Human milk oligosaccharides (HMOs) shape gut microbiota during infancy by acting as fermentable energy source. Using a semi-continuous colon simulator, effect of an HMO, 2′-fucosyllactose (2′-FL), on composition of the infant microbiota and microbial metabolites was evaluated in comparison to galacto-oligosaccharide (GOS) and lactose and control without additional carbon source. Data was analysed according to faecal sample donor feeding type: breast-fed (BF) or formula-fed (FF), and to rate of 2′-FL fermentation: fast or slow. Variation was found between the simulations in the ability to utilise 2′-FL. The predominant phyla regulated by 2′-FL, GOS and lactose were significant increase in Firmicutes, numerical in Actinobacteria, and numerical decrease in Proteobacteria compared to control. Verrucomicrobia increased in FF accounted forAkkermansia, whereas in fast-fermenting simulations Actinobacteria increased with trend for higherBifidobacterium, and Proteobacteria decrease accounted forEnterobacteriaceae. Short-chain fatty acids and lactic acid with 2′-FL were produced in intermediate levels being between ones generated by the control and GOS or lactose. In 2′-FL fast-fermenting group, acetic acid specifically increased with 2′-FL, whereas lactose and GOS also increased lactic acid. The results highlight specificity of 2′-FL as energy source for only certain microbes over GOS and lactose in the simulated gut model.

As plant-based diets become more popular, there is an interest in developing innovations to improve the bioaccessibility of plant protein. In this study, seven probiotic strains (Bifidobacterium animalis subsp. lactis B420, B. lactis Bl-04, Lactobacillus acidophilus NCFM, Lacticaseibacillus rhamnosus HN001, Lacticaseibacillus paracasei subsp. paracasei Lpc-37, Lactiplantibacillus plantarum Lp-115, and Lactococcus lactis subsp. lactis Ll-23) were evaluated for their capacity to hydrolyze soy and pea protein ingredients in an in vitro digestion model of the upper gastrointestinal tract (UGIT). Compared to the control digestion of protein without a probiotic, all the studied strains were able to increase the digestion of soy or pea protein, as evidenced by an increase in free α-amino nitrogen (FAN) and/or free amino acid concentration. The increase in FAN varied between 13 and 33% depending on the protein substrate and probiotic strain. The survival of probiotic bacteria after exposure to digestive fluids was strain-dependent and may have affected the strain’s capacity to function and aid in protein digestion in the gastrointestinal environment. Overall, our results from the standardized in vitro digestion model provide an approach to explore probiotics for improved plant protein digestion and bioaccessibility of amino acids; however, human clinical research is needed to evaluate the efficacy of probiotics on amino acid absorption and bioavailability in vivo.

Human milk oligosaccharides (HMOs) shape the developing infant gut microbiota. In this study, a semi-continuous colon simulator was used to evaluate the effect of 2 HMOs—2′-fucosyllactose (2′-FL) and 3-fucosyllactose (3-FL)—on the composition of infant faecal microbiota and microbial metabolites. The simulations were performed with and without a probiotic Bifidobacterium longum subspecies infantis Bi-26 (Bi-26) and compared with a control that lacked an additional carbon source. The treatments with HMOs decreased α-diversity and increased Bifidobacterium species versus the control, but the Bifidobacterium species differed between simulations. The levels of acetic acid and the sum of all short-chain fatty acids (SCFAs) trended toward an increase with 2′-FL, as did lactic acid with 2′-FL and 3-FL, compared with control. A clear correlation was seen between the consumption of HMOs and the increase in SCFAs (−0.72) and SCFAs + lactic acid (−0.77), whereas the correlation between HMO consumption and higher total bifidobacterial numbers was moderate (−0.46). Bi-26 decreased propionic acid levels with 2′-FL. In conclusion, whereas infant faecal microbiota varied between infant donors, the addition of 2′-FL and 3-FL, alone or in combination, increased the relative abundance and numbers Bifidobacterium species in the semi-continuous colon simulation model, correlating with the production of microbial metabolites. These findings may suggest that HMOs and probiotics benefit the developing infant gut microbiota.

A method using column switching and reversed-phase high performance liquid chromatography with diode array detection was developed for the screening of 16 diuretics, probenecid and caffeine in urine. First, a 40-μl sample is injected into a short ODS or ODP extraction column with water as eluent and polar matrix components are eluted to waste. The retained compounds are then eluted in backflush mode into the analytical column by means of a column switching valve and a gradient of 0.05 M phosphate buffer (pH 3.1) and acetonitrile. Wavelengths 230, 270 and 360 nm are used for the detection. Recoveries for spiked urine samples were near 100% and relative retention times showed good repeatability. Detection limits were 0.5–2.0 μg/ml.

Alginate oligosaccharides (AOS) are non-digestible carbohydrates from brown kelp. As such, they are dietary fibers and may have prebiotic potential. Therefore, we investigated the capacity of gut bacteria to utilize AOS with single-strain cultures and as a complex bacterial community. Bifidobacterium adolescentis, Lacticaseibacillus casei and Lacticaseibacillus paracasei showed weak growth (relative to unsupplemented medium; p < 0.05) in the presence of AOS and alginate, while strong growth (p < 0.01) was observed for Bacteroides ovatus when grown with alginate as carbohydrate source. Enterococcus faecium and Enterococcus hirae were for the first time reported to be able to grow on AOS. Further, AOS as substrate was investigated in a complex bacterial community with colonic fermentations in an in vitro gut model. The in vitro gut model indicated that AOS increased short-chain fatty acid (SCFA) levels in donors with a low endogenous SCFA production, but not to the same level as inulin. Bacteroides was found to dominate the bacteria community after in vitro gut simulation with alginate as substrate. Further, stimulation of Bacteroides was observed with AOS in the gut model for two out of three donors with the third donor being more resistant to change. Our results allowed the identification of AOS utilizers among common gut species. The results also demonstrated the capacity of AOS to elevate SCFA levels and positively modulate the gut microbiota during in vitro simulated colon fermentations, although some subjects appear to be resilient to perturbation via substrate changes.