Kinetics of Lactobacillus plantarum 44a in the faeces of tilapia (Oreochromis niloticus) after its intake in feed.

AIMS: To study the kinetic passage of Lactobacillus plantarum 44a from feed to faeces of tilapia in order to calculate the number of Lactobacillus excreted. METHODS AND RESULTS: In a single-dose experiment, duplicate lots of 26 fish devoid of intestinal lactobacilli were fed with diets containing c. 4.5 x 10(11), 6.3 x 10(8), 6.0 x 10(5) and 0 CFU of Lact. plantarum 44a per single feed ration. In the multiple-dose experiment, duplicate lots of 30 fish each were supplied with a diet containing 1 x l0(11) CFU of Lact. plantarum 44a as follows: 14 times in 14 days, five times in 14 days, once in 14 days and zero times in 14 days. Faeces were periodically collected and analysed for their lactobacilli content by using a selective media. The kinetics of Lactobacillus in the faeces was described as a pulse signal defined by three parameters: theta, A(o) and the time. theta, was identified as the time to reach the peak (x axis) and A(o) was a constant. A(o) divided by e, was identified as the height of the peak (y axis). The area below the curve A(o)theta allowed the calculation of the total number of lactobacilli excreted. The ability of the mathematical model to describe the actual values was tested by a linear regression analysis. In most of the cases, the equations showed an intercept close to zero (P > 0.05) and angular coefficients near one. CONCLUSIONS: Lactobacillus plantarum 44a was excreted in short pulse signals described by a mathematical model which allowed calculating the area below the curve and consequently the survival rate. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides a quantitative method to study the kinetics of excretion of a probiotic bacterium in the faeces.

Health and growth of veal calves fed milk replacers with or without probiotics.

Four experiments with 1-wk-old veal calves were conducted to assess the influence of probiotics on growth and health indicators. In experiments 1 and 2, the liquid probiotic supplements were administered daily from experimental d 1 to 15. The treatment period in experiments 3 and 4 was extended to 56 d. The probiotics used were a multispecies probiotic (MSPB) containing different probiotic species of human origin, or a calf-specific probiotic (CSPB) containing 6 Lactobacillus species isolated from calf feces and selected on the basis of a combination of characteristics. When the data for the 4 experiments were pooled, the probiotics enhanced growth rate during the first 2 wk. During the 8-wk experimental period, average daily gain and feed efficiency were significantly improved in the probiotic-treated groups. The MSPB-induced increase in weight gain was greater when the control calves were considered less healthy based on a health score (an index of diarrhea and therapeutic treatments). Probiotic treatment tended to diminish mortality. The CSPB treatment reduced the incidence of diarrhea and the fecal counts of coliforms. When therapeutic treatment was intensive in the control calves, the ingestion of probiotics reduced the percentage of calves that required therapy and the amount of treatments needed against digestive or respiratory diseases. There was no clear difference in the efficiency of the MSPB and CSPB preparations. Further research is necessary to identify underlying mechanisms and to evaluate the potential of probiotics to improve respiratory health in veal calf production.

Effects of dietary non-digestible oligosaccharides on microbial characteristics of ileal chyme and faeces in weaner pigs.

Fructooligosaccharides (FOS) and transgalactooligosaccharides (TOS), which are non-digestible oligosaccharides (NDO), were included at 10 and 40 g/kg in an NDO--free control diet at the expense of purified cellulose. Each of the 5 diets was fed to 4 weaner pigs and microbial characteristics of their ileal chyme and faeces were assessed. The NDO-pigs had lower ileal pH than the control pigs. Dietary NDO did not affect the ileal volatile fatty acid concentration, though FOS-pigs had a higher concentration of lactic acid and relatively more iso-valeric acid and less acetic acid than TOS-pigs. The NDO-pigs had lower ileal aerobic bacterial counts than the control pigs, whilst the FOS-pigs had a larger ileal anaerobic bacterial counts than the TOS-pigs. The NDO-pigs had an higher faecal pH and their faecal volatile fatty acid pool contained relatively more iso-butyric acid and iso-valeric acid than the control pigs. The TOS-pigs tended to have higher faecal anaerobic bacterial counts and had a smaller concentration of faecal volatile fatty acid than the FOS-pigs. We concluded that whilst effects at the faecal level may have been partly due to a reduced intake of cellulose, dietary NDO can exert precaecal prebiotic effects in weaner pigs.

Fermentation of plant cell wall derived polysaccharides and their corresponding oligosaccharides by intestinal bacteria.

New types of nondigestible oligosaccharides were produced from plant cell wall polysaccharides, and the fermentation of these oligosaccharides and their parental polysaccharides by relevant individual intestinal species of bacteria was studied. Oligosaccharides were produced from soy arabinogalactan, sugar beet arabinan, wheat flour arabinoxylan, polygalacturonan, and rhamnogalacturonan fraction from apple. All of the tested substrates were fermented to some extent by one or more of the individual species of bacteria tested. Bacteroides spp. are able to utilize plant cell wall derived oligosaccharides besides their reported activity toward plant polysaccharides. Bifidobacterium spp. are also able to utilize the rather complex plant cell wall derived oligosaccharides in addition to the bifidogenic fructooligosaccharides. Clostridium spp., Klebsiella spp., and Escherichia coli fermented some of the selected substrates in vitro. These studies do not allow prediction of the fermentation in vivo but give valuable information on the fermentative capability of the tested intestinal strains.

Transglycosidase activity of Bifidobacterium adolescentis DSM 20083 alpha-galactosidase.

Bifidobacterium adolescentis, a gram-positive saccharolytic bacterium found in the human colon, can, alongside other bacteria, utilise stachyose in vitro thanks to the production of an alpha-galactosidase. The enzyme was purified from the cell-free extract of Bi. adolescentis DSM 20083T. It was found to act with retention of configuration (alpha-->alpha), releasing alpha-galactose from p-nitrophenyl galactoside. This hydrolysis probably operates with a double-displacement mechanism, and is consistent with the observed glycosyltransferase activity. As alpha-galactosides are interesting substrates for bifidobacteria, we focused on the production of new types of alpha-galactosides using the transgalactosylation activity of Bi. adolescentis alpha-galactosides. Starting from melibiose, raffinose and stachyose oligosaccharides could be formed. The transferase activity was highest at pH 7 and 40 degrees C. Starting from 300 mM melibiose a maximum yield of 33% oligosaccharides was obtained. The oligosaccharides formed from melibiose were purified by size-exclusion chromatography and their structure was elucidated by NMR spectroscopy in combination with enzymatic degradation and sugar linkage analysis. The trisaccharide alpha-D-Galp-(1-->6)-alpha-D-Galp-(1-->6)-D-Glcp and tetrasaccharide alpha-D-Galp-(1-->6)-alpha-D-Galp- (1-->6)-alpha-D-Galp-(1-->6)-D-Glcp were identified, and this indicates that the transgalactosylation to melibiose occurred selectively at the C-6 hydroxyl group of the galactosyl residue. The trisaccaride alpha-D-Galp-(1-->6)-alpha- D-Galp-(1-->6)-D-Glcp formed could be utilised by various intestinal bacteria, including various bifidobacteria, and might be an interesting pre- and synbiotic substrate.

Comparison of media for the detection of bifidobacteria, lactobacilli and total anaerobes from faecal samples.

The interest in functional foods, probiotics and prebiotics requires a proper method to determine specific bacterial groups in the intestinal flora, especially bifidobacteria and lactobacilli. Three media for lactobacilli (MRS, Rogosa, LAMVAB), three media for bifidobacteria (RB, NPNL, Beerens medium) and nine media for total anaerobes have been tested for selectivity and recovery. For total anaerobes Faecal Reinforced Clostridial Agar (FRCA) showed the highest cfu/g, followed by Columbia Blood Agar and BHI Blood agar. There were no significant differences between the media tested. Reduced physiological salt solution was found to be the best dilution medium. For bifidobacteria and lactobacilli samples of human faeces, cat faeces and pig ileal contents were used. Bifidobacteria could reliably be determined on all three media tested in human faeces, but not on pig ileal contents or cat faeces. Absolute counts were highest in human samples. No lactobacilli could be isolated on MRS in either sample, none of the colonies in the countable plates were lactobacilli. For Rogosa over 90% of the colony types observed in human samples were not lactobacilli. For cat faeces this was 58%, but no false positives were observed in the pig ileal samples. For LAMVAB the percentages of false positive colony types were 9, 14 and 0% for human, cat and pig samples. It can be concluded that for bifidobacteria RB and Beerens medium show comparable results, and can be used to quantify bifidobacteria in human faeces, but none of the media tested is suitable for reliably counting bifidobacteria from pig and cat samples. For lactobacilli LAMVAB shows the highest sensitivity.

Effect of transgalactooligosaccharides on the composition of the human intestinal microflora and on putative risk markers for colon cancer.

BACKGROUND: Nondigestible oligosaccharides have been claimed to benefit the health of the colon by selectively stimulating the growth of bifidobacteria and by decreasing the toxicity of the colon contents. OBJECTIVE: We compared the effect of 2 doses of transgalactooligosaccharides and a placebo on the composition and activity of the intestinal microflora in 18 women and 22 men. DESIGN: Strictly controlled experimental diets were supplied to 3 intervention groups in a parallel design. The study was divided into 2 consecutive 3-wk periods during which each participant consumed a run-in diet followed by an intervention diet that differed only in the amount of transgalactooligosaccharides: 0 (placebo), 7.5, and 15 g/d. Breath samples and fecal samples were collected at the end of both the run-in and intervention periods. RESULTS: Apparent fermentability of transgalactooligosaccharides was 100%. The highest dose of transgalactooligosaccharides significantly increased the concentration of breath hydrogen by 130% (P < 0.01) and the nitrogen density of the feces by 8.5% (P < 0.05). The number of bifidobacteria increased after both placebo and transgalactooligosaccharides ingestion, but the differences between these increases were not significantly different. Transgalactooligosaccharides did not significantly affect bowel habits; stool composition; the concentration of short-chain fatty acids or bile acids in fecal water; the concentration of ammonia, indoles, or skatoles in feces; fecal pH; or the composition of the intestinal microflora. CONCLUSION: We conclude that transgalactooligosaccharides are completely fermented in the human colon, but do not beneficially change the composition of the intestinal microflora, the amount of protein fermentation products in feces, or the profile of bile acids in fecal water.

Growth of enterobacteria on fructo-oligosaccharides.

Fructo-oligosaccharides (FOS) can be fermented by most species of enterobacteria present in the human intestine. Fermentation was confirmed by increased growth rates, low final pH and degradation patterns using high performance anion exchange chromatography (HPAEC). Growth rates were increased when FOS was added to the growth medium. Growth rates on all substrates differed widely between strains within the same species. HPAEC analysis showed that each strain degraded the oligosaccharides differently, but a preference for the smaller oligosaccharides was observed. No differences were observed between the two commercial preparations, the inulo-oligosaccharides and neosugars. Fermentation was rapid as could be determined by acidification tests using cell suspensions. It can be concluded that enterobacteria may play a role in overall fermentation of FOS in the colon and, in addition, due to competitive exclusion, may prevent survival of ingested pathogenic enterobacteria.

In vitro cariogenicity of trans-galactosyl-oligosaccharides.

Trans-galactosyl-oligosaccharides (TOS) are a class of oligosaccharides produced by transgalactosylation of lactose. TOS are used as bifidogenic factors in human and animal nutrition. TOS can be present in the oral cavity and form a risk of caries. All oral bacteria tested were able to degrade and ferment both TOS and galactosyllactose (GLL), one of its components. Growth was improved compared with carbohydrate-free media and acid was produced after 24 h incubation of the bacteria with TOS and GLL. Degradation patterns, using HPAEC, showed degradation of most components. GLL was degraded only partially. Rapid acidification was only observed for Streptococcus mutans, resulting in a pH of 5.4 within 30 min. All other strains fermented TOS and GLL only slowly. Plaque formation could not be detected on both substrates. It can be concluded that TOS and GLL present only a small risk of caries formation, unless proven otherwise in animal studies.

Fate of fructo-oligosaccharides in the human intestine.

There is a need for studies on colonic fermentation in order to learn more about health and diseases of the colon. The aim of the present study was to evaluate the fate of two different doses of fructo-oligosaccharides (5 and 15 g/d) v. glucose in the intestine of healthy men. Twenty-four volunteers participated in a 5-week study. The study was a completely balanced multiple crossover trial using an orthogonal Latin-square design for three periods, with supplement periods of 7 d and two 7 d wash-out periods. Breath samples and faecal samples were collected. There was a clear gaseous response to the consumption of fructo-oligosaccharides. The highest dose significantly increased 24 h integrated excretion of breath H2 (P < 0.05). Breath H2 excretion after ingestion of 5 g fructo-oligosaccharides was higher than control, but did not reach significance. No effects on the total concentration of short-chain fatty acids in faeces were observed, no modification of the molar proportions of the various short-chain fatty acids was observed. The faecal pH did not change. No changes in faecal weight were observed. No fructo-oligosaccharides were recovered in faeces. We conclude that fructo-oligosaccharides added to the diet of young Western subjects are fully metabolized in the large intestine. The level of fermentation seem to be dose-dependent.

Degradation and fermentation of fructo-oligosaccharides by oral streptococci.

Fructo-oligosaccharides (FOS) are claimed to have a positive effect on the intestinal flora. They are being used in functional foods in Japan and Europe. This group have tested the degradation of two commercial FOS preparations by oral streptococci in order to predict the cariogenicity of these products. Both preparations could be fermented to some extent by the species of oral streptococci tested. The enzymes necessary for the degradation of FOS were inducible. Each strain showed a specific degradation pattern. All strains, particularly Streptococcus mutans rapidly produced acid, mainly lactic acid. Streptococcus mitis also produced high concentrations of acetic acid. Plaque formation by Strep. mutans was similar to the sucrose control. It is concluded that FOS are cariogenic to a similar extent as sucrose.

Fruit juice malabsorption: not only fructose.

Malabsorption of free fructose, when ingested in excess over glucose, is considered a significant factor in apple juice induced diarrhoea. Absorption of the carbohydrates in fruit juices was investigated by means of the hydrogen breath test in 15 healthy children aged 2.2-6.4 years, consuming 15 ml kg-1 of each juice with a maximum of 375 ml. Incomplete absorption was found following the ingestion of apple juice (5/5), grape juice (10/10) and bilberry juice (8/10), although the last two contain equivalent concentrations of fructose and glucose. When the same tests were repeated after yeast treatment of the juices, which leads to major reductions in fructose and glucose contents, malabsorption was found to persist. No symptoms were observed following any of the tests. Our results suggest a significant role for other carbohydrates than fructose, possibly those originating from the fruit skin, with respect to fruit juice-induced breath hydrogen excretion.

Fluid intake and industrial processing in apple juice induced chronic non-specific diarrhoea.

Dietary factors have been shown to contribute to the occurrence or persistence of chronic non-specific diarrhoea (CNSD). Among these are low dietary fat, high fluid consumption, and the consumption of apple juice. Prompted by the clinical impression that freshly pressed and unprocessed ('cloudy') apple juice was less likely to induce diarrhoea than normal, enzymatically processed ('clear') apple juice, both juices were compared in terms of carbohydrate malabsorption, gastric emptying, and effects on defecation patterns. Clear and cloudy apple juice differ in their fibre and non-absorbable monosaccharide and oligosaccharide contents. Ten healthy children aged 3.6 to 5.9 years ingested 10 ml/kg of clear and cloudy apple juice; in five of them it was enriched with 40 mg of [1-13C]-glycine. Clear apple juice resulted in increased (> or = 20 ppm) breath hydrogen excretion in 8/10, compared with 5/10 after cloudy apple juice; peak breath hydrogen was higher in the clear apple juice group (35 (4) and 18 (3) ppm, respectively). Gastric emptying as determined by means of labelled breath carbon dioxide (13CO2) excretion was similar with both juices. In a four week crossover clinical trial 12 children, formerly diagnosed as having CNSD, were given extra clear fluids (excluding fruit juices; > or = 50% over basal consumption), clear apple juice, or cloudy apple juice, for five day periods. Extra fluids and cloudy apple juice did not influence stool frequency and consistency compared with the basal period. In contrast, clear apple juice significantly promoted diarrhoea. It is suggested that, in addition to fructose, the increased availability of non-absorbable monosaccharides and oligosaccharides as a result of the enzymatic processing of apple pulp is an important aetiological factor in apple juice induced CNSD.

Incidence of Listeria species in seafood and seafood salads.

A total of 128 samples of seafood on the Icelandic market were tested for the presence of Listeria monocytogenes and other Listeria species. The samples included raw, smoked and dried fish, frozen shellfish and shrimps as well as several fish salads. These products are generally consumed without heating. Listeria spp. were present in 56% of the samples of raw fish, 29% of the smoked fish, 9% of the shrimps and 32% of the salads. No Listeria spp. were present in the shellfish or dried fish. In 46% of the positive samples L. monocytogenes could be demonstrated, either alone or together with L. innocua. The other positive samples contained L. innocua and, in one sample, L. welshimeri. All products sampled had been processed and packed in Iceland, mostly for use on the domestic market. It is suggested that consuming certain fish products and fish salads may form an additional risk factor for listeriosis in humans.

Improvement of nutritional measures during preoperative parenteral nutrition in patients selected by the prognostic nutritional index: a randomized controlled trial.

Patients undergoing major gastrointestinal surgery who had a prognostic nutritional index (PNI) score of greater than 30% were randomized to receive a preoperative course of 10 days of intravenous nutrition or to undergo surgery at the next convenient operation list. Two groups of 17 patients were well matched for age, sex, and nutritional status. Although they underwent diverse operations, the extent of these was similar: 12 +/- 3 days of parenteral nutrition resulted in weight gain, 3.2 +/- 2.3 kg p less than 0.01; increased triceps skinfold, 0.6 +/- 1.2 mm p less than 0.05; improved immunological state, p less than 0.02; and improved PNI, 5.5 +/- 10.1% p less than 0.05. The changes in serum albumin and transferrin were not significant. There were only three major complications with one death in the treatment group but this was not significantly different from the control group which had six major complications and three deaths. This study suggests that patients with demonstrable nutritional depletion who require major gastrointestinal surgery will benefit from a preoperative course of parenteral nutrition, but to conclusively prove this a large and probably multicentre study will be required.

Prolonged multipurpose venous access in burned patients: three years' experience with Hickman right atrial catheters.

We report the results of 3 years' experience with Hickman right atrial catheters in patients with 30-90% (mean, 52%) body surface burns. The catheters were used as multipurpose lines, including the administration of intravenous nutrition. The strict management protocol that was used is described: 76 catheters were inserted in 66 patients for a total of 9.5 patient years. Four patients had their catheters replaced because of fever but cultures were negative. Three patients had septicemia, from which two died. These results are similar to those reported following the use of rotating peripheral cannulae for fluid replacement only. However, Hickman right atrial catheters provide many nursing and patient advantages and are recommended to provide venous access for intravenous nutrition to patients with major burns.

Fine bore jejunostomy feeding following major abdominal surgery: a controlled randomized clinical trial.

A randomized controlled prospective clinical trial has been undertaken to examine the efficacy of the technique of early postoperative feeding using a fine bore catheter jejunostomy. Fifty patients undergoing surgery for gastrointestinal malignancy were randomly allocated into treatment and control groups. A low residue liquidized diet (Isocal) was administered to the patients in the treatment group. Control patients received routine intravenous therapy. Nutritional parameters (serum albumin, serum transferrin, serum prealbumin, weight, body fat and fat free mass) were measured pre-operatively and on the tenth postoperative day. Postoperative surgical complications were similar in both groups. There were 20 catheter complications and one death directly attributable to the jejunal catheter feeding. Postoperative stay was significantly longer (P less than 0.01) in the treatment group patients. Evaluation of the nutritional parameters showed no advantage for either the treatment group or a selected complication-free, 'successful treatment', subgroup. It is concluded that no significant clinical or nutritional advantage for jejunal catheter feeding has been demonstrated and because of the related complications, its routine use cannot be recommended.