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PubMed2002

Quercetin derivatives are deconjugated and converted to hydroxyphenylacetic acids but not methylated by human fecal flora in vitro.

By using a batch in vitro anaerobic fecal fermentation model, we have shown that the fecal microflora can rapidly deconjugate rutin, isoquercitrin, and a mixture of quercetin glucuronides. High levels of beta,D-glucosidase, alpha,L-rhamnosidase, and beta,D-glucuronidase were present. Rutin underwent deglycosylation, ring fission, and dehydroxylation. The main metabolite, 3,4-dihydroxyphenylacetic acid, appeared rapidly (2 h) and was dehydroxylated to 3-hydroxyphenylacetic acid within 8 h. The pattern of in vitro fermentation of rutin was not changed by changing the pH (6.0 or 6.9), fermentation scale (10 or 1000 mL), or donors of the inoculum. Hydroxyphenylacetic acids were not methylated by colon flora in vitro. The colonic microflora has enormous potential to transform flavonoids into lower molecular weight phenolics, and these might have protective biological activities in the colon. The site of absorption of flavonoids and the form in which they are absorbed are critical for determining their metabolic pathway and consequent biological activities in vivo.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2002

Inhibitory effect of natto, a kind of fermented soybeans, on LDL oxidation in vitro.

The oxygen radical scavenging activity of natto (fermented soybeans) and its inhibitory effect on the oxidation of rat plasma low-density lipoprotein (LDL) in vitro were investigated to evaluate the usefulness of the antioxidant properties of natto, which has been shown to have antioxidant activity. Natto was separated into three water-soluble fractions: high-molecular-weight viscous substance (HMWVS; Mw > 100 000), low-molecular-weight viscous substance (LMWVS; Mw < 100 000), and soybean water extract (SWE). LMWVS had the strongest radical scavenging activity for hydroxyl and superoxide anion radicals, as assessed by electron spin resonance. The increase of conjugated dienes in LDL oxidized by copper and an azo pigment was depressed by the addition of LMWVS and SWE. These results demonstrate that natto fractions have inhibitory effects on LDL oxidation as a result of their radical scavenging activity.

Animals↗
PubMed1995

Effects of soaking, cooking and fermentation on composition, in-vitro starch digestibility and nutritive value of common beans.

A common bean variety, grown in Burundi, was either fermented, soaked and/or cooked, and then assessed for nutrient composition, in-vitro starch digestibility and protein nutritive value. A decrease in ash, most minerals, vitamins, and some essential amino acids was noted for soaked, cooked and soaked-cooked beans. Compared to untreated beans, soaking decreased soluble sugar (9.8 percent) but increased starch (7.3 percent) and soluble fiber (16.9 percent). In cooked beans, an increase in soluble sugar (1.5 percent), and a decrease in thiamine (81.7 percent), starch (24.6 percent) and soluble fiber (16.6 percent) and nitrogen (2.9 percent) contents were observed. Crude fiber (6.9 percent) and starch (10.0 percent) increased while fat (17.6 percent), fatty acids (linoleic: 10.7 percent; linolenic: 14.3 percent) and soluble sugars (25.4 percent) and nitrogen (14.4 percent) decreased in soaked-cooked beans. Fermentation increased potassium (11.6 percent), soluble fiber (18.9 percent), and some amino acids but decreased fatty acids (linoleic: 13.5 percent; linolenic: 19.9 percent), soluble sugar (75.2 percent) and vitamin (riboflavin: 41.0 percent; niacin: 24.5 percent) contents in common beans. However, the in-vitro starch digestibility was greatly improved (12.3 percent) by cooking while it decreased in soaked beans (29.2 percent). Soaking-cooking and fermentation did not have any significant effect on the digestibility of common bean starch. Finally, among the five treatments applied to common beans, only fermentation showed a significant improvement (8.3 percent) on the protein nutritive value of this legume.

Amino Acids↗
PubMed2004

In vitro effects of individual fatty acids on protozoal numbers and on fermentation products in ruminal fluid from cattle fed a high-concentrate, barley-based diet.

The objective of this study was to investigate the effects of sodium salts of individual fatty acids on protozoal numbers and ruminal fermentation variables in vitro. Ruminal inoculum was obtained from two heifers fed a finishing diet consisting of (DM basis) 90% rolled barley grain, 4% barley silage, 5% soybean meal, and 1% mineralized salt. Fatty acids (FA) were included individually in the inoculum as follows: C6:0, C8:0, and C10:0 at concentrations (wt/vol) of 0.0625, 0.125, and 0.25%; C14:0 and C18:0 at concentrations of 0.125, 0.25, and 0.5%; and C12:0, C16:0, C18:1, C18:2, and C18:3 at concentrations of 0.25, 0.5, and 1.0%. 15N-Labeled casein was included as a N tracer. In the presence of medium-chain saturated FA (particularly C10:0 and C12:0), no ciliate protozoa (99.8%Entodinium spp.) were recovered from the incubation medium. Long-chain unsaturated FA (C18:3, C18:2, C18:1) also decreased (P < 0.05) protozoal numbers. At all concentrations tested, C10:0 and C12:0 decreased (P < 0.05) ammonia and total VFA concentrations (by 29 and 22%, respectively) and increased (P < 0.05) concentrations of total free amino acids, reducing sugars, and soluble protein. At the greatest concentrations of these FA, xylanase and amylase activities of the incubation media were decreased (P < 0.05). The C18 unsaturated FA increased (P < 0.05) the polysaccharide-degrading activities of the media. These in vitro results suggest that long-chain unsaturated FA in combination with medium-chain saturated acids have the potential to decrease protozoal numbers and ruminal ammonia utilization in cattle fed high-grain diets.

Ammonia↗
PubMed1987

Effect of fats and fatty acid combinations on ruminal fermentation in semi-continuous in vitro cultures.

Four in vitro trials were conducted to determine how ruminal fermentation is affected by source of fat, level of fat, and combinations of fatty acids. Trials I and II examined how volatile fatty acids (VFA) were changed by three sources of fat (blended animal-vegetable fat, corn oil and tallow fatty acids) each added to a hay substrate at six levels (0, 2, 4, 6, 8 and 10%). Increasing blended fat caused no changes in VFA levels except to decrease butyric acid from 12.1 to 9.9% of the total VFA (P less than .05). Corn oil and tallow fatty acids both increased propionic acid, causing the ratio of acetic to propionic acids (A/P) to decrease (P less than .01). Trial III tested different ratios of oleic/stearic and linoleic/stearic acids to determine if certain combinations were better for fermentation. There was no evidence of synergism among fatty acids since increasing the ratio of unsaturates steadily reduced A/P. Trial IV was designed to determine how changes in VFA levels reflect changes in fiber digestibility of substrates containing added fat. Volatile fatty acids having significant regressions with fiber digestibility were acetic acid (r = .648), propionic acid (r = -.670), total VFA concentration (r = .742) and A/P (r = .831). Results are interpreted to show that blended animal-vegetable fats are less toxic in the rumen than equal levels of other lipids, and the beneficial effects of blended fat cannot be attributed to a unique combination of fatty acids acting synergistically.

Animals↗
PubMed1997

Modification of colonic fermentation by bifidobacteria and pH in vitro. Impact on lactose metabolism, short-chain fatty acid, and lactate production.

Colonic fermentation plays an important role in the prevention of lactose intolerance and intestinal disorders. The objectives of this study were to evaluate whether supplementation with bifidobacteria modify colonic fermentation of lactose and short-chain fatty acid production and to assess influence of the pH in an in vitro continuous culture system. There was a significantly greater reduction in lactose concentrations at pH 6.7 than that at either pH 6.2 or pH 5.7, accompanied by the highest beta-galactosidase activity and D-lactate production. Bifidus supplementation reduced lactose and D-lactate concentrations and increased acetate production at pH 6.7. The study demonstrates that lactose is rapidly metabolized by colonic bacteria and lactose fermentation in vitro is pH dependent with a maximum rate at pH 6.7. Bifidobacteria supplementation may have the potential to improve lactose fermentation and to manipulate SCFA and lactate production.

Adult↗
PubMed2006

In vitro kinetic analysis of oligofructose consumption by Bacteroides and Bifidobacterium spp. indicates different degradation mechanisms.

The growth of pure cultures of Bacteroides thetaiotaomicron LMG 11262 and Bacteroides fragilis LMG 10263 on fructose and oligofructose was examined and compared to that of Bifidobacterium longum BB536 through in vitro laboratory fermentations. Gas chromatography (GC) analysis was used to determine the different fractions of oligofructose and their degradation during the fermentation process. Both B. thetaiotaomicron LMG 11262 and B. fragilis LMG 10263 were able to grow on oligofructose as fast as on fructose, succinic acid being the major metabolite produced by both strains. B. longum BB536 grew slower on oligofructose than on fructose. Acetic acid and lactic acid were the main metabolites produced when fructose was used as the sole energy source. Increased amounts of formic acid and ethanol were produced when oligofructose was used as an energy source at the cost of lactic acid. Detailed kinetic analysis revealed a preferential metabolism of the short oligofructose fractions (e.g., F2 and F3) for B. longum BB536. After depletion of the short fractions, the larger oligofructose fractions (e.g., F4, GF4, F5, GF5, and F6) were metabolized, too. Both Bacteroides strains did not display such a preferential metabolism and degraded all oligofructose fractions simultaneously, transiently increasing the fructose concentration in the medium. This suggests a different mechanism for oligofructose breakdown between the strain of Bifidobacterium and both strains of Bacteroides, which helps to explain the bifidogenic nature of inulin-type fructans.

Bacteroides↗
PubMed2002

Effect of probiotic fermentation on antinutrients and in vitro protein and starch digestibilities of indigenously developed RWGT food mixture.

Indigenously developed RWGT food mixture which contained rice flour, whey, sprouted green gram paste and tomato pulp (2:1:1:1 w/w) was autoclaved 1.5 kg/cm2, 15 min, 121 degrees C), cooled and fermented with 2% liquid culture (containing 10(6) cells/ml broth). Two types of fermentations were carried out i.e. single culture fermentation [L. casei, L. plantarum (37 degrees C, 24 hr.)] and sequential culture fermentation [S. boulardii (25 degrees C, 24 hr.) + L. casei (37 degrees C, 24 hr.)]; S. boulardii [(25 degrees C, 24 hr.) + L. plantarum (37 degrees C, 24 hr.)]. All the fermentations drastically reduced the contents of phytic acid, polyphenols and trypsin inhibitor activity while significantly improving the in vitro digestibilities of starch and protein. Sequential culture fermentations brought about higher changes as compared to single culture fermentations.

Analysis of Variance↗
PubMed1995

Effect of Pediococcus pentosaceus FBB61, pediocin A producer strain, in caecal fermentations.

The objective of this study was to investigate the effect of pediocin A in in vitro caecal fermentations. Pediococcus pentosaceus FBB61, pediocin A producer (bac+) and its isogenic mutant (bac-) Ped. pentosaceus FBB61-2 were added to fermentation vessels. Pediocin A did not alter the normal activity of caecal microflora. Nevertheless, the presence of pediocin A producer strain reduced proteolysis compared to the mutant strain as indicated by ammonia concentrations (P < 0.05), and isobutyric and isovaleric molar proportions (P < 0.05).

Ammonia↗
PubMed2006

New three-stage in vitro model for infant colonic fermentation with immobilized fecal microbiota.

The development and validation of a new three-stage culture system with immobilized fecal microbiota to simulate infant colonic ecosystem is described. Two continuous cultures with different fecal inocula were used to assess the validity and stability of the intestinal model. The total anaerobe populations measured in beads and effluent fermentations reached high concentrations similar to infant feces. Fluorescence in situ hybridization analyses and denaturing gradient gel electrophoresis profiles of effluent samples from the three reactors revealed complex patterns similar to that observed in the inoculum, indicating that fecal bacterial diversity was well-preserved and that dominant bacterial populations showed good stability among reactors. For both experiments, the bacterial populations and fermentation product concentrations were in the range of published data for infant feces. These results demonstrate that this new three-stage continuous culture with immobilized cells provides a useful tool for studying the infant colon ecosystem.

Bacteria↗
PubMed1984

Effect of selected dietary buffers upon utilization of concentrate- or roughage-based cattle diets: laboratory studies.

Four chemical buffers were evaluated with in vitro rumen fermentation studies using both an 80% concentrate and a 50% roughage diet. Treatments included a positive control (PC), negative control (NC) and four buffered diets in which 500 mg of either CaHPO4, CaCO3, NaHCO3 or Na4P2O7 were added. The PC consisted of unbuffered diet with one part rumen fluid and four parts McDougall's artificial saliva. In the unbuffered NC and buffered treatments, three-fourths of the artificial saliva was replaced by iso-osmotic saline. In the concentrate-based diet, NaHCO3 and Na4P2O7 elevated (P less than .05) pH above the NC. Starch digestion and total VFA were increased (P less than .05) by NaHCO3 compared with the NC while the molar proportion of individual VFA was not altered. Tetrasodium pyrophosphate had no effect on starch digestion or total VFA, but did increase (P less than .05) the molar proportion of acetic acid. Regarding the 50% roughage diet, both NaHCO3 and Na4P2O7 elevated (P less than .05) starch and cellulose digestion and total VFA compared with the NC. Both NaHCO3 and Na4P2O7 increased (P less than .05) the molar proportion of acetate to equal that of the PC. Tetrasodium pyrophosphate decreased (P less than .05) apparent starch digestion compared with the NC, but increased (P less than .05) the molar proportion of acetate. Compared with the NC, CaHPO4 and Na4P2O7 increased the quantity of microbial alpha-amino N in both diets. Soluble P was highly correlated with microbial protein synthesis in both the concentrate- and roughage-based diets (.92 and .90, respectively).

Ammonia↗
PubMed2001

Influence of supplemental chromium on concentrations of liver triglyceride, blood metabolites and rumen VFA profile in steers fed a moderately high fat diet.

This study evaluated the effects of supplemental Cr on liver triglycerides and blood metabolites in Holstein steers fed a moderately high fat (approximately 5.6% of dry matter) diet. Fourteen Holstein steers were blocked by BW and randomly assigned to a basal diet (control) or control diet supplemented with 0.8 mg/kg of Cr as chromium picolinate. Supplemental Cr had no effect on dry matter intake, average daily gain, serum glucose, insulin, cholesterol, and molar proportions of ruminal volatile fatty acids (VFA). Steers fed the diet supplemented with chromium picolinate had smaller concentrations of serum triglycerides at wk 3, plasma beta-hydroxybutyrate concentrations at wk 6, and liver triglycerides at wk 9. An in vitro mixed ruminal microorganism fermentation study was conducted to examine the effect of Cr on in vitro VFA production. Ruminal fluid from animals fed fescue hay and 1.1 kg of concentrate twice daily was added into a mixture containing 5 g of concentrate diet formulated to contain one of five concentrations of Cr (0, 0.2, 0.4, 0.8, or 1.6 mg/kg of Cr). The culture was incubated for 12 or 24 h. The molar proportion of propionate decreased, whereas butyrate and isobutyrate increased linearly with increasing Cr content at 12 h of incubation. Molar proportion of valerate alone increased linearly with increasing Cr content at 24 h of incubation. A second in vitro study evaluated the supplementation of Cr at concentrations of 0, 0.8, 1.6, 3.2, 6.4, 12.8, or 25.6 mg/kg. Molar proportions of acetate, propionate, and isovalerate, and total VFA production responded quadratically with increasing Cr content at 24 h. Results suggest that supplemental Cr may alter systemic lipid metabolism. In vitro fermentation altered VFA production with graded concentration of Cr and was not toxic to ruminal microorganisms at concentrations up to 25.6 mg/kg.

3-Hydroxybutyric Acid↗
PubMed1992

[In vitro simulation of rabbit cecal fermentation in a semi- continuous flow fermentor. II. Effect of inoculum type].

Two Rusitec fermentors were operated under identical conditions. One was seeded with an inoculum of rabbit caecal contents, and the other with bovine rumen contents. The fermentation substrate was rabbit feed that had been digested with amylase and pepsin. The substrate constituents (organic matter, OM and NDF) were lost in 48 h at a significantly higher rate in the presence of rumen inoculum (OM: +10%, NDF: +15%). The pHs of the 2 fermentors were similar at pH 6.6. The fermentors produced similar amounts of protein nitrogen per 24 h, after 6 d of adaptation. Volatile fatty acid production was slightly higher in the presence of rumen inoculum. The fermentor inoculated with rumen contents produced a higher percentage of propionic acid (25%) than of butyric acid (7%), while fermentation with rabbit caecal contents gave the opposite ratio (C3/C4 = 0.81). Consequently, only the rabbit caecal inoculum provided the fermentation profile characteristic of the species.

Amylases↗
PubMed1991

Sequential fermentation of pearl millet by yeasts and lactobacilli--effect on the antinutrients and in vitro digestibility.

Sequential culture fermentation by yeasts (S. diastaticus or S. cerevisiae) at 30 degrees C for 72 hr and then followed by lactobacilli fermentation (L. brevis or L. fermentum) at 30 degrees C for 72 h more resulted in a significant reduction in phytic acid and polyphenol content of pearl millet flour. Fermentation by S. diastaticus and L. brevis combination almost eliminated phytic acid from pearl millet flour. The combinations of S. diastaticus with both the lactobacilli reduced phytic acid more effectively than those of S. cerevisiae. The products fermented by S. cerevisiae and L. brevis and by S. diastaticus and L. brevis combinations had the highest protein and starch digestibility (in vitro).

Dietary Carbohydrates↗
PubMed1965

DETERMINATION OF STEAM-VOLATILE ORGANIC ACIDS IN FERMENTATION MEDIA BY GAS-LIQUID CHROMATOGRAPHY.

Five gas chromatographic liquid phases (25% Carbowax 20 M plus 4% H(3)PO(4), 17.5% dioctyl sebacate plus 7.5% sebacic acid, 17.5% dioctyl sebacate plus 7.5% docosanoic acid, 5% Tween 80, and 20% LAC-296 [poly (diethylene glycol adipate)] plus 2% H(3)PO(4)) were studied with respect to their utility in the separation and quantitation of steam-volatile organic acids commonly produced in fermentation. Optimal operating conditions and column stability for routine analysis were established. An Aerograph Hy-Fi gas chromatograph was used for all work, except the studies with Tween 80 in which an Aerograph A-90-C was employed. Chromatographic traces are presented of volatile fatty acid analyses with each of the liquid phases. Complete separation of all isomers of the fatty acids from C(2) to C(5) was accomplished by the Carbowax 20 M plus H(3)PO(4), dioctyl sebacate plus sebacic acid, and dioctyl sebacate plus docosanoic acid columns. The latter two liquid phases were extremely unstable and proved to be unsatisfactory for analysis of aqueous samples. A column of Carbowax 20 M + H(3)PO(4) separated steam-volatile organic acids completely. The volatile fatty acid isomers were separated by 5% Tween 80 somewhat less completely, and the peak shapes were not as sharp and symmetrical as that desired for good quantitative work. LAC-296 (20%) plus 2% H(3)PO(4) proved to be the most satisfactory of the liquid phases for routine analysis of deproteinated in vitro rumen fermentation media. The column has been used for routine analysis of rumen fermentation fluid and in vitro rumen incubation fluid. All the organic acids from C(2) to C(5), except isobutyric, could be quantitated with this column. Stability of the column with the aqueous solutions was extremely good. The standard deviation of the analysis of each volatile acid component in a fermentation fluid was less than 0.5 molar per cent. The short-chain organic acids (C(2) to C(5)) were shown to be extremely stable in aqueous solution for as long as 6 months after preparation for gas chromatographic analysis by protein precipitation with metaphosphoric acid-H(2)SO(4) and refrigeration at 4 C in stoppered tubes.

Animals↗
PubMed1983

In vitro effect of pH variations on rumen fermentation, and in vivo effects of buffers in lambs before and after adaptation to high concentrate diets.

An in vitro wheat fermentation study (Exp. 1) was conducted to investigate the effect of pH (pH 7, 6, 5 and 4) on rumen lactate and VFA production. In another study (Exp. 2), lambs were fed high concentrate diets containing either no additions (control), 2% sodium bentonite, 2% limestone, 2% NaHCO3 or 10% alfalfa hay. The effect of these diets was determined on ruminal and systemic measurements before and after dietary adaptation. Effect of the control, bentonite, limestone and NaHCO3 treatments on nutrient digestibilities and mineral retentions after adaptation were also determined. Lactate production in the rumen fluid incubated at pH 7 or 6 was negligible. Reducing incubation pH from 6 to 5 resulted in accumulation of both total and L(+)-lactate, but further reduction to pH 4 did not result in an additional increase in lactate production. Variations in incubation pH or time did not affect the ratio of D to L isomers. Lowering the incubation pH to below 6 reduced total VFA production and increased the acetate to propionate ratio. In Exp. 2, the feeding of buffers or alfalfa hay was effective in maintaining a more normal feed intake and ruminal pH, and reduced ruminal lactate. Blood measurements were not affected by dietary treatment. When animals were adapted to the experimental diets, the dietary buffers did not influence rumen and blood measurements. Lambs fed 2% NaHCO3 digested more (P less than .05) organic matter, crude protein, N-free extract and starch, and 2% limestone increased (P less than .05) fiber digestibility. Dietary buffers tended to increase fecal pH and reduce fecal starch Magnesium retention with 2% bentonite, Ca retention with 2% limestone and Na and Mg retention with NaHCO3 were all increased (P less than .05).

Animals↗
PubMed1990

Fermentative characteristics of cereal brans and vegetable fibers.

Dietary fiber has been suggested to alter the colonic environment and protect against colorectal diseases, but several recent epidemiological studies indicate that cereal and vegetable fibers may not confer the same benefit. To address this issue, five common cereal brans (barley, corn, oat, rice, and wheat) and five vegetable fiber isolates (broccoli, cabbage, carrot, cauliflower, and lettuce) were fermented in vitro with human fecal microbiota for 4, 8, 12, and 24 hours. Short-chain fatty acid (SCFA), hydrogen (H2), and methane (CH4) productions and neutral-detergent fiber (NDF) digestibility differed significantly with fiber source. The vegetable fibers were significantly more fermentable than were the cereal brans, as evidenced by greater NDF digestibility and increased productions of SCFA, H2, and CH4, despite the presence of fermentable starch and protein in the latter. We concluded that vegetable fibers may more effectively stimulate colonic fermentation than cereal brans do. These findings suggest an attribute (i.e., fermentability) that may partially explain previously observed differences between vegetable and cereal fiber consumption patterns and colorectal carcinogenesis.

Colorectal Neoplasms↗