Intestinal Bacterial Composition Research Articles

The effects of kelp powder and fucoidan on the intestinal digestive capacity, immune response, and bacterial community structure composition of large yellow croakers (Larimichthys crocea)

Feed terrestrial components can induce intestinal stress in fish, affecting their overall health and growth. Recent studies suggest that seaweed products may improve fish intestinal health. In this experiment, three types of feed were prepared: a basic diet (C group), a diet with 0.2 % fucoidan (F group), and a diet with 3 % kelp powder (K group). These diets were fed to large yellow croaker (Larimichthys crocea) over an 8-week period. Each feed was randomly assigned to three seawater cages (4.0 m × 4.0 m × 5.0 m) containing 700 fish per cage. The study assessed changes in growth and intestinal health, including intestinal tissue morphology, digestive enzyme activities, expression of immune-related genes, and bacterial community structure. Results showed that incorporating seaweed products into the diet improved the growth and quality traits of large yellow croakers and significantly enhanced their intestinal digestive capacity (P < 0.05). Specifically, the 0.2 % fucoidan diet significantly increased the intestinal villus length and the activities of digestive enzymes such as trypsin, lipase, and α-amylase (P < 0.05). The 3 % kelp powder diet significantly enhanced the intestinal crypt depth and the activities of trypsin and lipase (P < 0.05). Both seaweed additives significantly enhanced intestinal health by mitigating inflammatory factors. Notably, the control group's biomarkers indicated a high presence of potential pathogenic bacteria, such as Streptococcus, Pseudomonas, Enterococcus, Herbaspirillum, Neisseria, Haemophilus, and Stenotrophomonas. After the addition of seaweed additives, these bacteria were no longer the indicator bacteria, while the abundance of beneficial bacteria like Ligilactobacillus and Lactobacillus increased. Significant reductions in the expression of inflammatory factors (e.g., il-6, tnf-α, ifn-γ in the fucoidan group and il-8 in the kelp powder group) further supported these findings. Our findings suggested that both seaweed additives helped balance intestinal microbial communities and reduce bacterial antigen load. Considering the effects, costs, manufacturing, and nutrition, adding 3 % kelp powder to the feed of large yellow croaker might be preferable. This study substantiated the beneficial effects of seaweed on the aquaculture of large yellow croaker, particularly in improving intestinal health. These findings advocated for its wider and more scientifically validated use in fish farming practices.

The potential liver injury induced by metronidazole-provoked disturbance of gut microbiota: modulatory effect of turmeric supplementation.

It has been reported that the gut-liver axis and intestinal microbiome contribute crucially to different liver diseases. So, targeting this hepato-intestinal connection may provide a novel treatment modality for hepatic disorders such as drug-induced liver injury (DILI). The present study thought to investigate the protective effect of turmeric (TUR) on metronidazole (MNZ)-induced liver damage and the possible association of the gut-liver axis and gut microbiota as a suggested underlying mechanism. In the first experiment, a MNZ-induced liver injury rat model was reproduced after 130mg/kg oralMNZ administration for 30days. Meanwhile, the treatment group was orallytreated with 100mg/kg turmeric daily. In the second experiment, fecal microbiome transplantation (FMT) was conducted, in which the fecal microbiome of each group in the first experiment was transplanted to a healthy corresponding group in the second experiment. The liver enzymes (aminotransferase (ALT) and aspartate aminotransferase (AST)) and histopathological examination were estimated to assess liver function. Inflammatory cytokines and oxidative markers were evaluated in the liver tissues. Histological analysis, intestinal barrier markers, and expression of tight junction proteins were measured for assessment of the intestinal injury. Changes in the gut microbial community and possible hepatic bacterial transmission were analyzed using 16S rRNA sequencing. MNZ induced intestinal and liver injuries which were significantly improved by turmeric. Increased firmicutes/bacteroidetes ratio and bacterial transmission due to gut barrier disruption were suggested. Moreover, TUR has maintained the gut microbial community by rebalancing and restoring bacterial proportions and abundance, thereby repairing the gut mucosal barrier and suppressing bacterial translocation. TUR protected against MNZ-induced gut barrier disruption. Reshaping of the intestinal bacterial composition and prohibition of the hepatic microbial translocation were suggested turmeric effects, potentially mitigating MNZ-related liver toxicity.

The gut bacterial composition across life stages of Sarcophaga peregrina (Diptera: Sarcophagidae) and the effects of amikacin on their development.

Insects and microorganisms, ubiquitous organisms in the natural world, have developed intricate relationships throughout their evolutionary histories. However, most studies have concentrated on specific time points or life stages, but some limited studies have investigated the dynamics of microbial diversity within insects across life stages. Here, 16S rDNA sequencing technology was used to investigate the gut bacterial community across the life stages of Sarcophaga peregrina (Robineau-Desvoidy) (Diptera: Sarcophagidae). The results revealed that the gut bacterial diversity of S. peregrina varied with life stage and showed similarity in the nearby life stages. Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes were the dominant phyla in S. peregrina. Genera such as Providencia, Ignatzschineria, and Myroides are implicated in potentially pivotal roles during the developmental processes of this flesh fly. Furthermore, the effects of amikacin on the growth and development of S. peregrina were not statistically significant. However, we did observe significant changes at the protein level, which suggests a close association between protein-level alterations and growth and development. Additionally, we speculate that S. peregrina regulates its nutritional status during nonfeeding stages to meet the demands of eclosion. This study represents the first comprehensive examination of the intestinal bacterial composition across various life stages of S. peregrina. Our findings deepen our understanding of the gut microbiota in this flesh fly and lay the groundwork for further exploration into the intricate interactions between microorganisms and insects.

Effects of Different Stocking Densities on the Growth, Antioxidant Status, and Intestinal Bacterial Communities of Carp in the Rice–Fish Co-Culture System

Common carp (Cyprinus carpio) is a freshwater fish commonly farmed in rice fields, yet there were few studies on the intestinal functions and microbial community structure of common carp in the rice–carp co-culture system. Therefore, this study aimed to explore the effects of different stocking densities on the growth, antioxidant status, and intestinal bacterial composition of common carp in this system. This study was divided into three different stocking densities, including low density (LD, 10 fish, 52.9 g/m2), medium density (MD, 20 fish, 105.8 g/m2), and high density (HD, 30 fish, 158.7 g/m2), with a culturing period of 60 days. The results indicated that HD treatment inhibited the growth of common carp, as evidenced by the reduced final weight, WG, and SGR. In serum, the TG content in the HD group and the Cor content in the MD group were significantly increased. Meanwhile, HD treatment induced oxidative stress, manifesting specifically as increased SOD and CAT activities in the intestine or serum while reducing Gpx, GSH, and T-AOC in the serum. The 16S rDNA analysis indicated that the Simpson and Shannon indices of intestinal microbiota in the HD group were significantly higher than those in the LD group. At the phylum level, Proteobacteria, Cyanobacteria, and Firmicutes were dominant microbial communities in two groups. In addition, there was a significant difference between the two groups in the abundances of Actinobacterota and Bifidobacterium. Based on growth performances, biochemical indicators, and microbial diversity in rice–carp co-culture, low density (52.9 g/m2) may be more suitable in the rice–carp co-culture systems. In summary, this study contributes to a better understanding of common carp response to different stocking densities in the rice–carp co-culture system.

Effects of glyphosate-based herbicide on gut microbes and hepatopancreatic metabolism in Pomacea canaliculata

Roundup®, a prominent glyphosate-based herbicide (GBH), holds a significant position in the global market. However, studies of its effects on aquatic invertebrates, including molluscs are limited. Pomacea canaliculata, a large freshwater snail naturally thrives in agricultural environments where GBH is extensively employed. Our investigation involved assessing the impact of two concentrations of GBH (at concentrations of 19.98 mg/L and 59.94 mg/L, corresponding to 6 mg/L and 18 mg/L glyphosate) during a 96 h exposure experiment on the intestinal bacterial composition and metabolites of P. canaliculata. Analysis of the 16 S rRNA gene demonstrated a notable reduction in the alpha diversity of intestinal bacteria due to GBH exposure. Higher GBH concentration caused a significant shift in the relative abundance of dominant bacteria, such as Bacteroides and Paludibacter. We employed widely-targeted metabolomics analysis to analyze alterations in the hepatopancreatic metabolic profile as a consequence of GBH exposure. The shifts in metabolites primarily affected lipid, amino acid, and glucose metabolism, resulting in compromised immune and adaptive capacities in P. canaliculata. These results suggested that exposure to varying GBH concentrations perpetuates adverse effects on intestinal and hepatopancreatic health of P. canaliculata. This study provides an understanding of the negative effects of GBH on P. canaliculata and may sheds light on its potential implications for other molluscs.

Intestinal bacterial composition in laying pullet reared in tropical climate received betaine supplementation

Abstract Intestinal bacterial composition is one of the markers that can be observed in poultry under heat-stress conditions. This study evaluated the effects of dietary betaine on the intestinal bacterial composition of growing pullets reared in a tropical climate. The ninety-six Lohmann laying hens aged three weeks old were distributed into two dietary groups, each comprising six replicates of eight birds. This experiment used PAR-DOC (Japfa Comfeed ©) as basal diet (T0) and basal diet with 1.2g/kg betaine supplementation (T1). The next-generation sequencing method of the 16S rRNA gene region V3–V4 was applied to explore the taxonomy profile. Bacteria from the genus Faecalibacterium, Akkermansia, Desulfovibrio, and Lachnospiraceae UCG-002 were reported as markers in the heat stress condition. A t-test was applied using R software to evaluate the effect of each treatment. The relative abundance from the genus Akkermansia as a marker heat stress response in T1 treatment showed significantly lower than T0 (p&lt;0.05). Based on this result, we concluded that the lower population of the genus Akkermansia indicated that betaine supplementation could alleviate heat stress conditions in growing pullets.

Effect of Moxibustion on Diversity of Intestinal Flora in 46 Patients with Immune Reconstitution Insufficiency after ART

Objective: To analyze the effects of moxibustion +ART on intestinal bacterial community structure in HIV/AIDS patients, and to provide new ideas and methods for improving immune reconstitution in patients from the perspective of intervention of intestinal disorders and inhibition of immune activation. Methods: 16S rRNA high-throughput sequencing was used to compare and analyze the differences in the intestinal bacterial composition between the patients in ART group and moxibustion + ART group. Results: PCA score chart results show that the distribution of patients in the ART group and the moxibustion group was similar at baseline. After 48 weeks of treatment, the distribution locations and the phase limits of the samples in the ART group and the moxibustion group were significantly different, and compared with the ART group, the points represented by the moxibustion group after treatment and before treatment were far apart, that is, the composition and structure of microorganisms in the moxibustion group after treatment and before treatment were significantly different. Conclusion: moxibustion can improve the intestinal microbiological composition of HIV patients, and differ from the ART therapy that can improve the dominant bacteria.

Comparison of Bacterial Community Composition in Gut of Chinese Mitten Crabs from Three Distinct Rivers in Korea

The Chinese mitten crab (CMC) also known as Eriocheir sinensis has great significance in the aquaculture industry. The bacterial communities inhabiting the CMC’s gut may differ depending on the host habitat and can aid in their normal biological functioning. These microbes are also known to have certain effects on their flavor. In this study, we utilized MiSeq high-throughput sequencing technology to explore the diversity of bacterial communities in the gut of CMCs from three different geographical locations in Korea: the Geum (GD), Han (HD), and Tamjin (TD) rivers. Although most of the environmental parameters were similar at the three sites, significant differences in conductivity (CDS), dissolved oxygen (DO), and salinity were observed. The results show that CMCs sampled from these locations exhibited distinct microbial composition and abundance. For example, the genus Candidatus Hepatoplasma displayed significantly higher abundance in CMCs from HD than those in the other locations, suggesting nutritional stress. Similarly, the crabs collected from TD showed a higher abundance of pathogenic Helicobacter than those from HD and GD sites. We also observed differences in the amino acid, nucleotide, and lactic acid concentrations between different tissues such as the muscle, hepatopancreas, and testis of CMCs. However, only small differences were observed when these characteristics were compared in CMCs from different locations. Our results offer important insights into the intestinal bacterial composition in CMCs which in turn may help in designing better culturing strategies for these important species of crabs.

Challenges for heat stress: Intestinal culturable bacteria of Lohmann Brown chickens

This study aimed to assess how heat stress, specifically within the range of 35–38 °C, affects the populations of culturable intestinal lactobacilli, enterococci, and Escherichia coli, as well as the expression of Heat Shock Proteins (HSP70), in Lohmann Brown chickens. It also explored the influence of the chickens' blood transferrin and ceruloplasmin genotypes on these responses. Thirty chickens underwent eight hours of heat stress, maintained at an average temperature of 37 °C and a relative humidity of 75–80%, with continuous access to food and water. Behavioral monitoring was conducted throughout to prevent excessive heat-related mortality. The Lohmann Brown chickens from the Yerevan “Arax” poultry farm were initially classified based on their blood transferrin and ceruloplasmin genotypes to investigate potential correlations between intestinal bacterial composition and variations in these polymorphisms. A significant correlation was found between heat stress and the abundance of culturable enterococci within the intestinal microbiota, regardless of chicken TfAB, TfBC, CpAB, CpCC and TfAB, TfBC, CpAB, CpCD genotypes. Heat stress led to nearly double the HSP70 levels in chicken blood, along with a reduction in the culturable enterococci population by at least 10,000-fold in the intestinal microbiota. These findings are significant for targeted management strategies to mitigate heat stress in chicken populations.

Dysbiosis in Inflammatory Bowel Disease and Spondyloarthritis: Still a Long Way to Go?

The association between Inflammatory Bowel Disease (IBD) and Spondyloarthritis (SpA) has been known for years, as has the concept that IBD is associated with an altered intestinal bacterial composition, a condition known as "dysbiosis". Recently, a state of intestinal dysbiosis has also been found in SpA. Dysbiosis in the field of IBD has been well characterized so far, as well as in SpA. The aim of this review is to summarize what is known to date and to emphasize the similarities between the microbiota conditions in these two diseases: particularly, an altered distribution in the gut of Enterobacteriaceae, Streptococcus, Haemophilus, Clostridium, Akkermansia, Ruminococcus, Faecalibacterium Prausnitzii, Bacteroides Vulgatus, Dialister Invisus, and Bifidubacterium Adolescentis is common to both IBD and SpA. At the same time, little is known about intestinal dysbiosis in IBD-related SpA. Only a single recent study has found an increase in Escherichia and Shigella abundances and a decrease in Firmicutes, Ruminococcaceae, and Faecalibacterium abundances in an IBD-related SpA group. Based on what has been discovered so far about the altered distribution of bacteria that unite both pathologies, it is appropriate to carry out further studies aiming to improve the understanding of IBD-related SpA for the purpose of developing new therapeutic strategies.

Gut microbiota profile in CDKL5 deficiency disorder patients

CDKL5 deficiency disorder (CDD) is a neurodevelopmental condition characterized by global developmental delay, early-onset seizures, intellectual disability, visual and motor impairments. Unlike Rett Syndrome (RTT), CDD lacks a clear regression period. Patients with CDD frequently encounter gastrointestinal (GI) disturbances and exhibit signs of subclinical immune dysregulation. However, the underlying causes of these conditions remain elusive. Emerging studies indicate a potential connection between neurological disorders and gut microbiota, an area completely unexplored in CDD. We conducted a pioneering study, analyzing fecal microbiota composition in individuals with CDD (n = 17) and their healthy relatives (n = 17). Notably, differences in intestinal bacterial diversity and composition were identified in CDD patients. In particular, at genus level, CDD microbial communities were characterized by an increase in the relative abundance of Clostridium_AQ, Eggerthella, Streptococcus, and Erysipelatoclostridium, and by a decrease in Eubacterium, Dorea, Odoribacter, Intestinomonas, and Gemmiger, pointing toward a dysbiotic profile. We further investigated microbiota changes based on the severity of GI issues, seizure frequency, sleep disorders, food intake type, impairment in neuro-behavioral features and ambulation capacity. Enrichment in Lachnoclostridium and Enterobacteriaceae was observed in the microbiota of patients with more severe GI symptoms, while Clostridiaceae, Peptostreptococcaceae, Coriobacteriaceae, Erysipelotrichaceae, Christensenellaceae, and Ruminococcaceae were enriched in patients experiencing daily epileptic seizures. Our findings suggest a potential connection between CDD, microbiota and symptom severity. This study marks the first exploration of the gut-microbiota-brain axis in subjects with CDD. It adds to the growing body of research emphasizing the role of the gut microbiota in neurodevelopmental disorders and opens doors to potential interventions that target intestinal microbes with the aim of improving the lives of patients with CDD.

Liver cirrhosis and antibiotic therapy but not TIPS application leads to a shift of the intestinal bacterial communities: A controlled, prospective study.

The gut-liver axis is discussed to play an important role in hepatic cirrhosis. Decompensated liver cirrhosis is associated with portal hypertension, which can lead to a variety of complications. Transjugular intrahepatic portosystemic shunt (TIPS) is an established treatment option for the complications of portal hypertension. In this study we focused on the effect of TIPS on intestinal microbial composition in cirrhotic patients. Thirty patients with liver cirrhosis were compared to 18 healthy adults. Seventeen patients with cirrhosis and portal hypertension received a TIPS. Clinical characteristics, including age, sex, and liver function measured with a Child-Pugh score and model for end-stage liver disease score, were obtained. Intestinal microbial composition was assessed via 16S rRNA gene amplicon sequencing from stool probes before and after TIPS. TIPS led to a reduction of hepatic venous pressure gradient. However, TIPS did not cause a shift in the intestinal bacterial communities. Independent from the application of TIPS, antibiotic therapy was associated with a significant difference in the intestinal bacterial microbiota and also a reduced α-diversity. In addition, a significant difference was observed in the intestinal bacterial composition between patients with liver cirrhosis and healthy controls. The presence of liver cirrhosis and the use of antibiotic therapy, but not the application of TIPS, were associated with a significant shift of the intestinal bacterial communities, showing a high impact on the microbiota of patients with liver cirrhosis.

A189 INVESTIGATING THE ROLE OF BACTERIAL HISTAMINE METABOLISM IN VISCERAL HYPERALGESIA

Abstract Background Intestinal microbiota have been implicated in the expression of irritable bowel syndrome (IBS) as patients present with altered gut microbial profiles and microbial metabolic activity. We have previously identified bacterial histamine to strongly influence mast cell accumulation through only IBS activation of the H4 receptor, leading to visceral hyperalgesia in a subset of patients with IBS. We hypothesize that a subset of IBS patients with high histamine-producing microbiota exhibit an aberrant histamine metabolism. Investigating the microbiota-driven pathways involved in histamine metabolism is key to understanding abdominal pain pathophysiology in IBS patients. Aims 1. To study whether variations of histamine levels are due to bacterial metabolism using in vitro and in vivo approaches. 2. To identify the prevalence of high histamine-producing and histamine-degrading bacteria in a clinical cohort via in silico analyses. Methods Using in vitro approaches, stool samples from healthy control (HC) donors and IBS patients were inoculated in minimal media in aerobic/anaerobic conditions, with/without excess histidine or added histamine. Bacterial histamine production and degradation were assessed in culture supernatants by ELISA. After identification through Sanger sequencing, individual colony capacity to degrade and produce histamine was assessed. Host and microbial contributions to histamine metabolism will be identified through analyses of germ-free mice colonized with IBS and HC stool samples. Results IBS patients (n=23) tested were found to consistently produce higher levels of histamine compared to HC (n=3). Among the tested isolated colonies from IBS patients (n=179) 61% produced histamine compared to 33% of HC (n=54), and 20% degraded histamine compared to 11% of HC. Of these colonies, 13% of only IBS isolates demonstrated the capacity to both degrade and produce histamine. Facultative anaerobes were found to possess both higher production and degradation capacity. Both pH and histamine concentration determine bacterial ability to produce or degrade histamine. Conclusions Based on these findings, both healthy and IBS individuals exhibit varying levels of histamine production/degradation, most prominently through facultative anaerobes. The intestinal environment and bacterial community composition are major regulators of bacterial histamine metabolism. The observed in vitro capacity to produce/degrade histamine, and its biological implications, will be confirmed with gnotobiotic humanized mice, ultimately aiding in designing microbiota-directed therapies for the management of visceral hypersensitivity. Funding Agencies CIHRFarncombe Innovation Fund

Impact of Season on Intestinal Bacterial Communities and Pathogenic Diversity in Two Captive Duck Species.

Vertebrates and their gut bacteria interact in complex and mutually beneficial ways. The intestinal microbial composition is influenced by several external influences. In addition to food, the abiotic elements of the environment, such as temperature, humidity, and seasonal fluctuation are also important determinants. Fecal samples were collected from two captive duck species, Baikal teal (Sibirionetta formosa) and common teal (Anas crecca) across four seasons (summer, autumn, winter, and spring). These ducks were consistently fed the same diet throughout the entire experiment. High throughput sequencing (Illumina Mi-seq) was employed to analyze the V4-V5 region of the 16sRNA gene. The dominant phyla in all seasons were Proteobacteria and Firmicutes. Interestingly, the alpha diversity was higher in winter for both species. The NMDS, PCoA, and ANOSIM analysis showed the distinct clustering of bacterial composition between different seasons, while no significant differences were discovered between duck species within the same season. In addition, LefSe analysis demonstrated specific biomarkers in different seasons, with the highest number revealed in winter. The co-occurrence network analysis also showed that during winter, the network illustrated a more intricate structure with the greatest number of nodes and edges. However, this study identified ten potentially pathogenic bacterial species, which showed significantly enhanced diversity and abundance throughout the summer. Overall, our results revealed that season mainly regulated the intestinal bacterial community composition and pathogenic bacteria of captive ducks under the instant diet. This study provides an important new understanding of the seasonal variations in captive wild ducks' intestinal bacterial community structure. The information available here may be essential data for preventing and controlling infections caused by pathogenic bacteria in captive waterbirds.

Integrated microbiome and metabolomics revealed the protective effect of baicalin on alveolar bone inflammatory resorption in aging

BackgroundWith the growing aging population and longer life expectancy, periodontitis and tooth loss have become major health concerns. The gut microbiota, as a key regulator in bone homeostasis, has gathered immense interest. Baicalin, a flavonoid compound extracted from Scutellaria baicalensis Georgi, has shown antioxidant and anti-inflammatory activities. PurposeThis study investigated, for the first time, the protective mechanism of baicalin against alveolar bone inflammatory resorption in aging mice by regulating intestinal flora and metabolites, as well as intestinal barrier function. MethodsA ligature-induced periodontitis model was established in d-galactose (D-gal)-induced aging mice, and baicalin was administered at different dosages for 13 weeks. Body weight was measured weekly. The antioxidant and anti-inflammatory activity of baicalin were evaluated using serum superoxide dismutase (SOD), malonaldehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) levels. The immune capability was assessed by thymus and spleen indices. Histopathological changes were observed in the heart, liver, ileum, and periodontal tissues. Alveolar bone absorption of maxillary second molars was examined, and osteoclasts were counted by tartrate-resistant acid phosphatase (TRAP) staining. Furthermore, fecal samples were analyzed using 16S rRNA sequencing and non-targeted metabolomics to identify differences in intestinal bacterial composition and metabolites. ResultsBaicalin exhibited anti-aging properties, as evidenced by increased SOD activity and decreased levels of MDA, IL-6, and TNF-α in serum compared to the control group. Baicalin also ameliorated alveolar bone loss in the d-gal-induced aging-periodontitis group (p < 0.05). Furthermore, baicalin restored ileal permeability by up-regulating the expression of ZO-1 and occludin in aging-periodontitis groups (p < 0.05). Alpha diversity analysis indicated that baicalin-treated mice harbored a higher diversity of gut microbe. PCoA and ANOSIM results revealed significant dissimilarity between groups. The Firmicutes/Bacteroidetes (F/B) ratio, which decreased in periodontitis mice, was restored by baicalin treatment. Additionally, medium-dosage baicalin promoted the production of beneficial flavonoids, and enriched short-chain fatty acids (SCFAs)-producing bacteria. ConclusionIntestinal homeostasis is a potential avenue for treating age-related alveolar bone loss. Baicalin exerts anti-inflammatory, antioxidant, and osteo-protective properties by regulating the gut microbiota and metabolites.

Influenza A virus infection alters the resistance profile of gut microbiota to clinically relevant antibiotics.

Influenza virus infection affects both lung and intestinal bacterial community composition. Most of the published analyses focus on the characterization of the microbiota composition changes. Here we assess functional alterations of gut microbiota such as nutrient and antibiotic resistance changes during an acute respiratory tract infection. Upon influenza A virus (IAV) infection, cecal microbiota drops accompanied by a decrease in the ability to metabolize some common nutrients under aerobic conditions. At the same time, the cecal community presents an increase in resistance against clinically relevant antibiotics, particularly cephalosporins. Functional characterization of complex communities presents an additional and necessary element of analysis that nowadays is mainly limited to taxonomic description. The consequences of these functional alterations could affect treatment strategies, especially in multimicrobial infections.

Analysis of the gut microbiota using MALDI-TOF and cultural techniques in breastfed infants delivered vaginally and through caesarean section

Objectives: The gastrointestinal tract of newborns is colonised immediately after birth with microbes from the environment, mainly from the mother. According to studies, the early neonatal microbiota is crucial for developing the postnatal immune system. The objective of this study was to investigate the relationship between neonatal gut flora and the mode of delivery during gut microbiota colonisation. Material and Methods: A total of 30 neonates – 16 born vaginally and 14 by caesarean section – participated in this study of the intestinal bacterial composition at 3 days of age. Stool cultures and matrix-assisted laser desorption ionisation time-of-flight analyses determine aerobic and anaerobic bacterial species. Results: Neonates delivered by caesarean section appeared to have a less diverse gut microbiota regarding bacterial species than vaginally delivered neonates. Bifidobacterium species are absent from the gut microbiota after caesarean delivery. Even though every newborn vaginally born had a unique microbial profile, the most prevalent bacterial species were Streptococcus spp., Veillonella atypica, Bacteroides vulgatus and Bifidobacterium spp. Conclusion: Our results suggest that the mode of birth significantly influences the gut microbiota composition in the 1st year of human life. This study opens the path to further investigations to confirm the link between microbiota composition and enterotypes of the gut microbiome of breastfed neonates. In addition, we underline the importance of MALDI-TOF for species-level identification of organisms within a fraction of a second.

Comprehensive study on the effect of dietary leucine supplementation on intestinal physiology, TOR signaling and microbiota in juvenile turbot (Scophthalmus maximus L.)

Intestinal damage and inflammation are major health and welfare issues in aquaculture. Considerable efforts have been devoted to enhancing intestinal health, with a specific emphasis on dietary additives. Branch chain amino acids, particularly leucine, have been reported to enhance growth performance in various studies. However, few studies have focused on the effect of leucine on the intestinal function and its underlying molecular mechanism is far from fully illuminated. In the present study, we comprehensively evaluated the effect of dietary leucine supplementation on intestinal physiology, signaling transduction and microbiota in fish. Juvenile turbot (Scophthalmus maximus L.) (10.13 ± 0.01g) were fed with control diet (Con diet) and leucine supplementation diet (Leu diet) for 10 weeks. The findings revealed significant improvements in intestinal morphology and function in the turbot fed with Leu diet. Leucine supplementation also resulted in a significant increase in mRNA expression levels of mucosal barrier genes, indicating enhanced intestinal integrity. The transcriptional levels of pro-inflammatory factors il-1β, tnf-α and irf-1 was decreased in response to leucine supplementation. Conversely, the level of anti-inflammatory factors tgf-β, il-10 and nf-κb were up-regulated by leucine supplementation. Dietary leucine supplementation led to an increase in intestinal complement (C3 and C4) and immunoglobulin M (IgM) levels, along with elevated antioxidant activity. Moreover, dietary leucine supplementation significantly enhanced the postprandial phosphorylation level of the target of rapamycin (TOR) signaling pathway in the intestine. Finally, intestinal bacterial richness and diversity were modified and intestinal bacterial composition was re-shaped by leucine supplementation. Overall, these results provide new insights into the beneficial role of leucine supplementation in promoting intestinal health in turbot, offering potential implications for the use of leucine as a nutritional supplement in aquaculture practices.

Danggui Buxue Tang Alleviates Antibiotic-Induced Intestinal Structural Disorders by Affecting Intestinal Bacterial Composition and Thus Bile Acid Metabolism

Danggui Buxue Tang Alleviates Antibiotic-Induced Intestinal Structural Disorders by Affecting Intestinal Bacterial Composition and Thus Bile Acid Metabolism

Evaluation of the Enzymatic Production and Prebiotic Activity of Galactomannan Oligosaccharides Derived from Gleditsia microphylla

Oligosaccharides have received considerable attention as prebiotics because they exhibit potential health benefits related to their ability to modulate intestinal bacterial composition. This study evaluated the effects of galactomannan oligosaccharides (GMOS) derived from Gleditsia microphylla as a prebiotic on human intestinal bacteria. The β-mannanase used for the enzymatic hydrolysis of GMOS was produced by Trichoderma reesei Rut C-30. The enzymatic hydrolysis of GMOS was found to occur under optimal conditions at 50 °C, pH 5, 20 U/g-GM, and 20 g/L, and resulted in a yield of 70.78% ± 1.34%. The purity of GMOS after purification was 81.50%. Upon performing in vitro human fecal fermentation using GMOS as a carbon source, it was observed that GMOS effectively promoted the proliferation of intestinal bacteria, and the utilization efficiency of GMOS by intestinal bacteria was found to be at 98.40%. In addition, GMOS were found to have a stabilizing effect on intestinal pH. Additionally, 16S rRNA sequencing of GMOS revealed that GMOS significantly affected the diversity of gut microbiota. Specifically, GMOS exhibited a significant inhibitory effect on Fusobacteria at the phyla and genus level, and demonstrated a significant inhibitory effect on Fusobacterium. Moreover, the results for the prediction of metabolic function analysis showed that GMOS had a significant effect on the level two metabolism of carbohydrates, cofactors, and vitamins. Furthermore, during level three metabolism, the lipoic acid metabolism was significantly affected by GMOS. These results provide a theoretical basis for the potential use of galactomannan oligosaccharides from Gleditsia microphylla as prebiotics for regulating human intestinal bacteria.