Cetobacterium Somerae Research Articles

Vitamin D regulates glucose metabolism in zebrafish (Danio rerio) by maintaining intestinal homeostasis

Vitamin D (VD) is a steroid hormone that is widely known to play an important role in maintaining mineral homeostasis, and regulating various physiological functions. Our previous results demonstrated that the interruption of VD metabolism caused hyperglycemia in zebrafish. In the present study we further explored the mechanism that VD regulates glucose metabolism by maintaining intestinal homeostasis in zebrafish. Our results showed that the expression of several peptide hormones including gastric inhibitory peptide, peptide YY, and fibroblast growth factor 19 in the intestine decreased, while the expression of sodium glucose cotransporter-1 and gcg was increased in the intestine of the zebrafish fed with the VD3-deficient diet. Consistently, similar results were obtained in cyp2r1−/− zebrafish, in which endogenous VD metabolism is blocked. Furthermore, the results obtained from germ-free zebrafish exhibited that VD-regulated glucose metabolism was partly dependent on the microbiota in zebrafish. Importantly, the transplantation of gut microbiota collected from cyp2r1−/− zebrafish to germ-free zebrafish led to hyperglycemic symptoms in the fish, which were associated with the altered structure and functions of the microbiota in cyp2r1−/− zebrafish. Interestingly, the treatments with acetate or Cetobacterium somerae, a potent acetate producer, lowered the glucose contents whereas augmented insulin expression in zebrafish larvae. Notably, acetate supplementation alleviated hyperglycemia in cyp2r1−/− zebrafish and other diabetic zebrafish. In conclusion, our study has demonstrated that VD modulates the gut microbiota-SCFAs-gastrointestinal hormone axis, contributing to the maintenance of glucose homeostasis.

The effects of sodium propionate on intestinal barrier function of genetically improved farmed tilapia in a high-lipid formulation

Sodium propionate has long been used as a feed additive in fish diets for its remarkable anti-mold properties. In this study, two-month old genetically improved farmed (GIF) tilapia (initial weight 0.55 ± 0.0004 g/fish) were fed with five isonitrogenous diets, including a low-fat diet (LFD), high-fat diet (HFD), 0.25% sodium propionate-supplemented HFD (HFSP0.25), 0.5% sodium propionate-supplemented HFD (HFSP0.5) and 1.0% sodium propionate-supplemented HFD (HFSP1.0). This study investigated the effects of sodium propionate on fish growth performance, intestinal epithelium integrity and permeability, intestinal “physiological hypoxia” and gut microbiota composition of GIF tilapia fed with the HFD. After a four-week feeding trial, sodium propionate supplementation (0.25%, 0.5% and 1.0%) had no effects on survival rate, body weight gain and feed conversion ratio of GIF tilapia. However, feeding the HFSP0.5 and HFSP1.0 impaired tight junctions and lamina propria compared to feeding the HFD (P < 0.05). Serum fluorescence intensities of fish fed the HFSP0.5 and HFSP1.0 were higher than that fed the HFD after an oral gavage of fluorescein isothiocyanate-labeled carboxymethylated dextran (P < 0.05). Besides, the level of serum endotoxin was higher in fish fed the HFSP1.0 (P < 0.05). The expressions of genes encoding tight junction-related proteins including occludin and claudin-1 were remarkably decreased by feeding the HFSP0.5 and HFSP1.0 (P < 0.05). Moreover, intestinal pimonidazole retention was significantly reduced by HFSP1.0 feeding (P < 0.05). Furthermore, feeding the HFSP0.5 significantly increased the relative abundance of Cetobacterium somerae (P < 0.05) while feeding the HFSP1.0 significantly increased the relative abundance of Plesiomonas shigelloides (P < 0.05) in the gut. Consistently, the presence of Cetobacterium somerae was observed in the liver and muscle of fish fed the HFSP0.5 as well as in the muscle of fish fed the HFSP1.0. Presence of Plesiomonas shigelloides was observed in the liver of fish fed the HFSP1.0. In conclusion, higher levels of sodium propionate (0.5% and 1.0%) disrupt intestinal epithelium integrity and increase intestinal permeability of GIF tilapia when fed a HFD. Besides, sodium propionate at 1.0% additive amount abolishes intestinal “physiological hypoxia”. Sodium propionate supplementation alters the species diversity and composition of gut microbial community.

The attenuating effects of synbiotic containing Cetobacterium somerae and Astragalus polysaccharide against trichlorfon-induced hepatotoxicity in crucian carp (Carassius carassius)

This study aimed to investigate the hepatotoxic effects of trichlorfon on crucian carp (Carassius carassius) and the attenuating effects of a synbiotic combination of Cetobacterium somerae and Astragalus polysaccharide on hepatotoxicity. Results showed that trichlorfon did indeed induce hepatotoxicity in crucian carp and the synbiotic reversed this hepatotoxicity caused by trichlorfon. The synbiotic increased TC, TG, LDL-C, ALT and AST levels and decreased serum HDL-C levels caused by trichlorfon. H&E and Oil Red O staining demonstrated that the synbiotic ameliorated liver damage and abnormal lipid accumulation. The activity of antioxidant enzymes (T-SOD, CAT, GSH-Px) in the liver was also enhanced by the administration of the synbiotic. The supplementation of the synbiotic also increased the level of short-chain fatty acids in the intestine. In addition, the synbiotic balanced the gut microbial composition, leading to a reduction in the abundance of potentially pathogenic bacteria and an increase in the abundance of bacteria producing short-chain fatty acids. In conclusion, these findings indicate that trichlorfon can induce hepatotoxicity in crucian carp, whereas synbiotics can regulate gut microbiota, promote the growth of beneficial bacteria and increase the production of SCFAs, and alleviate trichlorfon-induced liver injury.

Vitamin B12 produced by Cetobacterium somerae improves host resistance against pathogen infection through strengthening the interactions within gut microbiota

BackgroundPathogen infections seriously affect host health, and the use of antibiotics increases the risk of the emergence of drug-resistant bacteria and also increases environmental and health safety risks. Probiotics have received much attention for their excellent ability to prevent pathogen infections. Particularly, explaining mechanism of action of probiotics against pathogen infections is important for more efficient and rational use of probiotics and the maintenance of host health.ResultsHere, we describe the impacts of probiotic on host resistance to pathogen infections. Our findings revealed that (I) the protective effect of oral supplementation with B. velezensis against Aeromonas hydrophila infection was dependent on gut microbiota, specially the anaerobic indigenous gut microbe Cetobacterium; (II) Cetobacterium was a sensor of health, especially for fish infected with pathogenic bacteria; (III) the genome resolved the ability of Cetobacterium somerae CS2105-BJ to synthesize vitamin B12 de novo, while in vivo and in vitro metabolism assays also showed the ability of Cetobacterium somerae CS2105-BJ to produce vitamin B12; (IV) the addition of vitamin B12 significantly altered the gut redox status and the gut microbiome structure and function, and then improved the stability of the gut microbial ecological network, and enhanced the gut barrier tight junctions to prevent the pathogen infection.ConclusionCollectively, this study found that the effect of probiotics in enhancing host resistance to pathogen infections depended on function of B12 produced by an anaerobic indigenous gut microbe, Cetobacterium. Furthermore, as a gut microbial regulator, B12 exhibited the ability to strengthen the interactions within gut microbiota and gut barrier tight junctions, thereby improving host resistance against pathogen infection.9wW3zJp3HpFrGEQCmLVC3SVideo

Characterization of Cetobacterium somerae CPU-CS01 isolated from the intestine of healthy crucian carp (Carassius auratus) as potential probiotics against Aeromonas hydrophila infection

Cetobacterium somerae is a commensal bacterium for many fish species. However, research on C. somerae has been limited so far, and its function and beneficial potential require to be further investigated. The objective of this study was to evaluate the probiotic properties of C. somerae CPU-CS01 isolated from the intestinal contents of crucian carp (Carassius auratus). Hemolytic activity, antibiotic susceptibility, acid tolerance, bile salt tolerance, free radical scavenging, and enzyme production properties were tested for in vitro. Caenorhabditis elegans and zebrafish (Danio rerio) model were used to evaluate the antioxidant and anti-infective effects of C. somerae CPU-CS01 in vivo. Our results showed that C. somerae CPU-CS01 had no hemolytic activity, it produced cellulase, amylase, and survived at low pH (2.0–3.0) and in the presence of bile salts. The cell-free culture supernatant (CFCS) of C. somerae CPU-CS01 possessed DPPH radical, hydroxyl radical, and superoxide anion scavenging activity. C. elegans fed with C. somerae CPU-CS01 were more resistant to hydrogen peroxide-induced oxidative stress and Aeromonas hydrophila infection. In addition, zebrafish-fed diets containing C. somerae CPU-CS01 showed improved survival after A. hydrophila infection. Based on these results, the positive probiotic properties of C. somerae CPU-CS01 isolated from the intestinal contents of crucian carp make it a potential candidate for probiotic.

Core species and interactions prominent in fish-associated microbiome dynamics

BackgroundIn aquatic ecosystems, the health and performance of fish depend greatly on the dynamics of microbial community structure in the background environment. Nonetheless, finding microbes with profound impacts on fish’s performance out of thousands of candidate species remains a major challenge.MethodsWe examined whether time-series analyses of microbial population dynamics could illuminate core components and structure of fish-associated microbiomes in the background (environmental) water. By targeting eel-aquaculture-tank microbiomes as model systems, we reconstructed the population dynamics of the 9605 bacterial and 303 archaeal species/strains across 128 days.ResultsDue to the remarkable increase/decrease of constituent microbial population densities, the taxonomic compositions of the microbiome changed drastically through time. We then found that some specific microbial taxa showed a positive relationship with eels’ activity levels even after excluding confounding effects of environmental parameters (pH and dissolved oxygen level) on population dynamics. In particular, a vitamin-B12-producing bacteria, Cetobacterium somerae, consistently showed strong positive associations with eels’ activity levels across the replicate time series of the five aquaculture tanks analyzed. Network theoretical and metabolic modeling analyses further suggested that the highlighted bacterium and some other closely-associated bacteria formed “core microbiomes” with potentially positive impacts on eels.ConclusionsOverall, these results suggest that the integration of microbiology, ecological theory, and network science allows us to explore core species and interactions embedded within complex dynamics of fish-associated microbiomes. 2gKjfWoBRNSUwrepeh_GG8Video

Effects of dietary Cetobacterium somerae on the intestinal health, immune parameters and resistance against Nocardia seriolae of largemouth bass, Micropterus salmoides

Largemouth bass (Micropterus salmoides), one of the most important freshwater commercial fish species has been widely cultivated in China. In recent years, the nocardiosis caused by Nocardia seriolae has greatly damaged the M. salmoides industry and there is no effective treatment at present. Currently, Cetobacterium somerae, the predominant bacteria in the gut of many freshwater fishes has been reported to be associated with fish health. However, whether the native C. somerae could protect the host from N. seriolae is unclear. In this study, M. salmoides were fed with three different diets, including control diet (CD), low C. somerae diet (106 CFU/g as LD) and high C. somerae diet (108 CFU/g as HD). After 8-week feeding, growth performance, gut health index, serum enzyme activities and the expression of inflammation-related genes were tested. Results showed that the LD and HD diets had no adverse effects on the growth performance. Moreover, dietary HD enhanced gut barrier and reduced intestinal ROS and ORP, as well as increased serum enzyme activities including ACP, AKP, SOD and LZM compared to the CD group. In addition, the HD diet significantly up-regulated the expression of TNF-α, IL8, IL-1β and IL15, while down-regulating the expression of TGF-β1 and IL10 in kidney. Moreover, the expression of antibacterial genes was significantly increased in HD group after being challenged by N. seriolae. And the fish fed HD diet exhibited higher survival rate (57.5%) than that in CD (37.5%) and LD groups (42.5%). To summarize, our study demonstrates that dietary HD can enhance gut health, improve immune response and strengthen pathogen resistance, suggesting that C. somerae is a potential probiotic for defending against N. seriolae infection in M. salmoides.

Vitamin D influences gut microbiota and acetate production in zebrafish (Danio rerio) to promote intestinal immunity against invading pathogens

ABSTRACT Although evidence has shown that vitamin D (VD) influences gut homeostasis, limited knowledge is available how VD regulates intestinal immunity against bacterial infection. In the present study, cyp2r1 mutant zebrafish, lacking the capacity to metabolize VD, and zebrafish fed a diet devoid of VD, were utilized as VD-deficient animal models. Our results confirmed that the expression of antimicrobial peptides (AMPs) and IL-22 was restrained and the susceptibility to bacterial infection was increased in VD-deficient zebrafish. Furthermore, VD induced AMP expression in zebrafish intestine by activating IL-22 signaling, which was dependent on the microbiota. Further analysis uncovered that the abundance of the acetate-producer Cetobacterium in VD-deficient zebrafish was reduced compared to WT fish. Unexpectedly, VD promoted the growth and acetate production of Cetobacterium somerae under culture in vitro. Importantly, acetate treatment rescued the suppressed expression of β-defensins in VD-deficient zebrafish. Finally, neutrophils contributed to VD-induced AMP expression in zebrafish. In conclusion, our study elucidated that VD modulated gut microbiota composition and production of short-chain fatty acids (SCFAs) in zebrafish intestine, leading to enhanced immunity.

Biodiversity of gut microorganisms in aquacultured African catfish

The article examines the intestinal microbiome of young and adult catfish Clarias gariepinus raised under aquaculture conditions. Genomic DNA was isolated from the large intestine of fish. The study was conducted using the 16S Metagenomics protocol, and the library pool was sequenced on Illumina MiSeq. The microbiota is characterized by a diverse set of both aerobic and anaerobic bacteria, the qualitative and quantitative composition of which is strictly individual for each individual. The microbiota of young catfish consisted mainly of opportunistic gram-negative bacteria Pseudomonas, as well as gram-negative anaerobic bacteria Cetobacterium somerae. In adult catfish, higher biodiversity and the appearance of opportunistic gram-positive bacteria of the genus Streptococcus in the dominant genera were revealed; the species Propionibacterium acnes was also common. The study results indicate that the diversity of the gut microbiome of the catfish Clarias gariepinus increases over time.

Adding an essential oil blend to the diet of juvenile Nile tilapia improves growth and alters the gut microbiota

In aquaculture, essential oils are considered promising supplements that can improve productive performance and modulate the fish's microbiota. Here we investigate how a blend of essential oils (carvacrol + thymol + cinnamaldehyde acid) affects the productive performance and the intestinal microbiota of juvenile Nile tilapia (Oreochromis niloticus, Thai strain). All fish were randomly distributed into 20 multifilament tanks (10-mm mesh and 2.4 m3 capacity). The experimental design comprised four treatments and five repetitions, with 20 individuals per experimental unit, for 60 days. Four diets were evaluated with increasing levels of essential oils (control and 3.3, 6.7, and 10 g kg−1 diet). Supplementation with 3.3 g kg−1 of essential oils improved growth performance compared to the control group. However, no differences were detected among the essential oil-supplemented groups (6.7 and 10 g kg−1). Survival was not different among the four groups. Using a Linear Response Plateau (LRP) model, we calculated maximum levels of 3.4, 3.5, 3.5 and 3.2 g kg−1 of the essential oils blend for final weight, weight gain, daily weight gain, and feed conversion, respectively. Verrucomicrobia, Firmicutes, Bacteroidetes, and Proteobacteria accounted for a high proportion of the species observed in tilapia's gut microbiota in the control and essential oil-supplemented groups. In both treatments, Candidatus xiphinematobacter (Verrucomicrobia) and Cetobacterium (Fusobacteria) were most predominant at the genus level. Cetobacterium somerae and Lactobacillus zeae were the most abundant species. At the species level, the Shannon index diversity value was higher in the control group than in the essential oil-supplemented groups (P = 0.046719; t = 2.0586). The bacterial community beta diversity analysis revealed an effect of diet on the tilapia's gut microbiota, demonstrating a distinct grouping among treatments. Linear discriminant analysis (LDA) associated with effect size (LEfSe) identified that microbiota's differential abundance was significant when comparing the control group and the 3.3 g kg−1 essential oil-supplemented group. The genera Candidatus xiphinematobacter, Staphylococcus, Caldilinea, and Synechococcus were more abundant in the microbiota of essential oil-fed juvenile Nile tilapia the control group. Pseudomonas, Acinetobacter, Enterococcus, and Lactobacillus were more predominant in the microbiota of fish from the control group. In conclusion, dietary the carvacrol + thymol + cinnamaldehyde acid blend (3.3 g kg−1) increased the growth performance and modulated the gut microbiota of juvenile Nile tilapia.

Nuclease-Treated Stabilized Fermentation Product of Cetobacterium somerae Improves Growth, Non-specific Immunity, and Liver Health of Zebrafish (Danio rerio).

High-fat diets (HFD) are harmful to fish health. Probiotics are commonly utilized to improve fish nutrition metabolism, immune response, and health. Nucleic acids of the probiotic bacterium can be hydrolyzed by nuclease to generate nucleotides. The present study aimed to evaluate the effects of stabilized fermentation product of nuclease-treated Cetobacterium somerae XMX-1 [XMX-1 (N)] on growth, non-specific immunity, and liver health of zebrafish (Danio rerio). Compared to the HFD group, 100 g/kg XMX-1 (N) significantly increased weight gain and decreased feed conversion ratio (FCR). However, 5 or 10 g/kg XMX-1 (N) had no influence on zebrafish growth. In addition, supplementation of 100 g/kg XMX-1 (N) significantly increased lysozyme activity and total antioxidant capacity in skin mucus, and the expression of inflammation related genes interleukin 1 beta (IL-1β), interleukin 10 (IL-10), and interleukin 6 (IL-6) in the gut as well as fatty acid oxidation related genes uncoupling protein 2 (UCP2) and proliferator-activated receptor γ coactivator 1α (PGC1α) in the liver, while decreased the content of hepatic triacylglycerol (TAG) in zebrafish. The gene sequencing, 16S rRNA, showed that 100 g/kg XMX-1 (N) enhanced the relative abundance of Firmicutes while lowered Proteobacteria and Actinobacteria. 10 g/kg XMX-1 (N) significantly increased lysozyme activity and complement component 4 (C4) in skin mucus, and intestinal expression of inflammation-related genes. In the 5 g/kg XMX-1 (N) group, however, only an increase in C4 level in skin mucus was observed. Together, these results reveal that dietary supplementation with nuclease-treated C. somerae XMX-1 (N) has a dose-dependent beneficial effect on fish health.

Gut microbiota of Anabas testudineus (Bloch, 1792) in the e-waste dismantling region: In situ status and relationship with internal metal burden.

Due to the production of large quantities of electronic waste (e-waste), unsafe dismantling has caused serious pollution as well as toxicological impacts on both wildlife and humans. As an important aspect of physiology and health, the wildlife's gut microbiota and its changes induced by pollution have been recruiting increasing concerns. To reveal the gut microbiota-related ecotoxicology induced by e-waste dismantling, this study resolves the gut microbiota profile of Anabas testudineus, a native highly adapted nonmodel fish under the in situ exposure, and reveals whether and how the microbiota was altered. The comparisons are made by collecting samples from different e-waste polluted sites in Guiyu (a town in South China) and a nearby reference (nonpolluted) site. The overall gut microbiota landscape of A. testudineus is similar to that of other reported fishes, with an average of ∼300 OTUs, and constituted by Firmicutes (34.51%), Fusobacteria (29.16%) as the major phyla. Obviously different liver metal burdens/fingerprints were observed between the e-waste and reference sites. Accordingly, although the alpha-diversity (ACE, Simpson, and Shannon) of the gut microbiota did not significantly vary, a detailed exploration of the microbiota constitution indicated significant differences at various taxonomic levels, including a series of significantly different species and biomarkers, and showing site-specific beta-diversity clustering patterns. Interestingly, a few bacteria with greater abundance in the fish gut of e-waste polluted sites were also reported to present in other contaminated environments, have a role in wastewater treatment, be capable to transform metal, etc. Redundancy analysis (RDA) and Pearson association analyses indicated significant associations between Mn and Cetobacterium somerae (Pearson r=0.3612, p=0.0008) and between Pb and Clostridium colicanis (Pearson r=0.5151, p < 0.0001). In summary, pollution from e-waste dismantling may have a role in altering the fish gut microbiota, and this research provides insights for better understanding e-waste ecotoxicology and improving future conservation.

Effects of water temperature on the gut microbiome and physiology of Chinook salmon (Oncorhynchus tshawytscha) reared in a freshwater recirculating system

Climate change and global warming pose particular concerns to the aquaculture industry as water temperature is one of the most important influences of health and growth performance in poikilotherms. Despite increased recognition of the importance of the gut microbiome in fish health, knowledge of temperature effects on the holobiont and implications for aquaculture performance are still limited. We assessed the effect of water temperature in a freshwater recirculating aquaculture system on the gut microbiome and the physiology, health and growth of New Zealand's most important farmed fish, the Chinook Salmon (Oncorhynchus tshawytscha). Fish were reared at four temperatures (8, 12, 16, 20 °C) for 41 to 49 days. Health, growth and feed intake were assessed at the beginning and end of the experiment. Haematology, plasma biochemistry, histology and tissue composition (e.g. fatty acids, amino acids, chemical composition) and gut microbiota (faeces and hindgut wall mucosa) were characterized. We found that increased temperature resulted in an increase in feed intake and growth (plateauing as it approached 20 °C) but did not impact feed conversion efficiency. Gut microbiome community composition assessed from both sample types changed with increasing temperature, with the dominance of Vibrionaceae (Photobacterium phosphoreum and/or pisciola) being gradually replaced by Fusobacteriaceae (Cetobacterium somerae) and Brevenemataceae (Brevinema). A significant effect of temperature was also observed on fish histology, fatty acids, chemical composition, haematology, plasma biochemistry and several internal biometrics, with significant correlation of most of these data layers with the gut microbiota. Notably, glucose, lactate and magnesium concentration in plasma, whole-body palmitic and the sum of the saturated fatty acids, and Cetobacterium were positively associated with increased temperature. This study provides further knowledge on how the Chinook salmon holobiont is influenced by water temperature and how the changes observed relate to fish growth performance and health. These results will help make more informed decisions for monitoring fish gut microbiota and tailoring dietary requirements to rearing water temperature.

Growth performance, hepatic enzymes, and gut health status of common carp (Cyprinus carpio) in response to dietary Cetobacterium somerae fermentation product

Intensive aquaculture practices compromise the health of fish. Probiotics especially those isolated from aquatic animals play important roles in improving fish health. The aim of the study was to evaluate the effects of stabilized fermentation product of Cetobacterium somerae (XMX-1) on the growth performance, gut and liver health of common carp. A total of 300 carps (initial weight of 2.32 ± 0.02 g) were divided into the control (fed a basal diet) and XMX-1 groups (fed a basal diet with 2 g/kg, 3 g/kg, 4 g/kg or 5 g/kg XMX-1 diet). After 8-week feeding, growth performance, serum lipopolysaccharide (LPS), diamine oxidase activity (DAO), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were evaluated. The intestinal total superoxide dismutase (SOD) activity, the expression of gut health related genes was tested. In addition, the liver triacylglycerol (TAG) and the expression of liver lipid metabolism related genes were conducted. Results showed that XMX-1 addition had no effect on the growth performance of carps at a supplementation level up to 5 g/kg (P > 0.05). However, dietary XMX-1 at addition levels ranging from 2 g/kg to 5 g/kg reduced serum LPS and DAO. Furthermore, all XMX-1 additions significantly increased total SOD activity compared with the control group (P < 0.05). In contrast, dietary 3 g/kg XMX-1 significantly increased the expression of intestinal hypoxia inducible factor 1 subunit alpha (HIF1α), Occludin, Hepcidin and zonula occludens (ZO)-1 (P < 0.05). Dietary 2 g/kg XMX-1 significantly increased the expression of intestinal Hepcidin and ZO-1 (P < 0.05). Moreover, dietary XMX-1 decreased the level of serum ALT (P ≤ 0.37) and liver TAG (P ≤ 0.07). Furthermore, we found that dietary XMX-1 significantly reduced the expression of genes related to lipid synthesis including sterol regulatory element-binding protein (SREBP1c) and peroxisome proliferator-activated receptor gamma (PPARγ) (P < 0.05). Meanwhile, dietary 3 g/kg XMX-1 significantly increased the expression of carnitine palmitoyltransferase 1 (CPT1) and peroxisome proliferator-activated receptor alpha (PPARα) compared with the control group (P < 0.05). Together, our findings suggest that XMX-1 additions of 3 g/kg had the best effect on fish health.

A New Biomarker of Fecal Bacteria for Non-Invasive Diagnosis of Colorectal Cancer.

BackgroundThe intestinal flora is correlated with the occurrence of colorectal cancer. We evaluate a new predictive model for the non-invasive diagnosis of colorectal cancer based on intestinal flora to verify the clinical application prospects of the intestinal flora as a new biomarker in non-invasive screening of colorectal cancer.MethodsSubjects from two independent Asian cohorts (cohort I, consisting of 206 colorectal cancer and 112 healthy subjects; cohort II, consisting of 67 colorectal cancer and 54 healthy subjects) were included. A probe-based duplex quantitative PCR (qPCR) determination was established for the quantitative determination of candidate bacterial markers.ResultsWe screened through the gutMEGA database to identify potential non-invasive biomarkers for colorectal cancer, including Prevotella copri (Pc), Gemella morbillorum (Gm), Parvimonas micra (Pm), Cetobacterium somerae (Cs), and Pasteurella stomatis (Ps). A predictive model with good sensitivity and specificity was established as a new diagnostic tool for colorectal cancer. Under the best cutoff value that maximizes the sum of sensitivity and specificity, Gm and Pm had better specificity and sensitivity than other target bacteria. The combined detection model of five kinds of bacteria showed better diagnostic ability than Gm or Pm alone (AUC = 0.861, P < 0.001). These findings were further confirmed in the independent cohort II. Particularly, the combination of bacterial markers and fecal immunochemical test (FIT) improved the diagnostic ability of the five bacteria (sensitivity 67.96%, specificity 89.29%) for patients with colorectal cancer.ConclusionFecal-based colorectal cancer-related bacteria can be used as new non-invasive diagnostic biomarkers of colorectal cancer. Simultaneously, the molecular biomarkers in fecal samples are similar to FIT, have the applicability in combination with other detection methods, which is expected to improve the sensitivity of diagnosis for colorectal cancer, and have a promising prospect of clinical application.

Stabilized fermentation product of Cetobacterium somerae improves gut and liver health and antiviral immunity of zebrafish

Probiotics are widely used in aquafeeds and exhibited beneficial effects on fish by improving host health and resisting pathogens. However, probiotics applied to aquaculture are mainly from terrestrial sources instead of the host animal. The purpose of the work was to evaluate the effects of stabilized fermentation product of commensal Cetobacterium somerae XMX-1 on gut, liver health and antiviral immunity of zebrafish. A total of 240 zebrafish were assigned to the control (fed a basal diet) and XMX-1 group (fed a basal diet with 10 g XMX-1/kg diet). After four weeks feeding, growth performance, feed utilization, hepatic steatosis score, TAG, lipid metabolism related genes and serum ALT were evaluated. Furthermore, serum LPS, the expression of Hif-1α, intestinal inflammation score, antioxidant capability and gut microbiota were tested. The survival rate and the expression of antiviral genes were analyzed after challenge by spring viremia of carp virus (SVCV). Results showed that dietary XMX-1 did not affect growth of zebrafish. However, dietary XMX-1 significantly decreased the level of serum LPS, intestinal inflammation score and intestinal MDA, as well as increased T-AOC and the expression of Hif-1α in zebrafish intestine (p < 0.05). Furthermore, XMX-1 supplementation decreased the relative abundance of Proteobacteria and increased Firmicutes and Actinobacteria. Additionally, XMX-1 supplementation significantly decreased hepatic steatosis score, hepatic TAG, serum ALT and increased the expression of lipolysis genes versus control (p < 0.05). Zebrafish fed XMX-1 diet exhibited higher survival rate after SVCV challenge. Consistently, dietary XMX-1 fermentation product increased the expression of IFNφ2 and IFNφ3 after 2 days of SVCV challenge and the expression of IFNφ1, IFNφ2 and MxC after 4 days of SVCV challenge in the spleen in zebrafish versus control (p < 0.05). In conclusion, our results indicate that dietary XMX-1 can improve liver and gut health, while enhancing antiviral immunity of zebrafish.

Effects of dietary Bacillus subtilis DSM 32315 supplementation on the growth, immunity and intestinal morphology, microbiota and inflammatory response of juvenile largemouth bass Micropterus salmoides

This study aimed at evaluating the effects of dietary inclusion of Bacillus subtilis DSM 32315 on the growth, immunity, intestinal architecture and gut microbiota of juvenile largemouth bass Micropterus salmoides (LMB). B. subtilis DSM 32315 was supplemented in the diets at the levels of 0 (control, CON), 1.5 (BS1.5, 3 × 106 CFU/g feed) and 3 g/kg (BS3, 6 × 106 CFU/g feed). Each diet was assigned to four replicate tanks of LMB juveniles (initial mean body weight, 8.32 ± 0.06 g) with 20 fish per tank for 9 weeks. The results showed that the growth and feed utilization of LMB were not sensitive to dietary modifications (p > .05). Compared with the CON fish, dietary BS supplementation did not affect the haematological parameters (white and red blood cell counts and haematocrit value) of LMB (p > .05), but the BS1.5 fish performed better than the BS3 fish. Serum innate immunity indicators (lysozyme activity and complement C3 and C4 levels) were improved with dietary BS supplementation at both doses, while higher serum IgM level was only recorded at 1.5 g/kg feed (p < .05). All the sampled fish exhibited intact intestines, but the intestinal architecture (villus height and muscular layer thickness) still benefited from dietary BS inclusion at both doses (p < .05). Although intestinal anti-inflammatory response (mRNA levels of IL-10 and TGF-β1) did not differ between the BS supplemented fish (p > .05), the BS1.5 fish obtained superior pro-inflammatory response (mRNA levels of IL-1β, IL-8, and TNF-α) over the BS3 fish (p < .05). Compared with the CON fish, the abundance of the harmful Plesiomonas shigelloides decreased in the gut microbiota of the BS1.5 fish (p < .05). Despite the BS3 fish obtained higher diversity of gut microbiota, the abundances of potential beneficial (Cetobacterium somerae and Shewanella xiamenensis) and harmful bacteria (Acinetobacter johnsonii and P. shigelloides) increased or decreased simultaneously (p < .05). Taken together, it was concluded that dietary BS DSM 32315 inclusion presented some positive effects on LMB. Although the BS1.5 fish performed better than the BS3 fish, the best supplemental dose need to be further studied.

Effects of Cetobacterium somerae fermentation product on gut and liver health of common carp (Cyprinus carpio) fed diet supplemented with ultra-micro ground mixed plant proteins

Improving the replacement percentage of fish meal by plant proteins is of value for the aquaculture industry. Cetobacterium is the dominant commensal bacterium in many fish species. However, the function and potential beneficial effects of Cetobacterium is unknown. In this study, carps were fed with a practical basal diet with partial fish meal replacement by plant proteins (Control), basal diet with improved fish meal replacement percentage by adding ultra-micro ground mixed plant proteins (uPP), or the uPP diet supplemented with the fermentation product of a commensal bacterial strain Cetobacterium somerae XMX-1 (uPP + XMX-1). The effects of C. somerae XMX-1 fermentation product on gut and liver health of carp fed uPP supplemented diet were evaluated. After 4-week feeding, growth performance, feed utilization, biometric parameters, inflammatory score, expression of inflammation-related and lipid metabolism related genes were evaluated. The levels of LBP, LPS, AST and ALT in serum were assessed. 16S rRNA gene pyrosequencing was used to evaluate intestinal microbiota. Results showed that dietary uPP and uPP + XMX-1 had no effect on survival rate and growth (p > 0.05). However, dietary uPP compromised gut and liver health of fish. The expressions of inflammation related genes in gut and liver and the levels of LBP, LPS, AST and ALT in serum were significantly increased in uPP group versus control (p < 0.05). Interestingly, uPP + XMX-1 significantly decreased the expressions of inflammation related genes in gut and liver, as well as the levels of LBP, LPS, AST and ALT in serum compared to the uPP group (p < 0.05). In addition, uPP + XMX-1 significantly reduced the formation of lipid droplets in liver and significantly up-regulated the expression of lipogenesis genes and down-regulated the expression of lipolysis genes (p < 0.05) in comparison to the uPP group. Taken together, our study suggests that dietary uPP can impair gut and liver health and induce fatty liver, whereas C. somerae XMX-1 fermentation product can improve gut and liver health of common carp and decrease lipid deposition in liver, suggesting that XMX-1 fermentation product can be used as feed additive to improve the efficacy of fish meal replacement by plant proteins.

Caracterización de las comunidades microbianas asociadas a un florecimiento cianoalgal en una presa de León, Gto. México mediante secuenciación de regiones variables de los genes que codifican la rARN 16S y 18S

Background. Algal blooms have become more frequent due human activity, including climate change. Analyzing of microbial diversity during the events provides information of how disturbances are shaping ecosystem. Metagenome-based analysis provides a molecular approach that gives an overview of the dynamic of the cultivable and uncultivable microbial communities during the bloom. Goals. Our goal was to determine the microbial diversity: the species richness, and their abundance in the dam “El Palote” Leon, Gto. that presented algal bloom. Methods. Prokaryotic and eukaryotic Microbial community composition was analyzed by 16S and 18S rRNA amplification and sequencing. Results. Biodiversity taxonomic analysis was measured by Shannon index showed similar distribution patterns between samples taken at surface and two-meter depth, while Simpson index presented differences. The prokaryotic dominant phyla were cyanobacteria of Planktothrix genera (67%, 0 m and 69%, 2 m), Proteobacteria (13.7 and 13%) and Bacteriodetes (6 and 8.2%). Regarding eukaryotes the dominant groups were Opistholokonta as well as Stramenopila, Alveolata and Rhizaria (SAR). Quantile based analysis showed relative abundance differences Flavobacterium spp. Aeromonas spp., Rheinheimera spp., Cetobacterium somerae and Cryptomonas curvata were majority at two meters depth, while Methylocaldum szegediense, Pseudospirillum and Aeromonas sobria presented high abundance at the surface. Conclusions The results showed an overview of microbial communities asociated with a cianoalgal bloom dominated by Planktothrix agardhii-rubescens.

Impact of Plastic Debris on the Gut Microbiota of Caretta caretta From Northwestern Adriatic Sea

Plastic pollution is nowadays a relevant threat for the ecological balance in marine ecosystems. Small plastic debris (PD) can enter food webs through various marine organisms, with possible consequences on their physiology and health. The loggerhead sea turtle (Caretta caretta), widespread across the whole Mediterranean Sea, is a “flagship species,” useful as indicator of the general pollution level of marine ecosystems. Ingested PD accumulate in the final section of turtles’ digestive tract before excretion. During their transit and accumulation, PD also interact with the residing microbial community, with possible feedback consequences on the host’s health. To explore the possible relationship between fecal microbial composition and PD ingestion, we collected fecal samples from 45 turtles rescued between 2017 and 2019 in the Northwestern Adriatic Sea (Italy), assessing occurrence and content of PD in the samples and in parallel the microbiome structure by 16S rRNA gene sequencing. According to our findings, almost all samples contained PD, mirroring the high level of plastic pollution in the area. We identified phylotypes associated to a high amount of PD, namelyCetobacterium someraeand other taxa, possibly responding to contamination by plastic-associated chemicals. Furthermore, putative marine pathogens were found associated to higher plastic contamination, supporting the hypothesis that PD can act as a carrier for environmental pathogenic bacteria into marine organisms. Besides confirming the role of the sea turtle as relevant flagship species for plastic pollution of the marine environment, our study paves the way to the exploration of the impact that PD ingestion can have on the microbial counterpart of large marine organisms, with potential feedback consequences on the animal and ecosystem health.