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At least 163 records · Page 9Linked to original sources
PubMed1997

Variability in anticancer lignan levels in flaxseed.

Flaxseed and its major mammalian lignan precursor secoisolariciresinol diglycoside have been shown to be protective against chemically induced carcinogenesis in animal models. Although flaxseed is the richest source of mammalian lignan precursors, it is not known whether these levels vary with source. Thus the objective of this study was to determine how lignan levels in flaxseed are affected by variety, growing location, harvest year, and seeding time. Ten varieties of flaxseed (AC Linora, Andro, Flanders, Linott, McGregor, Noralta, NorLin, NorMan, Somme, and Vimy) were subjected to 1) in vitro fermentation with human fecal inoculum for 24 hours under anaerobic conditions to assess mammalian lignan production and 2) high-performance liquid chromatography (HPLC) analysis for secoisolariciresinol levels. Three of these varieties (Linott, McGregor, and NorLin) were grown in four locations, seeded early (May) for three different years, and, in one year, seeded early (May) or late (June). Significant differences in lignan production were observed among the different varieties, ranging from 0.96 mumol/g for Linott to 3.15 mumol/g for Somme flaxseed (p < 0.05). Growing location had significant effects on lignan production from all three varieties. Harvest year significantly affected only the Linott variety (p < 0.05), whereas seeding time had no effect. A significant correlation (r = 0.572, p < 0.003) was observed between lignan values obtained from HPLC and in vitro fermentation methods, indicating that HPLC analysis of flaxseed may be used as a predictor of its lignan production levels. Differences due to variety, harvest location, and harvest year of flaxseed should be taken into consideration when tumorigenesis studies are designed.

Antineoplastic Agents↗
PubMed2003

Effect of the addition of malate on in vitro rumen fermentation of cereal grains.

Batch cultures of mixed rumen micro-organisms were used to study the effects of different concentrations of malate (Rumalato(R); Norel & Nature S.A., Barcelona, Spain; composed of disodium malate-calcium malate (0.16:0.84, w/w)) on the fermentation of four cereal grains (maize, barley, wheat and sorghum). Rumen contents were collected from four Merino sheep fed lucerne hay ad libitum and supplemented with 300 g concentrate/d. Rumalato(R) was added to the incubation bottles to achieve final concentrations of 0, 4, 7 and 10 mm-malate. Gas production was measured at regular intervals up to 120 h. Malate increased (P<0.01) the average fermentation rate of all substrates, and the lag time decreased (P<0.05) linearly with increasing concentrations of malate for all substrates, with the exception of sorghum. In 17 h incubations, the final pH and total volatile fatty acid production increased (P<0.001) linearly for all substrates as malate concentration increased from 0 to 10 mm. Propionate and butyrate production increased (P<0.05), while the value of the acetate : propionate ratio and l-lactate concentrations decreased (P<0.05) linearly with increasing doses of malate. Malate treatment increased (P<0.05) the CO2 production and decreased the production of CH4, although this effect was not significant (P>0.05) for maize. Malate at 4 and 7 mm increased (P<0.05) optical density of the cultures measured at 600 nm for maize, with no differences for the other substrates. The results indicate that malate may be used as a feed additive for ruminant animals fed high proportions of cereal grains, because it increased pH and propionate production and decreased CH4 production and l-lactate concentrations; however, in general, no beneficial effects of 10 compared with 7 mm-malate were observed.

Animal Feed↗
PubMed1997

Effects of a live yeast culture and enzymes on in vitro ruminal fermentation and milk production of dairy cows.

Live yeast culture (Saccharomyces cerevisiae) grew best on malt extract agar and required incubation under aerobic conditions to maximize the number of viable cells. In sterile, anaerobic ruminal fluid that had been supplemented with malt extract, yeast cells remained viable and metabolically active for up to 48 h, as indicated by the production of ethanol. A supplement containing live yeast and enzymes was fed twice daily with a diet of 50:50 (wt/wt) forage to concentrate (dry matter basis) to continuous fermentors inoculated with mixed ruminal microorganisms. The supplement had no effect on major fermentation acids or pH. After the last supplement with yeast was fed, numbers of yeast immediately decreased in the fermentors and were not detectable after 24 h. In the first of two lactation experiments, Holstein cows in midlactation were offered a diet with corn silage as the primary forage source. Half of the cows received a top-dressing based on corn that contained 10 g/d of the yeast and enzyme supplement. The supplement had no effect on milk production, milk composition, or dry matter intake. In a second lactation experiment, high producing cows in early lactation were fed 0, 10, and 20 g/d of the supplement. Cows fed the control diet produced 36.4 kg of milk/d, and milk production was 39.3 and 38.0 kg/d from cows fed 10 and 20 g of yeast/d, respectively.

Animal Feed↗
PubMed1998

The effect of porcine bile acids on methane production by rumen contents in vitro.

Hindgut fermentation differs from rumen fermentation by a lower methane production and the presence of reductive acetogenesis. Bile acids which are lost into the lower digestive tract may have a promoting effect on reductive acetogenesis in the hindgut. In this experiment it was investigated if bile acids induce reductive acetogenesis in rumen fermentation in vitro. Rumen contents from a fistulated cow were incubated in vitro with ground hay and increasing amounts of porcine bile acids or bile acid salts. Bile acids inhibited methane production up to 70% of the control incubation. The concomitant increase in propionate production compensated for the lower methane production so that the 2H-recoveries were in a normal range between 79-92%. Therefore the occurrence of reductive acetogenesis could be excluded. It is concluded, that bile acids are a controlling factor in caecal methanogenesis.

Animals↗
PubMed1992

Effect of guar, pectin, psyllium, soy polysaccharide, and cellulose on breath hydrogen and methane in healthy subjects.

Different types of dietary fiber are fermented to various extents in vitro, but little is known about the effects of fiber on breath hydrogen and methane levels in vivo. Therefore, we studied the effects on breath hydrogen and methane of 15 g of guar, pectin, psyllium, soy polysaccharide, or cellulose in eight healthy subjects over a 12-h period. None of the fibers had a significant effect on breath hydrogen or methane concentrations, compared with the control (fasting). The four methane producers had lower breath hydrogen levels than the nonproducers 1 h after 15 g of lactulose (3 +/- 1 vs. 42 +/- 9, p less than 0.005) and 5-12 h after the different fibers (3.3 vs. 4.8 ppm; pooled SEM = 0.8; p less than 0.025). When the methane responses of the methane producers were expressed as increments relative to the control, there were small differences between treatments, with guar producing a larger response, 8.2 +/- 3.3 ppm, than cellulose, -2.9 +/- 2.3 ppm (p less than 0.05). The incremental methane responses of the different fibers in vivo were related to the previously reported production of propionic acid (r = 0.94, n = 5, p less than 0.02) and methane (r = 0.93, n = 4, NS) from in vitro fermentation of the same fibers. We conclude that methane producers have lower breath hydrogen levels than nonproducers. Purified fermentable and nonfermentable dietary fibers have no effect on breath hydrogen levels over 12 h in subjects previously consuming a normal diet. However, fermentable fibers may produce small increases in breath methane in methane-producing subjects.

Adult↗
PubMed2004

Effects of Lactobacillus helveticus fermented milk on bone cells in vitro.

Milk fermented with Lactobacillus helveticus (L. helveticus) contains small peptides such as isoleucyl-prolyl-proline (IPP) and valyl-prolyl-proline (VPP), which inhibit the angiotensin converting enzyme (ACE). We investigated the effects of L. helveticus fermented milk whey (Lh-whey) and its components, sour milk whey, calcium and IPP and VPP peptides, on bone cells in vitro. An osteoblast assay was performed by determining the amount of deposited calcium as an index of bone formation in cultures of mouse osteoblasts formed from bone marrow-derived osteoblast precursor cells. An osteoclast assay was performed by determining the activity of tartrate-resistant acid phosphatase released into the culture medium in cultures of mouse osteoclasts formed from bone marrow-derived osteoclast precursor cells. The Lh-whey increased bone formation 1.3-1.4 times with the 1 x 10(-5), 1 x 10(-4) and 1 x 10(-3) solutions. The IPP and VPP peptides also demonstrated a significant 5-fold activation of bone formation in in vitro osteoblast cultures, whereas the sour milk whey and calcium had no effect. No significant effects were observed on osteoclasts in vitro with any of the study products. L. helveticus fermented milk whey contains bioactive components that increase osteoblastic bone formation in vitro. The effect may be due to the ACE-inhibitory IPP and VPP peptides, which showed a similar effect to that of the L. helveticus fermented milk whey.

Acid Phosphatase↗
PubMed1996

Fermentation of carbohydrate in rat ileal excreta is enhanced with cecal inocula compared with fecal inocula.

The differential fermentative capacities of microflora from two regions of the large bowel and how fermentation was altered by prior exposure of the microflora to the substrate to be fermented were studied using an in vitro fermentation system. Bacterial inocula were prepared from cecal contents and feces from three groups of rats fed purified diets containing 100 g/kg dietary fiber from canned peas or psyllium seed husk, or a nonpurified diet containing 170 g/kg dietary fiber. The substrate for all fermentations was ileal excreta from colectomized rats fed a purified diet containing 100 g/kg dietary fiber from canned peas. Anaerobic fermentations were conducted for 0, 3, 6, 12, 24, 48 and 96 h. Sugars of the unfermented polysaccharides were measured by gas chromatography following acid hydrolysis; disappearance was the measure of fermentation. Independent of inoculum source, > 90% of the starch and arabinose and 75% of the uronic acids, but < 30% of non-starch glucose (the measure of cellulose), were fermented by 24 h. Cecal inocula fermented arabinose and uronic acids more quickly (P < 0.05) and fermented more (P < 0.05) non-starch glucose than fecal inocula. Inocula adapted to psyllium seed husk fermented starch faster (P < 0.05) and non-starch glucose, arabinose and uronic acids more slowly (P < 0.05) than inocula adapted to peas or nonpurified diet. Bacterial efficiency of carbohydrate utilization, the increase in muramic acid/mole carbohydrate fermented, was greatest (P < 0.05) with cecal inocula adapted to peas. We conclude that using cecal microflora as the inoculum source provides a more accurate index of fermentation during transit through the large bowel and that noncellulosic and storage polysaccharides of the plant cell wall are utilized before cellulose.

Animals↗
PubMed2004

Effect of inhibitor concentration and end-product accumulation on estimates of ruminal in vitro protein degradation.

Effects of varying the concentrations of hydrazine sulfate (HS) and chloramphenicol (CAP), inhibitors of microbial-N uptake and protein synthesis, on rates of protein degradation estimated from net appearance of NH3 and total amino acids (TAA) were studied in a ruminal in vitro fermentation system. Without inhibitors, recoveries of N added as NH3 and TAA were 4 and 6% after 4-h incubations, and apparent degradation rates estimated from release of NH3 and TAA for casein, solvent soybean meal (SSBM), and expeller soybean meal (ESBM) approached 0. Increasing inhibitor concentrations from the standard amounts of 1 mM HS plus 30 mg of CAP/L to 2 mM HS plus 90 mg of CAP/ L gave rise to numerically greater N recoveries and degradation rates, but these differences were not statistically significant. Compared with the standard inhibitor concentrations, use of 2 mM HS, without CAP, yielded similar recoveries and rates, but 30 or 90 mg of CAP/L, without HS, was not satisfactory. Versus that with 1 mM HS plus 30 mg of CAP/L, media containing 2 mM HS plus 90 mg of CAP/L gave increased TAA recoveries and higher rates for casein, but not SSBM, in the presence of added starch. Faster degradation rates were obtained for casein, but slower rates for SSBM and ESBM, in Sweden versus Wisconsin using inocula from cows fed different diets but with similar CP and energy contents. Differences in microbial catabolism of peptides may account for differences in degradation rates observed between Sweden and Wisconsin. Adding NH3 plus free and peptide-bound amino acids to the inoculum reduced apparent degradation rates, possibly via end-product inhibition. Analysis of data from multiple time-point incubations indicated that casein degradation followed simple, first-order kinetics, while a biexponential model fitted degradation patterns for both SSBM and ESBM.

Amino Acids↗
PubMed1988

Susceptibility of dysgonic fermenter 2 to antimicrobial agents in vitro.

Dysgonic fermenter 2 (DF-2) is a fastidious, gram-negative organism well recognized as a cause of fulminant septicemia in patients without spleens or patients with alcoholic cirrhosis. In vitro antibiotic susceptibility testing of eight strains with a Schaedler broth dilution technique revealed DF-2 to be susceptible to all of the antibiotics tested except aztreonam. Previous reports that DF-2 is aminoglycoside resistant were based on disk diffusion or agar dilution assays that may be less reliable given the slow growth of the organism and its requirement for CO2 incubation. Penicillin is commonly used as prophylaxis after dog bites and has excellent activity against DF-2.

Anti-Bacterial Agents↗
PubMed2004

Effects of natural plant extracts on ruminal protein degradation and fermentation profiles in continuous culture.

Eight dual-flow continuous culture fermenters were used in four consecutive periods of 10 d to study the effects of six natural plant extracts on ruminal protein degradation and fermentation profiles. Fermenters were fed a diet with a 52:48 forage:concentrate ratio (DM basis). Treatments were no extract (CTR), 15 mg/kg DM of a mixture of equal proportions of all extracts (MIX), and 7.5 mg/kg DM of extracts of garlic (GAR), cinnamon (CIN), yucca (YUC), anise (ANI), oregano (ORE), or pepper (PEP). During the adaptation period (d 1 through 8), samples for ammonia N and VFA concentrations were taken 2 h after feeding. On d 9 and 10, samples for VFA (2 h after feeding), and peptide, AA, and ammonia N concentrations (0, 2, 4, 6, and 8 h after feeding) were also taken. Differences were declared at P < 0.05. During the adaptation period, total VFA and ammonia N concentrations were not affected by treatments. The acetate proportion was higher from d 2 to 6 in CIN, GAR, ANI, and ORE, and the propionate proportion was lower from d 2 to 4 in CIN and GAR, and from d 2 to 5 in ANI and ORE, compared with CTR. However, the proportion of individual VFA (mol/100 mol) was similar in all treatments after d 6, except for valerate in d 9 and 10, which was lower in PEP (2.8 +/- 0.27) compared with CTR (3.5 +/- 0.27). The average peptide N concentration was 31% higher in MIX, and 26% higher in CIN and YUC compared with CTR (6.5 +/- 1.07 mg/100 mL). The average AA N concentration was 17 and 15% higher in GAR and ANI, respectively, compared with CTR (7.2 +/- 0.77 mg/100 mL). The average ammonia N concentration was 31% higher in ANI and 25.5% lower in GAR compared with CTR (5.5 +/- 0.51 mg/100 mL). The accumulation of AA and ammonia N in ANI suggested that peptidolysis and deamination were stimulated. The accumulation of AA N and the decrease in ammonia N in GAR suggests that deamination was inhibited. The accumulation of peptide N and the numerical decrease in AA N in CIN suggest that peptidolysis was inhibited. Results indicate that plant extracts modified ruminal fermentation, but microbes were adapted to some extracts after 6 d of fermentation. Therefore, data from short-term in vitro fermentation studies may lead to erroneous conclusions, and should be interpreted with caution. Careful selection of these additives may allow the manipulation of protein degradation in the rumen.

Acetates↗
PubMed1994

Kinetics of niacin supplements in lactating dairy cows.

The kinetics of niacin supplements in lactating dairy cows and the stability of supplements during in vitro fermentation were examined. Four multiparous Holstein cows (200 DIM) with ruminal and duodenal cannulas were fed a TMR either unsupplemented or supplemented with 12 g/d of nicotinic acid, 12 g/d of nicotinamide, or 6 g/d combination of each niacin source in a 4 x 4 Latin square design. Ruminal and duodenal concentrations of nicotinic acid increased with niacin supplementation, but DMI, yields of milk and FCM, most measures of milk composition, ruminal VFA, and plasma NEFA and BHBA concentrations were unaffected by niacin supplementation at this stage of lactation. Apparent digestibilities of most nutrients were greater when both sources of niacin were supplemented than when either source was supplemented separately. Duodenal nicotinic acid concentrations were higher for cows supplemented with nicotinamide than for cows receiving nicotinic acid, but the opposite was true for nicotinic acid concentrations in plasma. The results of both experiments indicated that nicotinamide was converted rapidly to nicotinic acid by microorganisms in the reticulorumen. Supplementation with either nicotinic acid or nicotinamide effectively can increase the amount of nicotinic acid available to the cow; however, some source effects remain to be explained.

Animal Feed↗
PubMed2004

Polydextrose, lactitol, and fructo-oligosaccharide fermentation by colonic bacteria in a three-stage continuous culture system.

In vitro fermentations were carried out by using a model of the human colon to simulate microbial activities of lower gut bacteria. Bacterial populations (and their metabolic products) were evaluated under the effects of various fermentable substrates. Carbohydrates tested were polydextrose, lactitol, and fructo-oligosaccharide (FOS). Bacterial groups of interest were evaluated by fluorescence in situ hybridization as well as by species-specific PCR to determine bifidobacterial species and percent-G+C profiling of the bacterial communities present. Short-chain fatty acids (SCFA) produced during the fermentations were also evaluated. Polydextrose had a stimulatory effect upon colonic bifidobacteria at concentrations of 1 and 2% (using a single and pooled human fecal inoculum, respectively). The bifidogenic effect was sustained throughout all three vessels of the in vitro system (P = 0.01 seen in vessel 3), as corroborated by the bacterial community profile revealed by %G+C analysis. This substrate supported a wide variety of bifidobacteria and was the only substrate where Bifidobacterium infantis was detected. The fermentation of lactitol had a deleterious effect on both bifidobacterial and bacteroides populations (P = 0.01) and decreased total cell numbers. SCFA production was stimulated, however, particularly butyrate (beneficial for host colonocytes). FOS also had a stimulatory effect upon bifidobacterial and lactobacilli populations that used a single inoculum (P = 0.01 for all vessels) as well as a bifidogenic effect in vessels 2 and 3 (P = 0.01) when a pooled inoculum was used. A decrease in bifidobacteria throughout the model was reflected in the percent-G+C profiles.

Bacteria↗
PubMed1997

Effect of yeast culture and phenolic acids on the physiology of rumen fermentation determined in vitro.

The effect of p-hydroxybenzoic acid (HBA), syringic acid (SYA) and yeast culture (YS) on rumen fermentation in vitro has been investigated. Meadow hay was used as a substrate and rumen fluid as an inocula. The yeast culture Levucel contained 5x10(8) yeast cells Saccharomyces cerevisiae per 1 g of dry matter and was used in the amount of 0.5 g/l of the medium. The following combinations of additives were used: hay without additive, hay + YS, hay with 1, 5 or 10 mmol HBA or SYA, and hay + YS with 1, 5 or 10 mmol HBA or SYA. The test tubes were incubated for 96 hours at 39 degrees C. The results showed that 1 mmol HBA had a significant effect on yeast efficacy. This was manifested in the increased degradability of hay dry matter (P <0.05) and enhanced total gas production (P<0.05). SYA in the same amount combined with yeast had a similar effect on gas production (P<0.05), but hay dry matter degradability was not affected. The results showed a slight effect of phenolic acids and yeast culture on hay rumen fermentation in vitro.

Animals↗
PubMed1978

Effect of technical grade pentachlorophenol on rumen microorganisms.

The toxicity of technical grade pentachlorophenol to rumen microorganisms was tested by an in vitro fermentation procedure. Rumen fluid was collected from a fistulated mature steer fed a diet of all alfalfa hay. The compound was dissolved in absolute ethanol and added in vitro at concentrations ranging from 0 to 100 ppm. Digestion of cellulose and production of volatile fatty acids over 24 and 48 h of incubation was used to assess toxicity. Both cellulose digestion and propionic acid production were decreased at the 10 ppm concentration. The results suggest that technical grade pentachlorophenol has the potential to interfere with utilization of cellulose in ruminants.

Animals↗
PubMed2005

Symbiotic fermentation, digesta passage, and gastrointestinal morphology in bullfrog tadpoles (Rana catesbeiana).

Relative to other herbivorous vertebrates, the nutritional ecology and digestive physiology of anuran larvae remain poorly understood. Our objective was to compare gut structure and inhabitants, digesta passage, and microbial fermentation in bullfrog tadpoles (Rana catesbeiana) to those in other herbivores. Bullfrog tadpole gastrointestinal tracts were long and voluminous, with an enlarged colon that harbored a diverse symbiotic community. The transit time for particulate markers passing through bullfrog tadpoles was 6 h, the median retention time was 8-10 h, and gut clearance was 10-14 h postingestion. Relatively high levels of short-chain fatty acids in the hindgut of tadpoles indicated active microbial fermentation in this gut region. This report represents the first account of gastrointestinal fermentation in the class Amphibia. On the basis of in vitro fermentation assays, we estimated that microbial fermentation in the hindgut provides 20% of the total daily energy requirement of bullfrog tadpoles. These tadpoles also exhibited coprophagy, a practice that provides important nutritive gains in other herbivores. The physiological and behavioral characteristics of these tadpoles are remarkably similar to those of other small-bodied, hindgut-fermenting vertebrates, suggesting convergent digestive strategies among a broad range of herbivorous taxa.

Animals↗