Bacillus subtilis 29784 induces a shift in broiler gut microbiome toward butyrate-producing bacteria and improves intestinal histomorphology and animal performance

Unraveling the benefits of Bacillus subtilis DSM 29784 poultry probiotic through its secreted metabolites: an in vitro approach

The probiotic Bacillus subtilis 29784 (Bs29784) sustains chicken's intestinal health, enhancing animal resilience and performance through the production of the bioactive metabolites hypoxanthine (HPX), niacin (NIA), and pantothenate (PTH). Here, using enterocyte in vitro models, we determine the functional link between these metabolites and the three pillars of intestinal resilience: immune response, intestinal barrier, and microbiota. We evaluated in vitro the capacity of Bs29784 vegetative cells, spores, and metabolites to modulate global immune regulators (using HT-29-NF-κB and HT-29-AP-1 reporter cells), intestinal integrity (HT-29-MUC2 reporter cells and Caco-2 cells), and cytokine production (Caco-2 cells). Finally, we simulated intestinal fermentations using chicken's intestinal contents as inocula to determine the effect of Bs29784 metabolites on the microbiota and their fermentation profile. Bs29784 vegetative cells reduced the inflammatory response more effectively than spores, indicating that their benefit is linked to metabolic activity. To assess this hypothesis, we studied Bs29784 metabolites individually. The results showed that each metabolite had different beneficial effects. PTH and NIA reduced the activation of the pro-inflammatory pathways AP-1 and NF-κB. HPX upregulated mucin production by enhancing MUC2 expression. HPX, NIA, and PTH increased cell proliferation. PTH and HPX increased epithelial resilience to an inflammatory challenge by limiting permeability increase. In cecal fermentations, NIA increased acetate, HPX increased butyrate, whereas PTH increased acetate, butyrate, and propionate. In ileal fermentations, PTH increased butyrate. All molecules modulated microbiota, explaining the different fermentation patterns. Altogether, we show that Bs29784 influences intestinal health by acting on the three lines of resilience via its secreted metabolites.

IMPORTANCE

Probiotics provide beneficial metabolites to its host. Here, we describe the mode of action of a commonly used probiotic in poultry, Bs29784. By using in vitro cellular techniques and simulated chickens' intestinal model, we show the functional link between Bs29784 metabolites and the three lines of animal resilience. Indeed, both Bs29784 vegetative cells and its metabolites stimulate cellular anti-inflammatory responses, strengthen intestinal barrier, and positively modulate microbiota composition and fermentative profile. Taken together, these results strengthen our understanding of the effect of Bs29784 on its host and explain, at least partly, its positive effects on animal health, resilience, and performance.

Important role of Bacillus subtilis as a probiotic and vaccine carrier in animal health maintenance

Bacillus subtilis is a widespread Gram-positive facultative aerobic bacterium that is recognized as generally safe. It has shown significant application value and great development potential in the animal farming industry. As a probiotic, it is frequently used as a feed growth supplement to effectively replace antibiotics due to its favourable effects on regulating the intestinal flora, improving intestinal immunity, inhibiting harmful microorganisms, and secreting bioactive substances. Consequently, the gut health and disease resistance of farmed animals can be improved. Both vegetative and spore forms of B. subtilis have also been utilized as vaccine carriers for delivering the antigens of infectious pathogens for over a decade. Notably, its spore form is regarded as one of the most prospective for displaying heterologous antigens with high activity and stability. Previously published reviews have predominantly focused on the development and applications of B. subtilis spore surface display techniques. However, this review aims to summarize recent studies highlighting the important role of B. subtilis as a probiotic and vaccine carrier in maintaining animal health. Specifically, we focus on the beneficial effects and underlying mechanisms of B. subtilis in enhancing disease resistance among farmed animals as well as its potential application as mucosal vaccine carriers. It is anticipated that B. subtilis will assume an even more prominent role in promoting animal health with in-depth research on its characteristics and genetic manipulation tools.

Effects of fermented tofu processing wastewater on growth performance and meat quality of Xianghuang broilers

This study aimed to investigate the effects of fermented tofu processing wastewater (FTPW) on the growth performance and meat quality of Xianghuang broilers. A total of 160 six-week-old Xianghuang broilers were randomly assigned to control or FTPW groups with eight replicate pens of 10 birds each pen. Broilers received the same corn-soybean diet but different water. Broilers received ordinary water in the control group and 40% (volume: volume) FTPW (the solution has been filtered with four layers of sieve, containing Bacillus 1.52 × 10-7 CFU/mL) in FTPW group. The experiment lasted for 30 days. Results indicated that growth performance was not affected by treatment (p > 0.05). The value of pH45 min and a48 h increased and drip loss72 h and toughness decreased in breast muscle when broilers received FTPW solution compared with the control group (p < 0.05). The pH45 min, a45 min, a48 h value and crude fat concentration of thigh muscle were higher in FTPW group than that in control group (p < 0.05). Compared with control group, fibre area decreased but fibre density increased in thigh muscle when Xianghuang chickens supplemented with FTPW solution (p < 0.05). Supplementation of FTPW solution in drinking water significantly decreased malondialdehyde content in the breast muscle of Xianghuang chickens (p < 0.05). Gene expressions such as carnitine palmitoyltransferase 1A (CPT1) and glycogen synthase of breast muscle were downregulated in experimental group when compared with control group. In conclusion, FTPW supplementation in drinking water could improve meat quality of Xianghuang broilers by regulating pH value, redness and fibre morphology.

Dietary Supplementation of Brevibacillus laterosporus S62-9 Improves Broiler Growth and Immunity by Regulating Cecal Microbiota and Metabolites

Brevibacillus laterosporus has been added as a direct-fed microbiota to chicken. Yet, few studies have reported the effects of B. laterosporus on broiler growth and gut microbiota. The aim of this study was to evaluate the effects of B. laterosporus S62-9 on growth performance, immunity, cecal microbiota, and metabolites in broilers. A total of 160 1-day-old broilers were randomly divided into S62-9 and control groups, with or without 106 CFU/g B. laterosporus S62-9 supplementation, respectively. During the 42 days feeding, body weight and feed intake were recorded weekly. Serum was collected for immunoglobulin determination, and cecal contents were taken for 16S rDNA analysis and metabolome at Day 42. Results indicated that the broilers in S62-9 group showed an increase in body weight of 7.2% and 5.19% improvement in feed conversion ratio compared to the control group. The B. laterosporus S62-9 supplementation promoted the maturation of immune organs and increased the concentration of serum immunoglobulins. Furthermore, the α-diversity of cecal microbiota was improved in the S62-9 group. B. laterosporus S62-9 supplementation increased the relative abundance of beneficial bacteria including Akkermansia, Bifidobacterium, and Lactobacillus, while decreased the relative abundance of pathogens including Klebsiella and Pseudomonas. Untargeted metabolomics revealed that 53 differential metabolites between the two groups. The differential metabolites were enriched in 4 amino acid metabolic pathways, including arginine biosynthesis and glutathione metabolism. In summary, B. laterosporus S62-9 supplementation could improve the growth performance and immunity through the regulation of gut microbiota and metabolome in broilers.

Immunostimulant, hepatoprotective, and nephroprotective potential of Bacillus subtilis (NMCC-path-14) in comparison to dexamethasone in alleviating CFA-induced arthritis

To investigate and compare efficacy as well as safety of Bacillus subtilis and dexamethasone (Dexa) in complete Freund's adjuvant (CFA)-induced arthritis, we used glucocorticoid monotherapy (Dexa 5 mg/kg/day) and B. subtilis (1 × 108 CFU/animal/day p.o) as pre-treatment and concurrent treatment for a duration of 35 days. Specific emphasis was on chronic aspect of this study since long-term use of Dexa is known to produce undesirable side effects. Treatment with Dexa significantly attenuated the arthritic symptoms but produced severe side effects like weight loss, increased mortality, immunosuppression, and altered histology of liver, kidney, and spleen. Oxidative stress was also elevated by Dexa in these organs which contributed to the damage. Treatment with B. subtilis improved symptoms of arthritis without producing any deleterious side effects as seen with Dexa therapy. Immunohistochemistry (IHC) profile revealed decreased expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), interleukin (IL)-1β, tumor necrosis factor alpha (TNF-α), and increased nuclear factor erythroid 2-related factor 2 (Nrf-2) expression by B. subtilis and Dexa treatment in ankle joint of arthritic mice. Radiological scores were also improved by both treatments. This study concludes that B. subtilis could be an effective alternative for treating arthritis than Dexa since it does not produce life-threatening side effects on prolong treatment.

Different levels of single-strain probiotic (Bacillus subtilis) with proteolytic enzyme (serratiopeptidase) can be used as an alternative to antibiotic growth promoters in broiler

In the current study, the proteolytic enzyme (serratiopeptidase) was used to enhance the efficacy of Bacillus subtilis (B. subtilis) probiotic as a growth promotor in broiler chicken. The effects of serratiopeptidase on the efficacy of different levels of B. subtilis as a growth promotor in broiler chicks were evaluated regarding growth performance traits, villus histomorphometric characterization, and intestinal microbiota count. Day-old broiler chicks (n = 120) were allocated into 4 groups having 3 replicates/group. In the control group (C), the basal diet was kept without supplementation. In treatment groups (P100, P150, and P200), the basal diet was supplemented with 100, 150, and 200 mg probiotics, respectively besides 30 mg proteolytic enzyme in the 3 treated groups for 4 wk. The performance parameters were significantly affected by the supplementation of serratiopeptidase to the B. subtilis treatment groups. Feed intake (FI), body weight gain (WG), feed conversion ratio (FCR), and dressing percent were significantly improved in the treatment groups as compared to the control group. Significantly, the lowest feed intake was recorded for the P200 group. The highest body weight gain and dressing percentage were recorded for the P200 group. An improved FCR was recorded in the P200 group (1.7) as compared to the control group. The different levels of B. subtilis supplemented with serratiopeptidase revealed significant improvements (P<0.05) in the morphology of the intestine by showing increases in villus height and width and crypt depth of the small intestine. The microbial count revealed that E. coli and salmonella colonies were significantly reduced in the P200 group as compared to the control and other treatment groups. In conclusion, the supplementation of B. subtilis with serratiopeptidase as a growth promoter in broiler chicks significantly improved the overall performance, and intestinal health and reduced microbial load contributing to optimizing the performance of broiler chickens. The greatest improvement was observed in the P200 group fed with B. subtilis as a probiotic and serratiopeptidase enzyme (200 mg:30 mg).

Dynamic effects of black soldier fly larvae meal on the cecal bacterial microbiota and prevalence of selected antimicrobial resistant determinants in broiler chickens

BACKGROUND

We had earlier described the growth-promoting and -depressive effects of replacing soybean meal (SBM) with low (12.5% and 25%) and high (50% and 100%) inclusion levels of black soldier fly larvae meal (BSFLM), respectively, in Ross x Ross 708 broiler chicken diets. Herein, using 16S rRNA gene amplicon sequencing, we investigated the effects of replacing SBM with increasing inclusion levels (0-100%) of BSFLM in broiler diets on the cecal bacterial community composition at each growth phase compared to broilers fed a basal corn-SBM diet with or without the in-feed antibiotic, bacitracin methylene disalicylate (BMD). We also evaluated the impact of low (12.5% and 25%) inclusion levels of BSFLM (LIL-BSFLM) on the prevalence of selected antimicrobial resistance genes (ARGs) in litter and cecal samples from 35-day-old birds.

RESULTS

Compared to a conventional SBM-based broiler chicken diet, high (50 to100%) inclusion levels of BSFLM (HIL-BSFLM) significantly altered the cecal bacterial composition and structure, whereas LIL-BSFLM had a minimal effect. Differential abundance analysis further revealed that the ceca of birds fed 100% BSFLM consistently harbored a ~ 3 log-fold higher abundance of Romboutsia and a ~ 2 log-fold lower abundance of Shuttleworthia relative to those fed a BMD-supplemented control diet at all growth phases. Transient changes in the abundance of several potentially significant bacterial genera, primarily belonging to the class Clostridia, were also observed for birds fed HIL-BSFLM. At the finisher phase, Enterococci bacteria were enriched in the ceca of chickens raised without antibiotic, regardless of the level of dietary BSFLM. Additionally, bacitracin (bcrR) and macrolide (ermB) resistance genes were found to be less abundant in the ceca of chickens fed antibiotic-free diets, including either a corn-SBM or LIL-BSFLM diet.

CONCLUSIONS

Chickens fed a HIL-BSFLM presented with an imbalanced gut bacterial microbiota profile, which may be linked to the previously reported growth-depressing effects of a BSFLM diet. In contrast, LIL-BSFLM had a minimal effect on the composition of the cecal bacterial microbiota and did not enrich for selected ARGs. Thus, substitution of SBM with low levels of BSFLM in broiler diets could be a promising alternative to the antibiotic growth promoter, BMD, with the added-value of not enriching for bacitracin- and macrolide-associated ARGs.

Dietary probiotic based on a dual-strain Bacillus subtilis improves immunity, intestinal health, and growth performance of broiler chickens

The study investigated the effects of dietary probiotic of dual-strain Bacillus subtilis on production performance, intestinal barrier parameters, and microbiota in broiler chickens. In a randomized trial, male broiler chickens were allocated into 3 groups, a control group (basal diet), BS300 group (basal diet with 300 mg/kg of B. subtilis), and BS500 group (basal diet with 500 mg/kg of B. subtilis). The inclusion of 500 mg/kg of B. subtilis significantly reduced the feed conversion ratio by 4.55% during the starting phase. Both 300 and 500 mg/kg of B. subtilis supplementation increased jejunal villus height (by 17.89% and 24.8%, respectively) significantly and decreased jejunal crypt depth (by 27.2% and 31.9%, respectively) on day 21. The addition of 500 mg/kg of B. subtilis significantly elevated the gene expression of occludin on day 35. Moreover, of B. subtilis supplementation enhanced cytokine levels and immunoglobulins in both serum and jejunal mucosa. Microbial analysis indicated that B. subtilis increased the abundance of potential probiotics (Sutterella) and butyrate-producing bacteria (Lachnoclostridium, Tyzzerella, Anaerostipes, Clostridium_sensu_stricto_13, Prevotellaceae_NK3B31_group, and Lachnospiraceae_UCG-010). The abundances of Anaerostipes and Sutterella, are significantly correlated with growth performance and immune function. In conclusion, dietary supplementation with B. subtilis improved the growth performance, potentially through the regulation of immunity, intestinal barrier function, and microbiota in broilers. Notably, 500 mg/kg of B. subtilis exhibited more benefits for broilers compared to the 300 mg/kg.

Impact of feed additives and host-related factors on bacterial metabolites, mucosal integrity and immune response in the ileum of broilers

The present study aimed to investigate the effect of age, breed, and sex of broilers, as well as a probiotic or phytobiotic product on mucosal morphology, bacterial metabolites, and immune traits in the ileum of broilers. A total of 2,880 one-day-old male and female broiler chicks from two breeds (Ross308® and Cobb500®) were randomly assigned to 72 pens. Broilers were offered a wheat-soybean diet without (CO), or with either a probiotic (PO; 2.4 × 109 CFU/kg of Bacillus subtilis DSM32324 and DSM32325 and B. amyloliquefaciens DSM25840) or a phytobiotic (PY; grape extract, 165 ppm procyanidin and 585 ppm polyphenols of the diet) product. The trial was conducted with a 3 × 2 × 2 factorial arrangement of diet, breed, and sex in a completely randomized design (6 replicate-pens per treatment). At day 7, 21, and 35, one chicken per pen was slaughtered for collecting ileal tissue to evaluate of histomorphology and mRNA expression, as well as ileal digesta to measure bacterial metabolites. Data were subjected to ANOVA (the main factors; age, diet, breed, and sex) and Four-Way ANOVA (interactions) using GLM procedure. Overall, the concentration of acetate and total short chain fatty acids reached the peak and lactate decreased to its lowest on day 21, but their concentrations at day 7 and 35 were similar (p > 0.05). Spermine, spermidine, and ammonia decreased after day 7, while putrescine and cadaverine increased after day 21 (p < 0.05). mRNA expression of cytokines, mucin 2 (MUC2) and claudin 5 (CLDN5) was similar; increased from day 7 to 21 and decreased afterward (p < 0.05). Villus height, crypt depth and villus surface area increased with age (p < 0.05). Acidic goblet cells (GC) number and density increased after day 21 (p < 0.05). Ross broilers showed higher D-lactate concentration and IFN-γ expression, while Cobb broilers had greater IL-4, IL-6 and TNF-α expression and higher total GC number (p < 0.05). Female displayed higher villus height and GC number and density (mixed and total GC) than male (p < 0.05). The effect of dietary treatment was not found on any investigated variables (p > 0.05). In conclusion, aging of broilers affected ileal histomorphology, cytokine expression, and barrier integrity, as well as bacterial activity. These observed impacts could be attributed to host-microbiota interaction and the direct effects of bacterial metabolites on intestinal cells and immune system.

Stevia as a natural additive on gut health and cecal microbiota in broilers

Stevia mash (SM), leaves of Stevia rebaudiana Bertoni plant, is an additive used in poultry that enhances growth and health. Objective: to determine the effect of 1 % SM on productive parameters, gut health, and the cecal microbiome in broilers between the first 15 and 21 days old. One hundred sixty male, 1-day-old broilers (48.5 ± 2.5 g) were divided into Control (C) without SM and Treated (T) with 1 % SM on diet, during 15/21 days. Each subgroup had eight broilers/five repetitions/treatment. At day 15 or 21, all broilers were dissected, Fabricius Bursa and Gut removed and processed for histomorphometry, followed by Villi Height/Crypt Deep (VH/CD) ratio. Conversion Index (CI) was determined. The V3-V4 region of 16S rRNA gene was amplified from DNA obtained from pooled cecal contents and sequenced on Illumina Miseq PE 2 × 250 platform. Sequence processing and taxonomic assignments were performed using the SHAMAN pipeline. Both T groups have better VH/CD Ratios than C groups (p ≤ 0.05). In guts, increased plasmatic and goblet cells number and thicker mucus layer were found in T15 and T21. All groups received SM showed early immunological maturity in Fabricius Bursa. IC was similar between all treatments. Faecalibacterium, Ruminococcus torques group, and Bacteroides were the major genera modulated by SM addition. At 15 and 21 days old, SM exerts a impact on diversity and evenness of the cecal microbiome.  Conclusion: SM (1 %) produced early immunologic maturity on Fabricius Bursa, increased intestinal functionality, and modified the microbiota, increasing beneficial microbial genera and microbial diversity.

Both recombinant Bacillus subtilis Expressing PCV2d Cap protein and PCV2d-VLPs can stimulate strong protective immune responses in mice

Porcine circovirus type 2 (PCV2) is one of the most serious pathogens in pig herds worldwide. The Capsid protein (Cap), a structural protein of PCV2, is involved in the host's immune response; it induces neutralizing-antibody production and has good immunogenicity. The main PCV2 subtype currently prevalent in the Chinese pig herd is PCV2d. In this study, We constructed a recombinant Bacillus subtilis (B. subtilis) capable of secreting Cap protein, named pHT43-Cap/B. subtilis; we concentrated the supernatant of the recombinant bacteria and observed virus-like particles (VLPs) of PCV2d formed by Cap protein under transmission electron microscopy, named PCV2d-VLPs. The immunocompetence of the pHT43-Cap/B. subtilis and PCV2d-VLPs were then assessed by oral administration and by intramuscular injection into mice, respectively. The results showed that the levels of PCV2d-Cap protein-specific IgG in the serum and of PCV2d-Cap protein-specific sIgA in the small intestinal fluid of pHT43-Cap/B. subtilis immunized mice were elevated compared to the control group, both of them highly significant (p < 0.01), and the corresponding serum-specific IgG antibodies were effective in neutralizing PCV2d virulence. The virus load in the liver of the immunized mice was significantly lower than that in the control group (p < 0.01), as was the virus load in the spleen and lungs of the immunized mice (p < 0.05). In addition, the serum levels of PCV2d-Cap-specific IgG in mice immunized with PCV2d-VLPs by intramuscular injection were significantly elevated compared to the control group (p < 0.05), and the viral load in all tissues was significantly lower in immunized mice (p < 0.05). In conclusion, the recombinant bacterium pHT43-Cap/B. subtilis can induce effective mucosal and humoral immunity in mice, PCV2d-VLPs can induce humoral immunity in mice, and both vaccines have good immunogenicity; these results provide a theoretical and material basis for the development of a new vaccine against PCV2d.

Oh my gut! Is the microbial origin of neurodegenerative diseases real?

There is no cure or effective treatment for neurodegenerative protein conformational diseases (PCDs), such as Alzheimer's or Parkinson's diseases, mainly because the etiology of these diseases remains elusive. Recent data suggest that unique changes in the gut microbial composition are associated with these ailments; however, our current understanding of the bacterial role in the pathogenesis of PCDs is hindered by the complexity of the microbial communities associated with specific microbiomes, such as the gut, oral, or vaginal microbiota. The composition of these specific microbiomes is regarded as a unique fingerprint affected by factors such as infections, diet, lifestyle, and antibiotics. All of these factors also affect the severity of neurodegenerative diseases. The majority of studies that reveal microbial contribution are correlational, and various models, including worm, fly, and mouse, are being utilized to decipher the role of individual microbes that may affect disease onset and progression. Recent evidence from across model organisms and humans shows a positive correlation between the presence of gram-negative enteropathogenic bacteria and the pathogenesis of PCDs. While these correlational studies do not provide a mechanistic explanation, they do reveal contributing bacterial species and provide an important basis for further investigation. One of the lurking concerns related to the microbial contribution to PCDs is the increasing prevalence of antibiotic resistance and poor antibiotic stewardship, which ultimately select for proteotoxic bacteria, especially the gram-negative species that are known for intrinsic resistance. In this review, we summarize what is known about individual microbial contribution to PCDs and the potential impact of increasing antimicrobial resistance.

Dietary Effect of Brevibacillus laterosporus S62-9 on Chicken Meat Quality, Amino Acid Profile, and Volatile Compounds

Probiotics are being used in diets to improve the quality of chicken meat. The aim of the study was to investigate the effects of dietary supplementation with Brevibacillus laterosporus S62-9 microbial agent on the meat quality, amino acids, and volatile compounds of chicken. The experiment was carried out with 160 1-day-old Arbor Acres male broiler chickens, rearing for 42 d. The chickens were randomly divided into two groups of 8 replicates each, with 10 chickens in each group. No supplement was added to the basal diet in the control group and Brevibacillus laterosporus S62-9 microbial agent was added to the diet of the experimental group. At the end of the experiment, the meat quality, meat chemical composition, amino acid composition, and volatile compounds of chicken were determined. The results showed that pH (p < 0.05), pressing loss (p < 0.05), cooking loss (p < 0.05), and shear force (p < 0.01) were notably decreased, the percentage of breast meat (p < 0.01), protein content (p < 0.05) were visibly increased, and remarkable changes were observed in the amino acid composition (change in seven amino acids) and volatile compounds profile (an increase of about 20-fold in the contents of 1-octen-3-ol and hexanal). In summary, it was found that Brevibacillus laterosporus S62-9 microbial agent can be used as a novel and effective feed supplement to improve the nutritional quality and flavor characteristics of broilers.

Shatianyu (Citrus grandis L. Osbeck) Flavonoids and Dietary Fiber in Combination Are More Effective Than Individually in Alleviating High-Fat-Diet-Induced Hyperlipidemia in Mice by Altering Gut Microbiota

This study was aimed at exploring the separate and combined anti-hyperlipidemic effect of Shatianyu (Citrus grandis L. Osbeck) flavonoids (SPFEs) and DF (SPDF) on HFD-fed mice after 14-week administration in diet, together with the possible microbiota-mediated mechanisms. SPFEs and SPDF were more effective together than separately in improving serum lipid profiles, decreasing hepatic lipid accumulation, and upregulating the expression of hepatic CPT1a, CYP7A1, ABCG5, and ABCG8. Butyrate has been previously proved to have an anti-hyperlipidemic effect. The fecal butyrate contents were negatively correlative with serum/liver lipid but positively correlated with fecal total bile acids levels, and SPDF + SPFEs had the most fecal butyrate in this study. SPDF or SPFEs enriched microbiota related to acetic and propionic acids production, while SPDF + SPFEs also bloomed norank_f_Muribaculaceae, Dubosiella, Lachnoclostridium, and norank_f_Eubacterium_coprostanoligenes_group, which were positively correlated to fecal butyrate contents. Thus, SPFEs and SPDF might alleviate hyperlipidemia synergistically by regulating microbiota to produce butyrate, thereby regulating lipid metabolism.

Examining the effects of Salmonella phage on the caecal microbiota and metabolome features in Salmonella-free broilers

Bacteriophages selectively infect and kill their target bacterial host, being a promising approach to controlling zoonotic bacteria in poultry production. To ensure confidence in its use, fundamental questions of safety and toxicity monitoring of phage therapy should be raised. Due to its high specificity, a minimal impact on the gut ecology is expected; however, more in-depth research into key parameters that influence the success of phage interventions has been needed to reach a consensus on the impact of bacteriophage therapy in the gut. In this context, this study aimed to investigate the interaction of phages with animals; more specifically, we compared the caecum microbiome and metabolome after a Salmonella phage challenge in Salmonella-free broilers, evaluating the role of the phage administration route. To this end, we employed 45 caecum content samples from a previous study where Salmonella phages were administered via drinking water or feed for 24 h from 4, 5 to 6-weeks-old broilers. High-throughput 16S rRNA gene sequencing showed a high level of similarity (beta diversity) but revealed a significant change in alpha diversity between broilers with Salmonella-phage administered in the drinking water and control. Our results showed that the phages affected only a few genera of the microbiota's structure, regardless of the administration route. Among these, we found a significant increase in Streptococcus and Sellimonas in the drinking water and Lactobacillus, Anaeroplasma and Clostridia_vadinBB60_group in the feed. Nevertheless, the LC-HRMS-based metabolomics analyses revealed that despite few genera were significantly affected, a substantial number of metabolites, especially in the phage administered in the drinking water were significantly altered (64 and 14 in the drinking water and feed groups, respectively). Overall, our study shows that preventive therapy with bacteriophages minimally alters the caecal microbiota but significantly impacts their metabolites, regardless of the route of administration.

Connecting gut microbiomes and short chain fatty acids with the serotonergic system and behavior in Gallus gallus and other avian species

The chicken gastrointestinal tract has a diverse microbial community. There is increasing evidence for how this gut microbiome affects specific molecular pathways and the overall physiology, nervous system and behavior of the chicken host organism due to a growing number of studies investigating conditions such as host diet, antibiotics, probiotics, and germ-free and germ-reduced models. Systems-level investigations have revealed a network of microbiome-related interactions between the gut and state of health and behavior in chickens and other animals. While some microbial symbionts are crucial for maintaining stability and normal host physiology, there can also be dysbiosis, disruptions to nutrient flow, and other outcomes of dysregulation and disease. Likewise, alteration of the gut microbiome is found for chickens exhibiting differences in feather pecking (FP) behavior and this alteration is suspected to be responsible for behavioral change. In chickens and other organisms, serotonin is a chief neuromodulator that links gut microbes to the host brain as microbes modulate the serotonin secreted by the host's own intestinal enterochromaffin cells which can stimulate the central nervous system via the vagus nerve. A substantial part of the serotonergic network is conserved across birds and mammals. Broader investigations of multiple species and subsequent cross-comparisons may help to explore general functionality of this ancient system and its increasingly apparent central role in the gut-brain axis of vertebrates. Dysfunctional behavioral phenotypes from the serotonergic system moreover occur in both birds and mammals with, for example, FP in chickens and depression in humans. Recent studies of the intestine as a major site of serotonin synthesis have been identifying routes by which gut microbial metabolites regulate the chicken serotonergic system. This review in particular highlights the influence of gut microbial metabolite short chain fatty acids (SCFAs) on the serotonergic system. The role of SCFAs in physiological and brain disorders may be considerable because of their ability to cross intestinal as well as the blood-brain barriers, leading to influences on the serotonergic system via binding to receptors and epigenetic modulations. Examinations of these mechanisms may translate into a more general understanding of serotonergic system development within chickens and other avians.

Modified dietary fiber from cassava pulp affects the cecal microbial population, short-chain fatty acid, and ammonia production in broiler chickens

The objective of this study was to investigate the effects of modified dietary fiber from cassava pulp (M-DFCP) supplementation in broiler diets on cecal microbial populations, short-chain fatty acids (SCFAs), ammonia production, and immune responses. A total of 336, one-day-old male broiler chicks (Ross 308) were distributed over 4 dietary treatments in 7 replicate pens (n = 12 chicks) using a completely randomized design. Chicks were fed the control diet and 3 levels of M-DFCP (0.5, 1.0, and 1.5%) for an experimental duration of 42 d. The M-DFCP contained total dietary fiber (TDF), soluble dietary fiber (SDF), insoluble dietary fiber (IDF), cello-oligosaccharides (COS), and xylo-oligosaccharides (XOS) of approximately 280.70, 22.20, 258.50, 23.93, and 157.55 g/kg, respectively. The 1.0 and 1.5% M-DFCP supplementation diets showed positive effects on stimulating the growth of Lactobacillus spp. and Bifidobacterium spp., enhancing SCFAs (acetic, propionic, butyric acid, and branched SCFAs) and lactic acid concentrations during growing periods. Broilers fed 1.0 and 1.5% M-DFCP also exhibited a significant increase in caecal Lactobacillus spp. and lactic acid concentrations during the finisher period as well. In addition, M-DFCP also reduced cecal digesta and excreta ammonia production in broilers over both periods (0-21 and 22-42 d of age). However, M-DFCP did not exhibit any effect on total serum immunoglobulin (Ig) or lysozyme activity. In conclusion, this study shows that M-DFCP can be used as a dietary fiber source in broiler diets, with a recommended level of approximately 1.0%.

The effect of Escherichia coli ŽP strain with a conjugation-based colicin E7 delivery on growth performance, hematological, biochemical, and histological parameters, gut microbiota, and nonspecific immunity of broilers

The Escherichia coli ŽP strain (ŽP) was constructed based on the known probiotic E. coli strain Nissle 1917. It was genetically modified to carry the colicin E7 synthesis gene encoding DNase on a conjugative plasmid and the colicin E7 immunity gene in the chromosome. The aim of this study was to evaluate the effects of the daily ŽP per oral administration (5 × 10⁸ or 5 × 10¹⁰ CFU per bird) on the growth performance, hematological, biochemical, histological parameters, gut microbiota, and nonspecific immunity of the 4-24 days old broilers. The ŽP administration increased the abundance of genera Bacillus, Butyrivibrio, and Clostridium and did not influence the weight gain of 4-16 days old broilers. The biochemical parameters were within normal ranges for poultry in experimental and control groups. The ŽP administration had no effect on the erythrocyte numbers, hemoglobin and immunoglobulin Y concentrations, but significantly increased the serum lysozyme concentration, leukocyte numbers, and reactive oxygen species production by phagocytes compared with the control group. It did not cause inflammatory changes in intestinal mucosa, Peyer's patches, and spleen. Thus, the ŽP had no detrimental effects on broiler health and could be an efficient probiotic for the broiler colibacillosis prophylaxis.

Chicken Gut Microbiota Responses to Dietary Bacillus subtilis Probiotic in the Presence and Absence of Eimeria Infection

Coccidiosis is a well-known poultry disease that causes the severe destruction of the intestinal tract, resulting in reduced growth performance and immunity, disrupted gut homeostasis and perturbed gut microbiota. Supplementation of probiotics were explored to play a key role in improving growth performance, enhancing innate and adaptive immunity, maintaining gut homeostasis and modulating gut microbiota during enteric infection. This study was therefore designed to investigate the chicken gut whole microbiota responses to Bacillus subtilis (B. subtilis) probiotic feeding in the presence as well as absence of Eimeria infection. For that purpose, 84 newly hatched chicks were assigned into four groups, including (1) non-treated non-challenged control group (CG - ET), (2) non-treated challenged control group (CG + ET), (3) B. subtilis-fed non-challenged group (BS - ET) and (4) B. subtilis-fed challenged group (BS + ET). CG + ET and BS + ET groups were challenged with Eimeria tenella (E. tenella) on 21 day of housing. Our results for Alpha diversity revealed that chickens in both infected groups (CG + ET and BS + ET) had lowest indexes of Ace, Chao 1 and Shannon, while highest indexes of Simpson were found in comparison to non-challenged groups (CG - ET and BS - ET). Firmicutes was the most affected phylum in all experimental groups following Proteobacteria and Bacteroidota, which showed increased abundance in both non-challenged groups, whereas Proteobacteria and Bacteroidota affected both challenged groups. The linear discriminant analysis effect size method (lEfSe) analysis revealed that compared to the CG + ET group, supplementation of probiotic in the presence of Eimeria infection increased the abundance of some commensal genera, included Clostridium sensu stricto 1, Corynebacterium, Enterococcus, Romboutsia, Subdoligranulum, Bacillus, Turicibacter and Weissella, with roles in butyrate production, anti-inflammation, metabolic reactions and the modulation of protective pathways against pathogens. Collectively, these findings evidenced that supplementation of B. subtilis probiotic was positively influenced with commensal genera, thereby alleviating the Eimeria-induced intestinal disruption.

Effects of Dietary Lysophospholipid Inclusion on the Growth Performance, Nutrient Digestibility, Nitrogen Utilization, and Blood Metabolites of Finishing Beef Cattle

This study was conducted to evaluate the effect of dietary supplementation with lysophospholipids (LPLs) on the growth performance, nutrient digestibility, nitrogen utilization, and blood metabolites of finishing beef cattle. In total, 40 Angus beef bulls were blocked for body weight (447 ± 9.64 kg) and age (420 ± 6.1 days) and randomly assigned to one of four treatments (10 beef cattle per treatment): (1) control (CON; basal diet); (2) LLPL (CON supplemented with 0.012% dietary LPL, dry matter (DM) basis); (3) MLPL (CON supplemented with 0.024% dietary LPL, DM basis); and (4) HLPL (CON supplemented with 0.048% dietary LPLs, DM basis). The results showed that dietary supplementation with LPLs linearly increased the average daily gain (p < 0.01), digestibility of DM (p < 0.01), crude protein (p < 0.01), and ether extract (p < 0.01) and decreased the feed conversion ratio (p < 0.01). A linear increase in N retention (p = 0.01) and a decrease in urinary (p = 0.04) and fecal N (p = 0.02) levels were observed with increasing the supplemental doses of LPLs. Bulls fed LPLs showed a linear increase in glutathione peroxidase (p = 0.04) and hepatic lipase (p < 0.01) activity and a decrease in cholesterol (p < 0.01), triglyceride (p < 0.01), and malondialdehyde (p < 0.01) levels. In conclusion, supplementation with LPLs has the potential to improve the growth performance, nutrient digestibility, and antioxidant status of beef cattle.

Effects of supplementation with lysophospholipids on performance, nutrient digestibility, and bacterial communities of beef cattle

An experiment was conducted to investigate the influences of supplemental lysophospholipids (LPL) on the growth performance, nutrient digestibility, and fecal bacterial profile, and short-chain fatty acids (SCFAs) of beef cattle. Thirty-six Angus beef cattle [565 ± 10.25 kg body weight (BW)] were grouped by BW and age, and randomly allocated to 1 of 3 treatment groups: (1) control (CON, basal diet); (2) LLPL [CON supplemented with 0.5 g/kg LPL, dry matter (DM) basis]; and (3) HLPL (CON supplemented with 0.75 g/kg, DM basis). The Angus cattle were fed a total mixed ration that consisted of 25% roughage and 75% concentrate (dry matter [DM] basis). The results reveal that LPL inclusion linearly increased the average daily gain (P = 0.02) and the feed efficiency (ADG/feed intake, P = 0.02), while quadratically increasing the final weight (P = 0.02) of the beef cattle. Compared with CON, the total tract digestibilities of DM (P < 0.01), ether extract (P = 0.04) and crude protein (P < 0.01) were increased with LPL supplementation. At the phylum-level, the relative abundance of Firmicutes (P = 0.05) and ratio of Firmicutes: Bacteroidetes (P = 0.04) were linearly increased, while the relative abundances of Bacteroidetes (P = 0.04) and Proteobacteria (P < 0.01) were linearly decreased with increasing LPL inclusion. At the genus-level, the relative abundances of Clostridium (P < 0.01) and Roseburia (P < 0.01) were quadratically increased, and the relative abundances of Ruminococcus was linearly increased (P < 0.01) with LPL supplementation. Additionally, increasing the dose of LPL in diets linearly increased the molar proportion of butyrate (P < 0.01) and total SCFAs (P = 0.01) concentrations. A conclusion was drawn that, as a promising feed additive, LPL promoted growth performance and nutrient digestibility, which may be associated with the change of fecal microbiome and SCFAs.

Plant-Based Alkaline Fermented Foods as Sustainable Sources of Nutrients and Health-Promoting Bioactive Compounds

Traditional food fermentation is a practice that precedes human history. Acidic products such as yogurts and sourdoughs or alcoholic beverages produced through lactic acid or yeast fermentations, respectively, are widely described and documented. However, a relatively less popular group of fermented products known as alkaline fermented foods are common traditional products in Africa and Asia. These products are so called “alkaline” because the pH tends to increase during fermentation due to the formation of ammonia resulting from protein degradation by Bacillus species. Plant-based alkaline fermented foods (AFFs) are generally produced from legumes including soybean, non-soybean leguminous seeds, and other non-legume plant raw materials. Alkaline fermented food products such as natto, douchi, kinema, doenjang, chongkukjang, thua nao, meitauza, yandou, dawadawa/iru, ugba, kawal, okpehe, otiru, oso, ogiri, bikalga, maari/tayohounta, ntoba mbodi, cabuk, and owoh are produced at small industrial scale or household levels and widely consumed in Asia and Africa where they provide essential nutrients and health-promoting bioactive compounds for the population. Alkaline food fermentation is important for sustainable food security as it contributes to traditional dietary diversity, significantly reduces antinutritional components in raw plant materials thereby improving digestibility, improves health via the production of vitamins, and may confer probiotic and post-biotic effects onto consumers. In this review, we present currently available scientific information on plant-based AFFs and their role as sustainable sources of nutrients and bioactive compounds for improved health. Finally, we provide perspectives on research needs required to harness the full potential of AFFs in contributing to nutrition and health.

Intestinal Microbiota Regulate Certain Meat Quality Parameters in Chicken

Growing evidence of intestinal microbiota-muscle axis provides a possibility to improve meat quality of broilers through regulating intestinal microbiota. Water-holding capacity is a crucial factor to evaluate the meat quality. High quality of water-holding capacity is usually described as a low drip-losing rate. This study aimed to explore the relationship between intestinal microbiota and water-holding capacity of muscle in broilers. According to our results, two native breeds of broilers (the Arbor Acres broilers and the Beijing-You broilers) exhibited remarkable differences in microbiota composition. However, the regular of gut bacteria compositions gradually became similar when the two breeds of broiler were raised in a same feeding environment. Therefore, this similar regular of intestinal microbiota induced similar water-holding capacity of the muscle from the two breeds. In subsequent fecal microbiota transplantation (FMT) experiments, the intestinal microbiota community of the Arbor Acres broilers was remodeling by oral gavage of bacterial suspension that was derived from the Beijing-You broilers. Then, not only body weight and abdominal fat rate were increased, but also drip loss of muscle was decreased in the Arbor Acres broilers. Additionally, muscle fiber diameter of biceps femoris muscle and expression of MyoD1 were notably enlarged. Muscle fiber diameter and related genes were deemed as important elements for water-holding capacity of muscle. Simultaneously, we screened typical intestinal bacteria in both the two native breeds of broilers by 16S rDNA sequencing. Lachnoclostridium was the only bacteria genus associated with drip-losing rate, meat fiber diameter, body weight, and abdominal fat rate.

The Use of Disinfectant in Barn Cleaning Alters Microbial Composition and Increases Carriage of Campylobacter jejuni in Broiler Chickens

To maintain food safety and flock health in broiler chicken production, biosecurity approaches to keep chicken barns free of pathogens are important. Canadian broiler chicken producers must deep clean their barns with chemical disinfectants at least once annually (full disinfection [FD]) and may wash with water (water wash [WW]) throughout the year. However, many producers use FD after each flock, assuming a greater efficacy of more stringent cleaning protocols, although little information is known regarding how these two cleaning practices affect pathogen population and gut microbiota. In the present study, a crossover experiment over four production cycles was conducted in seven commercial chicken barns to compare WW and FD. We evaluated the effects of barn cleaning methods on commercial broiler performance, cecal microbiota composition, Campylobacter and Salmonella occurrence, and Campylobacter jejuni and Clostridium perfringens abundance, as well as on short-chain fatty acid (SCFA) concentrations in the month-old broiler gut. The 30-day body weight and mortality rate were not affected by the barn cleaning methods. The WW resulted in a modest but significant effect on the structure of broiler cecal microbiota (weighted-UniFrac; adonis P = 0.05, and unweighted-UniFrac; adonis P = 0.01), with notable reductions in C. jejuni occurrence and abundance. In addition, the WW group had increased cecal acetate, butyrate, and total SCFA concentrations, which were negatively correlated with C. jejuni abundance. Our results suggest that WW may result in enhanced activity of the gut microbiota and reduced zoonotic transmission of C. jejuni in broiler production relative to FD in the absence of a disease challenge. IMPORTANCE We compared the effects of barn FD and WW methods on gut microbial community structures and pathogen prevalence of broiler chickens in a nonchallenging commercial production setting. The results revealed that barn cleaning methods had little impact on the 30-day body weight and mortality rate of broiler chickens. In addition, the FD treatment had a subtle but significant effect on the broiler cecal microbiota with increased abundances of Campylobacter and decreased SCFA concentrations, which would support the adoption of WW as a standard practice. Thus, compared to FD, WW can be beneficial to broiler chicken production by inhibiting zoonotic pathogen colonization in the chicken gut with reduced cost and labor of cleaning.

Microbiota and Transcriptomic Effects of an Essential Oil Blend and Its Delivery Route Compared to an Antibiotic Growth Promoter in Broiler Chickens

This study evaluated the effect of the delivery of a commercial essential oil blend containing the phytonutrients star anise, cinnamon, rosemary, and thyme oil (via different routes) on broiler chickens’ ileal and ceca microbiota and liver transcriptome compared to an antibiotic growth promoter. Eggs were incubated and allocated into three groups: non-injected, in ovo saline, and in ovo essential oil. On day 18 of incubation, 0.2 mL of essential oil in saline (dilution ratio of 2:1) or saline alone was injected into the amnion. At hatch, chicks were assigned to post-hatch treatment combinations: (A) a negative control (corn-wheat-soybean diet), (B) in-feed antibiotics, (C) in-water essential oil (250 mL/1000 L of drinking water), (D) in ovo saline, (E) in ovo essential oil, and (F) in ovo essential oil plus in-water essential oil in eight replicate cages (six birds/cage) and raised for 28 days. On days 21 and 28, one and two birds per cage were slaughtered, respectively, to collect gut content and liver tissues for further analysis. Alpha and beta diversity differed significantly between ileal and ceca samples but not between treatment groups. In-feed antibiotic treatment significantly increased the proportion of specific bacteria in the family Lachnospiraceae while reducing the proportion of bacteria in the genus Christensenellaceae in the ceca, compared to other treatments. Sex-controlled differential expression of genes related to cell signaling and tight junctions were recorded. This study provides data that could guide the use of these feed additives and a foundation for further research.

Feeding Bacillus subtilis ATCC19659 to Broiler Chickens Enhances Growth Performance and Immune Function by Modulating Intestinal Morphology and Cecum Microbiota

This study investigated dietary supplementation with Bacillus subtilis (BS) ATCC19659 on growth performance, biochemical indices, intestinal morphology, and cecum microflora in broiler chicks. A total of 600 Arbor 1-day Acres broilers of either sex were allotted to 5 treatments: chicks were fed a corn- and soybean-based diet (CON); chicks were fed basal diet containing 500 mg ZnB/kg (ZnB); chicks were fed basal diet containing 1 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-1); chicks were fed basal diet containing 3 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-3); and chicks were fed basal diet containing 5 × 10⁸ CFU/g feed of BS-ATCC19659 (BS-5). Each treatment comprised 6 replicates with 20 birds for each replicate pen. Chicks in the BS-5 and BS-3 groups had higher body weight at the 21^st and 42^nd days and average daily gain from 1 to 21 days than that in the CON group (p < 0.05). Chicks in the BS-5 and ZnB groups had higher serum antioxidant activities and immunity response than those in the CON group (p < 0.05). Compared with the CON group, the liver mRNA abundance of GHR, TGF-β, IGF-1, IFN-γ, SOD, CAT, and GPX of chicks in three BS groups and the ileum villus length (μm) of chicks in BS-3 and ZnB groups was increased (p < 0.05). Compared with the CON group, the villus height-to-crypt depth ratio of the ileum of chicks in the BS-5 and BS-3 groups and the crypt depth and villus height-to-crypt depth ratio of the jejunum in the BS-5 and ZnB groups were increased (p < 0.05). The abundance of the Cyanobacteria phyla in the cecum decreased in response to treatment with both BS-ATCC19659 and ZnB groups (p < 0.05). Compared with the CON group, the cecum abundance of genera GCA-900066575 (Lachnospiraceae), Anaerofustis, and Papillibacter (Firmicutes phylum) in three BS groups were increased (p < 0.05); The abundance of genus Escherichia–Shigella reduced in the BS-3 group (p < 0.05). Compared with the CON group, the cecum abundance of genus Clostridia_unclassified in ZnB and BS-5 groups was decreased (p < 0.05) of broilers. Generally, Bacillus subtilis ATCC19659 as feed additive positively affected growth performance, immunity response, and cecal microflora of broilers.

The gut microbiota of chickens in a commercial farm treated with a Salmonella phage cocktail

The microbiota in broiler chicken intestines affects the animals' health, metabolism, and immunity both positively and negatively. Accordingly, it has a significant impact on animal productivity. Phages, host-specific parasites of bacterial cells, are a promising antimicrobial alternative that selectively target pathogens without disturbing the microbiota. The purpose of this study is to further characterize the commensal microbial community at production scale in broiler chickens treated with a Salmonella phage treatment. We evaluated the cecal microbiota of broilers reared in a commercial farming system where a phage cocktail against Salmonella, SalmoFree was supplied to animals. To do so, two field trials were conducted, incorporating three doses of phages in the broilers' drinking water. Our results showed that the core microbiome (taxa that were present in more than 50% of samples) contained species that are key to microbiota adaptation in the last stage of the production cycle. Among these, there are some important degraders of complex polysaccharides and producers of short chain fatty acids (SCFA) such as Eisenbergiella and Lachnoclostridium. The phage cocktail did not affect the normal development of the microbiota's structure. The addition of the phage cocktail resulted in a significant reduction in Campylobacter and an increase in Butyricimonas, Helicobacter and Rikenellaceae, which are common inhabitants in chicken gut with known negative and positive effects on their health and metabolism. Altogether, we consider that these results contribute valuable information to the implementation of large-scale phage therapy technologies.

Effects of Dietary Supplementation With Bacillus subtilis, as an Alternative to Antibiotics, on Growth Performance, Serum Immunity, and Intestinal Health in Broiler Chickens

Bacillus subtilis (B. subtilis) as in-feed probiotics is a potential alternative for antibiotic growth promoters (AGP) in the poultry industry. The current study investigated the effects of B. subtilis on the performance, immunity, gut microbiota, and intestinal barrier function of broiler chickens. A 42-day feeding trial was conducted with a total of 600 1-day-old Arbor Acres broilers with similar initial body weight, which was randomly divided into one of five dietary treatments: the basal diet (Ctrl), Ctrl + virginiamycin (AGP), Ctrl + B. subtilis A (BSA), Ctrl + B. subtilis B (BSB), and Ctrl + B. subtilis A + B (1:1, BSAB). The results showed significantly increased average daily gain in a step-wise manner from the control, B. subtilis, and to the AGP groups. The mortality rate of the B. subtilis group was significantly lower than the AGP group. The concentrations of serum immunoglobulin (Ig) G (IgG), IgA, and IgM in the B. subtilis and AGP groups were higher than the control group, and the B. subtilis groups had the highest content of serum lysozyme and relative weight of thymus. Dietary B. subtilis increased the relative length of ileum and the relative weight of jejunum compared with the AGP group. The villus height (V), crypt depth (C), V/C, and intestinal wall thickness of the jejunum in the B. subtilis and AGP groups were increased relative to the control group. Dietary B. subtilis increased the messenger RNA (mRNA) expression of ZO-1, Occludin, and Claudin-1, the same as AGP. The contents of lactic acid, succinic acid, and butyric acid in the ileum and cecum were increased by dietary B. subtilis. Dietary B. subtilis significantly increased the lactobacillus and bifidobacteria in the ileum and cecum and decreased the coliforms and Clostridium perfringens in the cecum. The improved performance and decreased mortality rate observed in the feeding trial could be accrued to the positive effects of B. subtilis on the immune response capacity, gut health, and gut microflora balance, and the combination of two strains showed additional benefits on the intestinal morphology and tight junction protein expressions. Therefore, it can be concluded that dietary B. subtilis A and B could be used as alternatives to synthetic antibiotics in the promotion of gut health and productivity index in broiler production.

Effects of Dietary Probiotic (Bacillus subtilis) Supplementation on Carcass Traits, Meat Quality, Amino Acid, and Fatty Acid Profile of Broiler Chickens

The aim of the present study was to evaluate the effects of dietary supplementation with or without Bacillus subtilis (B. subtilis) on carcass traits, meat quality, amino acids, and fatty acids of broiler chickens. In total, 160 1-day-old Arbor Acres male broiler chicks were divided into two groups with eight replicates of 10 chicks each. Chickens received basal diets without (CN group) or with 500 mg/kg B. subtilis (BS group) for 42 days. Eight chickens from each group were slaughtered at the end of the trial, and carcass traits, meat quality, chemical composition, amino acid, and fatty acid profile of meat were measured. The results showed that the breast muscle (%) was higher in BS than in CN (p < 0.05), while abdominal fat decreased (p < 0.05). The pH_24h of thigh muscle was increased (p < 0.05) when supplemented with BS; however, drip loss, cooking loss of breast muscle, and shear force of thigh muscle decreased (p < 0.05). Lysine (Lys), methionine (Met), glutamic acid (Glu), and total essential amino acid (EAA) in breast muscle and Glu in thigh muscle were greater in BS than in CN (p < 0.05). C16:1, C18:1n9c, and MUFA in breast muscle and thigh muscle were greater in BS than in CN (p < 0.05). In conclusion, dietary supplementation with B. subtilis could improve the carcass traits and meat quality of broilers, which is beneficial for the consumers due to the improved fatty acid profile and amino acid composition.

Effects of the Probiotic Activity of Bacillus subtilis DSM 29784 in Cultures and Feeding Stuff

The European Union banned the usage of antibiotic growth promoters in animal production. The probiotic microorganism of the genus Bacillus appeared to be an attractive candidate to replace antibiotics. The Bacillus subtilis DSM 29784 is one of these strains. To date, the probiotic effect has not been completely understood, but it is supposed that the effect depends on metabolites of the microorganism. Imaging high-performance thin-layer chromatography (HPTLC) is a powerful tool to visualize differences in the metabolite profile of bacteria with high genetic similarity to allow a better understanding of the probiotic effect. In comparison to other bacteria, especially these bacterial cells were more robust to harsh cultivation conditions and produced a higher level of antioxidants or bioactive substances such as surfactin. HPTLC enabled the comparison of pure cell cultures to the spore cultivation in the feed, and the results explain and support the probiotic effect.

Effects of Different Fermented Feeds on Production Performance, Cecal Microorganisms, and Intestinal Immunity of Laying Hens

Simple Summary

Fermented feed exerts beneficial effects on intestinal microorganisms, host health, and production performance. However, the effect of fermented feed on laying hens is uncertain due to the different types of inoculated probiotics, fermentation substrates, and fermentation technology. Hence, this experiment was conducted to investigate the effects of fermented feed with different compound strains on the performance and intestinal health of laying hens. Supplement fermented feed reduced the feed conversion ratio and promoted egg quality. Both dietary treatment (fermented feed A produced Bacillus subtilis, Lactobacillus, and Yeast and fermented feed B produced by C. butyricum and L. salivarius) influenced intestinal immunity and regulated cecal microbial structure. This may be because the metabolites of microorganisms in fermented feed and the reduced pH value inhibited the colonization of harmful bacteria, improved the intestinal morphology, and then had a positive impact on the production performance and albumen quality of laying hens.

Abstract

This experiment was conducted to investigate the effects of different compound probiotics on the performance, cecal microflora, and intestinal immunity of laying hens. A total of 270 Jing Fen No.6 (22-week-old) were randomly divided into 3 groups: basal diet (CON); basal diet supplemented with 6% fermented feed A by Bacillussubtilis,Lactobacillus, and Yeast (FA); and with 6% fermented feed B by C. butyricum and L. salivarius (FB). Phytic acid, trypsin inhibitor, β-glucan concentrations, and pH value in fermented feed were lower than the CON group (p < 0.05). The feed conversion ratio (FCR) in the experimental groups was decreased, while albumen height and Haugh unit were increased, compared with the CON group (p < 0.05). Fermented feed could upregulate the expression of the signal pathway (TLR4/MyD88/NF-κB) to inhibit mRNA expression of pro-inflammatory cytokines (p < 0.05). Fermented feed promoted the level of Romboutsia (in the FA group) Butyricicoccus (in the FB group), and other beneficial bacteria, and reduced opportunistic pathogens, such as Enterocooccus (p < 0.05). Spearman’s correlations showed that the above bacteria were closely related to albumen height and intestinal immunity. In summary, fermented feed can decrease the feed conversion ratio, and improve the performance and intestinal immunity of laying hens, which may be related to the improvement of the cecal microflora structure.

Probiotic Paenibacillus polymyxa 10 and Lactobacillus plantarum 16 enhance growth performance of broilers by improving the intestinal health

With the ever-growing strict prohibitions on antibiotic growth promoters (AGP) in animal production, in-feed probiotics are becoming attractive alternatives to antibiotics in the poultry industry. To investigate the effects of Paenibacillus polymyxa 10 and Lactobacillus plantarum 16 on the growth performance and intestinal health of broilers, 540 male Cobb 500 broilers of 1 d old were randomly divided into 3 groups with 6 replicates per group and 30 chicks per replicate. Broilers were fed with either a basal diet or basal diets supplemented with 1 × 108 colony-forming units (CFU)/kg P. polymyxa 10 (BSC10) or L. plantarum 16 (Lac16) for 42 d. Results showed that Lac16 treatment improved (P < 0.05) the growth performance (body weight and feed conversion) of broilers at the starter phase, while BSC10 treatment slightly improved (P > 0.05) the growth performance of the starter phase broilers. The increased villus height (P < 0.05) at d 14, 21 and 42 and villus height to crypt depth ratio (P < 0.05) at d 14 and 21 were observed in the ileum of the 2 probiotic groups. Besides, transmission electron microscopy results showed that the 2 probiotics enhanced the intestinal epithelial barrier. Both probiotic treatments up-regulated (P < 0.05) the mRNA expression of fatty acid binding protein 1 (FABP1) and sodium-dependent glucose transporters-1 (SGLT-1) in the ileal mucosa of broilers at d 21. In addition, BSC10 and Lac16 treatments significantly (P < 0.05) increased the relative abundance of short-chain fatty acids-producing bacteria, such as Butyricicoccus pullicaecorum, Faecalibacterium prausnitzii, Lachnospira and Coprococcu, and significantly (P < 0.05) decreased the relative abundance of enteric pathogens (Escherichia coli, Bacteroides fragilis and Shigella sonnei). Furthermore, the 2 probiotic treatments also increased the positive connection among the intestinal microbes and the carbohydrate metabolism-related pathways of the intestinal bacteria (P < 0.05), with decreasing (P < 0.05) nucleotides biosynthesis-related pathways of the intestinal bacteria. Overall, these results suggest that the 2 probiotics, especially Lac16, have a potential beneficial effect on the growth performance and intestinal health of starter phase broilers.

Effect of the use of probiotic Bacillus subtilis (QST 713) as a growth promoter in broilers: an alternative to bacitracin methylene disalicylate

The global poultry trend toward the more responsible use of antibiotics is becoming recurrent and has demanded the need to generate new natural alternatives. Probiotics have gained importance as an option to use as growth promoters. This study aimed to evaluate Bacillus subtillis QST713 as a substitute for an antibiotic growth promoter (BMD). A total of 150 male broilers were assigned to three dietary treatments: 1) control diet (CO), 2) control diet + 500 g/t of BMD (AGP), and 3) control diet + 100 g/t of B. subtilis QST713 (PB), respectively. Each treatment was monitored for 5 wk for the productive variables: body weight, accumulated feed consumption, food conversion, and European efficiency factor. At the end of each week, fresh fecal samples were cultured and quantified for E. coli, Enterococcus spp., and Lactobacillus spp. At the end of the trial, blood samples were analyzed for hemogram and intestinal samples (anterior portion) for histomorphometry. The data were statistically analyzed with an analysis of variance and subjected to a least significant difference test (Tukey). The zootechnical yields were similar in the AGP and PB groups (P ˃ 0.05); both superior to the control group. In the hematological profiles, no difference was observed between the experimental groups. E. coli and Enterococcus counts were significantly lower (P ˂ 0.05), and Lactobacillus counts were significantly (P ˂ 0.05) higher in the PB group, relative to CO and AGP groups. No differences (P ˃ 0.05) were found in bacterial counts between the CO and AGP groups. The intestinal mucosa and villi in the PB group were significantly (P ˂ 0.05) longer and with less deeper crypts than CO and AGP groups. We conclude that B. subtillis QST713, used at the suggested commercial dose (100 g/ton), is an effective growth-promoting alternative to BMD that modulates the microbiota and intestinal architecture, thus producing zootechnical yields consistent with BMD.

Effects of Bacillus subtilis and Bacillus licheniformis on growth performance, immunity, short chain fatty acid production, antioxidant capacity, and cecal microflora in broilers

This study investigated the effects of dietary supplementation with Bacillus subtilis (B. subtilis) or Bacillus licheniformis (B. licheniformis) on growth performance, immunity, antioxidant capacity, short chain fatty acid (SCFA) production, and the cecal microflora in broiler chickens. In total, 360 male, 1-day-old Cobb 500 birds were randomly divided into 3 groups: the control group was fed a basal diet; the B. subtilis group was fed a basal diet supplemented with 1.5 × 10⁹ CFU/kg B. subtilis; the B. licheniformis group was fed a basal diet supplemented with 1.5 × 10⁹ CFU/kg B. licheniformis. Results showed that chickens supplemented with either B. subtilis or B. licheniformis had comparatively higher (P < 0.05) body weight and average daily gain, whereas no difference (P > 0.05) was observed in feed efficiency. Concentrations of serum IgA, IgY, and IgM, as well as anti-inflammatory IL-10 were significantly increased (P < 0.05), and proinflammatory IL-1β and IL-6 were significantly decreased (P < 0.05) by B. subtilis or B. licheniformis supplementation. Moreover, chickens fed with diets supplemented by either B. subtilis or B. licheniformis had greater antioxidant capacity, indicated by the notable increases (P < 0.05) in glutathione peroxidase, superoxide dismutase, and catalase, along with decrease (P < 0.05) in malondialdehyde. Compared to the control group, levels of SCFA, excluding acetic and propionic acid, in cecal content had improved (P < 0.05) by adding B. licheniformis, and significant increase (P < 0.05) in acetic and butyric acid was observed with B. subtilis supplementation. Microbial analysis showed that both B. subtilis or B. licheniformis supplementation could increase butyrate-producing bacteria such as Alistipes and Butyricicoccus, and decrease pathogenic bacteria such as the Synergistetes and Gammaproteobacteria. In summary, dietary supplemented with B. subtilis or B. licheniformis improved growth performance, immune status, and antioxidant capacity, increased SCFA production, and modulated cecal microbiota in chickens. Moreover, B. licheniformis was more effective than B. subtilis with the same supplemental amount.

Association of Broiler Litter Microbiome Composition and Campylobacter Isolation

Infection with Campylobacter species is one of the leading causes of bacterial diarrhea in humans in the US. Chickens, which become colonized on the farm, are important reservoirs of this bacterium. Campylobacter can establish itself in the broiler house via a variety of sources, can survive in the litter of the house, and possibly persist over successive flock cycles. However, the role of the broiler litter microbiome on Campylobacter persistence is not clear. A matched case-control study was conducted to determine whether the broiler litter microbiome composition was associated with Campylobacter isolation within the broiler house. Flocks were classified as cases when either Campylobacter jejuni or Campylobacter coli was isolated in boot sock samples, or as controls otherwise. Case and control flocks were matched at the broiler house level. Composite broiler litter samples were collected and used for DNA extraction and 16S rRNA gene V4 region sequencing. Reads were processed using the DADA2 pipeline to obtain a table of amplicon sequence variants. Alpha diversity and differential bacterial relative abundance were used as predictors of Campylobacter isolation status in conditional logistic regression models adjusting for flock age and sampling season. Beta diversity distances were used as regressors in stratified PERMANOVA with Campylobacter isolation status as predictor, and broiler house as stratum. When Campylobacter was isolated in boot socks, broiler litter microbiome richness and evenness were lower and higher, respectively, without reaching statistical significance. Campylobacter isolation status significantly explained a small proportion of the beta diversity (genus-level Aitchison dissimilarity distance). Clostridium and Anaerostipes were positively associated with Campylobacter isolation status, whereas Bifidobacterium, Anaerosporobacter, and Stenotrophomonas were negatively associated. Our results suggest the presence of bacterial interactions between Campylobacter and the broiler litter microbiome. The negative association of Campylobacter with Bifidobacterium, Anaerosporobacter, and Stenotrophomonas in litter could be potentially exploited as a pre-harvest control strategy.

Bacillus Subtilis 29784 as a Feed Additive for Broilers Shifts the Intestinal Microbial Composition and Supports the Production of Hypoxanthine and Nicotinic Acid

The probiotic Bacillus subtilis strain 29784 (Bs29784) has been shown to improve performance in broilers. In this study, we used a metabolomic and 16S rRNA gene sequencing approach to evaluate effects of Bs29874 in the broiler intestine. Nicotinic acid and hypoxanthine were key metabolites that were produced by the strain in vitro and were also found in vivo to be increased in small intestinal content of broilers fed Bs29784 as dietary additive. Both metabolites have well-described anti-inflammatory effects in the intestine. Furthermore, Bs29784 supplementation to the feed significantly altered the ileal microbiome of 13-day-old broilers, thereby increasing the abundance of genus Bacillus, while decreasing genera and OTUs belonging to the Lactobacillaceae and Enterobacteriacae families. Moreover, Bs29784 did not change the cecal microbial community structure, but specifically enriched members of the family Clostridiales VadinBB60, as well as the butyrate-producing families Ruminococcaceae and Lachnospiraceae. The abundance of various OTUs and genera belonging to these families was significantly associated with nicotinic acid levels in the cecum, suggesting a possible cross-feeding between B. subtilis strain 29784 and these beneficial microbes. Taken together, the data indicate that Bs29784 exerts its described probiotic effects through a combined action of its metabolites on both the host and its microbiome.

Mandated restrictions on the use of medically important antibiotics in broiler chicken production in Canada: implications, emerging challenges, and opportunities for bolstering gastrointestinal function and health– A review

Chicken Farmers of Canada has been progressively phasing out prophylactic use of antibiotics in broiler chicken production. Consequently, hatcheries, veterinarians, and nutritionists have been mandated to contend with less reliance on use of preventive antibiotics. A topical concern is the increased risk of proliferation of enteric pathogens leading to poor performance, increased mortality and compromised welfare. Moreover, the gut harbors several taxa such as Campylobacter and Salmonella capable of causing significant illnesses in humans via contaminated poultry products. This has created opportunity for research and development of dietary strategies designed to modulate gastrointestinal environment for enhanced performance and food safety. Albeit with inconsistent responses, literature data suggests that dietary strategies such as feed enzymes, probiotics/prebiotics and phytogenic feed additives can bolster gut health and function in broiler chickens. However, much of the efficacy data was generated at controlled research settings that vary significantly with the complex commercial broiler production operations due to variation in dietary, health and environmental conditions. This review will summarize implications of mandated restrictions on the preventative use of antibiotics and emerging Canadian broiler production programs to meet processor specifications. Challenges and opportunities for integrating alternative dietary strategies in commercial broiler production settings will be highlighted.

High-throughput sequencing-based analysis of the intestinal microbiota of broiler chickens fed with compound small peptides of Chinese medicine

The objective of this study was to determine the effects of compound small peptides of Chinese medicine (CSPCM) on the intestinal microbiota of broilers. A total of thirty-six 1-day-old Arbor Acres broilers were assigned to 6 dietary treatments that include 250, 500, and 750 g/T of CSPCM in feed, 100 g/T of Bacillus subtilis and Clostridium butyricum in feed, and 100 g/T of 50,000 IU xylanase in feed. Each treatment had 2 replicates with 2 cages (3 birds per cage). The jejunal digesta samples were collected from chickens at 42 d. Operational taxonomic unit analysis showed that adding CSPCM at a concentration of 750 g/T of feed can increase the number of operational taxonomic unit samples than other groups. Compared with the control group, adding 250 g/T of CSPCM of feed can improve content of Lactobacillus, Cupriavidus, Ochrobactrum, Candidatus_Arthromitus, Acinetobacter, and Sphingomonas. Adding 500 g/T of CSPCM in feed resulted in varying degrees of improvement in Candidatus_Arthromitus, Acinetobacter, and Sphingomonas. Adding 750 g/T of CSPCM in feed can increase the content of Lactobacillus and Candidatus_Arthromitus. In PICRUSt function prediction analysis, CSPCM acts on the body by creating an environment suitable for the growth of beneficial bacteria. Adding 250 g/T of CSPCM in feed can improve amino acid metabolism, endocrine system function, membrane transport, and cell mobility function. Adding 500 g/T of CSPCM in feed can improve replication and repair and membrane transport function. Adding 750 g/T of CSPCM in feed can increase carbohydrate metabolism, replication and repair, and membrane transport function. Adding B. subtilis and C. butyricum in feed increased replication and repair and membrane transport function. Adding xylanase in feed increased membrane transport function. In conclusion, this study demonstrated that dietary supplementation of CSPCM to broiler diets increased beneficial flora content, metabolism of carbohydrates, amino acid metabolism, the deposition of proteins, renewal of bacteria, and maintenance of vigorous vitality. Among the 3 additive quantities of 250 g/t, 500 g/t, and 750 g/t of CSPCM in feed, 250 g/t of CSPCM improved parameters that are necessary for improved growth and production.

The storage stability of Bacillus subtilis spore displaying cysteine protease of Clonorchis sinensis and its effect on improving the gut microbiota of mice

Bacillus subtilis (B. subtilis) spore can serve as an ideal vehicle for expressing heterologous antigens, and elicit specific immune responses by oral administration. In previous studies, we successfully constructed the recombinant B. subtilis spores expressing cysteine protease of Clonorchis sinensis (C. sinensis, B.s-CsCP), and confirmed that oral administration of B.s-CsCP could elicit good protective immune responses in mice. In this study, Gram staining was used to observe the morphology of B.s-CsCP in different form, and the storage of liquid spores and lyophilized spores at different temperatures was compared. The mice were orally immunized with three different doses of spores (2×10⁸, 1×10⁹, and 5×10⁹ CFU/day) for three times in total at biweekly interval. Then, antibody levels of mice were measured, the safety of spores was evaluated, and the changes of gut microbiota after oral gavage of spores (1×10⁹ dose) were investigated. Results showed that B. subtilis was a typical Gram-positive bacterium, and its spore had good resistance to chemical dye. Liquid B. subtilis spores resuspended in sterile water could be stored for a long time at 4 °C or below, while lyophilized spores could be well stored even at RT and better at lower temperatures. Oral administration of B. subtilis spores to mice could stimulate both local mucosal and systemic immune responses in a dose-dependent manner without toxic side effects. Besides, beneficial bacteria producing butyrate such as Odoribacter were increased, while potential pathogens such as Escherichia-Shigella were decreased in mice intestine. Therefore, our work further confirmed that B. subtilis spores expressing CsCP could be a promising oral vaccine against C. sinensis with the advantages of stability, safety, easy storage, and promotion of intestinal health.Key Points• Recombinant CsCP B. subtilis spores could be easily preserved in either liquid or freeze-dried state.• Oral immunization of recombinant spores in mice could increase both local and system immune levels in a dose-dependent manner.• Oral administration of recombinant spores increased the number of beneficial bacteria and reduced the number of harmful bacteria in the intestinal tract of mice.

Effects of novel probiotic strains of Bacillus pumilus and Bacillus subtilis on production, gut health, and immunity of broiler chickens raised under suboptimal conditions

Probiotics are being developed as alternatives to antibiotic growth promoters. The aim of the study was to investigate the effects of 2 novel strains of Bacillus pumilus and Bacillus subtilis on production, intestinal microbiota, gut health, and immunity of broilers raised under suboptimal conditions. Day-old chicks (Cobb 500, n = 2,073) were randomly assigned into 6 groups: Con group (group fed with basal diet), Ab group (group treated with virginiamycin), groups treated with 2 levels of B. pumilus (low dose: 3 × 10⁸ cfu/kg of feed [BPL] and high dose: 1 × 10⁹ cfu/kg [BPH]), and groups treated with 2 levels of B. subtilis (low dose: 3 × 10⁸ cfu/kg [BSL] and high dose: 1 × 10⁹ cfu/kg [BSH]). Production parameters were recorded weekly. Cecal tonsils and content as well as ileum samples were collected on day 14 and day 42. Cecal tonsils were used to sort T-regulatory cells (CD4+CD8–CD25+ and CD4+CD8+CD25+) to study expression of IL-10 and interferon gamma, whereas cecal content was used for bacterial culture. Ileum samples were used to measure gene expression of tight junction proteins, mucin, and cytokines. BW and feed intake increased in the Ab, BPL, BSL, and BSH groups compared with the Con group between day 35 and day 42. The CD4+CD8-CD25+ cells expressed high levels of IL-10 in the BSH group on day 14 and in the BPL, BSL, and BSH groups on day 42 and high levels of interferon gamma in the BPL, BSL, and BSH groups on day 14 and in the BSL and BSH groups on day 42. The expression of IL-10 and interferon gamma in CD4+CD8+CD25+ cells was higher only in the BSH group on day 14 and day 42. Cecal bacterial populations of genera, Lactobacillus (day 14 and day 42) and Clostridium (day 14), were higher in the BSH group. Expression of tight junction protein increased significantly in the ileum on day 14 in the BPL (occludin, zona occludens 1 [ZO-1]), BSL (occludin, ZO-1), and BSH (occludin, ZO-1, junctional adhesion molecule 2 [JAM-2]) groups compared with that in the Con group and declined in all groups except in the BSH group (occludin, ZO-1, JAM-2) on day 42. Expression of MUC2 and IL-17F increased in all groups on day 14 and remained high on day 42 in the BSL and BSH groups. Taken together, both Bacillus probiotics altered the intestinal and immune activities, particularly on day 14, suggesting beneficial influence of probiotics.

Bacillus subtilis-fermented products ameliorate the growth performance and alter cecal microbiota community in broilers under lipopolysaccharide challenge

In this study, the effects of Bacillus subtilis–fermented products on the growth performance and cecal microbiota of broilers were investigated in response to lipopolysaccharide (LPS) challenge. A total of 120 one-day-old male broiler chicks (Ross 308) were randomly assigned to 4 dietary treatments, with 5 replicate cages per treatment and 6 birds per cage. The dietary treatments comprised a basal diet as the control, basal diet plus 5 mg/kg of LPS, and basal diet plus 5 mg/kg of LPS in combination with 1 and 3 g/kg of B. subtilis–fermented products. The results indicated that B. subtilis–fermented product supplementation increased (linear, P < 0.05) the body weight of broilers relative to LPS treatment alone at 21 d of age. At 15 to 21 d and 1 to 21 d of age, B. subtilis–fermented product supplementation improved (linear, P < 0.05) the average daily gain in broilers compared with LPS challenge alone. The inflammation-associated gene expression was decreased (P < 0.05), and intestinal barrier–associated gene expression was increased (P < 0.05) in the small intestine of the group treated with 3 g/kg of B. subtilis–fermented products in combination with LPS challenge. In cecal microbiota analysis, the richness of bacterial species was lower (P < 0.05) in the groups treated with 1 and 3 g/kg of B. subtilis–fermented products in combination with LPS challenge than in the control group. Principal coordinates analysis indicated distinct clusters between the groups treated with LPS alone and B. subtilis–fermented products in combination with LPS challenge. The abundance of the genera Erysipelatoclostridium and Ruminococcaceae_unclassified in the cecal digesta decreased (P < 0.05) in broilers fed with B. subtilis–fermented products compared with the control group. The average abundance of the genera Bacteroides and Romboutsia in the cecal digesta was positively correlated with the body weight and average daily gain of broilers in response to LPS challenge. Furthermore, the average abundance of the genera Bacteroides and Romboutsia in the cecal digesta was positively correlated with the concentration of B. subtilis–fermented products under LPS challenge. These results demonstrate that B. subtilis–fermented products can improve the growth performance and modulate the gut microflora composition of broilers under immune stress.

Effects of Gut Microbiome and Short-Chain Fatty Acids (SCFAs) on Finishing Weight of Meat Rabbits

Understanding how the gut microbiome and short-chain fatty acids (SCFAs) affect finishing weight is beneficial to improve meat production in the meat rabbit industry. In this study, we identified 15 OTUs and 23 microbial species associated with finishing weight using 16S rRNA gene and metagenomic sequencing analysis, respectively. Among these, butyrate-producing bacteria of the family Ruminococcaceae were positively associated with finishing weight, whereas the microbial taxa related to intestinal damage and inflammation showed opposite effects. Furthermore, interactions of these microbial taxa were firstly found to be associated with finishing weight. Gut microbial functional capacity analysis revealed that CAZymes, such as galactosidase, xylanase, and glucosidase, could significantly affect finishing weight, given their roles in regulating nutrient digestibility. GOs related to the metabolism of several carbohydrates and amino acids also showed important effects on finishing weight. Additionally, both KOs and KEGG pathways related to the membrane transportation system and involved in aminoacyl-tRNA biosynthesis and butanoate metabolism could act as key factors in modulating finishing weight. Importantly, gut microbiome explained nearly 11% of the variation in finishing weight, and our findings revealed that a subset of metagenomic species could act as predictors of finishing weight. SCFAs levels, especially butyrate level, had critical impacts on finishing weight, and several finishing weight-associated species were potentially contributed to the shift in butyrate level. Thus, our results should give deep insights into how gut microbiome and SCFAs influence finishing weight of meat rabbits and provide essential knowledge for improving finishing weight by manipulating gut microbiome.

The effects and combinational effects of Bacillus subtilis and montmorillonite on the intestinal health status in laying hens

This study was conducted to evaluate the effects and combinational effects of Bacillus subtilis (BS) and montmorillonite (MMT) on laying performance, gut mucosal oxidation status, and intestinal immunological and physical barrier functions of laying hens. Three hundred sixty laying hens (29-week-old) were randomly assigned to a 2 × 2 factorial arrangement of treatments (n = 6) for 10 wk as follows: (1) basal diet; (2) the basal diet plus 5 × 10⁸ cfu BS/kg; (3) the basal diet plus 0.5 g MMT/kg; and (4) the basal diet plus 5 × 10⁸ cfu BS/kg and 0.5 g MMT/kg. Dietary supplementation with BS increased egg production and egg mass, the activities of catalase (CAT) and total superoxide dismutase in the intestinal mucosa, and villus height and villus height-to-crypt depth ratio of the jejunum (P < 0.05) but downregulated the mRNA expression levels of toll-like receptor 4 and myeloid differentiation factor 88 (MyD88) in the duodenum and jejunum, interleukin 1 beta in the duodenum, and nuclear factor kappa B P65 (NF-κB P65) and tumor necrosis factor alpha in the jejunum (P < 0.05). Dietary supplementation with MMT increased egg production and egg mass, the concentration of secretory immunoglobulin A in the duodenum, and the occludin mRNA expression level in the jejunum (P < 0.05) but reduced feed conversion ratio, malondialdehyde concentration in the duodenum and jejunum, and the mRNA expression level of MyD88 in the jejunum (P < 0.05). In addition, there was an interaction effect between BS and MMT supplementation on the CAT activity and the MyD88 mRNA expression level in the duodenum and the mRNA expression level of occludin in the jejunum (P < 0.05). In conclusion, dietary BS and MMT and their combination may improve the intestinal health status of laying hens, which may contribute to the increase in hens' laying performance.

Effect of dietary supplementation of Bacillus subtilis DSM29784 on hen performance, egg quality indices, and apparent retention of dietary components in laying hens from 19 to 48 weeks of age

The aim of the current study was to evaluate egg production, quality, and apparent retention (AR) of components in response to a multi-dose application of a single strain Bacillus subtilis (SSB; DSM29784) in a corn-soybean meal basal diet fed to hens (19 to 48 wk of age). The treatments consisted of a basal diet with either no probiotic (control, CON), 1.1E+08 (low, LSSB), 2.2E+08 (medium, MSSB) or 1.1E+09 (high, HSSB) CFU/kg of diet. A total of 336, 19-wk old Shaver White layers were used at a stocking density of 7 and 6 hens/replicate-cage in layer I (week-19 to 28) and layer II (week-29 to 48) phases, respectively. Evaluated variables included feed intake (FI), body weight (BW), feed conversion ratio (FCR), egg production, weight, mass, and egg quality (shell thickness, shell breaking strength, albumen height (AH), and Haugh unit (HU)). Excreta was collected at the end of week-28 for AR of components and apparent metabolizable energy (AME). Supplementation of SSB increased (P = 0.008) FI during peak egg-lay (week-24) and BW increased linearly (P = 0.019) in early layer II (week-32). In layer I, LSSB compared with CON increased EM (g/egg) by 3.3% (P = 0.049). In layer II, SSB inclusion tended to improve FCR (linear, P = 0.094; g FI: g EM). Although shell breaking strength was lowest at week-20 with HSSB (4.518 vs. 4.889 kgf for HSSB vs. CON; P = 0.045), AH and HU were improved at higher dose of SSB, in both phases (P ≤ 0.005). Apparent retention of dry matter, AME, and minerals were improved (P < 0.0001) in a dose response. Hence, while the low dose of B. subtilis DSM29784 improved hen performance and maintained egg quality in both phases, a higher dose of SSB improved the interior protein quality of eggs (AH and HU).

Amelioration of non-alcoholic steatohepatitis by Qushi Huayu decoction is associated with inhibition of the intestinal mitogen-activated protein kinase pathway

BACKGROUND

Gut microbiota is increasingly recognized as the key participant in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) by translocation of its products, such as lipopolysaccharide (LPS), via the dysfunctional intestinal barrier. Qushi Huayu decoction (QHD), a traditional Chinese medicine, is developed specially for NAFLD and used in clinic in China for more than a decade and previously found to ameliorate non-alcoholic steatohepatitis (NASH) induced by high-fat diet (HFD) in mice accompanied with inhibited metabolic endotoxemia and hepatic LPS signalling.

PURPOSE

To investigate the mechanism of LPS gut-leakage inhibition by QHD in NASH.

METHODS

Effects of QHD on gut microbioa and intestinal barrier were evaluated in NASH induced by HFD in mice. 16S rRNA sequencing is employed to analyse the gut microbiota composition. To identify the potential signalling pathway responsible for tight junction regulation, the colonic phosphoprotein profile is screened via the Phospho Explorer Antibody Array and verified in NASH, intestinal barrier dysfunctional mouse and Caco-2 cells.

RESULTS

QHD ameliorates NASH accompanied with regulating the gut microbiota composition, protecting intestinal tight junctions and inhibiting LPS gut-leakage without decreasing the abundance of identified Gram-negative bacteria. The validated data of phosphorylated proteins suggested that mitogen-activated protein kinase (MAPK) pathway is predominantly responsible for the colonic tight junction regulation by QHD.

CONCLUSION

QHD inhibits LPS gut-leakage in NASH, which is associated with downregulation of intestinal MAPK pathway.