Aging-induced dysbiosis worsens sepsis severity but is attenuated by probiotics in D-galactose-administered mice with cecal ligation and puncture model.

INTRODUCTION: Despite the well-established effects of aging on brain function and gut dysbiosis (an imbalance in gut microbiota), the influence of aging on sepsis-associated encephalopathy (SAE) and the role of probiotics in this context remain less understood. METHODS: C57BL/6J mice (8-week-old) were subcutaneously administered with 8 weeks of D-galactose (D-gal) or phosphate buffer solution (PBS) for aging and non-aging models, respectively, with or without 8 weeks of oral Lacticaseibacillus rhamnosus GG (LGG). Additionally, the impact of the condition media from LGG (LCM) was tested in macrophages (RAW 264.7 cells), microglia (BV-2 cells), and hippocampal cells (HT-22 cells). RESULT: Fecal microbiome analysis demonstrated D-gal-induced dysbiosis (reduced Firmicutes and Desulfobacterota with increased Bacteroidota and Verrucomicrobiota), which LGG partially neutralized the dysbiosis. D-gal also worsens cecal ligation and puncture (CLP) sepsis severity when compared with PBS-CLP mice, as indicated by serum creatinine (Scr) and alanine transaminase (ALT), but not mortality, neurological characteristics (SHIRPA score), and serum cytokines (TNF-α and IL-6). Additionally, D-gal-induced aging was supported by fibrosis in the liver, kidney, and lung; however, CLP sepsis did not worsen fibrosis. Interestingly, LGG attenuated all parameters (mortality, Scr, ALT, SHIRPA, and cytokines) in non-aging sepsis (PBS-CLP) while improving all these parameters, except for mortality and serum IL-6, in aging sepsis (D-gal CLP). For the in vitro test using lipopolysaccharide (LPS) stimulation, LCM attenuated inflammation in some parameters on RAW264.7 cells but not BV-2 and HT-22 cells, implying a direct anti-inflammatory effect of LGG on macrophages, but not in cells from the brain. CONCLUSION: D-gal induced fecal dysbiosis and worsened sepsis severity as determined by Scr and ALT, and LGG could alleviate most of the selected parameters of sepsis, including SAE. However, the impact of LGG on SAE was not a direct delivery of beneficial molecules from the gut to the brain but partly due to the attenuation of systemic inflammation through the modulation of macrophages.

Impact of fermented wine lees on gut microbiota and metabolic responses in Guanling crossbred cattle.

BACKGROUND: The addition of wine lees to diets can make up for the deficiencies caused by traditional forages in beef cattle farming. However, the effects of different wine lees ratios on average daily weight, gastrointestinal microbial community structure and metabolites in Guanling crossbred cattle have been rarely studied. This study assessed the effects of feeds containing wine lees on weight gain, gastrointestinal microbial community structure, and metabolites in Guanling crossbred cattle and elucidated the metabolic responses induced by wine lees. Eighteen cows were randomly assigned to receive fed concentrate (C group), feed containing 15% wine lees (group A), or feed containing 30% wine lees (group B) for 60 days. RESULTS: The average daily weight gain of group A and group B increased by 76.75% and 57.65%, respectively, compared with group C. Microbial community analysis showed that wine lees increased the abundance of Prevotella_1 in the rumen, decreased the abundance of Ruminococcaceae UCG 011 and Lachnospiraceae_FCS020_group in the rumen, and increased the abundance of Tyzzerella_4, Family_Xlll_AD3011_group, Granulicella, and Eisenbergiella in the cecum. Metabolomics analyses showed that wine lees decreased the concentrations of indole-3-ethanol in the rumen, and complexity cecal metabolism. Notably, linoleic acid metabolism was significantly enriched in both the rumen and cecum. Mantel test analyses indicated that the adverse effects of WL were reduced by stimulating the metabolism of linoleic acid, α-linolenic acid, and tryptophan, and these changes were mediated by intestinal microorganisms. The Guanling cattle cecum was enriched for several unfavorable metabolic pathways when wine lees concentrations reached 30%, which increased the likelihood of intestinal lesions. CONCLUSION: This study shows that WL supplementation alters gut microbiota and metabolic pathways, improving cattle growth and health. Moderate WL levels (15%) enhance gut health and beneficial pathways (e.g., linoleic and alpha-linolenic acid metabolism). However, higher WL inclusion (30%) may activate adverse pathways, raising the risk of intestinal damage. To maximize benefits and minimize risks, WL levels should be carefully managed.

Inflammasome activation links enteric Salmonella Typhimurium infection to a rapid, cytokine-dependent increase in intestinal mucin release.

The host restricts Salmonella enterica serovar Typhimurium infection of the gut via inflammasome-dependent sloughing of infected epithelial cells. Here we determined that concurrent caspase 1/11-dependent release of the goblet cell-derived mucin, Muc2, into the intestinal lumen also controls Salmonella burdens in infected mice. The increased release of mucins from goblet cells in the cecum and nearby proximal colon, and the subsequent thickening of the protective mucus barrier layer in the distal colon, were all dependent on the cytokines interleukin (IL)-18 and IL-22, as deficiencies in either cytokine resulted in reduced mucin secretion. Supplementation of IL-18 into IL-22 deficient mice restored mucin secretion, indicating that IL-22 acted upstream of IL-18 secretion during infection. In contrast, IL-18 and IL-22 independent signaling through Nlrp6 underlies only a modest, infection-induced increase in mucin secretion from goblet cells in the distal colon. These findings reveal that inflammasome signaling orchestrates multiple levels of protection centered on the intestinal epithelium, including pyroptosis and expulsion of infected enterocytes, as well as the release of mucins by goblet cells in the cecum and along the length of the colon. Our studies underscore the pivotal, multi-faceted role of inflammasome signaling in promoting host defense at the intestinal mucosal surface.

Effect of orange pulp with or without zeolite on productive performance, nitrogen utilization, and antioxidative status of growing rabbits.

The current study was designed to investigate the effect of dried orange pulp inclusion (OP diet), natural zeolite addition (Z diet), or both (OPZ diet) compared to control (CON diet) on digestibility, growth performance, nitrogen utilization, blood biochemical, antioxidative status, and cecum microbiota of growing rabbits. Seventy-two V-line male rabbits (6 weeks old) were divided into 4 balanced experimental groups. Results showed that administration of dried orange pulp or zeolite especially the OPZ diet significantly improved nutrient digestibility and nutritive values. Rabbits fed the experimental diets (OP, Z, or OPZ) recorded significantly higher values of average daily gain, N-retention, and N-balance compared with those fed the CON diet. Data on blood biochemical, showed non-significant differences in globulin concentrations, and significant decreases in levels of cholesterol, LDL (low-density lipoproteins), triglycerides, and MDA (malondialdehyde) as an antioxidant biomarker with OP, Z, or OPZ diets. Moreover, the incorporation of orange pulp or zeolite in diets significantly decreased the cecal count of E. coli, with no significant difference in total bacterial count among the experimental groups. It could be concluded that a combination between dried orange pulp and natural zeolite in the diet can enhance the growth performance, antioxidant and health status of rabbits.

Consumption of Fructooligosaccharides Influences the Action of Fecal MicroRNAs in Altering the Structure of Cultured Gut Microbiota in Mice.

Fecal microRNAs (miRNAs) derived from intestinal epithelial cells have been suggested to influence gut microbiota homeostasis. We recently showed that supplementing murine fecal small RNAs, most likely miRNAs, alters the structure of cultured fecal microbiota in a sequence-dependent manner. The present study investigated the effect of consuming fructooligosaccharides (FOS) on the action of fecal small RNAs in altering the structure of cultured fecal microbiota. Female C57BL/6J mice were allowed free access to AIN-93G diet, and tap water supplemented with or without 4% (w/v) FOS for 2 wk. As assessed by 16S rRNA gene sequence analysis in cecal contents, the gut microbiota structure differed between mice supplemented with and without FOS. Fecal bacteria isolated from the cecal contents of mice without FOS supplementation were cultured for 24 h under anaerobic conditions. The structure of cultured microbiota differed between the cultures supplemented with small RNAs isolated from the cecal contents of mice supplemented with and without FOS. Microarray analysis showed that the miRNA profile in the cecal contents differed between mice supplemented with and without FOS. We propose that FOS consumption influences the action of intestinal epithelial cell-derived miRNAs in altering the structure of cultured gut microbiota, and such FOS action is associated with changes in the profile of miRNAs. It may be possible that intestinal epithelial cell-derived miRNAs contribute, at least in part, to diet-induced alteration of gut microbiota.

Immunoglobulin secretion influences the composition of chicken caecal microbiota.

The chicken caecum is colonised by hundreds of different bacterial species. Which of these are targeted by immunoglobulins and how immunoglobulin expression shapes chicken caecal microbiota has been addressed in this study. Using cell sorting followed by sequencing of V3/V4 variable region of 16S rRNA, bacterial species with increased or decreased immunoglobulin coating were determined. Next, we determined also caecal microbiota composition in immunoglobulin knockout chickens. We found that immunoglobulin coating was common and major taxa were coated with immunoglobulins. Similarly, more taxa required immunoglobulin production for caecum colonisation compared to those which became abundant in immunoglobulin-deficient chickens. Taxa with low immunoglobulin coating such as Lactobacillus, Blautia, [Eubacterium] hallii, Megamonas, Fusobacterium and Desulfovibrio all encode S-layer proteins which may reduce interactions with immunoglobulins. Although there were taxa which overgrew in Ig-deficient chickens (e.g. Akkermansia) indicating immunoglobulin production acted to exclude them from the chicken caecum, in most of the cases, immunoglobulin production more likely contributed to fixing the desired microbiota in the chicken caecum.

Garlic Bioconverted by Bacillus subtilis Stimulates the Intestinal Immune System and Modulates Gut Microbiota Composition.

SCOPE: This study evaluates the potential of bioconverted garlic ferments (BGFs) to stimulate the intestinal immune system and modulate cecal microbiota composition. METHODS AND RESULTS: In vitro, BGF significantly enhances Peyer's patch (PP)-mediated bone marrow cell proliferation and increases the production of interferon-gamma (IFN-γ), granulocyte macrophage-colony stimulating factor (GM-CSF), interleukin (IL)-6, and immunoglobulin A (IgA) but not IL-4, IL-5, and immunoglobulin E (IgE). Oral administration of BGF to C3H/HeN mice for 4 weeks significantly increases the GM-CSF (42.1-45.8 pg mL-1) and IFN-γ (6.5-12.1 pg mL-1) levels in PP cells. BGF also significantly elevates the levels of tumor necrosis factor-alpha (TNF-α, 165.0-236.3 pg mg-1), GM-CSF (2.4-3.0 ng mg-1), and IFN-γ (1.5-3.2 ng mg-1) in the small intestinal fluid, and TNF-α (2.2-3.1 pg mL-1) and IFN-γ (10.3-0.21.5 pg mL-1) in the mouse serum. Cecal microbial analysis reveals that BGF increases Bacteroidota and Verrucomicrobiota and decreases Actinobacteria and Bacillota at the phylum level in mice. At the genus level, BGF significantly increases the abundance of Fusimonas (250 mg kg-1 BW-1 day-1), Bacteroides (125 and 250 mg kg-1 BW-1 day-1), and Akkermansia (125 mg kg-1 BW-1 day-1) and decreases that of Bifidobacterium (62.5 and 250 mg kg-1 BW-1 day-1) and Limosilactobacillus (125 and 250 mg kg-1 BW-1 day-1). CONCLUSION: This study provides the first evidence of BGF's ability to modulate the intestinal immune system and gut microbiota, supporting its potential as a novel functional material to enhance gut immunity.

Microbiome-induced reprogramming in post-transcriptional landscape using nanopore direct RNA sequencing.

It has been widely recognized that the microbiota has the capacity to shape host gene expression and physiological functions. However, there remains a paucity of comprehensive study revealing the host transcriptional landscape regulated by the microbiota. Here, we comprehensively examined mRNA landscapes in mouse tissues (brain and cecum) from specific-pathogen-free and germ-free mice using nanopore direct RNA sequencing. Our results show that the microbiome has global influence on a host's RNA modifications (m6A, m5C, Ψ), isoform generation, poly(A) tail length, and transcript abundance in both brain and cecum tissues. Moreover, the microbiome exerts tissue-specific effects on various post-transcriptional regulatory processes. In addition, the microbiome impacts the coordination of multiple RNA modifications in host brain and cecum tissues. In conclusion, we establish the relationship between microbial regulation and gene expression. Our results help the understanding of the mechanisms by which the microbiome reprograms host gene expression.

Effects of the anti-inflammatory drug budesonide on the gut microbiota and cytokine production of 13-lined ground squirrels during prehibernation fattening.

The gut microbiome is essential for maintaining organismal health. Gut microbiota may be disrupted through external factors like dietary change, which can lead to gut inflammation, resulting in obesity. Hibernating mammals develop low-grade gut inflammation when they accumulate fat deposits in preparation for hibernation, making them useful models for studying the relationship between the microbiome, inflammation, and weight gain. Nonsteroidal anti-inflammatory drugs and steroids are commonly used in humans to target gut inflammation, but how these drugs affect the gut microbiome and its stability is unclear. We investigated the effect of the glucocorticoid drug budesonide on the gut microbiome and cytokine levels of an obligate hibernator, the 13-lined ground squirrel, during the fattening season. We used 16S rRNA gene sequencing to characterize bacterial communities in the lumen and mucosa of the cecum and colon and measured proinflammatory [tumor necrosis factor-α (TNF-α)/interleukin 6 (IL-6)] and anti-inflammatory (IL-10) cytokine levels. Budesonide affected the microbiome only in the cecum lumen, where bacterial diversity was higher in the control group, and communities significantly differed between treatments. Across gut sections, Marvinbryantia and Enterococcus were significantly higher in the budesonide group, whereas Sarcina was higher in the control group. TNF-α and IL-6 levels were higher in control squirrels compared with the budesonide group, but there was no difference in IL-10 levels. Overall, budesonide treatment affected the microbial community and diversity of 13-lined ground squirrels in the cecum lumen. Our study presents another step toward developing ground squirrels as a model for studying the interaction between the microbiota and host inflammation.NEW & NOTEWORTHY Disruptions of gut microbiota can lead to inflammation, resulting in weight gain. Inflammation can be treated with budesonide, but how budesonide affects gut microbiota is unclear. Thirteen-lined ground squirrels experience low-grade gut inflammation during prehibernation fattening, which compares with human inflammation-weight gain mechanisms. We showed that budesonide treatment decreased microbiome diversity and lead to a shift in community in the cecum lumen. Our study supports developing ground squirrels as a model for studying microbiome-inflammation interactions.

Regulation of Cecal Microbiota and Improvement of Blood Lipids Using Walnut Non-Dairy Creamer in High-Fat Mice: Replacing Traditional Non-Dairy Creamer.

Non-dairy creamer is a class of microencapsulated powdered fats and oils that are widely used in the food industry. However, the oils used in it are hydrogenated vegetable oils, which contain large amounts of saturated fatty acids and are extremely harmful to the human body. This study investigated the effects of replacing hydrogenated vegetable oil with walnut oil to prepare walnut non-dairy creamer on lipid levels and intestinal microorganisms in mice. The results show that low-dose walnut non-dairy creamer significantly decreased the contents of TC and TG in serum and increased the content of HDL-C (p < 0.01). The contents of MDA, ALT, and AST were significantly decreased, while the content of SOD was increased (p < 0.01). The abundance of Firmicutes in the walnut non-dairy creamer group decreased, and the abundance of Bacteroidetes/Firmicutes (B/F) increased, which significantly increased the richness of Lactobacillus and Oscillospira (p < 0.01). Allobaculum richness was significantly decreased (p < 0.01). In conclusion, a low dose of walnut non-dairy creamer can effectively promote the metabolism of blood lipids in vivo, alleviate oxidative stress injury and lipid accumulation damage to mouse hepatocytes, and ameliorate the adverse effects of a high-fat diet on the intestinal microbiota of mice. This study provides a theoretical basis for the replacement of traditional non-dairy creamer and the research and development of walnut deep processing.

Dynamic response of the intestinal microbiome to Eimeria maxima-induced coccidiosis in chickens.

Eimeria maxima is a major cause of coccidiosis in chickens and a key predisposing factor for other economically significant diseases such as necrotic enteritis. However, a detailed understanding of the intestinal microbiome response to E. maxima infection is still lacking. This study aimed to comprehensively investigate the dynamic changes of the intestinal microbiome for 14 days post-infection (dpi) with E. maxima. Bacterial 16S rRNA gene sequencing was performed with the ileal and cecal digesta collected from mock and E. maxima-infected chickens at the prepatent (3 dpi), acute (5 and 7 dpi), and recovery phases (10 and 14 dpi) of infection. Although no notable changes were observed at 3 dpi, significant alterations of the microbiota occurred in both the ileum and cecum at 5 and 7 dpi. By 14 dpi, the intestinal microbiota tended to return to a healthy state. Notably, Lactobacillus was enriched in response to E. maxima infection in both the ileum and cecum, although individual Lactobacillus, Ligilactobacillus, and Limosilactobacillus species varied in the temporal pattern of response. Concurrently, major short-chain fatty acid-producing bacteria, such as Faecalibacterium, were progressively suppressed by E. maxima in the cecum. On the other hand, opportunistic pathogens such as Escherichia, Enterococcus, and Staphylococcus were significantly enriched in the ileum during acute infection. IMPORTANCE: We have observed for the first time the dynamic response of the intestinal microbiota to Eimeria maxima infection, synchronized with its life cycle. Minimal changes occur in both the ileal and cecal microbiota during early infection, while significant alterations coincide with acute infection and disruption of the intestinal mucosal lining. As animals recover from coccidiosis, the intestinal microbiota largely returns to normal. E. maxima-induced intestinal inflammation likely creates an environment conducive to the growth of aerotolerant anaerobes such as Lactobacillus, as well as facultative anaerobes such as Escherichia, Enterococcus, and Staphylococcus, while suppressing the growth of obligate anaerobes such as short-chain fatty acid-producing bacteria. These findings expand our understanding of the temporal dynamics of the microbiota structure during Eimeria infection and offer insights into the pathogenesis of coccidiosis, supporting the rationale for microbiome-based strategies in the control and prevention of this condition.

Selection for amoxicillin-, doxycycline-, and enrofloxacin-resistant Escherichia coli at concentrations lower than the ECOFF in broiler-derived cecal fermentations.

Antimicrobial resistance (AMR) is an emerging worldwide problem and a health threat for humans and animals. Antimicrobial usage in human and animal medicine or in agriculture results in selection for AMR. The selective concentration of antimicrobial compounds can be lower than the minimum inhibitory concentration and differs between environments, which can be a reason for bacterial resistance. Therefore, knowledge of the minimal selective concentration (MSC), under natural conditions, is essential to understand the selective window of bacteria when exposed to residual antimicrobials. In this study, we estimated the MSCs of three antimicrobials, amoxicillin, doxycycline, and enrofloxacin in a complex microbial community by conducting fermentation assays with cecal material derived from broilers. We examined the phenotypic resistance of Escherichia coli, resistome, and microbiome after 6 and 30 hours of fermenting in the presence of the antimicrobials of interest. The concentrations were estimated to be 10-100 times lower than the epidemiological cut-off values in E. coli for the respective antimicrobials as determined by EUCAST, resulting in an MSC between 0.08 and 0.8 mg/L for amoxicillin, 0.4 and 4 mg/L for doxycycline, and 0.0125 and 0.125 mg/L for enrofloxacin. Additionally, resistome analysis provided an MSC for doxycycline between 0.4 and 4 mg/L, but amoxicillin and enrofloxacin exposure did not induce a significant difference. Our findings indicate at which concentrations there is still selection for antimicrobial-resistant bacteria. This knowledge can be used to manage the risk of the emergence of antimicrobial-resistant bacteria.IMPORTANCEAntimicrobial resistance possibly affects human and animal health, as well as economic prosperity in the future. The rise of antimicrobial-resistant bacteria is a consequence of using antimicrobial compounds in humans and animals selecting for antimicrobial-resistant bacteria. Concentrations reached during treatment are known to be selective for resistant bacteria. However, at which concentrations residues are still selective is important, especially for antimicrobial compounds that remain in the environment at low concentrations. The data in this paper might inform decisions regarding guidelines and regulations for the use of specific antimicrobials. In this study, we are providing these minimal selective concentrations for amoxicillin, doxycycline, and enrofloxacin in complex environments.

The role of intestinal microbiota in physiologic and body compositional changes that accompany CLA-mediated weight loss in obese mice.

OBJECTIVE: Obesity continues to be a major problem, despite known treatment strategies such as lifestyle modifications, pharmaceuticals, and surgical options, necessitating the development of novel weight loss approaches. The naturally occurring fatty acid, 10,12 conjugated linoleic acid (10,12 CLA), promotes weight loss by increasing fat oxidation and browning of white adipose tissue, leading to increased energy expenditure in obese mice. Coincident with weight loss, 10,12 CLA also alters the murine gut microbiota by enriching for microbes that produce short chain fatty acids (SCFAs), with concurrent elevations in fecal butyrate and plasma acetate. METHODS: To determine if the observed microbiota changes are required for 10,12 CLA-mediated weight loss, adult male mice with diet-induced obesity were given broad-spectrum antibiotics (ABX) to perturb the microbiota prior to and during 10,12 CLA-mediated weight loss. Conversely, to determine whether gut microbes were sufficient to induce weight loss, conventionally-raised and germ-free mice were transplanted with cecal contents from mice that had undergone weight loss by 10,12 CLA supplementation. RESULTS: While body weight was minimally modulated by ABX-mediated perturbation of gut bacterial populations, adult male mice given ABX were more resistant to the increased energy expenditure and fat loss that are induced by 10,12 CLA supplementation. Transplanting cecal contents from donor mice losing weight due to oral 10,12 CLA consumption into conventional or germ-free mice led to improved glucose metabolism with increased butyrate production. CONCLUSIONS: These data suggest a critical role for the microbiota in diet-modulated changes in energy balance and glucose metabolism, and distinguish the metabolic effects of orally delivered 10,12 CLA from cecal transplantation of the resulting microbiota.

The Effects of 1-Kestose on the Abundance of Inflammation-Related Gene mRNA in Adipose Tissue and the Gut Microbiota Composition in Rats Fed a High-Fat Diet.

Chronic inflammation in adipose tissue is thought to contribute to insulin resistance, which involves the gut microbiota. Our previous studies have demonstrated that ingestion of 1-kestose can alter the gut microbiota composition, increase cecal butyrate levels, and improve insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Additionally, we found that 1-kestose supplementation ameliorated insulin resistance in obese rat models fed a high-fat diet (HFD), although the effects of 1-kestose on the abundance of inflammation-related gene in adipose tissue and gut microbiota composition in these rats were not explored. This study aimed to investigate the impact of 1-kestose on these parameters in HFD-fed rats, compared to OLETF rats. Male Sprague-Dawley rats were divided into two dietary groups, control or HFD, for 19 wk. Each group was further subdivided to receive either tap water or tap water supplemented with 2% (w/v) 1-kestose throughout the study. We evaluated gene expression in adipose tissue, as well as short-chain fatty acids (SCFAs) levels and microbial composition in the cecum contents. 1-Kestose intake restored the increased relative abundance of tumor necrosis factor (Tnf) mRNA in adipose tissue and the reduced level of butyrate in the cecum contents of HFD-fed rats to those observed in control diet-fed rats. Additionally, 1-kestose consumption changed the composition of the gut microbiota, increasing Butyricicoccus spp., decreasing UGC-005 and Streptococcus spp., in the cecum contents of HFD-fed rats. Our findings suggest that 1-kestose supplementation reduces adipose tissue inflammation and increases butyrate levels in the gut of HFD-fed rats, associated with changes in the gut microbiota composition, distinct from those seen in OLETF rats.

Evaluation of lyophilized bacteriophage cocktail efficiency against multidrug-resistant Salmonella in broiler chickens.

Currently, phage biocontrol is increasingly used as a green and natural technology for treating Salmonella and other infections, but phages exhibit instability and activity loss during storage. Therefore, in this study, the effects of lyophilization on the activity and stability of phage cocktails for the control of multidrug-resistant Salmonella in broiler chickens were determined. Eight serotypes of Salmonella were isolated and identified from broiler chicken farms, and bacteriophages against multidrug-resistant Salmonella enterica subsp. enterica serovar Kentucky, Salmonella enterica subsp. enterica serovar Typhimrium and Salmonella enterica subsp. enterica serovar Enteritidis were isolated. The bacteriophage cocktail was prepared and lyophilized, and it was subjected to in vitro and in vivo examinations. A reconstituted lyophilized bacteriophage cocktail was used for the oral treatment of chicks before and after challenge with multidrug-resistant S. Kentucky. The colonization of cecum by S. Kentucky was detected by using real-time PCR, and the serum levels of IgM, IgA and IL-4 and pathological changes in the different groups were detected. Three Caudovirales phages families were identified including Autographiviridae, Straboviridae and Drexlerviridae against multidrug-resistant S. Kentucky, S. Typhimrium and S. Enteritidis. The groups treated with the bacteriophage cocktail showed no clinical signs, no postmortem lesions, and a mortality rate of 0%, which improved the growth performance parameters. Additionally, the estimated serum levels of IgM, IgA and IL-4 were significantly greater in the bacteriophage cocktail-treated groups. Lyophilization effectively preserves the long-term storage stability of phages. Therefore, lyophilized bacteriophage cocktail therapy is a valuable approach for controlling multidrug-resistant Salmonella infections in broiler chickens.

Dietary fibers boost gut microbiota-produced B vitamin pool and alter host immune landscape.

BACKGROUND: Dietary fibers can alter microbial metabolic output in support of healthy immune function; however, the impact of distinct fiber sources and immunomodulatory effects beyond short-chain fatty acid production are underexplored. In an effort to discern the effects of diverse fibers on host immunity, we employed five distinct rodent diets with varying fiber content and source in specific-pathogen-free, gnotobiotic (containing a 14-member synthetic human gut microbiota), and germ-free mice. RESULTS: Broad-scale metabolomics analysis of cecal contents revealed that fiber deprivation consistently reduced the concentrations of microbiota-produced B vitamins. This phenomenon was not always explained by reduced biosynthesis, rather, metatranscriptomic analyses pointed toward increased microbial usage of certain B vitamins under fiber-free conditions, ultimately resulting in a net reduction of host-available B vitamins. Broad immunophenotyping indicated that the local gut effector immune populations and activated T cells accumulate in a microbiota-dependent manner. Supplementation with the prebiotic inulin recovered the availability of microbially produced B vitamins and restored immune homeostasis. CONCLUSIONS: Our findings highlight the potential to use defined fiber polysaccharides to boost microbiota-derived B vitamin availability in an animal model and to regulate local innate and adaptive immune populations of the host. Video abstract.

Influences of Bacillus pumilus SA388 as an environmentally friendly antibiotic alternative on growth performance, blood biochemistry, immunology, cecal microbiota, and meat quality in broiler chickens.

The widespread use of antibiotics causes the development of antibiotic-resistant bacterial strains, which have a severe impact on poultry productivity and human health. As a result, research is continuing to develop safe natural antibiotic alternatives. In the current study, Bacillus pumilus SA388 was isolated from the chicken feces and confirmed to be a probiotic. The selected strain was tested for its antimutagenic and antioxidant capabilities before being employed as a probiotic food supplement and antibiotic alternative. The effect of B. pumilus SA388 impact on broiler chickens' growth performance, gut microbiome, blood biochemical markers, immunological response, and meat quality was also studied. B. pumilus SA388 showed significant bactericidal activity against Streptococcus pyogenes, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Klebsiella pneumonia. A total of 200 chickens were used in the present study, divided equally among four experimental groups (ten birds per group with 5 replicates): group 1 (control, G1) received a basal diet without B. pumilus SA388, group 2 (G2) received a basal diet supplemented with 0.4 mg/kg of B. pumilus SA388, group 3 (G3) received a basal diet supplemented with 0.8 mg/kg of B. pumilus SA388, and group 4 (G4) received a basal diet supplemented with 1.6 mg/kg of B. pumilus SA388. Over 35 d, the B. pumilus SA388-supplemented groups outperformed the G1 in terms of body weight gain, performance index, and feed conversion ratio, with a preference for the G4 treatment. The levels of alanine aminotransferase (ALT), aspartate transaminase (AST), low-density lipoprotein (LDL), and total cholesterol decreased significantly (P < 0.05) with increasing B. pumilus SA388 dosages compared to the control G1 group. Dietary supplementation of B. pumilus SA388 at 1.6 mg/kg (G4) significantly (P < 0.05) resulted in improved lipid profile, immunological response, thyroid function, and gut microbiota compared to the control group (G1). Compared to the broilers in the control treatment (G1), the addition of B. pumilus SA388 to broilers in G4 significantly (P < 0.05) enhanced juiciness, tenderness, aroma, and taste. Adding B. pumilus SA388 to chicken feed at different doses significantly (P < 0.05) decreased average feed intake while increasing economic and relative efficiency measures. In conclusion, B. pumilus SA388 has been proven to be an effective antibiotic and nutritional supplement.

Dietary starch structure modulates nitrogen metabolism in laying hens via modifying glucose release rate.

The objective of this study was to investigate the effects of starch structure (Amylopectin/Amylose, AP/AM) in a low-protein diet on production performance, nitrogen utilization efficiency, and cecal flora in laying hens. Four hundred eighty 45-wk-age Hy-Line Gray laying hens were randomly allocated to five dietary groups and subjected to a 12-wk feeding trial. The AP/AM ratios of the five experiment diets were 1.0, 1.5, 2.0, 3.0, and 4.0. The results indicated that compared to other groups, laying hens fed with AP/AM 4.0 diets showed significantly improved average egg weight and feed conversion ratio (P < 0.05). Furthermore, as the AP/AM ratio increased, there was a significant linear enhancement in intestinal amino acids apparent digestibility, apparent metabolizable energy, and villus area (P < 0.05). Compared to the high AP groups, high-AM diets significantly increased eggshell thickness, crude protein digestibility, and reduced energy supply from amino acid oxidation in ileum (P < 0.05). Additionally, moderate-AM diets enriched with short-chain fatty acid-producing bacteria in the cecum, such as Lactobacillus, Rikenellaceae_RC9_gut_group, and Christensenellaceae_R-7_group, which are associated with the promoting nitrogen utilization. These findings may offer useful information on optimizing starch structure for the design of food products and relevant therapies due to the potential effects on nutrient metabolism and gut homeostasis.

Infectious bronchitis virus vaccination, but not the presence of XCR1, is correlated with large differences in chicken caecal microbiota.

The chicken immune system and microbiota play vital roles in maintaining gut homeostasis and protecting against pathogens. In mammals, XCR1+ conventional dendritic cells (cDCs) are located in the gut-draining lymph nodes and play a major role in gut homeostasis. These cDCs sample antigens in the gut luminal contents and limit the inflammatory response to gut commensal microbes by generating appropriate regulatory and effector T-cell responses. We hypothesized that these cells play similar roles in sustaining gut homeostasis in chickens, and that chickens lacking XCR1 were likely to contain a dysbiotic caecal microbiota. Here we compare the caecal microbiota of chickens that were either heterozygous or homozygous XCR1 knockouts, that had or had not been vaccinated for infectious bronchitis virus (IBV). We used short-read (Illumina) and long-read (PacBio HiFi) metagenomic sequencing to reconstruct 670 high-quality, strain-level metagenome assembled genomes. We found no significant differences between alpha diversity or the abundance of specific microbial taxa between genotypes. However, IBV vaccination was found to correlate with significant differences in the richness and beta diversity of the microbiota, and to the abundance of 40 bacterial genera. In conclusion, we found that a lack of XCR1 was not correlated with significant changes in the chicken microbiota, but IBV vaccination was.

Christensenella minuta protects and restores intestinal barrier in a colitis mouse model by regulating inflammation.

Christensenella minuta DSM 22607 has recently been suggested as a potential microbiome-based therapy for inflammatory bowel disease (IBD) because it displays strong anti-inflammatory effects both in vitro and in vivo. Here, we aimed to decipher the mechanism(s) underlying the DSM 22607-mediated beneficial effects on the host in a mouse model of chemically induced acute colitis. We observed that C. minuta plays a key role in the preservation of the epithelial barrier and the management of DNBS-induced inflammation by inhibiting interleukin (IL)-33 and Tumor necrosis factor receptor superfamily member 8 (Tnfrsf8) gene expression. We also showed that DSM 22607 abundance was positively correlated with Akkermansia sp. and Dubosiella sp. and modulated microbial metabolites in the cecum. These results offer new insights into the biological and molecular mechanisms underlying the beneficial effects of C. minuta DSM 22607 by protecting the intestinal barrier integrity and regulating inflammation.