Ratio Of Firmicutes Research Articles

Dietary Solid-state-fermentation product of Bacillus velezensis T23 alleviate hepatic steatosis, oxidative stress, gut barrier damage, and microbiota dysbiosis in juvenile genetically improved farmed tilapia (GIFT, Oreochromis niloticus)

The application of commensal probiotic bacteria is one of the preferable green feed additives for antibiotic substitution in aquaculture, while the application methods and detailed action mechanisms of commensal bacteria isolated from aquatic animals are not consistent with normal mammalian-derived probiotics. The purpose of this study was to evaluate the effects of solid-state fermentation product of autochthonous Bacillus velezensis T23 on improving hepatic steatosis, liver antioxidation capacity, gut injury and gut microbiota profile of genetically improved farmed tilapia (GIFT, Oreochromis niloticus). The T23 probiotic was added to the basal diet at a level of 0.00, 0.05, 0.1, 0.2 and 0.3 g/kg to develop five experimental diets, respectively. After 4 weeks of the feeding trial, the results showed that T23 supplementation notably reduced the hepatocytes vacuolization and the content of liver TAGs by downregulated the mRNA expression of the lipogenesis gene (fas), while upregulated the mRNA expression of lipid degradation genes (cpt1 and pparα) (p < 0.05). Compared with the control, the 0.3T23 group showed significantly upregulated expression levels of anti-inflammatory cytokine genes (tgf-β and il-10) in the liver of the fish (p < 0.05). Besides, the activities of antioxidase SOD and CAT were significantly upregulated in T23 treatment groups, compared with the control (p < 0.05). Fish groups fed with 0.2 g/kg and 0.3 g/kg T23 supplemented diet also exhibited significantly lower intestinal injury and intestinal inflammation via upregulating the expression of tight junction protein gene claudin, anti-inflammatory factor gene il-10 (p < 0.05). However, markedly downregulation of the mRNA level of pro-inflammatory cytokine il-1β (p < 0.05) was observed in 0.05 and 0.3T23 groups, compared with the control. 16S rRNA sequencing analysis data on gut microbiota indicated that supplementation of T23 at lower levels (0.05, 0.1 and 0.2) resulted in a remarkable elevation of the abundance of phylum Firmicutes and reduced the abundance of Proteobacteria, and the ratio of (Firmicutes +Bacteroidota +Fusobacteria) /Proteobacteria. On the contrary, feeding with 0.3T23 negatively affects the gut microbiota diversity and structure of tilapia. Therefore, a 0.2 g/kg dose is suggested to supplement the diet of Nile tilapia to improve liver health and modulate the gut microbiota profile of the fish positively. Overall, these findings provide a shred of beneficial evidence of the application of B. velezensis T23 as a green feed additive to improve the productivity and profitability of tilapia farming.

Modulating Gut Microbiota for Treating Antibiotic-Associated Diarrhea from Clostridium difficile Infection: Insights from Lizhong Decoction and Its Polysaccharide Component.

To investigate whether the polysaccharide component of the traditional Chinese medicine formula Lizhong Decoction (LZD) has therapeutic effects and regulates gut microbiota in antibiotic-associated diarrhea related to Clostridium difficile infection, a polysaccharide was extracted from LZD, consisting of rhamnose, five monosaccharides, arabinose, galactose, glucose, and galacturonic acid in a molar ratio of 1.12:8.49:4.06:80.67:5.66. An antibiotic-associated diarrhea model related to Clostridium difficile infection was established using clindamycin gavage and oral colonization with Clostridium difficile. Subsequently, oral treatment experiments with LZD polysaccharides and different doses of the decoction were conducted. The results indicated that the polysaccharide showed the best therapeutic effect on antibiotic-associated diarrhea related to Clostridium difficile infection, with post-treatment gut microbiota clustering closest to the normal control group. The polysaccharide from LZD has therapeutic effects on antibiotic-associated diarrhea related to Clostridium difficile infection, possibly achieved through the regulation of gut microbiota. It modulates the dominant gut microbiota, specifically increasing the abundance of beneficial bacteria by adjusting the ratio of Bacteroidetes and Firmicutes, thereby reversing the dysbiosis caused by Clostridium difficile infection and antibiotics. Thus, LZD polysaccharide may be one of the important active components for gut microbiota regulation in this traditional Chinese medicine formula.

Lactiplantibacillus plantarum Y44 Complex Fermented Milk Regulates Lipid Metabolism in Mice Fed with High-Fat Diet by Modulating Gut Microbiota.

The benefits of fermented milk containing Lactiplantibacillus plantarum (L. plantarum) Y44, known for its weight loss properties, remain unclear. For this, we evaluated the effects of the complex fermented milk (Y44-CFM), obtained through the cofermentation of cow's milk and soybean milk with L. plantarum Y44 and traditional starters, on high-fat diet (HFD)-fed C57BL/6 mice. Our study found that the oral administration of Y44-CFM significantly reduced body weight gain and hepatic lipid accumulation in HFD-fed mice while also mitigating liver injury. Additionally, Y44-CFM regulated the expression of enzymes associated with lipid metabolism in the serum, as well as the corresponding or related genes in the liver, such as fatty acid synthase. Furthermore, HFD-induced systemic inflammation, oxidative stress, and intestinal barrier dysfunction were improved. The primary alterations in hepatic metabolism involved glycerophospholipids and amino acids, including the biosynthesis of valine, leucine, and isoleucine. The diversity and overall structure of the gut microbiota were also regulated, resulting in a significant decrease in the ratio of Firmicutes to Bacteroidetes (F/B) and unclassified_f_Lachnospiraceae, along with a notable increase in Oscillospiraceae. The correlation analysis indicated that Y44-CFM influenced hepatic lipid metabolism by mediating intestinal flora and its production of short-chain fatty acids, ultimately leading to weight reduction.

Hypoglycemic and intestinal microbiota-regulating effects of melanoidins in diabetic mice.

The aqueous extraction of sesame oil is a traditional process that generates a large amount of melanoidins. However, little is known about the characteristics and bioactive functions of these melanoidins. Electronic tongue, fluorescence emission spectroscopy, and Fourier transform infrared spectroscopy analyses indicated that melanoidins from sesame residues (MELs) are brown macromolecular compounds with protein skeletons and heteroaromatic ring structures, a bitter taste, and instability in strong oxidative and reductive environments. The MELs demonstrated inhibitory effects on α-glucosidase, α-amylase and pancreatic lipase in vitro. These MELs mitigated weight loss in mice with type 2 diabetes (T2DM), reduced their fasting blood glucose to 54.73% (500 mg kg-1 day-1) of the initial value, increased the glycogen levels in the liver and skeletal muscles, lowered blood lipid levels, and protected the liver. Western blot analysis revealed that MELs inhibited the activities of enzymes such as PEPCK, FBPase, and G6Pase through the IRS-1/PI3K/Akt and AMPK pathways, increased the activity of the enzymes hexokinase (HK) and pyruvate kinase (PK), enhanced liver glycolytic ability, and promoted liver glycogen synthesis, thereby reducing blood glucose levels in T2DM mice. Moreover, MELs reduced the ratio of Firmicutes to Bacteroides (F/B) in the intestines of T2DM mice, increased the relative abundance of beneficial bacteria such as Lactobacillus, Coprococcus, and Ruminococcus, and reduced the propionic acid content. Melanoidins can regulate T2DM by activating the IRS-1/PI3K/Akt and AMPK-signaling pathways and ameliorating gut microbiota imbalances in T2DM mice. © 2024 Society of Chemical Industry.

Ingesting Stellera chamaejasme Significantly Impacts the Gastrointestinal Tract Bacterial Community and Diversity in Plateau Zokors (Eospalax baileyi).

Intestinal bacteria are considered the "second genome" of the host, playing a crucial physiological role in assisting the host in degrading plant secondary compounds, nutrient absorption, immune regulation, and other aspects. To explore the effects of Stellera chamaejasme on the bacterial community of the gastrointestinal tract of plateau zokor, this study uses the 16S rRNA gene high-throughput sequencing technology, and the biodiversity and the community structure of gut bacteria in different gastrointestinal tract segments (the stomach and cecum) of plateau zokors. The results showed that at the phylum level, the dominant flora in the stomach and cecum of plateau zokors before and after ingesting Stellera chamaejasme were Firmicutes and Bacteroidetes. In plateau zokors that ingested Stellera chamaejasme, the relative abundance of Firmicutes in the stomach and cecum decreased, the relative abundance of Bacteroidetes increased, and the ratio of Firmicutes to Bacteroidetes decreased. After plateau zokors ingested Stellera chamaejasme, the ACE index demonstrated a significant reduction in the richness of the stomach bacterial community, while cecal bacterial community richness showed no significant change. Stellera chamaejasme exhibits significantly different effects on the bacterial communities in different segments of the gastrointestinal tract. Beta diversity analysis revealed that, after plateau zokors ingested Stellera chamaejasme, there were notable distinctions in the bacterial communities within both the stomach and cecum, alongside a marked reduction in the variability of the intestinal bacterial profiles across individuals. The results show that ingesting Stellera chamaejasme has a significant impact on the composition and structure of the gastrointestinal tract bacterial community in plateau zokors.

Gut microbiota combined with serum metabolites to reveal the effect of Morchella esculenta polysaccharides on lipid metabolism disordered in high-fat diet mice

The ameliorating effects and mechanisms of Morchella esculenta polysaccharides (MEP-1) on lipid metabolism were investigated in high-fat diet (HFD) mice. The results showed that MEP-1 intervention significantly reduced serum TC, TG, LDL-C, and inflammatory factors (TNF-α, IL-1β and IL-6) in HFD mice in a dose-dependent manner, and high-dose (400 mg/kg/d) exhibited the most significant reductive effects. In addition, MEP-1 significantly recovered the gut microbiota disorders caused by HFD, especially decreasing the ratio of Firmicutes and Bacteroidetes (F/B) and increasing the dominant bacterial of Muribaculaceae_genus, Bacteroides, Alistipes and Enterococcus. Moreover, MEP-1 promoted the production of SCFAs and increased the expression levels of Occludin, Claudin and Muc2, also regulated lipid metabolism disorder and inflammation by inhibiting TLR4/MyD88/NF-κB via the gut-liver axis. In addition, serum metabolomic analysis revealed that l-phenylalanine, l-arginine and acetylcholine were significantly upregulated with MEP-1 intervention, and were negatively correlated with blood lipid level, in which l-arginine could activate NO/PPARα/CPT1A pathway to ameliorate lipid metabolism disorders. Such results demonstrated that gut microbiota, amino acid metabolic and insulin secretion pathways might be the important factors that mediated the regulation of MEP-1 in lipid metabolism. The results also provided new evidence and strategies for the application of MEP-1 as functional foods.

Insights into the intestinal microbiota of Exopalaemon annandalei and Exopalaemon carinicauda in the Yangtze River estuary.

The gut microbiota plays a crucial role in food webs, carbon cycling, and related elements. Exopalaemon annandalei and Exopalaemon carinicauda are two important forage species in the Yangtze River estuary with extremely similar living habits and morphological characteristics. Exploring the microorganisms in the guts of these two shrimp species can help us understand the survival status of forage species and gut microbiota in the Yangtze River estuary. Therefore, this study analyzed the similarities and differences in the intestinal flora of E. annandalei and E. carinicauda through high-throughput sequencing of 16S rRNA gene amplicons. The results showed that the dominant bacteria in the intestinal flora of E. annandalei and E. carinicauda at the phylum level were Proteobacteria and Firmicutes, respectively. At the genus level, the intestinal flora had higher concentrations of Psychrobacter, Bacillus, Pseudomonas, Acinetobacter, and Macrococcus. In both shrimp species, the contents of Acinetobacter and Macrococcus were higher in spring than in winter. The most important potential functions of the intestinal microbiota were amino acid metabolism and purine metabolism. Additionally, the functions of metabolism and diseases in the intestinal microbiota of E. annandalei were greatly influenced by the season. Furthermore, the experimental results indicated that a lower ratio of Firmicutes to Bacteroidetes was associated with a larger body weight in shrimp. Overall, this study provides a theoretical reference for understanding the intestinal bacterial community of shrimp in estuaries and the healthy cultivation of E. annandalei and E. carinicauda.

Seasonal variations in composition and function of gut microbiota in grazing yaks: Implications for adaptation to dietary shift on the Qinghai-Tibet plateau.

Gut microbiome of animals is affected by external environmental factors and can assist them in adapting to changing environments effectively. Consequently, elucidating the gut microbes of animals under different environmental conditions can provide a comprehensive understanding of the mechanisms of their adaptations to environmental change, with a particular focus on animals in extreme environments. In this study, we compared the structural and functional differences of the gut microbiome of grazing yaks between the summer and winter seasons through metagenomic sequencing and bioinformatics analysis. The results indicated that the composition and function of microbes changed significantly. The study demonstrated an increase in the relative abundance of Actinobacteria and a higher ratio of Firmicutes to Bacteroidetes (F/B) in winter, this process facilitated the adaptation of yaks to the consumption of low-nutrient forages in the winter. Furthermore, the network structure exhibited greater complexity in the winter. Forage nutrition exhibited a significant seasonal variation, with a notable impact on the gut microbiota. The metagenomic analysis revealed an increase in the abundance of enzymes related to amino acid metabolism, axillary activity, and mucin degradation in the winter. In conclusion, this study demonstrated that the gut microbiome of grazing yaks exhibits several adaptive characteristics that facilitate better nutrient accessibility and acid the host in acclimating to the harsh winter conditions. Furthermore, our study offers novel insights into the mechanisms of highland animal adaptation to external environments from the perspective of the gut microbiome.

Effects of Green Tea and Java Pepper Mixture on Gut Microbiome and Colonic MicroRNA-221/222 in Mice with Dextran Sulfate Sodium-Induced Colitis.

In this study, we aimed to investigate the regulatory effects of a green tea and java pepper mixture (GTP) on the gut microbiome and microRNA (miR)-221/222 expression in mice with dextran sulfate sodium (DSS)-induced colitis. Male C57BL/6J mice were divided into four groups: DSS-, DSS+, GTP50, and GTP100. In the GTP50 and GTP100 groups, GTP was orally administered to mice at doses of 50 and 100 mg/kg body weight, respectively, every day for 2 weeks, and colitis was induced in the DSS+, GTP50, and GTP100 groups by adding 3% DSS to their drinking water for 1 week. GTP was found to mitigate the severity of inflammation and the damage to goblet cells caused by DSS-induced colitis. The results showed that compared with the DSS- group, the relative abundance of Bacteroidetes was increased and that of Proteobacteria and Candidatus Melainabacteria was decreased in the GTP100 group. The ratio of Firmicutes to Bacteroidetes was also reduced in the GTP100 group. However, GTP administration did not modulate the microbial diversity. GTP administration upregulated the mRNA and protein levels of occludin and zonula occludens 1. In addition, GTP effectively downregulated the expression of miR-221 and miR-222. Overall, GTP altered the gut microbiota composition and downregulated colonic miR-221/222 expression in mice with DSS-induced colitis.

HUC-MSCs mitigate atherosclerosis induced by a high-fat diet in ApoE−/− mice by regulating the intestinal microbiota

BackgroundThe mechanism underlying human umbilical cord mesenchymal stem cells (hUC-MSCs) regulating the stability of atherosclerotic plaque was explored by establishing mice models of atherosclerosis induced by a high-fat diet and hUC-MSCs intervention. MethodsThe ApoE−/− mice atherosclerosis model was constructed using a high-fat diet, and mice were divided into a normal diet group (ND), high-fat diet group (HFD), hUC-MSCs treatment group (HFDM), while the blank control (BC) consisted of C57BL/6J mice. After successful establishment of the model, the feces, hearts, and aorta of mice were collected. Morphological features were detected using HE, oil red O, and Masson staining. Afterward, 16s rRNA gene sequences was used to detect the species and abundance of the intestinal flora in mice, and an atomic force microscope (AFM) was used to detect the Young's modulus of the fibrous cap of atherosclerotic plaques. Lastly, the expression level of the inflammatory factors NLRP3, IL-1β, and IL-18 were detected via immunohistochemistry and immunofluorescence assays. ResultsIn terms of morphological characteristics, the expression level of NLRP3, Young's modulus of the fibrous cap, and plaque stability were significantly reduced in HFD, whereas the ratio of Firmicutes to Bacteroidetes (F/B) was significantly increased. Interestingly, hUC-MSCs treatment reversed the above indices, thus enhancing plaque stability. ConclusionHFD led to dysregulation of intestinal flora homeostasis and induced aberrant expression levels of NLRP3, resulting in a decrease in the Young's modulus of plaques. However, hUC-MSCs treatment improved the biomechanical properties of plaque by modulating the intestinal flora and NLRP3, thereby elevating plaque stability and minimizing the risk of plaque rupture.

Association of Firmicutes/Bacteroidetes Ratio with Body Mass Index in Korean Type 2 Diabetes Mellitus Patients.

The gut microbiome, which is the collection of microorganisms living in the gastrointestinal tract, has been shown to play a significant role in the development of metabolic disorders such as obesity and type 2 diabetes mellitus (T2DM). Studies have found that the ratio of Firmicutes to Bacteroidetes (F/B) is higher in obese individuals compared to lean individuals and tends to decrease with weight loss. However, the relationship between the F/B ratio and T2DM in Korean individuals, with or without obesity, is not fully understood. The objective of this study is to compare the F/B ratios and metabolic profiles of lean and obese Korean individuals with T2DM. In this study, 36 individuals with type 2 diabetes mellitus (T2DM) were recruited and classified into four groups (I, II, III, and IV) based on their body mass index (BMI). Group I had a BMI of less than 23.0, group II had a BMI between 23.0 and 24.9, group III had a BMI between 25.0 and 29.9, and group IV had a BMI of 30 kg/m2 or greater. Fecal samples were collected from all participants and sent to Chunlab Inc. (located in Seoul, Republic of Korea) for analysis. The changes in the major microbial phyla within the samples were investigated using quantitative real-time PCR. The collected data were then statistically analyzed using the SPSS program. The levels of triglycerides and alanine transaminase in group I were significantly lower than in the other three groups. The amount of Actinobacteria in group IV was the highest among all four groups. The ratio of Firmicutes to Bacteroidetes increased as BMI increased, and this ratio was positively correlated with AST activity. Our study showed that there is a correlation between the degree of obesity in individuals with diabetes and their gut microbiome. Additionally, the ratio of Firmicutes to Bacteroidetes (F/B ratio) may play a role in the metabolic effects of fatty liver disease, as it may contribute to obesity.

Analysis of the characteristics of intestinal microbiota in patients with different severity of obstructive sleep apnea

Intestinal microbiota imbalance plays an important role in the progression of obstructive sleep apnea (OSA), and is considered to be the main mediator that triggers metabolic comorbidities. Here, we analyzed the changes in intestinal microbiota in patients with different severities of OSA based on apnea hypopnea index (AHI) classification, and explored the role of intestinal microbiota in the severity of OSA. This study included 19 healthy volunteers and 45 patients with OSA [5 ≤ AHI < 15 (n = 14), 15 ≤ AHI < 30 (n = 13), AHI ≥ 30 (n = 18)]. Relevant sleep monitoring data and medical history data were collected, and microbial composition was analyzed using 16S rRNA high-throughput sequencing technology. The diversity analysis of intestinal microbiota among different groups of people was conducted, including alpha diversity, beta diversity, species diversity, and marker species as well as differential functional metabolic pathway prediction analysis. With the increase of AHI classification, the alpha diversity in patients with OSA significantly decreased. The results revealed that the severity of OSA is associated with differences in the structure and composition of the intestinal microbiota. The abundance of bacteria producing short-chain fatty acids (such as Bacteroides, Ruminococcacea, and Faecalibacterium) in severe OSA is significantly reduced and a higher ratio of Firmicutes to Bacteroidetes. Random forest analysis showed that Parabacteroides was a biomarker genus with important discriminatory significance. The differential metabolic pathway prediction function shows that the main function of maintaining intestinal microbiota homeostasis is biosynthetic function. Our results show that the differences in the composition of intestinal microbiota in patients with different severities of OSA are mainly related to short-chain fatty acid-producing bacteria. These changes may play a pathological role in OSA combined with metabolic comorbidities.

Modifications in the Composition of the Gut Microbiota in Rats Induced by Chronic Sleep Deprivation: Potential Relation to Mental Disorders.

Sleep deprivation(SD) has numerous negative effects on mental health. A growing body of research has confirmed the implication of gut microbiota in mental disorders. However, the specific modifications in mammalian gut microbiota following SD exhibit variations across different studies. Male specific-pathogen-free Wistar rats were given a modified multiple-platform exposure for 7 days of SD. Fecal samples were obtained from the control and SD groups both at baseline and after 7 days of SD. We utilized 16S rDNA gene sequencing to investigate the gut microbial composition and functional pathways in rats. Analysis of the microbiota composition revealed a significant change in gut microbial composition after chronic SD, especially at the phylum level. The relative abundances of p_Firmicutes, g_Romboutsia, and g_Enterococcus increased, whereas those of p_Bacteroidetes, p_Verrucomicrobia, p_Fusobacteria, g_Akkermansia, and g_Cetobacterium decreased in animals after chronic SD compared with controls or animals before SD. The ratio of Firmicutes to Bacteroidetes exhibited an increase following SD. The relative abundance of gut microbiota related to the functional pathways of GABAergic and glutamatergic synapses was observed to be diminished in rats following SD compared to pre-SD. Collectively, these findings suggest that chronic SD causes significant alterations in both the structural composition and functional pathways of the gut microbiome. Further researches are necessary to investigate the chronological and causal connections among SD, the gut microbiota and mental disorders.

Gut microbiota and rheumatic diseases: new insights into pathogenesis

Background: Rheumatic diseases are a group of disorders characterised by a loss of immune tolerance, which leads to chronic inflammation, degeneration or metabolic abnormalities in various organs or tissues. Despite the lack of clarity surrounding the causes of these diseases, both environmental and genetic factors play an important role. Recent research indicates that alterations in the composition of the gut microbiota, known as gut dysbiosis, may contribute to the development of a number of rheumatic diseases, including rheumatoid arthritis, systemic lupus, ankylosing spondylitis, systemic scleroderma and Sjögren's syndrome. The gut microbiota influences the balance between pro- and anti-inflammatory immune responses, which may have important implications for the pathogenesis of these diseases. Furthermore, studies have indicated that the composition of the gut microbiota may be associated with the response to therapies used to treat rheumatic diseases, thus opening up new avenues for the development of microbiota-targeted treatments for these conditions. Aim of the study: The objective of this review is to investigate the impact of the gut microbiota on the pathogenesis of rheumatic diseases and to evaluate potential therapies targeting the manipulation of the gut microbiota. Material and methods: The present study is based on literature available in scientific databases from 2019-2024, such as PubMed, Corchane Library and Google Scholar.Results and conclusions: A growing body of evidence suggests a potential link between the gut microbiota and rheumatic diseases. Patients often exhibit a reduced ratio of Firmicutes to Bacteroidetes and abnormal numbers of Bacteroides. Molecular mimicry and a potential association with short-chain fatty acids have also been observed. Further human studies are needed to more fully understand the role of the gut microbiota and potential therapeutic interventions.

Structural characteristics of areca nut seed neutral polysaccharide and its impact on gut microbiota from human feces

Areca nut (Areca catechuL.) is considered as the fourth most common psychoactive substance globally. Although areca nut seeds (ACS) are typically discarded as processing waste, some studies indicate that amounts of polysaccharides exist in the seeds. However, research on these polysaccharides remains limited. In this study, polysaccharide (ACSP) from areca catechu seeds was isolated into three fractions, among which neutral fraction had a highest yield up to 31.8%. Subsequently, the structural features of neutral fraction (ACSP-0) were analyzed, along with its impact on short-chain fatty acids and human gut microbiota through in vitro feces fermentation. It was found that the backbone chain of ACSP-0 was composed of →4)α-D-Glcp-(1→, α-D-Glcp-(1→, →3,4)α-D-Glcp-(1→ and →4)β-D-Glcp, and the side chain was consisted of α-D-Glcp-(1 → . In vitro digestion experiments demonstrated that ACSP-0 could pass through the upper digestive system without being broken down. Furthermore, in vitro fecal fermentation of ACSP-0 resulted in an increased concentration of short-chain fatty acids and promoted the growth of beneficial bacteria such as norank_f_norank_o_Clostridium UCG-014, which are known to produce generate antibacterial compounds and mitigate gut barrier damage. Additionally, by reducing the abundance ratio of Firmicutes to Bacteroidota, ACSP-0 may hold potential for obesity management. In conclusion, ACSP-0 shows potential as an innovative ingredient for enhancing gut health in humans. This study suggests a novel utilization strategy for areca nut seeds, which could be beneficial for the areca nut processing industry.

Pichia pastoris composition expressed aerolysin mutant of Aeromonas veronii as an oral vaccine evaluated in zebrafish (Danio rerio)

Vaccines are one of the most practical means to stop the spreading of Aeromonas veronii in aquaculture. In this study, virulence factor aerolysin mutant NTaer which has lost its hemolytic activity was used as a target antigen. Pichia pastoris constitutive secretory expression NTaer (GS115-NTaer) was used as a potential safe oral vaccine to evaluate its effectiveness on zebrafish immunity. The result shows that vaccination of GS115- NTaer for four weeks did not affect the growth performance of the host, while eliciting an effective immune protective response. Compared with the control group, the GS115-NTaer could significantly up-regulate the relative expression level of the intestinal tight junction protein 1α (TJP1α) gene, and significantly increased the contents of lysozyme (LYZ), complement C3 and C4 in the gut, indicating that the innate immune response of the fish was activated. The relative gene expression levels of macrophage-expressed gene 1 (MPEG1) and T cell receptor (TCR-α) in the gut, and MPEG1, CD4, CD8, TCR-α, GATA3, and T-bet in the spleen were all increased significantly, indicating that the cellular immune response of the fish was activated. Furthermore, the contents of serum IgM and intestinal mucosa IgZ antibodies were significantly increased, which showed that humoral immunity was also activated. Moreover, inoculation with GS115-NTaer significantly changed the structure of gut microbiota. In particular, the relative ratio of (Firmicutes + Fusobacteriota + Bacteroidota)/Proteobacteria was significantly higher than that of the control and GS115 groups. Lastly, the vaccinated fish were challenged with A. veronii, and the relative percent survival of GS115 and the GS115-NTear groups was 14.28% and 33.43%. This improvement of immunity was not only due to the specific immune response but also attributed to the improvement of innate immunity and the gut microbiota which was demonstrated by the germ-free zebrafish model. Collectively, this study provides information on the effectiveness of GS115-NTear as an oral vaccine for the green prevention and control of A. veronii infection in fish aquaculture.

Lactoferrin alleviates chronic low‑grade inflammation response in obese mice by regulating intestinal flora.

Chronic low‑grade inflammation defines obesity as a metabolic disorder. Alterations in the structure of gut flora are strongly associated with obesity. Lactoferrin (LF) has a biological function in regulating intestinal flora. The present study aimed to investigate the therapeutic and anti‑-inflammatory effects of LF in obese mice based on intestinal flora. A total of 30 C57BL/6 mice were divided into three groups consisting of 10 mice each. Subsequently, one group was fed a normal diet (Group K), another group was fed a high‑fat diet (Group M) and the remaining group switched from regular drinking to drinking 2% LF water (Group Z2) after 2 weeks of high‑fat diet; all mice were fed for 12 weeks. After the experiment, the mouse blood lipid and lipopolysaccharide levels, levels of inflammatory factors and intestinal tight junction proteins were assessed. Mouse stool samples were analyzed using 16S ribosomal RNA sequencing. The results showed that LF reduced serum total cholesterol, triglycerides and low‑density lipoprotein levels, elevated high‑density lipoprotein levels, suppressed metabolic endotoxemia and attenuated chronic low‑grade inflammatory responses in obese mice. In addition, LF upregulated zonula occludens‑1 and occludin protein expression levels in the intestine, thereby improving intestinal barrier integrity. LF altered the intestinal microbial structure of obese mice, reduced the ratio of Firmicutes and an elevated ratio of Bacteroidota, modifying the bacterial population to the increased relative abundance of Alistipes, Acidobacteriota, Psychrobacter and Bryobacter.

Dietary Pectin from Premna microphylla Turcz Leaves Prevents Obesity by Regulating Gut Microbiota and Lipid Metabolism in Mice Fed High-Fat Diet.

The present study was designed to investigate the protective effects of pectin extracted from Premna microphylla Turcz leaves (PTP) against high-fat-diet (HFD)-induced lipid metabolism disorders and gut microbiota dysbiosis in obese mice. PTP was made using the acid extraction method, and it was found to be an acidic pectin that had relative mole percentages of 32.1%, 29.2%, and 26.2% for galacturonic acid, arabinose, and galactose, respectively. The administration of PTP in C57BL/6J mice inhibited the HFD-induced abnormal weight gain, visceral obesity, and dyslipidemia, and also improved insulin sensitivity, as revealed by the improved insulin tolerance and the decreased glucose levels during an insulin sensitivity test. These effects were linked to increased energy expenditure, as demonstrated by the upregulation of thermogenesis-related protein UCP1 expression in the brown adipose tissue (BAT) of PTP-treated mice. 16S rRNA gene sequencing revealed that PTP dramatically improved the HFD-induced gut dysbiosis by lowering the ratio of Firmicutes to Bacteroidetes and the quantity of potentially harmful bacteria. These findings may provide a theoretical basis for us to understand the functions and usages of PTP in alleviating obesity.

Guava polysaccharides attenuate high fat and STZ-induced hyperglycemia by regulating gut microbiota and arachidonic acid metabolism

This study investigated the hypoglycemic mechanism of guava polysaccharides (GP) through the gut microbiota (GM) and related metabolites. Our findings demonstrated that GP significantly mitigated high-fat diet- and streptozotocin-induced hyperglycemia, insulin resistance, hyperlipidemia, elevated alanine aminotransferase, high hepatic inflammation levels, and prevented pancreatic atrophy and hepatomegaly. Interestingly, the benefits of GP were attributed to alterations in the GM. GP decreased the ratio of Firmicutes to Bacteroidetes, significantly inhibiting deleterious bacteria, including Uncultured_f_Desulfovibrionaceae, Bilophila, and Desulfovibrio, while promoting the proliferation of probiotic Bifidobacterium and Bacteroides. In addition, GP promoted the generation of short-chain fatty acids. Notably, the arachidonic acid (AA) metabolism pathway was enriched in liver metabolites. GP significantly elevated hepatic AA and 15-hydroxyeicosatetraenoic acid, while reducing prostaglandin E2 and 5- and 12-hydroxyeicosatetraenoic acid. This modulation is accompanied by the downregulation of hepatic cyclooxygenase-1, 12-lipoxygenase, P38, and c-Jun N-terminal kinase mRNA expression, and the upregulation of cytochrome P4502J5 and insulin receptor substrate 1/2 mRNA expression. However, GP antibiotic treatment did not induce significant alterations in FBG and AA levels or gene expression. Overall, our findings suggest that the hypoglycemic effect of GP may be intricately linked to alterations in AA metabolism, which depends on the GM.

Junshanyinzhen tea extract prevents obesity by regulating gut microbiota and metabolic endotoxemia in high-fat diet fed rats

Obesity is associated with gut dysbiosis and metabolic endotoxin. Junshanyinzhen tea extract (JSTE) reduced fat accumulation and body weight in obese mice. However, the effects and mechanism of JSTE in preventing obesity were unclear. Therefore, we used different doses of JSTE (75, 150 and 300 mg/(kg∙d)) to evaluate the effect on high-fat diet (HFD)-induced rats under 8 weeks of intervention. Here, our results showed that JSTE could significantly reduce body weight gain, blood lipid levels and fat accumulation, improve fatty damage in liver tissue (P < 0.05). In addition, JSTE increased the expression of intestinal tight junction proteins (P < 0.05), relieved metabolic endotoxemia (P < 0.05) and chronic low-grade inflammation in HFD rats. Sequencing of fecal samples showed that JSTE could effectively reverse the microbial diversity and the ratio of Firmicutes to Bacteroidetes to normal levels in HFD-fed rats. Desulfovibrioceae and Erysipelotrichaceae, which are positively related to obesity, were decreased by JSTE intervention (P < 0.05). while Bifidobacteriaceae, Bacteroidaceae, Akkermansia, and Clostridium, which are negatively related to obesity, were increased. Together, these results suggested that JSTE might effectively prevent obesity by modulating gut microbiota dysbiosis, intestinal barrier dysfunction, metabolic endotoxemia and chronic low-grade inflammation in HFD-induced rats.