The piglet as a model for studying dietary components in infant diets: effects of galacto-oligosaccharides on intestinal functions.

Prebiotic oligosaccharides, including galacto-oligosaccharides (GOS), are used in infant formula to mimic human milk oligosaccharides, which are known to have an important role in the development of the intestinal microbiota and the immune system in neonates. The maturation of the intestines in piglets closely resembles that of human neonates and infants. Hence, a neonatal piglet model was used to study the multi-faceted effect of dietary GOS in early life. Naturally farrowed piglets were separated from the mother sow 24-48 h postpartum and received a milk replacer with or without the addition of GOS for 3 or 26 d, whereafter several indicators of intestinal colonisation and maturation were measured. Dietary GOS was readily fermented in the colon, leading to a decreased pH, an increase in butyric acid in caecum digesta and an increase in lactobacilli and bifidobacteria numbers at day 26. Histomorphological changes were observed in the intestines of piglets fed a GOS diet for 3 or 26 d. In turn, differences in the intestinal disaccharidase activity were observed between control and GOS-fed piglets. The mRNA expression of various tight junction proteins was up-regulated in the intestines of piglet fed a GOS diet and was not accompanied by an increase in protein expression. GOS also increased defensin porcine ß-defensin-2 in the colon and secretory IgA levels in saliva. In conclusion, by applying a neonatal piglet model, it could be demonstrated that a GOS-supplemented milk replacer promotes the balance of the developing intestinal microbiota, improves the intestinal architecture and seems to stimulate the intestinal defence mechanism.

Exploring the effects of galacto-oligosaccharides on the gut microbiota of healthy adults receiving amoxicillin treatment.

In the present double-blind, randomised, parallel intervention study, the effects of the intake of galacto-oligosaccharides (GOS) on the gut microbiota of twelve healthy adult subjects (aged 18-45 years with a normal BMI (18-25 kg/m²)) receiving amoxicillin (AMX) treatment were determined. All the subjects were treated with AMX (375 mg; three times per d) for 5 d and given either GOS (n 6) or placebo (maltodextrin, n 6) (2·5 g; three times per d) during and 7 d after AMX treatment. Faecal samples were collected twice before starting the treatment and on days 2, 5, 8, 12, 19 and 26. Due to AMX treatment, a decrease in the abundance of Bifidobacterium spp., an overgrowth of Enterobacteriaceae, and a disruption of the metabolic activity of the microbiota (increase in succinate, monosaccharide and oligosaccharide levels in the faecal samples) were observed in both groups (P< 0·05). Positive effects of GOS intake were observed on the levels of bifidobacteria, although not found to be significant. Data revealed that the levels of bifidobacteria were higher upon GOS intake than upon placebo intake, especially after AMX treatment. The activity of bifidobacteria and subsequent cross-feeding activity of the microbiota upon GOS intake compared with those upon placebo intake were reflected by the significant increase in butyrate levels (P< 0·05) in the faecal samples after AMX treatment. Despite the small number of subjects, our findings confirm previous results obtained in vitro, namely that GOS intake supports the recovery of the beneficial bifidobacteria and, indirectly, the production of butyrate after AMX treatment.

Selective carbohydrate utilization by lactobacilli and bifidobacteria.

AIM: To evaluate the ability of specific carbohydrates, including commercially available products, to support the growth of representatives of two well-known groups of gut commensals, namely lactobacilli and bifidobacteria. METHODS AND RESULTS: Sixty-eight bacterial strains, representing 29 human-derived lactobacilli and 39 bifidobacteria (both human- and animal-derived), were tested for their ability to metabolize 10 different carbohydrates. Analysis of growth and metabolic activity was performed using a combination of diagnostic parameters, such as final OD600 , final pH, fermentation end products and growth rate. CONCLUSIONS: The data assembled in this study provide significant complementary and comparative information on the growth-promoting properties of a range of carbohydrates, while also investigating interspecies differences between lactobacilli and/or bifidobacteria with regard to their carbohydrate utilization abilities. Galacto-oligosaccharides (GOS) and lactulose were shown to support the most favourable growth characteristics, whereas relatively poor growth of lactobacilli and bifidobacteria was observed on inulin, maltodextrin and polydextrose. GOS/inulin (9 : 1) and fructo-oligosaccharides (FOS)/inulin mixtures supported mostly similar growth abilities to those obtained for GOS and FOS, respectively. Microbial consumption of GOS, as determined by high-performance anion-exchange chromatography with pulsed amperometric detection, was evident for both lactobacilli and bifidobacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: These results may allow for the rational prediction of lactobacilli and/or bifidobacteria to be used in conjunction with prebiotics, such as GOS, as synbiotics.

Inactivity and weight loss: effective criteria to identify frailty.

The effectiveness was examined of inactivity and weight loss as criteria to identify a frail subgroup within independently living elderly persons participating in the SENECA study (Survey in Europe on Nutrition and the Elderly, a Concerted Action). Eight-hundred-forty-nine participants (aged 75 to 80) from nine countries were classified in four subgroups: 1) inactive elderly (lowest tertile activity score: n = 204); 2) weight losing elderly (lowest quintile: * 6.3% weight loss over 4-5 years: n = 108); 3) both inactive and weight losing (n = 54); 4) neither inactive nor weight losing: reference (n = 483). Differences in health, physical functioning and nutritional characteristics between groups 1, 2 and 3 respectively, and the reference group were evaluated. Compared to the weight-stable, active reference group, both inactive, weight losing (group 3) and inactive subjects (group 1) reported significantly more chronic diseases (2.2 and 1.8 vs. 1.1), disabilities (81 and 80 vs. 43%), use of medications (both 2.3 vs. 1.1) and care services (26 and 21 vs. 6%), and a lower self-rated health (2.8 and 3.1 vs. 3.8), relative health (1.9 and 2.1 vs. 2.6), and physical performance score (17 and 18 vs. 22). In addition, inadequate micronutrient intake and biochemical deficiencies were more prevalent. Weight-losing elderly were not significantly different from the reference group with respect to these characteristics. Therefore, physical inactivity alone or in combination with weight loss seems to be a practical and inexpensive screening criterion for identifying a subgroup of elderly with less favourable health and nutritional characteristics and poorer physical functioning among non-institutionalised elderly.

High-throughput analysis of the impact of antibiotics on the human intestinal microbiota composition.

Antibiotic treatments can lead to a disruption of the human microbiota. In this in-vitro study, the impact of antibiotics on adult intestinal microbiota was monitored in a new high-throughput approach: a fermentation screening-platform was coupled with a phylogenetic microarray analysis (Intestinal-chip). Fecal inoculum from healthy adults was exposed in a fermentation screening-platform to seven widely-used antibiotics during 24h in-vitro fermentation and the microbiota composition was subsequently determined with the Intestinal-chip. Phylogenetic microarray analysis was first verified to be reliable with respect to variations in the total number of bacteria and presence of dead (or inactive) cells. Intestinal-chip analysis was then used to identify and compare shifts in the intestinal microbial composition after exposure to low and high dose (1µgml(-1) and 10µgml(-1)) antibiotics. Observed shifts on family, genus and species level were both antibiotic and dose dependent. Stronger changes in microbiota composition were observed with higher doses. Shifts mainly concerned the bacterial groups Bacteroides, Bifidobacterium, Clostridium, Enterobacteriaceae, and Lactobacillus. Within bacterial groups, specific antibiotics were shown to differentially impact related species. The combination of the in-vitro fermentation screening platform with the phylogenetic microarray read-outs has shown to be reliable to simultaneously analyze the effects of several antibiotics on intestinal microbiota.