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PubMedDate not supplied

Blood cultures evaluation by gas chromatography of volatile fatty acids.

The volatile fatty acid profiles were determined by a simple gas chromatographic method in 375 microbiologically positive and negative blood cultures. Aerobic bacteria yielded profiles with low content of acids, some of which were chromatographically negative. Anaerobic bacteria produced more acids and more distinctive profiles. The method makes it possible to confirm the microbiological findings and to select the blood cultures containing anaerobic bacteria within 30 minutes.

Animals↗
PubMed2003

Effect of tartaric acid and dietary fibre from sun-dried raisins on colonic function and on bile acid and volatile fatty acid excretion in healthy adults.

Sun-dried raisins are a source of dietary fibre and tartaric acid. The effects of tartaric acid on colon function have not been the focus of extensive research. The purpose of the present study was to evaluate the effects of dietary fibre and tartaric acid from sun-dried raisins on colon function and on faecal bile acid and short-chain fatty acid (SCFA) excretion in healthy adults. Thirteen healthy subjects were fed 120 g sun-dried raisins/d or 5 g cream of tartar (equivalent to the tartaric acid in 120 g sun-dried raisins)/d for 9 weeks, divided into 3-week cycles. The experimental diets were fed in a crossover design after an initial control period. Faeces were collected for the last 4 d of each cycle for analysis of SCFA and bile acids. Intestinal transit time decreased from 42 h on the baseline diet to 31 h on cream of tartar (P<0.1) and to 28 h on sun-dried raisins (P<0.05). Faeces were softer on both sun-dried raisins and cream of tartar, but sun-dried raisins increased faecal wet weight (P<0.05), while cream of tartar did not. Sun-dried raisins caused significant reductions from baseline values in total bile acid concentration (from 1.42 (SD 1.03) to 1.09 (SD 0.76) mg/g, P<0.05), whereas cream of tartar did not (1.40 (SD 1.06) mg/g). Sun-dried raisins also significantly reduced the lithocholic (LC):deoxylithocholic acid (DC) ratio (from 1.63 (SD 0.85) to 1.09 (SD 0.50), P<0.02), whereas cream of tartar reduced the ratio, but to a lesser extent (1.29 (SD 0.79), NS). Both faecal bile acids and the LC:DC ratio are indicators of reduced risk for colon cancer. Sun-dried raisins increased total SCFA excretion (from 5.6 (SD 3.4) to 7.6 (SD 3.0) g/4 d, P<0.05), which remained unchanged with cream of tartar (5.6 (SD 3.0) g/4 d). Both sun-dried raisins and cream of tartar appear to be good stool softeners and to shorten intestinal transit time, although the fibre in sun-dried raisins has the added benefit of increasing faecal weight. Both sun-dried raisins and cream of tartar modulate the composition of faecal bile acids and SCFA in a way that has potential health benefits.

Adult↗
PubMed2001

Effects of tannic acid on cecal volatile fatty acids and susceptibility to Salmonella typhimurium colonization in broiler chicks.

Young chickens are more susceptible to Salmonella colonization than older chickens that have developed resistance with age as native microflora become established. Elevated concentrations of cecal propionic acid and total volatile fatty acids (VFA) have been observed by many researchers to be indicators of establishment of anaerobic microflora and protection against Salmonella colonization of the ceca. Disruption of the native microflora or competitive exclusion (CE) cultures by components of diets, such as tannic acid (TA), could alter the concentrations of propionic acid and total VFA and possibly affect Salmonella colonization. Two experiments were conducted using day-of-hatch, mixed-sex broiler chicks to evaluate the effects of TA on cecal VFA and the susceptibility to Salmonella colonization. All chicks in both experiments were challenged orally with 10(4) cfu of Salmonella typhimurium (ST) on Day 3 (Experiment 1) or Day 4 (Experiment 2). One-half of the chicks were orally gavaged on the day of hatch with a CE culture (PREEMPT) and were fed diets containing 0, 0.75, or 1.5% TA for up to 12 d of age. Chicks were maintained in batteries in separate rooms for the experimental period. There were some alterations in concentrations of cecal propionic acid or total VFA in chicks fed diets containing 0.75 or 1.5% TA in non CE-treated chicks and in CE-treated chicks. No significant differences were observed for numbers of Salmonella cecal culture-positive chicks or in the numbers of ST in the cecal contents due to dietary content of TA. With minor exceptions, the chicks treated with the CE culture had higher cecal concentrations of propionic acid and were less susceptible to Salmonella colonization than the non CE-treated chicks. Further research is necessary to determine the biological significance of these changes.

Animals↗
PubMed1976

Synthesis of ruminal microbial protein and volatile fatty acid production in vitro.

Growth of a mixed ruminal population taken from a sheep on a protein-free (all urea) purified diet was estimated by an in vitro fermentation technique including precipitation of microbial protein by trichloracetic acid. Volatile fatty acid production in vitro was determined, and the associated a denosine triphosphate was estimated as moles volatile fatty acids X 2.4. On this basis, the quantity of microbial protein synthesized per mole of adenosine triphosphate increased at higher microbial growth rates.

Adenosine Triphosphate↗
PubMed1976

Volatile fatty acid metabolism in sheep. 1. Average daily volatile fatty acid production in the rumen of sheep fed lucerne hay.

Changes in the total concentration of the volatile fatty acid (VFA) pool in the rumen were followed over a 24 hour period in 2 groups of sheep, 1 fed at 08h00 and the other twice daily at 08h00 and 20h00. Although similar maximum (143 and 147 meq/1) and average (100, 3 and 102, 1 meq/1) levels were found in the 12 and 24 h groups respectively, the twice daily feeding regimen resulted in a lower variation (S.D.=17, 0 meq/1 and 28, 9 meq/1 respectively). It was concluded from changes in the percentage molar composition of the VFA pool over the same period that the other of VFA absorption from the rumen was propionate greater than acetate greater than butyrate for both groups, but that the differences were less marked for the twice daily fed sheep. Long term infusions of 14C labelled acetic, propionic and butyric acids into the rumen of sheep fed a total of 1 600 g lucerne hay twice daily (08h00 and 20h00), gave an average net total VFA production rate of 4,52+/-1,01 moles/800 g/12 hours irrespective of the acid infused. The net individual turnover rates for acetic (2,81 moles/12 h), propionic acid (0,82 moles/12 h) and butyric acid (0,55 moles/12 h), derived by the subtraction of the inter-conversion factors from the gross production rates of the acids, and expressed as the percentage contribution of each acid to the total net VFA turnover (acetic=62%, propionic=18% and butyric=12%) closely resembled the percentage molar composition of the VFA pool in the rumen (acetic=60%, propionic=23% and butyric=12%). The total net VFA production was found to be directly proportional to the total VFA concentration in the rumen (correlation coefficient=0,83), and the relationships can be described by the equation y=0,034 x + 0,16 where y=VFA production in moles/12 hour and x=VFA concentration in meq/1. A specific VFA production rate of 0,85 moles per 100 g digestible organic matter was calculated from the average daily VFA production rate and the composition of the lucerne hay.

Acetates↗
PubMed1984

[Rumen fermentation with special reference to volatile fatty acid production during reproduction. 1. Methods and results of volatile fatty acid levels and production rates in vitro].

The target of the investigations was to register part of the synthesis performance in the rumen of ewes during the complete reproduction cycle. With the help of in-vitro experiments with artificial rumen the concentration and production rates of volatile fatty acids in the rumen fluid were measured. From the experiments the measured data of fertility-accentuated crossbreeding (experiment 1) and crossbreeding (experiment 2) ewes were contrasted. The average concentrations of volatile fatty acids in ewes are 95.4 m mol/l in experiment 1 and 109.2 m mol/l in experiment 2 during the early stage gestation, 121.4 m mol/l in experiment 1 and 99.8 m mol/l in experiment 2 in the last stage stage of gestation, 129.6 m mol/l in experiment 1 and 112.8 m mol/l in experiment 2 during lactation and 106.6 m mol/l in experiment 1 and 112.9 m mol/l in experiment 2 during the dry period. The production rates of volatile fatty acids calculated form their concentration amount to 4.8 m mol/l X h in experiment 1 and 2.6 m mol/l X h in experiment 2 in the early stage of gestation, 3.5 m mol/l X h in experiment 1 and 3.1 m mol/l X h in experiment 2 in the last stage of gestation, 3.2 m mol/l X h in experiment 1 and 2.7 m mol/l X h in experiment 2 during lactation and 3.7 m mol/l X h in experiment 1 and 2.9 m mol/l X h in experiment 2 in the dry period. The correlation between the concentration and the production rate of volatile fatty acids is not significantly negative in either of the ewe experiments. The scattering of the individual values is wide so that the individual influence of the test animals as well as the influence of the in-vitro method used permit the conclusion that a significant statement on the influence of the genotype and the stage of reproduction on the production rates cannot be made.

Animals↗
PubMed1979

Studies on digestion and absorption in the intestines of growing pigs. 8. Measurements of the flow of total lipid, acid-detergent fibre and volatile fatty acids.

1. Seventeen pigs fitted with single re-entrant cannulas in either the duodenum (posterior to the point of entry of the bile and pancreatic ducts), the mid-jejunum, or the terminal ileum, and a further twenty-four non-cannulated pigs were used. 2. Three diets were used: these contained barley, fine wheat offal, white fish meal, minerals and vitamins (diet BWF); starch, sucrose, maize oil, cellulose, minerals, vitamins and either groundnut meal (diet SSG) or casein (diet SSC). 3. The quantities of total lipid (TL), acid-detergent fibre (ADF) and volatile fatty acids (VFA) passing through the re-entrant cannulas and excreted in the faeces in 24 h were measured. These were used to determine the net absorption (or synthesis or secretion) in the different regions of the intestine. 4. There was substantial secretion of TL into the proximal small intestine and major absorption from the distal portion for all three diets. In the large intestine there was little or no further net absorption for diets SSG and SSC, but significant synthesis or secretion for diet BWF. 5. Fibre digestion occurred in both the small and large intestines and the apparent absorption of ADF in the different regions studied was influenced by diet. 6. There were detectable amounts of VFA at all sites but only at the ileum and in the faeces could they be accurately measured. Diet did not affect the molar proportions of acetate, propionate and butyrate in ileal digesta, but did have an effect on these VFA in the faeces.

Animals↗
PubMed1987

In vitro lactic acid inhibition and alterations in volatile fatty acid production by antimicrobial feed additives.

Batch culture fermentations were used to determine the effects of avoparcin, lasalocid, monensin, narasin, salinomycin, thiopeptin, tylosin, virginiamycin, monensin + tylosin combination, and two new ionophore compounds (RO22-6924/004 and RO21-6447/009) on lactic acid and volatile fatty acid (VFA) production. Ruminal fluid from cattle fed a high alfalfa hay diet was incubated with glucose for 12 h in a buffered medium to determine the effect of antimicrobial compounds on lactic acid concentration. Fermentations treated with antimicrobial compounds had higher final pH and lower L(+) lactic acid concentration. Narasin and salinomycin were more inhibitory than other ionophore compounds. Monensin and tylosin in combination was more effective than monensin alone. Among the nonionophore compounds, avoparcin was the least effective and thiopeptin, tylosin and virginiamycin were extremely effective in reducing lactic acid concentration. Ruminal fluid from cattle fed a diet of alfalfa hay and grain (50:50) was incubated with a mixture of sugars, casein and urea for 12 h in a buffered medium to determine the effect of antimicrobial compounds on VFA production. Generally, total VFA concentration was not affected by antimicrobial compounds except RO22-6924/004, tylosin and virginiamycin, which caused a reduction at high concentrations. Tylosin, monensin and tylosin mixture, thiopeptin and virginiamycin at high concentrations (greater than 6.0 micrograms/ml) increased the acetate proportion. All compounds increased the molar proportion of propionate. Tylosin and virginiamycin at high concentrations (greater than 6.0 micrograms/ml) decreased the proportion of propionate. Monensin and tylosin in combination had no effect on propionate proportion. Among the compounds tested, narasin and salinomycin were the most effective in enhancing propionate proportion. Ionophore compounds were more inhibitory to butyrate production than the nonionophore compounds. Batch culture fermentations may be used to quantitate the relative efficacy of antimicrobial compounds to alter ruminal fermentation characteristics.

Animals↗
PubMed1987

[Influence of purified cellulose level in the diet of pigs on intestinal absorption of volatile fatty acids].

Nutrient and volatile fatty acid (VFA) absorption to portal blood was measured twice at 7 days interval in five pigs fed a semi-synthetic diet containing 6 (R6) or 16% (R16) purified cellulose for 21 or 7 days. The daily absorption (24 hrs.) of VFA in the large intestine which was larger (NS) when the cellulose level rose, increased significantly (P less than 0.05) with increasing length of adaptation (21 to 28 d.) to the diet whatever the cellulose level. The supplementary daily supply of energy in the form of VFA after increase of the cellulose level did not compensate for the corresponding deficit of absorption of reducing sugars and crude protein in the small intestine.

Animal Feed↗
PubMed1985

[Studies on rumen fermentation with special reference to the volatile fatty acid production rate in ewes during reproduction. 2. Production rate of volatile fatty acids and rumen volume].

Methods and results of the measuring of the rumen volume and the passage rate as well as the dependence of the production of volatile fatty acids on the parameters mentioned are described. The correlative relations between rumen volume on the one hand and feed passage on the other hand to the production quotas are investigated. Passage rates and rumen volumes were determined with the help of the isotope dilution method. In the course of reproduction rumen volumes of 7.81, 6.41, 8.91, 7.11 in experiment 1 and 5.41, 5.81, 9.51 and 4.71 in experiment 2 were measured in the sequence early stage of gestation, late stage of gestation, lactation and the period between pregnancies. The average total production of volatile fatty acids within 12 hours amounted to 475 mmol, 265 mmol, 313 mmol and 351 mmol in experiment 1 and 155 mmol, 175 mmol, 271 mmol and 144 mmol in experiment 2 in the same sequence. The average passage duration of the feed through the digestive tract of the ewes was 32.4 h in experiment 1 and 33.6 h in experiment 2. The relatively high feed intake of the ewes resulted in a short passage duration and could be a cause of the low production quotas of the volatile fatty acids.

Animals↗