• Journal of Microbiology and Biotechnology
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• v.34 no.5
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• pp.1109-1118
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• 2024

Probiotics, specifically Lacticaseibacillus rhamnosus, have garnered attention for their potential health benefits. This study focuses on evaluating the probiotic properties of candidate probiotics L. rhamnosus IDCC 3201 (3201) using the Caenorhabditis elegans surrogate animal model, a well-established in vivo system for studying host-bacteria interactions. The adhesive ability to the host's gastrointestinal tract is a crucial criterion for selecting potential probiotic bacteria. Our findings demonstrated that 3201 exhibits significantly higher adhesive capabilities compared with Escherichia coli OP50 (OP50), a standard laboratory food source for C. elegans and is comparable with the widely recognized probiotic L. rhamnosus GG (LGG). In lifespan assay, 3201 significantly increased the longevity of C. elegans compared with OP50. In addition, preconditioning with 3201 enhanced C. elegans immune response against four different foodborne pathogenic bacteria. To uncover the molecular basis of these effects, transcriptome analysis elucidated that 3201 modulates specific gene expression related to the innate immune response in C. elegans. C-type lectin-related genes and lysozyme-related genes, crucial components of the immune system, showed significant upregulation after feeding 3201 compared with OP50. These results suggested that preconditioning with 3201 may enhance the immune response against pathogens. Metabolome analysis revealed increased levels of fumaric acid and succinic acid, metabolites of the citric acid cycle, in C. elegans fed with 3201 compared with OP50. Furthermore, there was an increase in the levels of lactic acid, a well-known antimicrobial compound. This rise in lactic acid levels may have contributed to the robust defense mechanisms against pathogens. In conclusion, this study demonstrated the probiotic properties of the candidate probiotic L. rhamnosus IDCC 3201 by using multi-omics analysis.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.8
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• pp.1243-1251
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• 2007

This study was conducted to evaluate the feasibility of using L. reuteri Pg4, a strain isolated from the gastrointestinal (GI) tract of healthy broilers, as a probiotic. In preliminary in vitro studies the Pg4 strain was proven capable of tolerating acid and bile salts, inhibiting pathogenic bacteria and can adhere to intestinal epithelial cells. The probiotic properties were then evaluated on the basis of the broiler's growth performance, intestinal microbial population and cecal volatile fatty acid and lactic acid concentrations under conventional feeding. Dietary supplementation of dried L. reuteri Pg4 decreased significantly feed intake in grower chickens and improved significantly the feed conversion by 5% in a 0-6 weeks feeding period compared with the control group. The Lactobacillus counts in the crop, ileum, and cecum of the probiotic group were higher than in the control group. The L. reuteri Pg4 strain was traceable in the GI tract of probiotic supplemented chicks and showed capability of survival in the intestine for a protracted period. The probiotic group had a higher lactic acid concentration and lower pH value in the cecum than the control chicks. Probiotic supplement also affected the histology of the intestinal mucosa of chicks. The present findings demonstrated that L. reuteri Pg4 possesses probiotic characteristics and it is suggested, therefore, that the organism could be a candidate for a new probiotic strain.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.11
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• pp.1715-1724
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• 2019

Objective: As laying hens become aged, laying performance and egg quality are generally impaired. One of the practical methods to rejuvenate production and egg quality of aged laying hens with decreasing productivity is a forced molting. However, the changes in intestinal microbiota after forced molting of aged hens are not clearly known. The aim of the present study was to analyze the changes in excreta bacterial communities after forced molting of aged laying hens. Methods: A total of one hundred 66-wk-old Hy-Line Brown laying hens were induced to molt by a 2-d water removal and an 11-d fasting until egg production completely ceased. The excreta samples of 16 hens with similar body weight were collected before and immediately after molting. Excreta bacterial communities were analyzed by high-throughput sequencing of bacterial 16S rRNA genes. Results: Bacteroidetes, Firmicutes, and Proteobacteria were the three major bacterial phyla in pre-molting and immediate post-molting hens, accounting for more than 98.0%. Lactobacillus genus had relatively high abundance in both group, but decreased by molting (62.3% in premolting and 24.9% in post-molting hens). Moreover, pathogenic bacteria such as Enterococcus cecorum and Escherichia coli were more abundant in immediate post-molting hens than in pre-molting hens. Forced molting influenced the alpha diversity, with higher Chao1 (p = 0.012), phylogenetic diversity whole tree (p = 0.014), observed operational taxonomic unit indices (p = 0.006), and Simpson indices (p<0.001), which indicated that forced molting increased excreta bacterial richness of aged laying hens. Conclusion: This study improves the current knowledge of bacterial community alterations in the excreta by forced molting in aged laying hens, which can provide increasing opportunity to develop novel dietary and management skills for improving the gastrointestinal health of aged laying hens after molting.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.75-81
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• 2021

Recent gut microbiota studies have revealed the important roles of gut microbiota for our health. Increasing numbers of health functional foods have been developed every year. Development of functional food often includes ex- and in-vivo experiment to verify the beneficial effects of the functional food. To investigate effects of functional food on gut microbiota, animal models were often conducted. Beneficial effects of food can be evaluated based on how gut microbiota was shifted by food, which results in either increase in beneficial bacteria, decrease in potentially pathogenic bacteria or both. As animal experiments are generally time-consuming and laborious, we investigate how well in-vitro investigation of fecal microbiota may reflect dietary health benefits. Here, we tested 15 kinds of diets using two human subjects' fecal materials. Our results showed varying gut microbiota shifts according to diets, which suggested generally known beneficial diets (i.e. Kimchi, Chunggukjang) increased Lactobacillus and Bifidobacterium. Therefore, we suggest that in vitro fecal microbiota analysis could be used to evaluate beneficial effects of diets. Moreover, this method may be ideal to establish personalized diet.

• Food Science of Animal Resources
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• v.26 no.2
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• pp.263-268
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• 2006

Probiotics including Lactobacillus acidophilus, refer to a group of nonpathogenic organisms that protect the human host against gastrointestinal(GI) infections by pathogenic bacteria such as Shiga toxin-producing E. coli(STEC). In the study, the inhibitory effects of STEC ATCC 43894 adhesion by L. acidophilus A4 was investigated on the HT-29 epithelial cells. Specific proteins regulated by cell Iysates of L. acidophilus A4 on STEC ATCC 43894 were also characterized by proteomic analysis. Both cell mass and Iysate of L. acidophilus A4 have exhibited the profound inhibitory activity on the HT-29 cells(about 1.5 log scale reduction). Two-dimensional gel electrophoresis(2-DE) revealed seven proteins that were up-regulated by cell Iysates of L. acidophilus A4 and three proteins that were down-regulated. In addition, three protein spots were only detected in the presence of cell Iysates. These results suggest that inhibitory effects of STEC adhesion by L. acidophilus may be due to the regulation of specific protein of STEC.

• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.215-221
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• 2010

Salmonella is an important food-and water-borne pathogen associated with acute gastrointestinal illnesses around the world. The most common serotypes isolated from humans are Salmonella enterica serotype Typhimurium (S. Typhimurium) and S. Enteritidis. Traditional detection methods for Salmonella are based on cultures using selective media and characterization of suspicious colonies by biochemical and serological tests. These methods are generally time-consuming and not so highly sensitive. Recently, the Loop Mediated Isothermal Amplification and real-time PCR has been used as a highly sensitive, specific, and rapid test for the presence of pathogenic bacteria. In this study, a LAMP and real-time PCR was used to detect S. Typhimurium and S. Enteritidis. We selected target genes, which were the in invA and a randomly cloned sequence specific for the genus Salmonella. With LAMP and real-time PCR, random sequence was detected from Salmonella spp, invA were detected from all strain of S. Typhimurium and S. Enteritidis. This assay indicate that the specificity, sensitivity and rapid of the LAMP and real-time PCR make them potentially valuable tools for detection of S. Typhimurium and S. Enteritidis.