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At least 109 records · Page 6Linked to original sources
PubMed1989

Ileal ecology after pouch-anal anastomosis or ileostomy. A study of mucosal morphology, fecal bacteriology, fecal volatile fatty acids, and their interrelationship.

Ileal mucosal morphology, fecal bacteriology, fecal volatile fatty acids, and their interrelationships were studied in 15 patients with an ileal pouch-anal anastomosis and 14 patients with an ileostomy after proctocolectomy for ulcerative colitis. Pouch effluent, compared with ileostomy effluent, had a greater ratio of anaerobes to aerobes (p less than 0.05), and greater numbers of Bacteroides (p less than 0.01) and Bifidobacteria (p less than 0.05). Fecal volatile fatty acids, products of anaerobic bacterial fermentation, were also increased in pouch effluent compared with ileostomy effluent (propionate, p less than 0.05; butyrate, p less than 0.01). Mucosal change in the pouches showed no significant correlation with frequency of defecation, completeness of emptying, or pouch design, but the degree of villous atrophy was correlated with the number of Bacteroides (rs = 0.93, p less than 0.01) and with fecal butyrate (rs = 0.68, p less than 0.05). Fecal propionate was significantly correlated with the percentage of stool retained after defecation (rs = 0.82, p less than 0.01). These findings indicate that the bacterial ecology of ileal pouches has an important influence on the morphology of their mucosal lining.

Adult↗
PubMed1982

Influence of unrefined potato starch on cecal fermentations and volatile fatty acid absorption in rats.

The effect of uncooked potato starch in the diet on cecal fermentation and absorption of volatile fatty acids and on changes in the digestive supply of nutrients were investigated. Dietary potato starch (25%) markedly increased cecal size and the cecal pool of volatile fatty acids. These were maximal in the postabsorptive state, whereas the most acidic cecal pH readings were observed during the late absorptive period. Compared to the basal diet, feeding potato starch did not change arterial concentrations of glucose, lactate or alanine. Nevertheless, blood acetate was increased, whereas plasma triglycerides and cholesterol were reduced. The digestive balance of nutrients was determined by measurements of portal blood flow and arteriovenous differences across the digestive tract: the digestive supply of glucose was maximal during the absorptive period, but was lower in rats fed the potato starch diet. The absorption of volatile fatty acids was strongly increased by feeding potato starch and was maximal in the postabsorptive state, whereas glucose absorption was finished. The volatile fatty acids the constituted the main source of energetic fuels coming from the digestive tract. These results indicate that the effect of potato starch on digestion and metabolism is similar to that of dietary fibers, and that the regular supply of large amounts of volatile fatty acids, particularly during the postabsorptive period, could bring about substantial changes in liver metabolism.

Alanine↗
PubMed1984

Absorption and metabolism of the volatile fatty acids in the hind-gut of the rabbit.

Volatile fatty acids (VFA) absorption in the large intestine of the anaesthetized rabbit was evaluated by measuring variations in the concentration of VFA in intestinal loops and plasma arteriovenous differences. Metabolic conversions were studied using [1-14C]acetate, [1-14C]propionate and [3,4-14C]butyrate. The hind-gut tissues metabolized the three VFA, although this metabolism varied with the segment studied. Butyrate was the best respiratory fuel for the colonic wall, followed by propionate; acetate participated also, but it was mainly converted to glutamate. The liver was the main organ metabolizing absorbed propionate and butyrate; acetate was available for extrahepatic tissue metabolism. For the rabbit, VFA represented about 40% of the maintenance energy requirement.

Acetates↗
PubMed1987

Origin and utilization of volatile fatty acids and lactate in the rabbit: influence of the faecal excretion pattern.

Interrelations between bacterial metabolites (volatile fatty acids, lactate) in the gut contents and the blood in relation to the faecal excretory cycle (soft or hard faeces) were studied in anaesthetized rabbits. It appeared that the level of organic acids in the alimentary tract varied cyclicly with the faecal excretion pattern. The lactate entering the portal circulation originates from the stomach, while the volatile fatty acids (VFA) originate from the hind-gut. Net absorption from the digestive tract and hepatic utilization of fermentation acids were greater when the rabbits produced hard faeces (hard-phase) compared with soft faeces (soft-phase). Propionate and butyrate reaching the liver were almost quantitatively removed; acetate and lactate were available for extra-hepatic tissue metabolism. Whatever the excretion pattern the levels of VFA in the arterial circulation remained remarkably constant; blood lactate, however, was lower during the soft-phase. Absorption of bacterial metabolites, like their metabolism in the liver, showed a circadian rhythm parallel to the changes in the activity of the adrenal glands, i.e. the activity was enhanced during the hard-phase.

Animals↗
PubMed1983

Effects of volatile fatty acids and ketone bodies on lipolysis in isolated adipocytes from Norwegian reindeer (Rangifer tarandus).

The effect of volatile fatty acids (acetate and propionate) and ketone bodies (acetoacetate and DL-3-hydroxybutyrate) on adrenaline stimulated lipolysis have been studied in isolated adipocytes from Norwegian reindeer. All four substances caused a strong (63-90%) inhibition of lipolysis, measured as glycerol release, at low concentrations of adrenaline (5 nM). At higher adrenaline concentrations (50 nM) inhibition only took place in the presence of propionate (30% inhibition) or DL-3-hydroxybutyrate (43% inhibition). DL-3-hydroxybutyrate caused a marked reduction in adrenaline stimulated glycerol release, even at very low concentrations. The effective dose causing 50% inhibition (ED50) was 1.5 mM. It is suggested that both volatile fatty acids and ketone bodies can act as important volatile regulators of lipopolysis in this high arctic ruminant undergoing great seasonal changes in volatile fatty acid and supposedly ketone body production.

3-Hydroxybutyric Acid↗
PubMed1975

[Effect of different types of rations on various characteristics of ruminal and intermediary metabolism in sheep. 1. Formation of volatile fatty acids].

Studies on Ruminal Physiology were made with 15 growing female Merino sheep to investigate the influence of different types of rations on the fermentation of volatile fatty acids. The rations were constructed of green feed, straw and concentrates (type 1) or chemically treated straw pellets + concentrates (type 2). One ration (type 3) consisted of concentrates only. With regard to the total concentration of acids ration 3 was significantly superior to the 2 other types of rations. Moreover, ration 3 produced a specific fermentation pattern of the volatile fatty acids. This was characterized by a significant reduction in the molar proportion of acetate compared with ration 1 and 2 and a significant increase in the level of propionic and valeric acid relative to ration 1. Differences in the fermentation pattern between rations 1 and 2 were mainly limited to differences in the absolute and molar proportions of propionate where the straw pellet rations in each case produced the significant higher values. The acetate to propionate ratio was narrowed in the order of ration 1-3 (4.1 :1, 3.1:1, 2.6-2.9 :1). Statistically wellestablished negative correlations were found to exist between the concentrations of volatile fatty acids and the pH values which were established simultaneously.

Animal Feed↗
PubMed1992

Comparison of triplicated (S) and quadruplicated (W) pelvic ileal reservoirs. Studies on manovolumetry, fecal bacteriology, fecal volatile fatty acids, mucosal morphology, and functional results.

Capacity and compliance, efficiency of evacuation, fecal bacteriology, fecal volatile fatty acids, mucosal morphology, and functional outcome were studied in 20 patients with triplicated (S) and 20 patients with quadruplicated (W) reservoirs after ileal pouch-anal anastomosis. Compared with patients with S reservoirs, patients with W reservoirs were found to have greater efficiency of evacuation of radiolabeled synthetic stool [97% (91%-98%) vs. 74% (62%-89%); P less than 0.05], and their reservoirs were more capacious [350 mL (320-400 mL) vs. 228 mL (175-290 mL); P less than 0.01] and compliant [16.0 mL/cm H2O (13.8-19.0 mL/cm H2O) vs. 12.3 mL/cm H2O (7.4-14.6 mL/cm H2O); P less than 0.01]. Effluent from S reservoirs contained significantly greater numbers of bacteroides (P less than 0.05) and concentrations of acetic and propionic acids (P less than 0.05) than effluent from W reservoirs. The degree of mucosal inflammation and villous atrophy in each design of reservoir was not significantly different. The ratio of anaerobes to aerobes in pouch effluent was significantly correlated with the degree of mucosal inflammation (rs = 0.433; P = 0.035). Fecal volatile fatty acids were significantly correlated with the percentage of stool retained after defecation and degree of mucosal inflammation. The frequency of bowel action was significantly less in patients with W reservoirs than in patients with S reservoirs [3.5/day (3-4/day) vs. 6.0/day (4-7/day); P less than 0.01]. The results indicate marked differences between these two ileal reservoir designs.

Adolescent↗
PubMed1980

[Influence of pH on the transfer of volatile fatty acids in the isolated cecal wall of the rat].

The influence of pH on the transfer of acetic, propionic and butyric acids was studied in vitro using everted sacs of the rat caecum. The sacs were filled with 2 ml of saline medium and then shaken 1 hr at 38 degrees C in flasks containing the same medium. A Krebs-Ringer phosphate incubation medium was used with O2 as gas phase. Incubation mediums containing 15 mM acetic, propionic and butyric acids were adjusted to give three different pH values: 7.91, 7.00 and 6.03. After incubation the mucosal and serosal fluids were collected and samples were taken to determine the pH and the volatile fatty acid concentrations. The pH values of mucosal and serosal fluids changed slightly during the course of the experiments. There was net volatile fatty acid influx into caecal tissue from the serosal medium and into the mucosal medium from the caecal tissue. Lowering the pH from 7.00 to 6.03 resulted in a significant decrease of serosal volatile fatty acid influxes. Caecal tissue retained more volatile fatty acids by lowering the pH from 7.91 to 7.00 and 6.03. Acetic acid accumulated in the caecal tissue against its electro-chemical gradient at pH 6.03. Two different mechanisms appeared to favor the transport of ionized and non-ionized forms of volatile fatty acids through the caecal membranes.

Acetates↗
PubMed1979

Recovery of volatile fatty acids from biological materials for direct analysis by gas chromatography.

A simple and efficient methodology for preparing aqueous extracts of volatile fatty acids from biological materials, for direct analysis by gas chromatography is described. Peak areas and responses relative to n-butyric acid were used to calculate concentrations of the individual acids. An example is given for analysis of the volatile fatty acids found in the blood of the lugworm Aerinocola marina.

Animals↗
PubMed1973

Volatile fatty acids in the faeces of patients in 'germ-free' isolation.

Faecal volatile fatty acids represent the end products of the metabolism of the anaerobic flora of the large bowel. The excretion of these volatile acids has been investigated in five leukaemic patients maintained in plastic ;germ-free' isolators. Under ;isolator' conditions there is a pronounced fall in volatile fatty acid excretion. The possibility that the measurement of these acids may be used to monitor anaerobic overgrowth and recolonization in these patients is discussed.

Adult↗
PubMedDate not supplied

Effect of dietary lactose on cecal pH, bacteriostatic volatile fatty acids, and Salmonella typhimurium colonization of broiler chicks.

One-day-old broiler chicks were inoculated with volatile fatty acid producing cecal flora from adult chickens. The chicks were divided into four groups and provided 1) no lactose, 2) 2.5% lactose in water, 3) 5% lactose in feed, or 4) 10% lactose in feed, until 10 days of age. All groups were challenged at 3 days of age with 10(6) or 10(8) S. typhimurium. At 10 days, the number of Salmonella in the ceca of the chicks challenged with 10(6) Salmonella was significantly decreased (P less than 0.01) in the groups provided lactose as compared with the controls. A significant decrease (P less than 0.01) in Salmonella numbers occurred in the chicks challenged with 10(8) Salmonella and provided 10% lactose. Providing 2.5% lactose or 5% lactose failed to inhibit Salmonella growth in chicks challenged with 10(8) Salmonella. The pH of the ceca of the groups provided lactose decreased significantly (P less than 0.05) and was accompanied by significant increases (P less than 0.01) in the concentrations of bacteriostatic acetic and propionic acids. Results showed that providing dietary lactose to broiler chicks and inoculation with normal cecal flora decreased cecal pH, increased the concentrations of bacteriostatic volatile fatty acids, and inhibited Salmonella colonization.

Animals↗
PubMed1976

The determination of volatile fatty acids in the caecum of the conscious rabbit.

1. A method of obtaining dialysed samples from the caecum of the conscious rabbit is described. 2. Values for total volatile fatty acid content and for molar proportions of individual volatile fatty acids in dialysate samples were in good agreement with those obtained from caecal material. 3. The volatile fatty acid level in the caecum throughout the day was determined using two groups of animals, one group fed ad lib. and the other group on a restricted food intake. These results indicated a marked diurnal fluctuation in volatile fatty acid level in the caecum of rabbits fed once/d which was not evident in those fed ad lib.

Acetates↗
PubMed1981

Absorption of volatile fatty acid, Na, and H2O by the colon of the dog.

Volatile fatty acid (VFA) concentrations were examined in the gastrointestinal tract of dogs 24 and 48 hours after a meal. Small concentrations of VFA were present in the stomach and small intestine. Large concentrations were present in the large intestine at both periods after the meal, but the total quantity was reduced markedly between 24 and 48 hours. Colonic absorption and transport of VFA also were examined with in vitro and in vivo perfusion procedures. Both demonstrate that VFA were rapidly absorbed and that the rate of absorption/cm2 of colonic mucosa ws equivalent to that measured in the pig. In vivo results showed that VFA and Na were absorbed at the same rate, and their absorption showed a parallel increase with a decrease in pH of the perfusate. Absorption of Na and VFA alone could account for osmotic absorption of H2O from the colon. Results indicated that although the total quantity of VFA absorbed by the colon of the dog would be nutritionally insignificant, their absorption is of major importance to normal colonic absorptive processes.

Animals↗