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BACKGROUND: Fructooligosaccharides (FOS) are a kind of prebiotic. Previous studies concerning the effect of FOS on intestinal microbiota have focused on Bifidobacterium and Lactobacillus. However, the presence of other FOS‐utilizing bacteria makes it necessary to investigate the quantitative changes in these bacterial species in the intestine after FOS intake. In this study, the composition of cecal and fecal microbiota was analyzed using MiSeq sequencing, and the abundance of FOS‐utilizing bacteria was detected using quantitative polymerase chain reaction after the oral administration of FOS. RESULTS: Species‐specific primers for FOS‐utilizing bacteria were designed with superior amplification efficiency for quantification. After FOS intervention, the relative abundance of Bifidobacterium pseudolongum in feces increased to 17.37% and the abundance reached 2.28 × 1010 CFU g−1. The abundance of Bifidobacterium longum and Bifidobacterium breve did not change significantly. Whereas the abundance of Ligilactobacillus murinus decreased, that of Lactiplantibacillus plantarum, Lacticaseibacillus paracasei, and Lacticaseibacillus rhamnosus remained at approximately 104 CFU g−1. CONCLUSION: Species‐specific primers for FOS‐utilizing bacteria were successfully developed, and we confirmed that FOS significantly increased the relative abundance and the abundance of B. pseudolongum in mice, while decreasing the proportion of Lactobacillus. The detection of these species using 16S ribosomal DNA sequencing and quantitative polymerase chain reaction showed the same results. Further investigations are needed to reveal the response of the intestinal microbiota to different FOS compositions. These techniques will contribute to future studies about the composition and dynamics of the intestinal microflora. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Fructooligosaccharides (FOS) have been identified as important prebiotics. Previous studies have found that they can significantly promote the proliferation of Bifidobacterium pseudolongum in the mouse intestine. However, it is still unclear which other bacteria in the mouse intestine can utilize FOS, and the differences in the ability to utilize FOS. In this study, the bacteria capable of utilizing FOS were isolated from mice feces and their ability to utilize FOS was compared. Draft genome sequencing was also applied to explain the differences in FOS utilization at the gene levels. RESULTS: A total of 15 species were isolated from mouse feces and 13 species were able to utilize fructofuranosylnystose (GF2). Eleven species could utilize nistose (GF3), but not Enterococcus hirae and Lactobacillus reuteri. In contrast, 1‐kestose (GF4) was hardly utilized. The enzyme activity determination and draft genome sequencing‐based analyses revealed that all isolated species used the phosphotransferase system or permease system to transport FOS into the cells before hydrolysis by β‐fructofuranosidase. Although β‐fructofuranosidase exists in all strains, there are big differences in the corresponding coding genes between bifidobacteria and non‐bifidobacteria. CONCLUSION: Compared with the other isolates, Bifidobacterium species exhibited higher enzyme activity and shorter generation time, leading to a stronger ability to utilize FOS. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND Lactulose was one of the earliest prebiotics to be identified. To assess the potential risk of large intakes of lactulose to the intestinal microbiota, mice were fed a diet containing lactulose (0%, 5% and 15%, w/w) for 2 weeks and the changes in the fecal microbiota were evaluated by 16S rRNA high‐throughput sequencing. RESULTS: Lactulose intervention decreased the α‐diversity of the fecal microbiota in both low‐dose and high‐dose groups. The relative abundance of Actinobacteria was significantly increased, while that of Bacteroidetes was significantly decreased after lactulose intervention. At the genus level, the relative abundance of Bifidobacterium belonging to Actinobacteria was significantly increased, and that of Alistipes belonging to Bacteroidetes was decreased in both low‐dose and high‐dose groups. The relative abundance of Blautia was significantly increased from 0.2% to 7.9% in the high‐dose group and one strain of Blautia producta was isolated from the mice feces. However, the strain could not utilize lactulose. CONCLUSION: Overall, the microbial diversity was decreased after lactulose treatment, with significant increases in the relative abundance of Bifidobacterium. We also provide a strategy to increase the relative abundance of Blautia in the intestine by lactulose feeding at high doses, although the mechanism is not revealed. This will help us understand the prebiotic effect of lactulose on the host health. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Lactobacillus plantarum is an important probiotic with a variety of physiologic functions. Studies have focused on the effects of L. plantarum on host physiology and microbiota, but studies of the fate of strains after they enter the intestine are lacking. In this study, L. plantarum ST‐III was genetically engineered to express green fluorescent protein (GFP). Mice were administered ST‐III‐GFP, and fluorescence imaging was used to study the distribution, location and quantity of strains within 8 h after entry into the intestine. Results: The results indicated that genetic modification did not affect the growth of ST‐III, tolerance to simulated gastric juice and intestinal fluid or tolerance to antibiotics (with the exception of chloramphenicol). Fluorescence imaging and colony counting indicated that ST‐III‐GFP can be detected in the small intestine 5 min after oral gavage. After 30 min, nearly all ST‐III‐GFP was located in the small intestine. After 1.5 h, ST‐III‐GFP was detected in both the cecum and large intestine. After 4 and 8 h, ST‐III‐GFP was mainly concentrated in the cecum and large intestine. Compared to the initial amount ingested, the survival rate of ST‐III‐GFP within the intestine of mice was 10% after 8 h. In addition, a strong linear relationship was found between the fluorescence intensity and the viable count of ST‐III‐GFP. Conclusions: The obtained data indicate that the amount of ST‐III‐GFP can be estimated by measuring the fluorescence intensity of this novel strain within the intestinal tract. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Astaxanthin ester (Asta‐E) is used as functional nutraceuticals in many food products. Unfortunately, Asta‐E utilization is currently limited owing to its chemical instability and low bioavailability. The purpose of this study is to investigate the promotion effect of oil matrixes on the stability, antioxidant activity, bioaccessibility and bioavailability of Asta‐E. RESULTS: The results showed that the stability of Asta‐E in six oil matrixes was improved. Based on the 2, 2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity experiment, the antioxidant activity of Asta‐E was positively correlated with the degree of unsaturation of the oil matrixes, but not with the side chain length. The in vitro gastrointestinal tract (GIT) simulation model and in vivo experiment using mice were also employed to investigate the digestion and absorption characteristics of Asta‐E in various oil matrixes. The results demonstrated that the bioaccessibility and bioavailability of Asta‐E increased with the increase of fatty acid chain length of oil matrixes (triglyceride oleate > triglyceride caprylate > triglyceride butyrate), as well as with the decrease of unsaturation degree (olive oil > corn oil > fish oil). CONCLUSION: Monounsaturated fatty acids (MUFA) and long‐chain triglyceride (LCT) in an oil matrix were the factors that could efficiently improve the bioavailability of Asta‐E. Moreover, the size of the mixed micelles of Asta‐E during digestion was the main factor influencing the bioaccessibility of Asta‐E. This study provides references for the design of suitable oil matrixes for Asta‐E. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]