Lactobacillus reuteri FYNLJ109L1 Attenuating Metabolic Syndrome in Mice via Gut Microbiota Modulation and Alleviating Inflammation

Differences in anti-obesity effects between raw and ripened Pu-erh tea polyphenols: impact on gut microbiota enterotypes

BACKGROUND

Pu-erh tea, a dark tea from China, is classified into raw and ripened types. Both have significant anti-obesity effects. Polyphenols are among their major bioactive components. This study aimed to explore the anti-obesity properties and mechanisms of raw (R-TP) and ripened (F-TP) Pu-erh tea polyphenols.

RESULTS

The results showed that R-TP and F-TP significantly reduced body weight, improved insulin resistance, and enhanced glucose and lipid metabolism in high-fat-diet (HFD)-induced obese mice. Mild differences were observed in their impact on fat metabolism, carbohydrate metabolism, and inflammation levels. Both R-TP and F-TP were able to restore the disrupted intestinal flora caused by HFD treatment, returning them to a composition and levels similar to those of normal mice. Interestingly, the gut microbiota of all the mice could be reclassified into three enterotypes (enterotype Type-1, Type-2, and Type-HFD). Lactobacillaceae predominated in Type-1. Lactobacillaceae, Muribaculaceae, and Lachnospiraceae were the most common in Type-2. Type-HFD was primarily composed of Atopobiaceae, Lachnospiraceae, Lactobacillaceae, Ruminococcaceae, and Erysipelotrichaceae. The small differences in the effects of R-TP and F-TP may be due to variations in enterotypes.

CONCLUSION

These findings indicate that R-TP and F-TP can alleviate obesity by regulating the enterotype of gut microbiota, suggesting that they possess the potential for application in the treatment of obesity and the development of anti-obesity agents. © 2025 Society of Chemical Industry.

Lactobacillus reuteri ZJ617 attenuates metabolic syndrome via microbiota-derived spermidine

Metabolic syndrome (MetS) is a difficult-to-manage disease that poses a significant risk to human health. Here, we show that the supplementation of Lactobacillus reuteri ZJ617 ameliorates symptoms of MetS in mice induced by the high-fat diet. L. reuteri ZJ617 modulates host metabolism by interacting with the microbiome, resulting in the production of spermidine synthesized by the microbiota. L. reuteri ZJ617 serves as a source of substrates for the microbiota to synthesize spermidine, hence preventing the decline of bacteria responsible for spermidine production. Spermidine treatment mimics the metabolic effects of L. reuteri ZJ617, whereas pharmacological inhibition of spermidine biosynthesis in mice abolishes these benefits. Our findings reveal the mechanism by which L. reuteri ZJ617 alleviates MetS symptoms and provide support for its potential use as a probiotic for promoting metabolic health.

The effects of the gut bacterial product, gassericin A, on obesity in mice

BACKGROUND

Obesity can arise from various physiological disorders. This research examined the impacts of the bacteriocin, gassericin A, which is generated by certain gut bacteria, using an in vivo model of obesity.

METHODS

Fifty Swiss NIH mice were randomly assigned to five different groups. One group was given a standard diet, while the remaining groups were fed a diet high in fat and sugar. The test groups received gassericin A at doses of 0.75, 1.5, or 3 mIU/kg through intraperitoneal injection, daily for 10 weeks. Body weight, fasting blood sugar, serum lipid profile, and hepatic function indicators were then assessed. Additionally, the blood profile, markers of oxidative stress, and expression levels of specific genes associated with obesity, Zfp423, and Fabp4, were evaluated in abdominal adipose tissue.

RESULTS

A high-calorie diet negatively impacted abdominal fat, serum cholesterol, LDL, and hepatic enzymes. However, gassericin A significantly improved these effects, despite increasing weight gain and abdominal fat. Furthermore, it improved redox status, downregulated the Zfp423 gene, and enhanced the expression of the Fabp4 gene. Finally, the bacteriocin caused thrombocytopenia and mild decreases in erythrocytes, hematocrit, and hemoglobin levels.

CONCLUSIONS

These results suggest that, despite causing weight gain, gassericin A may improve obesity-related complications.

Current research progress, opportunities, and challenges of Limosillactobacillus reuteri-based probiotic dietary strategies

Limosillactobacillus reuteri (L. reuteri), a type of Lactobacillus spp., stands out as the most extensively researched probiotic. Its remarkable intestinal adhesion has led to widespread applications in both the food and medical sectors. Notably, recent research highlights the probiotic efficacy of L. reuteri sourced from breast milk, particularly in influencing social behavior and mitigating atopic dermatitis. In this review, our emphasis is on surveying recent literature regarding the promotion of host's health by L. reuteri. We aim to provide a concise summary of the latest regulatory effects and potential mechanisms attributed to L. reuteri in the realms of metabolism, brain- and immune-related functions. The mechanism through which L. reuteri promotes host health by modulating the intestinal microenvironment primarily involves promoting intestinal epithelial renewal, bolstering intestinal barrier function, regulating gut microbiota and its metabolites, and suppressing inflammation and immune responses. Additionally, this review delves into new technologies, identifies shortcomings, and addresses challenges in current L. reuteri research. Finally, the application prospects of L. reuteri are provided. Therefore, a better understanding of the role and mechanisms of L. reuteri will contribute significantly to the development of new probiotic functional foods and enable precise, targeted interventions for various diseases.

The anti-hyperuricemic and gut microbiota regulatory effects of a novel purine assimilatory strain, Lactiplantibacillus plantarum X7022

PURPOSE

Probiotics have been reported to effectively alleviate hyperuricemia and regulate the gut microbiota. The aim of this work was to study the in vivo anti-hyperuricemic properties and the mechanism of a novel strain, Lactiplantibacillus plantarum X7022.

METHODS

Purine content and mRNA expression of purine assimilation related enzymes were determined by HPLC and qPCR, respectively. Hyperuricemic mice were induced by potassium oxonate and hypoxanthine. Uric acid (UA), blood urea nitrogen, creatinine and renal inflammation were examined by kits. The expression of renal UA transporters was subjected to western blotting. Kidney tissues were sectioned for histological analysis. The fecal short-chain fatty acids (SCFAs) were determined by HPLC, and gut microbiota was investigated using the 16S rDNA metagenomic sequencing.

RESULTS

L. plantarum X7022 possesses a complete purine assimilation pathway and can exhaust xanthine, guanine, and adenine by 82.1%, 33.1%, and 12.6%, respectively. The strain exhibited gastrointestinal viability as 44% at the dose of 109 CFU/mL in mice. After four-week administration of the strain, a significant decrease of 35.5% in the serum UA level in hyperuricemic mice was achieved. The diminished contents of fecal propionate and butyrate were dramatically boosted. The treatment also alleviated renal inflammation and restored renal damage. The above physiological changes may due to the inhibited xanthine oxidase (XO) activity, as well as the expressional regulation of UA transporters (GLUT9, URAT1 and OAT1) to the normal level. Notably, gut microbiota dysbiosis in hyperuricemic mice was improved with the inflammation and hyperuricemia related flora depressed, and SCFAs production related flora promoted.

CONCLUSION

The strain is a promising probiotic strain for ameliorating hyperuricemia.

Comparative profiling of gut microbiota and metabolome in diet-induced obese and insulin-resistant C57BL/6J mice

Diet-based models are commonly used to investigate obesity and related disorders. We conducted a comparative profiling of three obesogenic diets HFD, high fat diet; HFHF, high fat high fructose diet; and HFCD, high fat choline deficient diet to assess their impact on the gut microbiome and metabolome. After 20 weeks, we analyzed the gut microbiota and metabolomes of liver, plasma, cecal, and fecal samples. Fecal and plasma bile acids (BAs) and fecal short-chain fatty acids (SCFAs) were also examined. Significant changes were observed in fecal and cecal metabolites, with increased Firmicutes and decreased Bacteroidetes in the HFD, HFHF, and HFCD-fed mice compared to chow and LFD (low fat diet)-fed mice. Most BAs were reduced in plasma and fecal samples of obese groups, except taurocholic acid, which increased in HFCD mice's plasma. SCFAs like acetate and butyrate significantly decreased in obesogenic diet groups, while propionic acid specifically decreased in the HFCD group. Pathway analysis revealed significant alterations in amino acid, carbohydrate metabolism, and nucleic acid biosynthesis pathways in obese mice. Surprisingly, even LFD-fed mice showed distinct changes in microbiome and metabolite profiles compared to the chow group. This study provides insights into gut microbiome dysbiosis and metabolite alterations induced by obesogenic and LFD diets in various tissues. These findings aid in selecting suitable diet models to study the role of the gut microbiome and metabolites in obesity and associated disorders, with potential implications for understanding similar pathologies in humans.

The supplementation of the multi-strain probiotics WHHPRO™ alleviates high-fat diet-induced metabolic symptoms in rats via gut-liver axis

Metabolic syndrome (MS) has emerged as one of the major global health concerns, accompanied by a series of related complications, such as obesity and type-2 diabetes. The gut-liver axis (GLA) is a bidirectional communication between the gut and the liver. The GLA alterations have been revealed to be closely associated with the development of MS. Probiotics within Lactobacillus and Bifidobacterium confer beneficial effects on improving MS symptoms. WHHPRO™ is a mixture of four probiotic strains, with potential MS-improving abilities. This study aimed to investigate the effects of WHHPRO™ on MS symptoms using a high-fat diet (HFD) rat model. Oral administration of WHHPRO™ for 12 weeks improved glucose tolerance, blood lipid, body weight, and liver index in HFD rats. WHHPRO™ shaped the gut microbiome composition by increasing the abundance of Lactobacillus and Akkermansia and normalized the reduced SCFA levels in HFD rats. Besides, WHHPRO™ modulated the fecal bile acids (BAs) profile, with decreased levels of T-b-MCA and 12-KDCA and increased levels of LCA and ILCA. Meanwhile, WHHPRO™ increased total unconjugated BAs in feces and liver and reduced the accumulation of total hepatic BA pool size in HFD rats. Moreover, WHHPRO™ reversed the expression of genes associated with impaired BA metabolism signaling in the ileum and liver. Our findings suggest that WHHPRO™ exerted beneficial effects on improving MS symptoms, involving the modulation of the gut microbiome composition, SCFAs, and the FXR-FGF15 signaling along the GLA. Supplementation of WHHPRO™ may serve as a novel strategy for improving MS symptoms.

Modulation of the Altered Intestinal Microbiota by Use of Antibiotics with a Novel Synbiotic on Wistar Rats

The use of antibiotics unbalances the intestinal microbiota. Probiotics, prebiotics, and synbiotics are alternatives for these unbalances. The effects of a new synbiotic composed of probiotic Saccharomyces boulardii CNCM I-745 and fructans from Agave salmiana (fAs) as prebiotics were assessed to modulate the intestinal microbiota. Two probiotic presentations, the commercial probiotic (CP) and the microencapsulated probiotic (MP) to improve those effects, were used to prepare the synbiotics and feed Wistar rats subjected to antibiotics (AB). Eight groups were studied, including five controls and three groups to modulate the microbiota after the use of antibiotics: G5: AB + MP-synbiotic, G6: AB + CP-synbiotic, and G8: AB + fAs. All treatments were administered daily for 7 days. On days 7 and 21, euthanasia was performed, cecum tissue was recovered and used to evaluate histological analysis and to study microphotograph by TEM, and finally, bacterial DNA was extracted and 16S rRNA gene metabarcode sequencing was performed. Histological analysis showed less epithelial damage and more abundance of the intestinal microbiota in the groups G5, G6, and G8 in comparison with the AB control group after 7 days. Microphotograph of the cecum at 2 weeks post treatment showed that G5 and G6 presented beneficial effects in epithelial reconstruction. Interestingly, in the groups that used the synbiotic without AB (G3 and G4) in addition to contributing to the recovery of the autochthonous microbiota, it promotes the development of beneficial microorganisms; those results were also achieved in the groups that used the synbiotic with AB enhancing the bacterial diversity and regulating the impact of AB.

Role of microencapsulated Lactobacillus plantarum in alleviating intestinal inflammatory damage through promoting epithelial proliferation and differentiation in layer chicks

The alleviating effects of Lactobacillus plantarum in microencapsulation (LPM) on lipopolysaccharide (LPS)-induced intestinal inflammatory injury were investigated in layer chicks. A total of 252 healthy Hy-Line Brown layer chicks were randomly divided into six groups. Birds were injected with saline or LPS except for the control, and the diets of birds subjected to LPS were supplemented with nothing, L. plantarum, LPM, and wall material of LPM, respectively. The viable counts of LPM reached 109 CFU/g, and the supplemental levels of L. plantarum, LPM, and WM were 0.02 g (109 CFU), 1.0 g, and 0.98 g, per kilogram feed, respectively. LPS administration caused intestinal damage in layer chicks, evidenced by increased proinflammatory factors accompanied by poor intestinal development and morphology (p < 0.05). LPM/LPS significantly increased body weight, small intestine weight and length, villus height, villus height/crypt depth, and mRNA relative expression of tight junction protein genes (p < 0.05) and performed better than free L. plantarum. These findings could be attributed to the significant increase in viable counts of L. plantarum in the small intestine (p < 0.05), as well as the enhanced levels of Actinobacteriota, Lactobacillaceae, and Lactobacillus in intestinal microbiota (p < 0.05). Such results could further significantly increase goblet and PCNA+ cell percentage (p < 0.05); the mRNA relative expressions of epithelial cell, fast-cycling stem cell, quiescent stem cell, endocrine cell, and Paneth cell; and goblet and proliferative cell marker genes, including E-cadherin, Lgr-5, Bmi-1, ChA, Lysozome, Mucin-2, and PCNA (p < 0.05). Furthermore, the mRNA relative expressions of key genes involved in epithelial cell proliferation, namely, c-Myc, Cyclin-1, Wnt-3, Lrp-5, and Olfm-4, exhibited significant upregulation compared with the LPS treatment, as well as the differentiating genes Notch-1 and Hes-1 (p < 0.05). To sum up, microencapsulated L. plantarum supplementation could alleviate intestinal injury in layer chicks induced by LPS by promoting the proliferation and differentiation of intestinal epithelial cells, which could be attributed to the increase in viable count of L. plantarum in the gut and optimization in intestinal microbial flora.

Lactoferrin deficiency during lactation increases the risk of depressive-like behavior in adult mice

BACKGROUND

Lactoferrin is an active protein in breast milk that plays an important role in the growth and development of infants and is implicated as a neuroprotective agent. The incidence of depression is currently increasing, and it is unclear whether the lack of lactoferrin during lactation affects the incidence of depressive-like behavior in adulthood.

RESULTS

Lack of lactoferrin feeding during lactation affected the barrier and innate immune functions of the intestine, disrupted the intestinal microflora, and led to neuroimmune dysfunction and neurodevelopmental delay in the hippocampus. When exposed to external stimulation, adult lactoferrin feeding-deficient mice presented with worse depression-like symptoms; the mechanisms involved were activation of the LPS-TLR4 signalling pathway in the intestine and hippocampus, reduced BDNF-CREB signaling pathway in hippocampus, increased abundance of depression-related bacteria, and decreased abundance of beneficial bacteria.

CONCLUSIONS

Overall, our findings reveal that lactoferrin feeding deficient during lactation can increase the risk of depressive-like behavior in adults. The mechanism is related to the regulatory effect of lactoferrin on the development of the "microbial-intestinal-brain" axis.

Obese Ningxiang pig-derived microbiota rewires carnitine metabolism to promote muscle fatty acid deposition in lean DLY pigs

The gut microbiota consistently shows strong correlations with lipid metabolism in humans and animals, and whether the gut microbiota contributes to muscle fatty acid (FA) deposition and meat traits in farm animals has not been fully resolved. In this study, we aimed to unveil the microbial mechanisms underlying muscle FA deposition in pigs. First, we systematically revealed the correlation between the gut microbiome and muscle FA levels in 43 obese Ningxiang pigs and 50 lean Duroc Landrace Yorkshire (DLY) pigs. Mutual fecal microbial transplantation showed that the obese Ningxiang pig-derived microbiota increased the muscle FA content and improved meat quality by reshaping the gut microbial composition in lean DLY pigs. Lactobacillus reuteri has been identified as a potential microbial biomarker in obese Ningxiang pig-derived microbiota-challenged DLY pigs. A gavage experiment using lean DLY pigs confirmed that L. reuteri XL0930 isolated from obese Ningxiang pigs was the causal species that increased the muscle FA content. Mechanistically, SLC22A5, a carnitine transporter, was downregulated in L. reuteri XL0930-fed DLY pigs, resulting in reduced muscle carnitine levels. Muscle and intestinal L-carnitine levels, which correlated with the muscle FA content, impeded fat synthesis and FA accumulation in in vitro and in vivo models. In conclusion, we uncovered an unexpected and important role of the obese Ningxiang pig-derived microbiota in regulating muscle FA metabolism via the SLC22A5-mediated carnitine system.

Limosilactobacillus reuteri consumption significantly reduces the total cholesterol concentration without affecting other cardiovascular disease risk factors in adults: A systematic review and meta-analysis

As one of the most significant probiotics, Limosilactobacillus reuteri (L. reuteri) has been exploited as a nutritional supplement. We hypothesized that L. reuteri consumption might improve the significant risk factors of cardiovascular disease, including blood pressure, blood lipid, and blood glucose. However, previous clinical studies have shown controversial results. This study aims to explore the effect of L. reuteri consumption on these risk factors. PubMed, Embase, Scopus, the Cochrane Library, and Web of Science were searched for eligible randomized controlled trials published before May 2022. A total of 6 studies with 4 different L. reuteri strains and including 512 participants were included. The results showed that L. reuteri consumption significantly reduced total cholesterol (TC) by -0.26 mmol/L compared with the control group. In contrast, it did not affect systolic blood pressure, diastolic blood pressure, fasting blood glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), or triglycerides. Subgroup analysis showed a significant reduction in TC when participants were <55 years old, had a body mass index between 25 and 30, or had hypercholesterolemia. In addition, TC decreased significantly when L. reuteri supplementation was >5 × 109 colony-forming unit or the length of the intervention was <12 weeks. Strain subgroup analysis showed that L. reuteri NCIMB 30242 significantly reduced TC and LDL-C. In conclusion, L. reuteri consumption has a significant TC-lowering effect, which can effectively reduce the risks of cardiovascular disease associated with hypercholesterolemia. However, the results do not support the effectiveness of L. reuteri consumption on other metabolic outcomes. Further examination of larger sample sizes is needed to confirm these findings.

The Preventive Mechanisms of Bioactive Food Compounds against Obesity-Induced Inflammation

Dietary patterns are promising strategies for preventing and treating obesity and its coexisting inflammatory processes. Bioactive food compounds have received considerable attention due to their actions against obesity-induced inflammation, with limited harmful side effects. They are perceived as food ingredients or dietary supplements other than those necessary to meet basic human nutritional needs and are responsible for positive changes in the state of health. These include polyphenols, unsaturated fatty acids, and probiotics. Although the exact mechanisms of bioactive food compounds' action are still poorly understood, studies have indicated that they involve the modulation of the secretion of proinflammatory cytokines, adipokines, and hormones; regulate gene expression in adipose tissue; and modify the signaling pathways responsible for the inflammatory response. Targeting the consumption and/or supplementation of foods with anti-inflammatory potential may represent a new approach to obesity-induced inflammation treatment. Nevertheless, more studies are needed to evaluate strategies for bioactive food compound intake, especially times and doses. Moreover, worldwide education about the advantages of bioactive food compound consumption is warranted to limit the consequences of unhealthy dietary patterns. This work presents a review and synthesis of recent data on the preventive mechanisms of bioactive food compounds in the context of obesity-induced inflammation.

Remodeling of the gut microbiome by Lactobacillus johnsonii alleviates the development of acute myocardial infarction

Introduction

The gut microbial community, which can be disturbed or repaired by changes in the internal environment, contributes to the development of acute myocardial infarction (AMI). Gut probiotics play a role in microbiome remodeling and nutritional intervention post-AMI. A newly isolated Lactobacillus johnsonii strain EU03 has shown potential as a probiotic. Here, we investigated the cardioprotective function and mechanism of L. johnsonii through gut microbiome remodeling in AMI rats.

Methods

A rat model of left anterior descending coronary artery ligation (LAD)-mediated AMI was assessed with echocardiography, histology, and serum cardiac biomarkers to evaluate the beneficial effects of L. johnsonii. The immunofluorescence analysis was utilized to visualize the intestinal barrier changes. Antibiotic administration model was used for assessing the gut commensals’ function in the improvement of cardiac function post-AMI. The underlying beneficial mechanism through L. johnsonii enrichment was further investigated by metagenomics and metabolomics analysis.

Results

A 28-day treatment with L. johnsonii protected cardiac function, delayed cardiac pathology, suppressed myocardial injury cytokines, and improved gut barrier integrity. The microbiome composition was reprogrammed by enhancing the abundance of L. johnsonii. Microbiome dysbiosis by antibiotics abrogated the improvement of cardiac function post-AMI by L. johnsonii. L. johnsonii enrichment caused remodeling of gut microbiome by increasing the abundance of Muribaculaceae, Lactobacillus, and decreasing Romboutsia, Clostridia UCG-014, which were correlated with cardiac traits and serum metabolic biomarkers 16,16-dimethyl-PGA2, and Lithocholate 3-O-glucuronide.

Conclusion

These findings reveal that gut microbiome remodeling by L. johnsonii ameliorates the cardiac function post-AMI and might advance microbiome-targeted nutritional intervention.

Safety Evaluation of Goat Milk Added with the Prebiotic Inulin Fermented with the Potentially Probiotic Native Culture Limosilactobacillus mucosae CNPC007 in Co-culture with Streptococcus thermophilus QGE: Analysis of Acute and Repeated Dose Oral Toxicity

Despite functional goat milk products having emerged due to their importance for human nutrition and health, few studies have assessed the safety of consumption of goat dairy products containing potentially probiotic autochthonous lactic acid bacteria supplemented with prebiotic carbohydrates. Aiming this field, this study evaluated the safety of goat's milk fermented with Streptococcus thermophilus QGE, the autochthonous Limosilactobacillus mucosae CNPC007 culture, and the prebiotic inulin, through single- and repeated-dose oral toxicity tests (SDT and RDT, respectively) in animals. Ten female Swiss Webster mice were used for SDT evaluation - 2 groups, SDTc (20 mL/kg of filtered water) and SDTt (20 mL/kg of fermented milk) - and 40 Wistar rats for RDT - RDT3, RDT6, and RDT12 (treated with fermented milk at doses of 3 mL/kg, 6 mL/kg, and 12 mL/kg, respectively) and also RDTc (12 mL/kg of filtered water). For SDT, no signs of mortality or toxicity were observed, and the animals maintained the expected weight gain and feed intake. The RDT trials did not show mortality or signs of toxicity, as well as no change in body weight and organs, in the hematological and biochemical parameters, and also in relation to morphology and histology. Since the fermented milk did not cause any toxic effect in the conditions evaluated, it can be said that its no-adverse effect level (NOAEL) was considered to be higher than 20 mL/kg/day. Thus, the fermented milk with L. mucosae CNPC007 and inulin was considered to be of low toxicity, safe for use in rodents, and allowed for use in further studies.

Fortified Fermented Rice-Acid Can Regulate the Gut Microbiota in Mice and Improve the Antioxidant Capacity

The study aimed to explore the effects of fortified fermented rice-acid on the antioxidant capacity of mouse serum and the gut microbiota. Hair characteristics, body mass index, intestinal villus height, intestinal crypt depth, serum antioxidant capacity, and gut microbiota of mice were first measured and the correlation between the antioxidant capacity of mouse serum and the gut microbiota was then explored. The mice in the lactic acid bacteria group (L-group), the mixed bacteria group (LY-group), and the rice soup group (R-group) kept their weight well and had better digestion. The mice in the L-group had the better hair quality (dense), but the hair quality in the R-group and the yeast group (Y-group) was relatively poor (sparse). In addition, the inoculation of Lactobacillus paracasei H4-11 (L. paracasei H4-11) and Kluyveromyces marxianus L1-1 (K. marxianus L1-1) increased the villus height/crypt depth of the mice (3.043 ± 0.406) compared to the non-inoculation group (R-group) (2.258 ± 0.248). The inoculation of L. paracasei H4-11 and K. marxianus L1-1 in fermented rice-acid enhanced the blood antioxidant capacity of mouse serum (glutathione 29.503 ± 6.604 umol/L, malonaldehyde 0.687 ± 0.125 mmol/L, catalase 15.644 ± 4.618 U/mL, superoxide dismutase 2.292 ± 0.201 U/mL). In the gut microbiota of L-group and LY-group, beneficial microorganisms (Lactobacillus and Blautia) increased, but harmful microorganisms (Candidatus Arthromitus and Erysipelotrichales) decreased. L. paracasei H4-11 and K. marxianus L1-1 might have a certain synergistic effect on the improvement in antibacterial function since they reduced harmful microorganisms in the gut microbiota of mice. The study provides the basis for the development of fortified fermented rice-acid products for regulating the gut microbiota and improving the antioxidant capacity.