminal epithelium is limited, which would explain the increasing portal recovery of butyrate and valerate with increasing infusion rate of butyrate, when infusion rate of VFA carbon is unchanged.

Acetates↗
PubMed1983

Volatile fatty acids and the role of the large intestine in the control of feed intake in ponies.

The roles of volatile fatty acids (VFA) and of the large intestine in the control of feeding in ponies were investigated. Ponies with cecal fistulas were adapted to ad libitum access to pelleted feed. Treatment solutions were given as a bolus 15 min before the animals were allowed free access to feed after a 4-h fast. Each dose of VFA solution was tested in a crossover design with a water control. When the ponies were permitted to eat after the treatments, the latency to eat, first meal size, and duration and first intermeal interval were recorded. Feed intakes were measured at 3 and 18 h after the treatments were given. Intracecal infusions of .4 mmol propionate (Prop)/kg body weight (BW) increased (P less than .05) total feed intake 7.5% relative to control values. Higher doses of Prop (.75 mmol/kg BW) and acetate (1.00 and 1.25 mmol/kg BW) reduced (P less than .05) feed intake by prolonging the first intermeal interval 143% (Prop) and 71 to 74% (acetate), although 24-h intakes did not differ from controls. The highest dose of Prop tested (1.00 mmol/kg BW) reduced first meal size 22% (P less than .01) without affecting subsequent feeding behaviors. The results indicate that changes in cecal VFA concentration can generate cues that may contribute to the control of meal size and frequency in ponies.

Acetates↗
PubMed1988

Effect of propionate level in a volatile fatty acid salt mixture fed to lambs on weight gain, body composition and plasma metabolites.

Chopped hay supplemented with a volatile fatty acid salt mixture at 20% of metabolizable energy (ME) was fed to 30 Suffolk X Corriedale lambs (mean wt 29.6 kg) to determine the effects of dietary propionate on weight gain, body composition and plasma metabolites. Propionate accounted for 0, 25, 50, 75 or 100% of the salt mixture energy, and acetate accounted for the remainder. Each diet was fed at two levels of daily intake (158.7 and 130.6 kcal ME/W.75). Lambs on the high level of intake lost more (P less than .05) energy in feces, lost less (P less than .05) energy in CH4 and had carcasses with more (P less than .10) water and fat than lambs on the low intake level. Percentage of propionate in the salt mixture had no effect on ME or body composition of lambs. Increasing the percentage of propionate in the salt mixture increased plasma propionate in blood samples taken at 1 and 2 h after feeding (linear, P less than .05). Empty body weight gain per megacalorie of ME above maintenance increased as the percentage of propionate in the salt mixture increased, but not until propionate reached 75% of the salt mixture (linear, P less than .05; cubic, P less than .05). These results show that propionate in the blood has a positive, but nonlinear, effect on weight gain, even when energy intake is held constant.

Animals↗
PubMedDate not supplied

[Gas chromatographic study of volatile fatty acids produced by 14 species of Pseudomonas].

A quantitative gas-liquid chromatographic method for the determination of the volatile fatty acids produced in standardized liquid culture media by Pseudomonas reference strains belonging to 14 species, some of medical interest, is proposed here. This method, using 14 reference strains, permitted a precise identification of Pseudomonas species according to characteristic chromatograms. The key used for this identification gave us a classification corresponding to the DNA homology groups.

Chemical Phenomena↗
PubMed1997

In situ derivatisation and extraction of volatile fatty acids entrapped on anion-exchange resin from aqueous solutions and urine as a test matrix using pentafluorobenzyl bromide in supercritical carbon dioxide.

The simultaneous extraction and derivatisation of anion-exchange resin-trapped volatile fatty acids (C2-C5) as their pentafluorobenzyl esters has successfully been performed under CO2 supercritical fluid extraction conditions. Volatile fatty acid standards of acetic, propionic and n-butyric acids (at 20 and 100 ppm) as their ester derivatives were recovered at 78.0-101.5% (C.V. 3.5-7.5%, n=6 and 7). Likewise, acrylic acid recoveries were 57.0-61.0% (C.V. 5.5-5.6%, n=6 and 7). This methodology was applied to the quantitation of acetic, propionic, n-butyric and n-valeric acids in spiked urine as a test matrix. Initial clean-up of phosphate and sulfate in the urine was required prior to anion-exchange application and this was achieved by barium salt precipitation. Recoveries ranged from 36 to 66.5% (C.V. 5.9-14.4%, n=9 and 6).

Anion Exchange Resins↗
PubMed1980

Rapid temperature programmed gas-liquid chromatography of volatile fatty acids (C1-C7) for the identification of anaerobic bacteria.

A gas liquid chromatography method for the separation of 10 volatile fatty acids (C1-C7 and isomers) has been improved by using oven temperature programmed conditions. In our conditions, the proprietary stationary phase SP 1220 introduced by Supelco Inc., gave sharp separation of volatile fatty acids in less than 8 min. This method was suitable for analyses with both thermal conductivity and flame ionization detectors.

Anaerobiosis↗
PubMed1988

Partition of portal-drained visceral net flux in beef steers. 2. Net flux of volatile fatty acids, D-beta-hydroxybutyrate and L-lactate across stomach and post-stomach tissues.

1. Net flux of volatile fatty acids (VFA), D-beta-hydroxybutyrate (BOHB) and L-lactate across post-stomach (anterior mesenteric-drained viscera (MDV], stomach and total hepatic portal-drained viscera (PDV) tissues was measured in two beef steers (mean live weight 390 kg). 2. Net flux was measured while steers were fed, in sequence, on (1) chopped lucerne (Medicato sativa) (twelve meals/d), (2) chopped lucerne (two meals/d) and (3) a pelleted concentrate diet containing 780 g ground maize/kg (two meals/d). 3. Five hourly net flux measurements were obtained on 2 d for each dietary regimen, beginning 0.5 h before a meal delivered at 08.00 hours. Net flux was calculated as venous-arterial concentration differences (VA) multiplied by blood flow (measured by downstream dilution of p-aminohippurate (PAH]. 4. Stomach tissues accounted for 85 to over 100% of net VFA and BOHB appearance across PDV. Net appearance across stomach tissues represented 74% of net PDV L-lactate appearance. 5. When lucerne was given, there was net utilization of arterial acetate and BOHB across MDV. This MDV utilization may reflect acetate and BOHB use as an energy source or their incorporation into mesenteric fat. 6. When concentrate was given, more n-butyrate and n-valerate and less L-lactate appeared across PDV and less 3-methylbutyrate appeared across stomach tissues than when lucerne was given. Postprandial increases in VFA, BOHB and L-lactate net flux across PDV followed meal-feeding of lucerne. 7. On a net basis, the relative contribution of MDV tissues of total PDV net appearance of VFA and BOHB was small (less than 15%) in these steers.

3-Hydroxybutyric Acid↗
PubMed1975

[Distribution of volatile fatty acids in digestive tract contents of rabbit. I.--Rabbits fed with lucern and oat (author's transl)].

The distribution of volatile fatty acids (VFA) in digestive tract contents of Rabbits was studied using gas chromatography. VFA concentration in the posterior zones of the digestive tract were very high and comparable to values for ruminants. The distribution of the three principal VFA was different from that found in polygastric as well as monogastric animals. In Rabbits, butyrate concentration is higher than that of propionate. A selective absorption of butyrate, resembling an active transport, has been shown in the colon.

Animal Feed↗
PubMed2005

Inhibition of volatile fatty acid production in granular sludge from a UASB reactor.

Inhibition of volatile fatty acids (VFA), namely acetate, butyrate, and propionate, on the activity of acetoclastic methanogens within a full-scale upflow anaerobic sludge blanket (UASB) reactor was investigated using specific methanogenic activity (SMA) test. SMA tests were carried out at acetate concentrations in a range of 1000-25,000 mg l(-1), butyrate concentrations in a range of 3000-25,000 mg l(-1) and propionate concentrations between 500-10,000 mg l(-1). Maximum potential methane production (PMP) rates were obtained as 389 ml CH4 gTVS(-1) x d(-1) at 3000 mg l(-1) acetate concentration, 432 ml CH4 gTVS(-1) x d(-1) at butyrate concentration of 5000 mg l(-1), and 162 mlCH4 gTVS(1) x d(-1) at 1000 mg l(-1) propionate concentration. App. 50% and 100% inhibition occurred at acetate concentrations of 13,000 mg l(-1) and 25,000 mg l(-1), butyrate concentrations of 15,000 mg l(-1) and 25,000 mg l(-1), and propionate concentrations of 3500 mg l-1) and 5000 mg l(-1), respectively.

Acetates↗
PubMed1965

VOLATILE FATTY ACID REQUIREMENT OF A STRAIN OF LISTERIA MONOCYTOGENES.

Larson, A. D. (Louisiana State University, Baton Rouge), L. V. Hattier, and C. S. McCleskey. Volatile fatty acid requirement of a strain of Listeria monocytogenes. J. Bacteriol. 89:819-824. 1965.-Listeria monocytogenes strain 2 requires either isobutyric or 2-methylbutyric acid for growth. Elucidation of this requirement began with characterization of the growth-enhancing substance in culture filtrates of Aerobacter aerogenes. A. aerogenes required tryptose, glucose, and aerobic conditions for excretion of active fatty acids into the medium. Commercial preparations of isobutyric, 2-methylbutyric, isovaleric, 3-methylvaleric, and n-valeric acid supported the growth of strain 2. Purification of these fatty acids by gas chromatography demonstrated that strain 2 responded significantly only to isobutyric and 2-methylbutyric acid. Amines, alcohols, and hydroxy fatty acids, which were structurally related to the active acids, did not satisfy the fatty acid requirement of L. monocytogenes strain 2. Only one isolate (strain 2) of 128 cultures of L. monocytogenes required volatile fatty acid for growth.

Alcohols↗