• Journal of Dairy Science and Biotechnology
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• v.37 no.1
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• pp.15-26
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• 2019

A common belief is that human milk is sterile. However, the development of culture-independent molecular methods, especially Next Generation Sequencing, has revealed that human milk harbors diverse and rich bacterial communities. Although studies aimed at characterizing the microbiota of human milk have produced different findings, Staphylococcus and Streptococcus are presumed to be normal members of the microbiota. Factors that influence variation in the microbiota are unclear; however, the postpartum time, route of delivery, maternal obesity, and health status may be influential. The origin of the microbiota is a hotly debated topic. Human milk bacteria are thought to be introduced through bacterial exposure of the mammary duct during breast feeding and/or the entero-mammary pathway from the maternal gastrointestinal tract. Although the exact mechanism related to the entero-mammary pathway is unknown, it is presumed that bacteria penetrate the intestinal epithelium and then migrate to the mammary gland, dendritic cells, and macrophages. In this review, various relevant studies are introduced.

• Journal of Digestive Cancer Research
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• v.12 no.1
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• pp.6-14
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• 2024

Gastric cancer is the 4th leading cause of death worldwide. The primary cause of gastric cancer is known to be Helicobacter pylori (H. pylori). The advancement of molecular biology has enabled the identification of microbiomes that could not be confirmed through cultivation, and it has been revealed that the microbial communities vary among normal mucosa, atrophic gastritis, intestinal metaplasia, and gastric cancer. It has also been confirmed that the composition of the microbial community differs depending on the presence or absence of H. pylori. Whether changes in the microbiome are causative factors in the carcinogenesis process is not yet clear. Experiments using animal models and in vitro studies on the role of microbes other than H. pylori in the carcinogenic process are underway, but the data is still insufficient.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.9
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• pp.1332-1339
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• 2017

Objective: This study investigated the effects of Bacillus subtilis CSL2 (B. subtilis CSL2) administration before Salmonella challenge on the fecal microbiota and microbial functionality of Hy-line Brown (HLB) laying hens. Methods: Fecal samples were collected from control (CON), Salmonella-infected (SAL) and Salmonella-infected, probiotic-treated (PRO) groups before and after Salmonella challenge for microbiome analysis using 16S rRNA gene pyrosequencing. Results: Infection with Salmonella led to decreased microbial diversity in hen feces; diversity was recovered with Bacillus administration. In addition, Salmonella infection triggered significant alterations in the composition of the fecal microbiota. The abundance of the phylum Firmicutes decreased while that of Proteobacteria, which includes a wide variety of pathogens, increased significantly. Bacillus administration resulted in normal levels of abundance of Firmicutes and Proteobacteria. Analysis of bacterial genera showed that Salmonella challenge decreased the population of Lactobacillus, the most abundant genus, and increased populations of Pseudomonas and Flavobacterium genera by a factor of 3 to 5. On the other hand, Bacillus administration caused the abundance of the Lactobacillus genus to recover to control levels and decreased the population of Pseudomonas significantly. Further analysis of operational taxonomic units revealed a high abundance of genes associated with two-component systems and secretion systems in the SAL group, whereas the PRO group had more genes associated with ribosomes. Conclusion: The results of this study indicate that B. subtilis CSL2 administration can modulate the microbiota in HLB laying hens, potentially acting as a probiotic to protect against Salmonella Gallinarum infection.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.1
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• pp.1-14
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• 2020

The latest definition of a prebiotic is "a substrate that is selectively utilized by host microorganisms conferring a health benefit"; it now includes non-food elements and is applicable to extra-intestinal tissues. Prebiotics are recognized as a promising tool in the promotion of general health and in the prevention and treatment of numerous juvenile diseases. Prebiotics are considered an immunoactive agent, with the potential for long-lasting effects extending past active administration of the prebiotic. Because of its extremely low risk of serious adverse effects, ease of administration, and strong potential for influencing the composition and function of the microbiota in the gut and beyond, the beneficial clinical applications of prebiotics are expanding. Prebiotics are the third largest component of human breast milk. Preparations including galactooligosaccharides (GOS), fructooligosaccharides (FOS), 2'-fucosyllactose, lacto-N-neo-tetraose are examples of commonly used and studied products for supplementation in baby formula. In particular, the GOS/FOS combination is the most studied. Maintaining a healthy microbiome is essential to promote homeostasis of the gut and other organs. With more than 1,000 different microbial species in the gut, it is likely more feasible to modify the gut microbiota through the use of certain prebiotic mixtures rather than supplementing with a particular probiotic strain. In this review, we discuss the latest clinical evidence regarding prebiotics and its role in gut immunity, allergy, infections, inflammation, and functional gastrointestinal disorders.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.776-782
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• 2022

Corn-soybean meal diets are commonly used in the pork industry as a primary source of energy and protein. However, such a diet generally contains non-starch polysaccharides (NSPs) which present a challenge in finding ways to improve their availability and digestibility. Dietary multi-carbohydrases (MCs) have been proposed as an efficient approach to utilize NSPs, and can result in improved growth performance and host intestinal fitness. In this study, we evaluated the effects of MC in lactation diets on gut microbiota composition of lactating sows and their litters. The experimental design contained two dietary treatments, a diet based on corn-soybean meal (CON), and CON supplemented with 0.01% multigrain carbohydrases (MCs). Sow and piglet fecal samples were collected on days 7 and 28 after farrowing. Based on the results from 16S rRNA gene amplicon sequencing, MC led to changes in species diversity and altered the microbial compositions in lactating sows and their piglets. Specifically, the MC treatment induced an increase in the proportions of Lactobacillus in piglets. Clostridium and Spirochaetaceae showed a significantly reduced proportion in MC-treated sows at day 28. Our results support the beneficial effects of dietary carbohydrases and their link with improved production due to better host fitness outcomes and gut microbiota composition.

• Food Science of Animal Resources
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• v.44 no.5
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• pp.1080-1095
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• 2024

In contemporary society, the increasing number of pet-owning households has significantly heightened interest in companion animal health, expanding the probiotics market aimed at enhancing pet well-being. Consequently, research into the gut microbiota of companion animals has gained momentum, however, ethical and societal challenges associated with experiments on intelligent and pain-sensitive animals necessitate alternative research methodologies to reduce reliance on live animal testing. To address this need, the Fermenter for Intestinal Microbiota Model (FIMM) is being investigated as an in vitro tool designed to replicate gastrointestinal conditions of living animals, offering a means to study gut microbiota while minimizing animal experimentation. The FIMM system explored interactions between intestinal microbiota and probiotics within a simulated gut environment. Two strains of commercial probiotic bacteria, Enterococcus faecium IDCC 2102 and Bifidobacterium lactis IDCC 4301, along with a newly isolated strain from domestic dogs, Lactobacillus acidophilus SLAM AK001, were introduced into the FIMM system with gut microbiota from a beagle model. Findings highlight the system's capacity to mirror and modulate the gut environment, evidenced by an increase in beneficial bacteria like Lactobacillus and Faecalibacterium and a decrease in the pathogen Clostridium. The study also verified the system's ability to facilitate accurate interactions between probiotics and commensal bacteria, demonstrated by the production of short-chain fatty acids and bacterial metabolites, including amino acids and gamma-aminobutyric acid precursors. Thus, the results advocate for FIMM as an in vitro system that authentically simulates the intestinal environment, presenting a viable alternative for examining gut microbiota and metabolites in companion animals.

• Clinical and Experimental Pediatrics
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• v.63 no.8
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• pp.301-309
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• 2020

Human breast milk (HBM) is essential for the infant's growth and development right after birth and is an irreplaceable source of nutrition for early human survival. Various infant formulas have many similarities to HBM in many components, but there is no perfect substitute for HBM. Recently, various breast milk components and their roles have been studied according to the development of various analysis techniques. As is already well known, HBM contains about 87%-88% water, and 124-g/L solid components as macronutrients, including about 7% (60-70 g/L) carbohydrates, 1% (8-10 g/L) protein, and 3.8% (35-40 g/L) fat. The composition may vary depending on the environmental factors, including maternal diet. Colostrum is low in fat but high in protein and relatively rich in immuneprotective components. Although HBM contains enough vitamins to ensure normal growth of the infant, vitamins D and K may be insufficient, and the infant may require their supplementation. Growth factors in HBM also serve as various bioactive proteins and peptides on the intestinal tract, vasculature, nervous system, and endocrine system. In the past, HBM of a healthy mother was thought to be sterile. However, several subsequent studies have confirmed the presence of rich and diverse microbial communities in HBM. Some studies suggested that the genera Staphylococcus and Streptococcus may be universally predominant in HBM, but the origin of microbiota still remains controversial. Lastly, milk is the one of most abundant body fluid of microRNAs, which are known to play a role in various functions, such as immunoprotection and developmental programming, through delivering from HBM and absorption by intestinal epithelial cells. In conclusion, HBM is the most important source of nutrition for infants and includes microbiomes and miRNAs for growth, development, and immunity.

• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1186-1194
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• 2022

The intake of probiotic lactic acid bacteria not only promotes digestion through the microbiome regulated host intestinal metabolism but also improves diseases such as irritable bowel syndrome and inflammatory bowel disease, and suppresses pathogenic harmful bacteria. This investigation aimed to evaluate the immunomodulatory effects in intestinal epithelial cells and to study the clinical efficacy of the selected the Bifidobacterium breve and Bifidobacterium longum groups. The physiological and biochemical properties were characterized, and immunomodulatory activity was measured against pathogenic bacteria. In order to find out the mechanism of inflammatory action of the eight viable and sonicated Bifidobacterium spp., we tried to confirm the changes in the pro-inflammatory cytokines (TNF-α, interleukin (IL)-6, IL-12) and anti-inflammatory cytokine (IL-10), and chemokines, (monocyte chemoattractant protein-1, IL-8) and inflammatory enzymatic mediator (nitric oxide) against Enterococcus faecalis ATCC 29212 infection in Caco-2 cells and RAW 264.7 cells. The clinical efficacy of the selected B. breve and B. longum group was studied as a probiotic adjuvant for acute diarrhea in children by oral administration. The results showed significant immunomodulatory effects on the expression levels of TNF-α, IL-6, IL-12, MCP-1, IL-8 and NO, in sonicated Bifidobacterium extracts and viable bifidobacteria. Moreover, each of the Bifidobacterium strains was found to react more specifically to different cytokines. However, treatment with sonicated Bifidobacterium extracts showed a more significant effect compared to treatment with the viable bacteria. We suggest that probiotics functions should be subdivided according to individual characteristics, and that personalized probiotics should be designed to address individual applications.

• The Korean Journal of Physiology and Pharmacology
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• v.28 no.2
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• pp.153-164
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• 2024

This study aimed to identify metabolic biomarkers and investigate changes in intestinal microbiota in the feces of healthy participants following administration of Lactococcus lactis GEN-001. GEN-001 is a single-strain L. lactis strain isolated from the gut of a healthy human volunteer. The study was conducted as a parallel, randomized, phase 1, open design trial. Twenty healthy Korean males were divided into five groups according to the GEN-001 dosage and dietary control. Groups A, B, C, and D1 received 1, 3, 6, and 9 GEN-001 capsules (1 × 10¹¹ colony forming units), respectively, without dietary adjustment, whereas group D2 received 9 GEN-001 capsules with dietary adjustment. All groups received a single dose. Fecal samples were collected 2 days before GEN-001 administration to 7 days after for untargeted metabolomics and gut microbial metagenomic analyses; blood samples were collected simultaneously for immunogenicity analysis. Levels of phenylalanine, tyrosine, cholic acid, deoxycholic acid, and tryptophan were significantly increased at 5-6 days after GEN-001 administration when compared with predose levels. Compared with predose, the relative abundance (%) of Parabacteroides and Alistipes significantly decreased, whereas that of Lactobacillus and Lactococcus increased; Lactobacillus and tryptophan levels were negatively correlated. A single administration of GEN-001 shifted the gut microbiota in healthy volunteers to a more balanced state as evidenced by an increased abundance of beneficial bacteria, including Lactobacillus, and higher levels of the metabolites that have immunogenic properties.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.125-137
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• 2022

This study aimed to determine the effects of dietary microalgae (Tetradesmus sp. (TO)) on intestinal immunity and microbiota of pre-starter broilers. One hundred and twenty 1-day-old birds (Ross 308) were allocated to two dietary treatment groups with six blocks in a randomized complete block design. The two experimental diets consisted of a corn-soybean meal-based basal diet and a diet with 0.5% TO powder instead of cornstarch in the basal diet. After feeding the experimental diets for ten days, all birds' body weight and feed intake were measured, and representative eight birds were selected from each treatment group. Small intestinal lamina propria cells were isolated using flow cytometry to examine the frequency of immune cells. Cecal feces were harvested for 16s rRNA gut microbiota analysis and fecal IgA levels. Here, we found that 0.5% TO supplementation increased CD3⁺CD4⁺ T cells in the small intestine, but decreased CD3⁺CD8⁺ T cells in the small intestine. Gut microbial analysis showed that TO supplementation significantly increased the alpha diversity of the gut microbiome. Taxonomic analysis showed that TO treatment increased the abundance of Firmicutes and decreased that of Bacteroidetes at the phylum level. The distribution of Enterobacteriaceae containing many harmful bacteria at the family level, was lower in the TO group. In the LEfSe analysis, the TO group had a significantly enriched abundance of Agathobaculum at the genus level. Overall, results show that Tetradesmus sp. supplementation influences intestinal T-cell immunity and induces the expansion of beneficial gut microbes in pre-starter broiler chickens.