Stability Of Microbiota Research Articles

Intestinal microbiota protects against methylmercury-induced neurotoxicity.

Methylmercury (MeHg) remains a global public health issue because of its frequent presence in human food sources obtained from the water. The excretion of MeHg in humans occurs slowly with a biological half-time of 32-47 days. Short-term MeHg exposure may cause long-lasting neurotoxicity. The excretion through feces is a major route in the demethylation of MeHg. Accumulating evidence suggests that the intestinal microbiota plays an important role in the demethylation of MeHg, thereby protecting the host from neurotoxic effects. Here, we discuss recent developments on the role of intestinal microbiota in MeHg metabolism, based on in vitro cell culture experiments, experimental animal studies and human investigations. Demethylation by intestinal bacteria is the rate-limiting step in MeHg metabolism and elimination. The identity of bacteria strains responsible for this biotransformation is currently unknown; however, the non-homogenous distribution of intestinal microbiota may lead to different demethylation rates in the intestinal tract. The maintenance of intestinal barrier function by intestinal microbiota may afford protection against MeHg-induced neurotoxicity, which warrant future investigations. We also discuss studies investigating the effects of MeHg exposure on the population structural stability of intestinal microbiota in several host species. Although this is an emerging area in metal toxicity, current research suggests that a change in certain phyla in the intestinal microbiota may indicate MeHg overexposure.

Toxicity of Polystyrene Nanoplastics in the Liver and Intestine of Normal and High-Fat-Diet Juvenile Zebrafish.

Nanoplastics (NPs) are widely found and threaten environmental and biological safety, because they do not degrade completely. We aimed to preliminarily explore the toxicity of NPs in obese children, because childhood obesity is a growing global health concern. We used zebrafish as a vertebrate toxicological model to examine the hepatic lipid metabolism and gut microbiota in juvenile zebrafish exposed to 1000 μg/L polystyrene NPs and a high-fat diet (HFD) using Raman spectroscopy, pathological examination, transcriptome analysis, and 16S sequencing techniques. Our study showed that polystyrene NPs perturb the lipid metabolism and gut microbiota stability in zebrafish. Furthermore, the combined effects of polystyrene NPs and HFD resulted in gastrointestinal injury. Our study is one of the first to investigate the toxicity of polystyrene NPs to normal-diet and HFD juvenile zebrafish using confocal Raman spectroscopy. Our results show the importance of a healthy diet and a reduction in the use of plasticware. Environ Toxicol Chem 2024;43:147-158. © 2023 SETAC.

Mycobacterium tuberculosis Rv1987 protein attenuates inflammatory response and consequently alters microbiota in mouse lung.

Healthy lung microbiota plays an important role in preventing Mycobacterium tuberculosis (Mtb) infections by activating immune cells and stimulating production of T-helper cell type 1 cytokines. The dynamic stability of lung microbiota relies mostly on lung homeostasis. In our previous studies, we found that Mtb virulence factor, Rv1987 protein, can mediate host immune response and enhance mycobacterial survival in host lung. However, the alteration of lung microbiota and the contribution of lung microbiota dysbiosis to mycobacterial evasion in this process are not clear so far. M. smegmatis which does not contain the ortholog of Rv1987 protein was selected as a model strain to study the effects of Rv1987 on host lung microbiota. The lung microbiota, immune state and metabolites of mice infected by M. smegmatis overexpressing Rv1987 protein (MS1987) were detected and analyzed. The results showed that Rv1987 inhibited inflammatory response in mouse lung and anaerobic bacteria and Proteobacteria, Bacteroidota, Actinobacteriota and Acidobacteriota bacteria were enriched in the lung tissues correspondingly. The immune alterations and microbiota dysbiosis affected host metabolic profiles, and some of significantly altered bacteria in MS1987-infected mouse lung, such as Delftia acidovorans, Ralstonia pickettii and Escherichia coli, led to anti-inflammatory responses in mouse lung. The secretory metabolites of these altered bacteria also influenced mycobacterial growth and biofilm formation directly. All these results suggested that Rv1987 can attenuate inflammatory response and alter microbiota in the lung, which in turn facilitates mycobacterial survival in the host.

High-fibre diets regulate antioxidative capacity and promote intestinal health by regulating bacterial microbiota in growing pigs.

This experiment was conducted to investigate the effects of a high-fibre diet on growth performance, nutrients digestibility, intestinal health, and intestinal microbiota composition of growing pigs. Twelve healthy "Duroc × Landrace × Yorkshire" castrates (49 ± 1.35 kg) were randomly divided into two groups with six replicates and one pig per replicate. The two diet treatments were fed the basal diet (CON) based on corn and soybean meal and high fibre diet (HF)respectively. The nutritional levels of the two treatments were the same. The experiment lasted 28 days. The results showed that the addition of 16% wheat bran fibre to the diet of growing pigs did not affect growth performance (p > 0.05). Compared with the CON, contents of isobutyric and butyric acid, GSH-PX and T-AOC in serum were increased in the HF. It decreased the gross energy digestibility and acetic acid content in feces of growing pigs (p < 0.05), the contents of GSH-PX and T-AOC in serum. It decreased the gross energy digestibility and acetic acid content in feces of growing pigs (p < 0.05). Compared with the CON, the Shannon, and Chao1 indexes of the HF were increased (p < 0.05). At the phylum level, the abundance of g_Lactobacillus increased in the HF (p < 0.05). Correlation analysis showed that a total of 18 microbial genera were correlated with antioxidant capacity and volatile fatty acid levels (p < 0.05). In summary, this study showed that adding 16% wheat bran to the diet of growing pigs had no effect on growth performance but helped to improve the richness and stability of intestinal microbiota, promote posterior intestinal fermentationand increase serum antioxidant capacity.

Vaginal microbiota stability as a marker of successful outcomes of pregnancy

Overcoming the problem of miscarriage still remains relevant today. Its' significant contribution to the structure of premature birth is due to the invasion of conditionally pathogenic microflora from the lower parts of the genital tract into the amniotic cavity. It can thus trigger an inflammatory reaction, causing early termination of pregnancy. The microbiota of the genital tract is characterized by the least diversity and high stability over time compared to any other location of the body. The dominance of certain types of lactobacilli in the vaginal biotope may be a marker of well-being, or a harbinger of termination of pregnancy. The aim of this review article is to summarize the current understanding of the vaginal microbiota during pregnancy in order to determine the relationship between its composition and stability throughout pregnancy, as well as the risk of early termination of pregnancy.

16S rRNA and transcriptome analysis of the FOS-mediated alleviation of Aeromonas hydrophila-induced intestinal damage in Megalobrama amblycephala

This study was conducted to elucidate the effects of FOS that alleviate Aeromonas hydrophila-induced intestinal damage. The results showed that A. hydrophila disrupted the intestinal structure and increased intestinal permeability, causing abnormalities in mucosal pathology. Additionally, A. hydrophila induced an imbalance in the intestinal flora and disturbed its stability. Dietary FOS ameliorated the injury to the intestinal structure of fish, but also in part improved the condition of the intestinal tight junction complex. Transcriptomic analysis showed that 120 genes were up-regulated and 320 genes were down-regulated. The intestinal immune network for the IgA production signalling pathway was enriched following A. hydrophila infection, and the change in the FOS group was mainly in the Tight junction signalling pathway. Similarly, dietary FOS reduced the disruption of the intestinal microbiota induced by A. hydrophila and improved the intestinal microbiota's stability; FOS was also partially implicated in the upregulation of Tight junction and Adhesion junction pathways by transcriptomic analysis. After further analysis, it was found that fish fed FOS had upregulated expression of genes related to apoptosis, antigen presentation, and the T-cell-mediated immune response in the intestine compared with those in the A. hydrophila group, which may be related to changes in the intestinal microbiome.

Mogroside V ameliorates broiler pulmonary inflammation via modulating lung microbiota and rectifying Th17/Treg dysregulation in lipopolysaccharides-induced lung injury

The dysbiosis of lung microbiota and inflammatory factors play a crucial role in the occurrence of lipopolysaccharides (LPS)-induced lung injury. Recently, mogroside V (MGV) has received increasing attention due to its potential health benefits in pneumonia, but its complex mechanism needs further experimental elucidation. In this study, we established an LPS-induced chicken lung injury model to investigate the protective effect of MGV on LPS-induced acute lung injury in broiler and its related mechanisms. A total of 192 one-day-old white-finned broilers were randomly assigned into 4 groups with 6 replicates: 1) control group: basal diet (d 1-44), saline (d 43); 2) LPS group: basal diet (d 1-44), LPS (d 43); 3) MGV group: basal diet+0.2% MGV (d 1-44), saline (d 43); 4) MGV-LPS group: basal diet+0.2% MGV (d 1-44), LPS (d 43). The results showed that pathological examination showed that lung tissue inflammation infiltration was reduced after MGV treatment. In addition, MGV can promote the balance of Th17 and Treg cell cytokines, significantly inhibit the expression of proinflammatory cytokines (IL-1β (P < 0.01), IL-6 (P < 0.001), IL-17F (P < 0.05)), and decrease immunosuppressive target expression (PD-L1 (P < 0.01), PD-1 (P < 0.001), RORα (P < 0.001)), activating the immune system. Furthermore, 16S rRNA sequencing analysis showed that MGV treatment could increase the abundance of beneficial bacteria in the lung and reduce the abundance of bacteria associated with inflammation. Generally, MGV intervention has a preventive effect on the pathological damage induced by lipopolysaccharides. Its mechanism is related to inhibiting the inflammatory response, regulating the Th17/Treg balance, and maintaining the stability of lung microbiota.

Effects of alcohol on the symptoms of gouty arthritis and taxonomic structure of gut microbiota in C57BL/6 mice.

Gout is an acute arthritis caused by the elevated levels of serum uric acid (UA), and its prevalence has been rapidly increasing. Alcohol abuse could lead to a series of health problems. Multiple pieces of evidence suggest that alcohol intake affects the development and progression of gout, while the gut microbiota plays an important role in the development of gout and the long-term alcohol consumption could affect the stability of the gut microbiota. This study aimed to explore the effects of alcohol intake at different concentrations on gouty arthritis based on the gut microbiota. We investigated the effects of different concentrations of alcohol on gouty arthritis in mouse models of acute gouty arthritis established by injection of monosodium urate (MSU) crystals into C57BL/6 mice. The results indicated that the high-alcohol consumption not only exacerbated joint swelling and pain, increased the levels of UA, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), but also showed dramatic effects on the composition and structure of the gut microbiota in gouty mice. Two key microorganisms, Parasutterella and Alistipes, could aggravate gout symptoms through lipopolysaccharide biosynthesis, riboflavin metabolism, phenylalanine metabolism, and arginine and proline metabolisms. In conclusion, our study suggested that high-concentrations of alcohol altered the gut microbiota structure in gouty mice induced by MSU crystals, which could exacerbate gouty symptoms by enhancing pro-inflammatory pathways.

Neuroimmunological Effect of Vitamin D on Neuropsychiatric Long COVID Syndrome: A Review.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19). COVID-19 is now recognized as a multiorgan disease with a broad spectrum of manifestations. A substantial proportion of individuals who have recovered from COVID-19 are experiencing persistent, prolonged, and often incapacitating sequelae, collectively referred to as long COVID. To date, definitive diagnostic criteria for long COVID diagnosis remain elusive. An emerging public health threat is neuropsychiatric long COVID, encompassing a broad range of manifestations, such as sleep disturbance, anxiety, depression, brain fog, and fatigue. Although the precise mechanisms underlying the neuropsychiatric complications of long COVID are presently not fully elucidated, neural cytolytic effects, neuroinflammation, cerebral microvascular compromise, breakdown of the blood-brain barrier (BBB), thrombosis, hypoxia, neurotransmitter dysregulation, and provoked neurodegeneration are pathophysiologically linked to long-term neuropsychiatric consequences, in addition to systemic hyperinflammation and maladaptation of the renin-angiotensin-aldosterone system. Vitamin D, a fat-soluble secosteroid, is a potent immunomodulatory hormone with potential beneficial effects on anti-inflammatory responses, neuroprotection, monoamine neurotransmission, BBB integrity, vasculometabolic functions, gut microbiota, and telomere stability in different phases of SARS-CoV-2 infection, acting through both genomic and nongenomic pathways. Here, we provide an up-to-date review of the potential mechanisms and pathophysiology of neuropsychiatric long COVID syndrome and the plausible neurological contributions of vitamin D in mitigating the effects of long COVID.

Temporal stability and assembly mechanisms of gut microbiota in sea cucumbers response to nanoplastics treatment

Aquaculture provides essential food for humans, and the health of farmed species is particularly important for the aquaculture industry. Aquaculture environment could be a sink of plastic debris (PDs) due to the enclosed character and heavy use of plastics. Gut microbiota of aquaculture species could respond to the exogenous pollutants and regulate the health of hosts. Here, variations in gut microbiota of Apostichopus japonicus induced by the ingested nanoplastics (NPs) were investigated by a lab experiment. We selected a NPs concentration gradient of 100 mg/kg and 500 mg/kg to simulate microplastic pollution to A. japonicus, and the significant differences in gut microbiota composition after 21 days of NP exposure were evaluated. According to the high-throughput sequencing from time series samples, a decrease of diversity in gut microbiota of A. japonicus with dietary NPs was observed. In addition, the gut microbiota compositions of sea cucumbers with and without NPs exposure were also distinct, expressing as enrichment of Bacteroidota while reducement of Proteobacteria under NPs stresses. Combined the results of network analysis, the less complexity and stability of gut microbiota in sea cucumbers with dietary NPs were proved. Based on the neutral community model, the ingested NPs elevated the contribution of stochastic processes for the gut microbiota assembly in sea cucumbers. Our study showed that substantial variations in gut microbiota of A. japonicus under NPs stresses, and also explored the underlying mechanisms regulating these changes. This research would offer new meaningful insights into the toxicity of NPs on sea cucumbers, contributing a solid fundament to improve the health of sea cucumbers under NPs stresses.

Consistent features of the gut microbiota in response to diverse shrimp Litopenaeus vannamei diseases: A meta‐analysis

AbstractDysbiosis in the gut microbiota has been intimately implicated in shrimp (Litopenaeus vannamei, Penaeidae) diseases. However, considering the variety of shrimp diseases and the variability in experimental conditions, studies addressing common features of the gut microbiota−shrimp disease relationship are limited. Through an unbiased subject‐level meta‐analysis framework, 463 shrimp gut bacterial communities from 27 studies were re‐analysed, including six lifestages and eight diseases of shrimp, with the causal agents of viral, bacterial, eukaryotic, and unknown pathogens. Shrimp lifestages and diseases were the predominant factors governing the gut microbiota. After ruling out the top lifestage‐ and disease‐specific discriminatory amplicon sequence variants (ASVs) from the gut microbiota, the top 27 disease common‐discriminatory ASVs were identified, contributing to an overall accuracy of 95.9% in diagnosing shrimp health status. By using these optimisation procedures, the accuracy of our diagnosis model was unbiased by shrimp lifestage, specific disease, sampling size, hypervariable region and sequencing platform. The shrimp eight diseases consistently and significantly increased the relative importance of stochasticity, the relative abundance of pathogenic potentials and diversified core ASVs, whereas decreased the diversity and stability of gut microbiota. Collectively, these findings illustrate the effectiveness of meta‐analysis in determining the robust and common features of the shrimp gut microbiota in response to diverse diseases. In particular, disease common‐discriminatory ASVs could accurately diagnose shrimp health status, although the data are divergent in biotic and technical variances.

Bacteriophage and Their Potential Use in Bioaugmentation of Biological Wastewater Treatment Processes

In wastewater treatment plants, the stability of the related microbiota is pivotal for a steady and appropriate operation in biological wastewater treatment (BWT). The interactions between phages, which are high in amounts and diversity, and their particular hosts are significant due to their specificity in this microbial community. As drivers of diversity, phages are capable of changing the microbial structure by affecting host cells. This study aimed to enhance the stability of the functional microbiota, a primary concern of BWT, by evaluating the influence of bioaugmentation with bacteriophage cocktails. The sequencing data revealed significant alterations in the entire microbiome, including microeukaryotes, induced by the bacteriophages. These alterations led to a reduction in opportunistic microorganisms while preserving the beneficial ones. The genus Proteobacteria was found unaffected by three antibiotics in the bioreactor due to its antibiotic-resistant members, leading to its further growth, while the antibiotic-sensitive genus decreased in quantity. Furthermore, the phages notably influenced the metabolic pathway such as nitrogen, carbohydrate, and amino acid metabolisms by eliminating opportunistic microbes and providing improved growth conditions to bacterial species that are essential for effective reactor performance and wastewater treatment.

Early-life prophylactic antibiotic treatment disturbs the stability of the gut microbiota and increases susceptibility to H9N2 AIV in chicks

BackgroundAntibiotics are widely used for prophylactic therapy and for improving the growth performance of chicken. The problem of bacterial drug resistance caused by antibiotic abuse has previously attracted extensive attention; however, the influence of early-day use of prophylactic antibiotics on the gut microflora and on the disease resistance ability in chicks has not been explored. Here, we comprehensively evaluate the growth performance, gut microbial dynamics, level of antibiotic resistance genes (ARGs) in the gut microbial community, and resistance to H9N2 avian influenza virus (AIV) in chickens following long-term and short-term early-day prophylactic antibiotic treatment.ResultsUnexpectedly, long-term prophylactic enrofloxacin treatment slowed the growth rate of chickens, whereas short-term antibiotics treatments were found to increase the growth rate, but these changes were not statistically significant. Strikingly, expansions of Escherichia-Shigella populations were observed in early-life prophylactic antibiotics-treated groups of chickens, which is in contrast to the general perception that antibiotics should control their pathogenicity in chicks. The gut microbiota composition of chickens treated long term with antibiotics or received early-day antibiotics treatment tend to be more dramatically disturbed compared to the gut microbiome of chickens treated with antibiotics for a short term at a later date, especially after H9N2 AIV infection.ConclusionsOur data provide evidence that early-day and long-term antibiotic treatments have a more adverse effect on the intestinal microbiome of chickens, compared to short-term late age antibiotic treatment. Furthermore, our metagenomic data reveal that both long-term and short-term antibiotic treatment increase the relative abundance of ARGs. Our findings highlight the adverse effects of prophylactic antibiotic treatment and provide a theoretical basis for the cautious administration of antibiotics in food-producing animal management.Ao91n5eHkkQPyDkUXXsk_bVideo

Protective effect of Limosilactobacillus reuteri-fermented yogurt on mouse intestinal barrier injury induced by enterotoxigenic Escherichia coli.

Enterotoxigenic Escherichia coli (ETEC) is a pathogen that causes traveler's diarrhea, for which an effective vaccine is lacking. Previous studies showed that Limosilactobacillus reuteri could inhibit E. coli, effectively increase the expression of its tight junction protein, and reduce the adhesion of ETEC to the intestinal epithelial Caco-2 cell line. In this study, three kinds of yogurt with different starter cultures were first prepared: Lm. reuteri yogurt (fermented by Lm. reuteri alone), traditional yogurt (fermented by Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus at a ratio of 1:1) and mixed yogurt (fermented by Lm. reuteri, S. thermophilus and L. delbrueckii subsp. bulgaricus at a ratio of 1:1:1). The physiological properties, oxidative stress, intestinal barrier function, tight junction protein, pathological conditions and intestinal microbiota composition were investigated. The data showed that Lm. reuteri-fermented yogurt pregavage could effectively alleviate the intestinal barrier impairment caused by ETEC in mice. It alleviated intestinal villus shortening and inflammatory cell infiltration, decreased plasma diamine oxidase concentration and increased claudin-1 and occludin expression in the jejunum of ETEC-infected mice. In addition, Lm. reuteri-fermented yogurt significantly reduced the ETEC load in fecal samples, reversed the increase in Pseudomonadota abundance and decreased Bacteroidota abundance caused by ETEC infection. Furthermore, the composition of the intestinal microbiota could maintain a stable state similar to that in healthy mice. These findings indicate that Lm. reuteri-fermented yogurt could alleviate intestinal barrier damage, inhibit ETEC growth and maintain the stability of the intestinal microbiota during ETEC infection. © 2023 Society of Chemical Industry.

Gut microbiota in children with split-dose bowel preparations revealed by metagenomics.

Split-dose polyethylene glycol (PEG) is routinely used for bowel preparation before colonoscopy. This study aimed to investigate the composition of gut microbiota and its functions in pediatric patients undergoing split-dose PEG bowel preparation for colonoscopy to understand the stability and resilience of gut microbiota. From September to December 2021, 19 pediatric patients were enrolled at Shenzhen Children's Hospital and 76 samples (4 time points) were analyzed using metagenomics. Time points included Time_1 (one day before bowel preparation), Time_2 (one day after colonoscopy), Time_3 (two weeks after bowel preparation), and Time_4 (four weeks after bowel preparation). Alpha diversity comparison at both the species and gene levels showed a decrease in community richness after colonoscopy, with little statistical significance. However, the Shannon diversity index significantly decreased (P<0.05) and gradually returned to pre-preparation levels at two weeks after bowel preparation. The genus level analysis showed six genera (Eubacterium, Escherichia, Intertinibacter, Veillonella, Ruminococcaceae unclassified, and Coprobacillus) significantly different across the four time periods. Additionally, at the species level, the abundance of Escherichia coli, Bacteroides fragilis, and Veillonella parvula significantly increased at one day after colonoscopy before gradually decreasing at two weeks after bowel preparation. In contrast, the abundance of Intertinibacter bartlettii decreased at one day after colonoscopy but then recovered at two weeks after bowel preparation, reaching the preoperative level at four weeks after bowel preparation. Furthermore, five functional pathways (base excision repair, biosynthesis of ansamycins, biosynthesis of siderophore group nonribosomal peptide, flavonoid biosynthesis, and biosynthesis of type II polyketide products) were significantly different across the four time periods, with recovery at two weeks after bowel preparation and reaching preoperative levels at four weeks after bowel preparation. Gut microbiota at the genus level, species level, and functional pathways are impacted in pediatric patients undergoing split-dose PEG bowel preparation and colonoscopy, with recovery two weeks following bowel preparation. However, the phylum level was not impacted. Modifications in gut microbiota composition and function may be investigated in future studies of bowel preparation. This study highlights the stability and resilience of gut microbiota among pediatric patients during bowel preparation.

Major royal-jelly proteins intake modulates immune functions and gut microbiota in mice

In this study, we investigated the effects of major royal jelly proteins (MRJPs) on the estrogen, gut microbiota, and immunological responses in mice. Mice given 250 or 500 mg/kg, not 125 mg/kg of MRJPs, enhanced the proliferation of splenocytes in response to mitogens. The splenocytes and mesenteric lymphocytes activated by T-cell mitogens (ConA and anti-CD3/CD28 antibodies) released high levels of IL-2 but low levels of IFN-γ and IL-17A. The release of IL-4 was unaffected by MRJPs. Additionally, splenocytes and mesenteric lymphocytes activated by LPS were prevented by MRJPs at the same dose as that required for producing IL-1β and IL-6, two pro-inflammatory cytokines. The production of IL-1β, IL-6, and IFN-γ was negatively associated with estrogen levels, which were higher in the MRJP-treated animals than in the control group. Analysis of the gut microbiota revealed that feeding mice 250 mg/kg of MRJPs maintained the stability of the natural intestinal microflora of mice. Additionally, the LEfSe analysis identified biomarkers in the MRJP-treated mice, including Prevotella, Bacillales, Enterobacteriales, Gammaproteobacteria, Candidatus_Arthromitus, and Shigella. Our results showed that MRJPs are important components of royal jelly that modulate host immunity and hormone levels and help maintain gut microbiota stability.

Evaluation of Gut Microbiota Stability and Flexibility as a Response to Seasonal Variation in the Wild François' Langurs (Trachypithecus francoisi) in Limestone Forest.

The coevolution between gut microbiota and the host markedly influences the digestive strategies of animals to cope with changes in food sources. We have explored the compositional structure and seasonal variation in the gut microbiota of François' langur in a limestone forest in Guangxi, southwest China, using 16S rRNA sequencing. Our results demonstrated that Firmicutes and Bacteroidetes were the dominant phyla in langurs, followed by Oscillospiraceae, Christensenellaceae, and Lachnospiraceae at the family level. The top five dominant phyla did not show significant seasonal variations, and only 21 bacterial taxa differed at the family level, indicating stability in gut the microbiota possibly with respect to foraging for several dominant plants and high-leaf feeding by the langurs. Moreover, rainfall and minimum humidity are important factors affecting the gut microbiota of the langurs, but they explain few changes in bacterial taxa. The activity budget and thyroid hormone levels of the langurs did not differ significantly between seasons, indicating that these langurs did not respond to seasonal changes in food by regulating behavior or reducing metabolism. The present study indicates that the gut microbiota's structure is related to digestion and energy absorption of these langurs, providing new perspectives on their adaptation to limestone forests. IMPORTANCE François' langur is a primate that particularly lives in karst regions. The adaptation of wild animals to karst habitats has been a hot topic in behavioral ecology and conservation biology. In this study, gut microbiota, behavior, and thyroid hormone data were integrated to understand the interaction of the langurs and limestone forests from the physiological response, providing basic data for assessing the adaptation of the langurs to the habitats. The responses of the langurs to environmental changes were explored from the seasonal variations in gut microbiota, which would help to further understand the adaptive strategies of species to environmental changes.

Effects of fermented soybean meal substitution for fish meal on intestinal flora and intestinal health in pearl gentian grouper.

This study explored the role of replacing fish meal protein with fermented soybean meal (FSBM) protein on the growth performance and intestinal morphology, immunity, and microbiota of the pearl gentian grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂). Three isonitrogenous and isolipidic diets with increasing levels of FSBM (0%, 20% and 40%; referred to as FM, FSBM20 and FSBM40 diets, respectively) as a replacement for fish meal were selected for this study. The pearl gentian grouper were fed these diets for 10 weeks. The findings revealed that the growth of fish fed the FSBM diets (FSBM20 and FSBM40) were remarkably lower than the fish fed the FM diet. Pathological manifestations of intestinal inflammation, such as shortened intestinal mucosal folds and thickened lamina propria, were observed in the fish fed the FSBM diets. Moreover, the gene expression levels of IL1β, IL12, IL17, and TNFα were remarkably upregulated in fish fed the FSBM40 diet, in contrast to the gene expression levels of IL4, IL5, IL10, and TGFβ1, which were remarkably downregulated (p < 0.05). The FSBM diets significantly affected the stability of the fish gut microbiota. Photobacterium was the dominant phylum in all experimental groups, and the proportion of these bacteria gradually decreased with increasing FSBM substitution. The composition of intestinal flora at the genus level was not the same in the three experimental groups, with a richer composition of intestinal bacteria detected in the FSBM20 and FSBM40 groups (p < 0.05). The correlation between intestinal flora balance and immune gene expression revealed that only Photobacterium was negatively correlated with the above upregulated genes, while other bacteria were positively correlated with these pro-inflammatory factors (p < 0.05). Photobacterium was positively correlated with the above downregulated genes, while other bacteria were negatively correlated with these anti-inflammatory factors (p < 0.05). In conclusion, high levels of substitution of FSBM for fish meal causes intestinal inflammation in pearl gentian grouper. This is likely associated with changes to the intestinal flora. More attention should be paid to the negative role of dietary FSBM on intestinal flora.

Red Ginseng Dietary Fiber Shows Prebiotic Potential by Modulating Gut Microbiota in Dogs.

Red ginseng, widely used in traditional medicine for various conditions, imparts health benefits mainly by modulating the gut microbiota in humans. Given the similarities in gut microbiota between humans and dogs, red ginseng-derived dietary fiber may have prebiotic potential in dogs; however, its effects on the gut microbiota in dogs remain elusive. This double-blinded, longitudinal study investigated the impact of red ginseng dietary fiber on the gut microbiota and host response in dogs. A total of 40 healthy household dogs were randomly assigned to low-dose (n = 12), high-dose (n = 16), or control (n = 12) groups and fed a normal diet supplemented with red ginseng dietary fiber (3 g/5 kg body weight per day, 8 g/5 kg per day, or no supplement, respectively) for 8 weeks. The gut microbiota of the dogs was analyzed at 4 weeks and 8 weeks using 16S rRNA gene sequencing of fecal samples. Alpha diversity was significantly increased at 8 and 4 weeks in the low-dose and high-dose groups, respectively. Moreover, biomarker analysis showed that short-chain fatty acid producers such as Sarcina and Proteiniclasticum were significantly enriched, while potential pathogens such as Helicobacter were significantly decreased, indicating the increased gut health and pathogen resistance by red ginseng dietary fiber. Microbial network analysis showed that the complexity of microbial interactions was increased by both doses, indicating the increased stability of the gut microbiota. These findings suggest that red ginseng-derived dietary fiber could be used as a prebiotic to modulate gut microbiota and improve gut health in dogs. IMPORTANCE The canine gut microbiota is an attractive model for translational studies, as it responds to dietary interventions similarly to those in humans. Investigating the gut microbiota of household dogs that share the environment with humans can produce highly generalizable and reproducible results owing to their representativeness of the general canine population. This double-blind and longitudinal study investigated the impact of dietary fiber derived from red ginseng on the gut microbiota of household dogs. Red ginseng dietary fiber altered the canine gut microbiota by increasing diversity, enriching short-chain fatty acid-producing microbes, decreasing potential pathogens, and increasing the complexity of microbial interactions. These findings indicate that red ginseng-derived dietary fiber may promote canine gut health by modulating gut microbiota, suggesting the possibility of its use as a potential prebiotic.

Unbalanced diets enhance the complexity of gut microbial network but destabilize its stability and resistance

Stability is a fundamental ecological property of the gut microbiota and is associated with host health. Numerous studies have shown that unbalanced dietary components disturb the gut microbial composition and thereby contribute to the onset and progression of disease. However, the impact of unbalanced diets on the stability of the gut microbiota is poorly understood. In the present study, four-week-old mice were fed a plant-based diet high in refined carbohydrates or a high-fat diet for four weeks to simulate a persistent unbalanced diet. We found that persistent unbalanced diets significantly reduced the gut bacterial richness and increased the complexity of bacterial co-occurrence networks. Furthermore, the gut bacterial response to unbalanced diets was phylogenetically conserved, which reduced network modularity and enhanced the proportion of positive associations between community taxon, thereby amplifying the co-oscillation of perturbations among community species to destabilize gut microbial communities. The disturbance test revealed that the gut microbiota of mice fed with unbalanced diets was less resistant to antibiotic perturbation and pathogenic bacteria invasion. This study may fill a gap in the mechanistic understanding of the gut microbiota stability in response to diet and provide new insights into the gut microbial ecology.