Effects of Bacillus coagulans supplementation on the growth performance and gut health of broiler chickens with Clostridium perfringens-induced necrotic enteritis

Alpiniae oxyphyllae fructus improves production performance and egg quality of laying breeder hens by regulating reproductive hormones, antioxidant function, immunity and intestinal health

Alpiniae oxyphylla fructus was extensively utilized both as dietary supplements and traditional herbal medicines for healthcare functions and has exhibited a positive impact on animal health. The present study aimed to investigate the effects of Alpiniae oxyphyllae fructus powder (AOP) on production performance, egg quality, egg yolk fatty acid composition, reproductive hormones, antioxidant capacity, immunity, anti-apoptosis ability, and intestinal health in hens. A total of 252 Hainan Wenchang laying hens (30-wk-old) were randomly divided into 3 groups with 6 replicates, a basic diet with 0 (CON), 1 g/kg AOP (AOP1), and 3 g/kg (AOP3) mixed AOP. The AOP supplementation was found to decrease the feed conversion ratio and embryo mortality but to increase the laying rate, average egg weight, and oviduct index linearly (p < 0.05). Furthermore, AOP treatment reduced the total saturated fatty acids and palmitic acid (C16:0) in the egg yolk while increasing eggshell strength, albumen height, and Haugh unit (p < 0.05). The serum levels of albumin and phosphorus were increased, whereas total cholesterol, triglycerides, and glucose levels decreased as a result of AOP treatment (p < 0.05). The inclusion of 3 g/kg AOP had higher 17 β-estradiol and follicle-stimulating hormone levels in serum, while it up-regulated follicle-stimulating hormone receptor and gonadotropin-releasing hormone expression in ovary (p < 0.05). Dietary AOP strengthened the expression of nuclear factor erythroid2-related factor 2 in ovary and increased the activity of superoxide dismutase and total antioxidant capacity, but had a lower malondialdehyde content in serum (p < 0.05). AOP at 3 g/kg up-regulated superoxide dismutase 1 and heme oxygenase 1 expression in jejunum and ovary (p < 0.05). Meanwhile, AOP supplementation down-regulated p53 expression in ovary and bcl-2-associated x expression in liver and jejunum, especially 3 g/kg of AOP had lower caspase-8 concentrations and down-regulated bcl-2-associated x and caspase-3 expression in ovary (p < 0.05). AOP treatment increased serum levels of immunoglobulin A and immunoglobulin M and upregulated interleukin-4 expression in the liver, while decreasing interleukin-1β expression in liver and ovary and nod-like receptor protein 3 expression in jejunum (p < 0.05). Dietary AOP increased the ratio of villus height to crypt depth but decreased crypt depth in jejunum, especially when 1 g/kg AOP increased expression levels of occludin, mucin-2, peptide-transporter 1, and sodium glucose cotransporter 1 in jejunum (p < 0.05). AOP treatment altered the composition of the cecal microbial community, as evidenced by increased abundance of Oscillospira and Phascolarctobacterium and reduced richness of Clostridiaceae_Clostridium. Dietary AOP supplementation enriched lipid, amino acid, and propanoate metabolism. Spearman's correlation analysis revealed that the genera Oscillospira, Blautia, and Megasphaera were related to laying performance and intestinal integrity. In brief, supplementation of AOP, especially at 3 g/kg, could improve production performance and egg quality of hens via modulating reproductive hormones, antioxidant capacity, immunity, intestinal barrier, and cecal microbiota. Overall, the present work recommends the dietary inclusion of AOP as a beneficial additive for improving the performance of hens.

Effects of microencapsulated essential oils and organic acids preparation on growth performance, slaughter characteristics, nutrient digestibility and intestinal microenvironment of broiler chickens

To develop effective antibiotics alternatives is getting more and more important to poultry healthy production. The study investigated the effects of a microencapsulated essential oils and organic acids preparation (EOA) on growth performance, slaughter performance, nutrient digestibility and intestinal microenvironment of broilers. A total of 624 1-day-old male Arbor Acres broilers were randomly divided into 6 groups including the control group (T1) fed with basal diet, the antibiotic group (T2) supplemented with basal diet with 45 mg/kg bacitracin methylene disalicylate (BMD), and 4 inclusion levels of EOA-treated groups (T3, T4, T5, T6 groups) chickens given basal diet with 200, 400, 600, and 800 mg EOA/kg of diet, respectively. Results showed that compared with the control, the 200 mg/kg EOA group increased average daily gain (ADG) and average body weight (ABW) during the early stage (P < 0.05). EOA addition decreased crypt depth of the ileum (P < 0.05), but villus height to crypt depth ratio was increased by EOA addition at 200 and 400 mg/kg at d 21 (P < 0.05). Compared with the control, dietary addition EOA at 200, 400 and 600 mg/kg increased the lipase activity in the duodenum at d 21 (P < 0.05). Increased lactic acid bacteria population was found in cecal digesta of the 400 mg/kg EOA group at d 21 (P < 0.05), and higher concentration of butyric acid level was observed in cecal digesta at d 21 and d 42 in the 200 mg/kg EOA group compared with the control (P < 0.05). RT-PCR analysis found that dietary EOA addition decreased the gene expression of IL-1β, COX-2 and TGF-β4 in the ileum at d 21 (P < 0.05), while only the 200 mg/kg EOA increased the gene expression of IL-10, TGF-β4, Claudin-1, ZO-1, CATH-1, CATH-3, AvBD-1, AvBD-9 and AvBD-12 in the ileum at d 42 (P < 0.05) compared with the control. In summary, adding 200 mg/kg and 400 mg/kg of the EOA to the diet could improve the growth performance and intestinal microenvironment through improving intestinal morphology, increasing digestive enzymes activity and cecal lactic acid bacteria abundance and butyric acid content, improving intestinal barrier function as well as maintaining intestinal immune homeostasis. The improving effect induced by EOA addition in the early growth stage was better than that in the later growth stage. Overall, the EOA product might be an effective antibiotic alternative for broiler industry.

Bacillus amyloliquefaciens SC06 Relieving Intestinal Inflammation by Modulating Intestinal Stem Cells Proliferation and Differentiation via AhR/STAT3 Pathway in LPS-Challenged Piglets

Bacillus amyloliquefaciens is a well-accepted probiotic, with many benefits for both humans and animals. The ability of intestinal stem cells (ISCs) to develop into several intestinal epithelial cell types helps accelerate intestinal epithelial regeneration. Limited knowledge exists on how bacteria regulated ISCs proliferation and regeneration. Our study investigated the effects of Bacillus amyloliquefaciens supplementation on ISC proliferation and regeneration and intestinal mucosal barrier functions in piglets exposed to lipopolysaccharide (LPS). Eighteen piglets (male, 21 days old) were randomly split into 3 clusters: CON cluster, LPS cluster, and SC06+LPS cluster. On day 21, 100 μg/kg body weight of LPS was intraperitoneally administered to the SC06+LPS and LPS groups. We found SC06 supplementation maintained the intestinal barrier integrity, enhanced intestinal antioxidant capacity, reduced generation of inflammatory response, and suppressed enterocyte apoptosis against the deleterious effects triggered by LPS. In addition, our research indicated that the SC06 supplementation not only improved the ISC regeneration, but also resulted in upregulation of aryl hydrocarbon receptor (AhR) in LPS-challenge piglets. Further studies showed that SC06 also induced ISC differentiation toward goblet cells and inhibited their differentiation to intestinal absorptive cells and enterocytes. The coculture system of SC06 and ileum organoids revealed that SC06 increased the growth of ISCs and repaired LPS-induced organoid damage through activating the AhR/STAT3 signaling pathway. These findings showed that SC06, possibly through the AhR/STAT3 pathway, accelerated ISC proliferation and promoted epithelial barrier healing, providing a potential clinical treatment for IBD. Our research demonstrated that SC06 is effective in preventing intestinal epithelial damage after pathological injury, restoring intestinal homeostasis, and maintaining intestinal epithelial regeneration.

Enhancing effect of oregano essential oil and Bacillus subtilis on broiler immune function, intestinal morphology and growth performance

The present study evaluated the effect of two categories of feed additives on chicken performance through immunological and intestinal histo-morphometric measurements. A total of 150 one-day-old male broiler chicks (Cobb) were randomly assigned to three groups. Group I received a non-supplemented basal diet. While groups II and III were treated with a basal diet supplemented with oregano essential oil (OEO) and Bacillus subtilis, respectively, in water for 28 days. Blood samples were taken at 6, 18 and 28 days for hematological analysis, phagocytosis, lymphocyte proliferation and measuring antibody responses. Additionally, growth performance indices were recorded weekly. The results showed that groups supplemented with OEO and B. subtilis improved growth performance expressed by a significant increase in weight gain (P < 0.05), with a significant reduction (P < 0.05) in feed conversion ratio (FCR). Hematological findings indicated a significant increase in blood parameters as well as a significant increase in phagocytic % & phagocytic index at all time points with a greater probiotic effect. On the other hand, OEO produced a significant increase in lymphocyte proliferation at 18 & 28 days. Humoral immunity revealed a significant increase in serum antibody titer phytobiotic & probiotic-fed groups at time points of 18 & 28 days with a superior phytobiotic effect. The histological examination showed a significant increase in villi length, villi width, crypt depth & V/C ratio. In conclusion, these results indicated positive effects of B. subtilis & OEO on both growth and immunity and could be considered effective alternatives to the antibiotic.

Expression of Toll-like receptors and host defence peptides in the cecum of chicken challenged with Eimeria tenella

Chicken coccidiosis, caused by Eimeria protozoa, affects poultry farming. Toll-like receptors (TLRs) and host defence peptides (HDPs) help host innate immune responses to eliminate invading pathogens, but their roles in Eimeria tenella infection remain poorly understood. Herein, 14-day-old chickens were treated orally with 50,000 E. tenella oocysts and the cecum was dissected at different timepoints. mRNA expression of 10 chicken TLRs (chTLRs) and five HDPs was measured by quantitative real-time PCR. chTLR7 and chTLR15 were upregulated significantly at 3 h post-infection while other chTLRs were downregulated (p < .05). chTLR1a, chTLR1b, chTLR2b and chTLR4 peaked at 36 h post-infection, chTLR3, chTLR5 and chTLR15 peaked at 72 h post-infection and chTLR21 expression was highest among chTLRs, peaking at 48 h post-infection (p < 0.05). For HDPs, cathelicidin (CATH) 1 to 3 and B1 peaked at 48 h post-infection, liver-expressed antimicrobial peptide 2 peaked at 96 h post-infection, and CATH 2 expression was highest among HDPs. CATH2 and CATH3 were markedly upregulated at 3 h post-infection (p < .05). The results provide insight into innate immune molecules during E. tenella infection in chicken, and indicate that innate immune responses may mediate resistance to chicken coccidiosis.

Effects of Lactobacillus plantarum HW1 on Growth Performance, Intestinal Immune Response, Barrier Function, and Cecal Microflora of Broilers with Necrotic Enteritis

The purpose of the study was to investigate the effects of Lactobacillus plantarum HW1 on growth performance, intestinal immune response, barrier function, and cecal microflora of broilers with necrotic enteritis. In total, 180 one-day-old male Cobb 500 broilers were randomly allocated into three groups comprising a non-infected control (NC) group, basal diet + necrotic enteritis challenge (NE) group, and basal diet + 4 × 106 CFU/g Lactobacillus plantarum HW1 + necrotic enteritis challenge (HW1) group. Broilers in the NE and HW1 groups were orally given sporulated coccidian oocysts at day 14 and Clostridium perfringens from days 19 to 21. The results showed that the HW1 treatment increased (p < 0.05) the average daily gain of broilers from days 15 to 28 and from days 0 to 28 compared with the NE group. Moreover, the HW1 treatment decreased (p < 0.05) the oocysts per gram of excreta, intestinal lesion scores, ileal interleukin (IL) 1β and tumor necrosis factor α levels, and serum D-lactic acid and diamine oxidase levels, while increasing (p < 0.05) the ileal IL-10 level, thymus index, and protein expressions of ileal occludin and ZO-1. Additionally, the HW1 treatment decreased (p < 0.05) the jejunal and ileal villus height, jejunal villus height/crypt depth value, and cecal harmful bacterial counts (Clostridium perfringens, Salmonella, Escherichia coli, and Staphylococcus aureus), and increased (p < 0.05) the cecal Lactobacillus count. In conclusion, dietary supplementation with 4 × 106 CFU/g Lactobacillus plantarum HW1 could relieve necrotic enteritis infection-induced intestinal injury and improve growth performance in broilers by improving intestinal barrier function and regulating intestinal microbiology.

The protective effects of Bacillus licheniformis against inflammatory responses and intestinal barrier damage in broilers with necrotic enteritis induced by Clostridium perfringens

BACKGROUND

Bacillus licheniformis is a gram-positive bacterium that has strong environmental adaptability and can improve the growth performance, immunity, and antioxidant function of broilers. The current study aimed to elucidate the protective capability of B. licheniformis against inflammatory responses and intestinal barrier damage in broilers with necrotic enteritis (NE) induced by Clostridium perfringens (CP).

RESULTS

The results showed that B. licheniformis enhanced the final body weight in broilers compared with that of broilers in the CP group after the stress of infection (P < 0.05). Bacillus licheniformis reversed the decreased levels of serum and jejunum mucosa immunoglobulins and anti-inflammatory cytokines, reduced the values of villus height and the ratio of villus height to crypt depth, and mitigated the increased levels of serum d-lactic acid and diamine oxidase in CP-challenged broilers (P < 0.05). Moreover, B. licheniformis modulated the expression levels of genes involved in the TLR4/NF-κB signalling pathway, the NLRP3 inflammasome activation pathway, and the sirt 1/Parkin signalling pathway in CP-challenged broilers. Compared with the CP challenge group, the B. licheniformis-treated group exhibited reduced abundance values of Shuttleworthia and Alistipes and enhanced abundance values of Parabacteroides in the caecal contents (P < 0.05).

CONCLUSION

Bacillus licheniformis improved the final body weight and alleviated the inflammatory response and intestinal barrier function damage in birds with NE induced by CP by maintaining intestinal physiological function, enhancing immunity, regulating inflammatory cytokine secretion, modulating the mitophagy response, and increasing the abundance of beneficial intestinal flora. © 2023 Society of Chemical Industry.

Effect of synbiotic supplementation on production performance and severity of necrotic enteritis in broilers during an experimental necrotic enteritis challenge

To evaluate the efficacy of synbiotic during a necrotic enteritis (NE) infection, a total of 360 day-old chicks were randomly assigned into 4 experimental groups in a 2 × 2 factorial setup: control, challenge, synbiotic (1 g/kg), and challenge + synbiotic, with 6 replicates. NE was induced by gavaging 1 × 104Eimeria maxima oocysts and 1 × 108 CFU/mL of Clostridium perfringens on d 14 (D14) and D19, 20, and 21, respectively. At D35, the NE challenge decreased the BW gain (P < 0.001) and increased feed conversion ratio (P = 0.03), whereas synbiotic supplementation decreased the feed intake (P = 0.04). At D21, NE challenge increased gut permeability (P < 0.001), decreased regulatory T cells (Tregs) in the cecal tonsil (CT) (P = 0.02), increased Tregs in the spleen (P = 0.02), decreased nitric oxide (NO) production in the spleen (P = 0.04) and decreased IL-10 expression in CT (P = 0.02), whereas synbiotic supplementation increased CD4+:CD8+ T cells in the spleen (P < 0.001) and decreased interferon (IFN)-γ expression in the jejunum (P = 0.07), however, synbiotic supplementation during NE challenge decreased mid-gut lesion score (P < 0.001), increased CD4+:CD8+ T cells in CT and decreased IgA production in bile (P < 0.001), compared to the control group. At D28, synbiotic supplementation decreased CD4+:CD8+ T cells in CT (P < 0.001), whereas synbiotic supplementation during NE challenge decreased Tregs in CT (P < 0.001) and increased NO production in the spleen (P = 0.04), compared to the control group. At D35, the NE challenge decreased CD4+:CD8+ T cells in the spleen (P = 0.03), decreased IgA production in bile (P = 0.02), decreased IL-10 expression in CT (P = 0.04), and decreased IL-10 (P = 0.009), IFN-γ (P = 0.03) and inducible nitric oxide synthase (P = 0.02) expression in the jejunum, whereas synbiotic supplementation increased Tregs in the spleen (P = 0.04), compared to control group. Synbiotic supplementation during the NE challenge decreased both IL-1β (P = 0.02) and IFN-γ (P = 0.001) expression in CT, compared to the control group. It can be concluded that synbiotic supplementation increases production performance by decreasing mid-gut lesions and enhancing protective immunity against NE, and efficiency of synbiotic could be improved by blending additional probiotics and prebiotics.

Effects of Eimeria maxima infection doses on growth performance and gut health in dual-infection model of necrotic enteritis in broiler chickens

The objective of this study was to investigate the effects of the different doses of Eimeria maxima (EM) oocysts on growth performance and intestinal health in broiler chickens challenged with a dual infection model of necrotic enteritis (NE) using EM and NetB+ Clostridium perfringens (CP). A total of 432 fourteen-d-old male Cobb 500 broiler chickens were divided into 6 groups with 6 replicates each. The six different groups were as follows: Control, non-challenged; T0+, challenged with CP at 1 × 109 colony forming unit; T5K+, T0+ + 5,000 EM oocysts; T10K+, T0+ + 10,000 EM oocysts; T20K+; T0+ + 20,000 EM oocysts; and T40K+; T0+ + 40,000 EM oocysts. The challenge groups were orally inoculated with EM strain 41A on d 14, followed by NetB+ CP strain Del-1 on 4 days post inoculation (dpi). Increasing EM oocysts decreased d 21 body weight, body weight gain, feed intake (linear and quadratic, p < 0.001), and feed efficiency (linear, p < 0.001) from 0 to 7 dpi. Increasing EM oocysts increased jejunal NE lesion score and intestinal permeability on 5, 6, and 7 dpi (linear, p < 0.05). On 7 dpi, increasing the infection doses of EM oocysts increased jejunal CP colony counts (linear, p < 0.05) and increased fecal EM oocyst output (linear and quadratic, p < 0.001). Furthermore, increasing the infection doses of EM oocysts decreased the villus height to crypt depth ratios and the goblet cell counts (linear, p < 0.05) on 6 dpi. Increasing EM oocysts downregulated the expression of MUC2, B0AT, B0,+AT, PepT1, GLUT2, AvBD3 and 9, LEAP2, and TLR4, while upregulating CLDN1, CATHL3, IL-1β, IFN-γ, TNFSF15, TNF-α, IL-10, and Gam56 and 82 on 6 dpi (linear, p < 0.05). Additionally, increasing EM oocysts decreased Pielou's evenness and Shannon's entropy (linear, p < 0.01). In conclusion, increasing the infection doses of EM significantly aggravated the severity of NE and exerted negative impact on intestinal health from 5 to 7 dpi.

Dietary Macleaya cordata extract supplementation improves the growth performance and gut health of broiler chickens with necrotic enteritis

BACKGROUND

The poultry industry needs effective antibiotic alternatives to control outbreaks of necrotic enteritis (NE) caused by Clostridium perfringens.

METHODS

The aim of this study was to investigate the effects of dietary supplementation with Macleaya cordata extract (MCE) on the immune function and gut microbiota of broilers with NE. A total of 288 1-day-old broiler chicks were randomly assigned to a 2 × 2 factorial arrangement with two concentrations of dietary MCE supplementation (0 or 350 mg/kg of diet) and two disease challenge statuses (control or NE).

RESULTS

The results revealed that NE significantly increased the feed conversion rate (FCR), mortality, intestinal lesion score, the levels of IL-1β, IL-17 and IFN-γ/IL-4 in serum and IL-17/IL-10 in the jejunal mucosa, mRNA levels of TLR2, IFN-γ and pIgR in the jejunum, and Clostridium perfringens concentrations in the cecum. NE significantly decreased the body weight (BW), body weight gain (BWG), jejunal villus height, V/C, mRNA level of AMPK-α1 in jejunum, IL-4 level in the jejunal mucosa and lactic acid bacteria abundance in the cecum. MCE significantly increased BW, BWG, jejunal villus height, V/C, mRNA levels of occludin, ZO-1 and AMPK-α1 in the jejunum, the levels of IgA and IgG in serum and IL-10 in the jejunal mucosa and mRNA levels of NF-κB, IL-10 and MHC-II in the jejunum. Additionally, MCE significantly decreased the FCR, mortality, intestinal lesion score, jejunal crypt depth, the levels of IFN-γ and IL-17 in serum and IL-17/IL-10 in the jejunal mucosa, Clostridium perfringens concentrations in the cecum, and mRNA levels of IL-17/IL-10 in the jejunum. Moreover, NE significantly increased the abundance of bacteria that are associated with inflammation, obesity and depression (Alistipes, Barnesiella, Intestinimonas, RF39 and UCG-005) and significantly decreased the abundance of short-chain fatty acid (SCFA)-producing bacteria (Anaerotruncus, Butyricicoccus and Bacteroides) in the cecum. MCE significantly increased the abundance of SCFA-producing bacteria (Streptococcus, Ruminococcus_torques_group and Lachnospiraceae_NK4A136_group) and significantly reduced the abundance of bacteria that are associated with inflammation and obesity (Alistipes, Barnesiella and UCG-010) in the cecum. In the cecum of broilers with NE, the relative abundance of Barnesiella and Alistipes was higher and that of Lachnoclostridium and Shuttleworthia was lower. Interestingly, these trends were reversed by the addition of MCE to the diet. Spearman correlation analysis showed that Barnesiella and Alistipes were associated with enhanced intestinal inflammation and inhibited growth performance, whereas Lachnoclostridium and Shuttleworthia were associated with anti-inflammatory effects.

CONCLUSIONS

MCE ameliorated the loss of growth performance in broiler chickens with NE, probably by regulating the intestinal barrier, immune function, and gut microbiota.

Effects of Tannic Acid Supplementation on the Intestinal Health, Immunity, and Antioxidant Function of Broilers Challenged with Necrotic Enteritis

Clostridium perfringens causes necrotic enteritis (NE) after proliferation in the intestine of poultry, resulting in considerable losses to the poultry industry. This study aimed to investigate the impact of tannic acid on the antioxidant, immunity, and gut health of broilers with NE. In the experiment, 630 one-day-old Cobb500 male chicks were randomly divided into six treatment groups, with seven replicate cages and with fifteen birds in each cage. The treatment groups were as follows: control group (NC), challenged group (PC), and challenged NE chickens treated with 250, 500, 750, and 1000 mg/kg tannic acid (PTA1, PTA2, PTA3, and PTA4, respectively). To induce NE, coccidia vaccine and Clostridium perfringens were administered on day 19 and days 22-28, respectively. Indexes related to antioxidant, immune, and intestinal health were measured on days 28 and 35. During the infection period, we observed significant increases in fecal water content, D-LA, TNF-α, and malondialdehyde concentrations (p < 0.05). Conversely, significant decreases were noted in chyme pH and in T-AOC, IL-4, and IL-10 concentrations (p < 0.05). The addition of tannic acid exhibited a linear decrease in fecal water content and TNF-α concentration (p < 0.05). Furthermore, tannic acid supplementation resulted in a quadratic curve decrease in D-LA concentration and linear increases in T-AOC, IL-4, and IL-10 (p < 0.05). Cecal microbiological analysis revealed that Ruminococcaceae and Butyricimona were dominant in PTA3. In conclusion, the dietary addition of tannic acid may reduce the negative effects of NE by increasing antioxidant and anti-inflammatory capacity, improving the intestinal barrier, and regulating the intestinal flora.

Dietary supplemental coated essential oils and organic acids mixture improves growth performance and gut health along with reduces Salmonella load of broiler chickens infected with Salmonella Enteritidis

BACKGROUND

Reducing Salmonella infection in broiler chickens by using effective and safe alternatives to antibiotics is vital to provide safer poultry meat and minimize the emergence of drug-resistant Salmonella and the spread of salmonellosis to humans. This study was to first evaluate the protective efficacy of feeding coated essential oils and organic acids mixture (EOA) on broiler chickens infected with Salmonella Enteritidis (S. Enteritidis, SE), and then its action mechanism was further explored.

METHODS

A total of 480 1-day-old Arbor Acres male chickens were randomly assigned into five treatments with six replicates, including non-challenged control fed with basal diet (A), SE-challenged control (B), and SE-infected birds fed a basal diet with 300 mg/kg of EOA (BL), 500 mg/kg of EOA (BM) and 800 mg/kg of EOA (BH), respectively. All birds on challenged groups were infected with Salmonella Enteritidis on d 13.  RESULTS: Feeding EOA showed a reversed ability on negative effects caused by SE infection, as evidenced by decreasing the feed conversion rate (FCR) and the ratio of villus height to crypt depth (VH/CD) (P < 0.05), obviously decreasing intestinal and internal organs Salmonella load along with increasing cecal butyric acid-producing bacteria abundance (P < 0.05). Moreover, supplemental different levels of EOA notably up-regulated claudin-1 (CLDN-1), occludin (OCLN), zonula occludens-1 (ZO-1), mucin-2 (MUC-2), fatty acid binding protein-2 (FABP-2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), myeloid differential protein-88 (MyD88) and interleukin-6 (IL-6) mRNA levels in the ileum of the infected chickens after challenge, whereas down-regulated toll-like receptor-4 (TLR-4) mRNA levels (P < 0.05). Linear discriminant analysis combined effect size measurements analysis (LEfSe) showed that the relative abundance of g_Butyricicoccus, g_Anaerotruncus and g_unclassified_f_Bacillaceae significantly was enriched in infected birds given EOA. Also, phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis showed that alpha-linolenic acid metabolism, fatty acid metabolism and biosynthesis of unsaturated fatty acids were significantly enriched in the EOA group.

CONCLUSION

Our data suggest that the essential oils and organic acids mixture can be used as an effective strategy to ameliorate and alleviate Salmonella Enteritidis infection in broilers.

Dietary Probiotics Modulate Gut Barrier and Immune-Related Gene Expression and Histomorphology in Broiler Chickens under Non- and Pathogen-Challenged Conditions: A Meta-Analysis

Data published in the literature about the favorable effects of dietary probiotics on gut health in broiler chickens are inconsistent. To obtain a more comprehensive understanding, we conducted a meta-analysis to assess the effects of probiotics on the gut barrier and immune-related gene expression, histomorphology, and growth in chickens that were either challenged or non-challenged with pathogens. From the 54 articles published between 2012 and 2022, subsets of data, separately for non-challenged and challenged conditions, for response variables were created. The mean dietary probiotic concentrations ranged from 4.7 to 6.2 and 4.7 to 7.2 log₁₀ colony-forming unit/kg under non-challenged and challenged conditions, respectively. Probiotics increased the expression of genes for mucins and tight junction proteins in the jejunum and ileum at weeks 3 and 6. The stimulatory effect of probiotics on tight junction protein expression was partly stronger in challenged than in non-challenged birds. Meta-regressions also showed an anti-inflammatory effect of probiotics under challenged conditions by modulating the expression of cytokines. Probiotics improved villus height at certain ages in the small intestine while not influencing growth performance. Dietary metabolizable energy, crude protein, and days post-infection modified the effects of probiotics on the observed variables. Overall, meta-regressions support the beneficial effects of probiotics on gut integrity and structure in chickens.

Encapsulated peracetic acid as a valid broad-spectrum antimicrobial alternative, leading to beneficial microbiota compositional changes and enhanced performance in broiler chickens

BACKGROUND

Antimicrobial alternatives are urgently needed, including for poultry production systems. In this study, we tested the potential broad-range antimicrobial alternative peracetic acid, delivered in feed via the hydrolysis of encapsulated precursors through a 28-day study using 375 Ross 308 broiler chickens. We tested two peracetic acid concentrations, 30 and 80 mg/kg on birds housed on re-used litter, and we evaluated the impact of both levels on gut microbial communities, bacterial concentration, antimicrobial resistance genes relative abundance and growth performance when compared to control birds housed on either clean or re-used litter.

RESULTS

Body weight gain and feed conversion ratio improved in peracetic acid fed birds. At d 28, birds given 30 mg/kg of peracetic acid had a decreased Firmicutes and an increased Proteobacteria abundance in the jejunum, accompanied by an increase in Bacillus, Flavonifractor and Rombustia in the caeca, and a decreased abundance of tetracycline resistance genes. Chicken given 80 mg/kg of peracetic acid had greater caecal abundance of macrolides lincosamides and streptogramins resistance genes. Growth performance on clean litter was reduced compared to re-used litter, which concurred with increased caecal abundance of Blautia, decreased caecal abundance of Escherichia/Shigella, Anaerostipes and Jeotgalicoccus, and greater gene abundance of vancomycin, tetracycline, and macrolides resistance genes.

CONCLUSIONS

Peracetic acid could be used as a safe broad-spectrum antimicrobial alternative in broilers. Encapsulated precursors were able to reduce the bacterial concentration in the jejunum whilst promoting the proliferation of probiotic genera in the caeca, especially at the low peracetic acid concentrations tested, and improve growth performance. Moreover, our findings offer further insights on potential benefits of rearing birds on re-used litter, suggesting that the latter could be associated with better performance and reduced antimicrobial resistance risk compared to clean litter rearing.

Effects of tannic acid on the immunity and intestinal health of broiler chickens with necrotic enteritis infection

BACKGROUND

In broiler chickens, necrotic enteritis (NE) infection can reduce production performance. Tannic acid has shown great potential as a treatment of NE in broilers. However, the appropriate dosage of tannic acid in NE of broilers and the improvement effect on intestinal health are not very clear. In this study, we aimed to investigate the effects of different doses of tannic acid on the production performance, immunity, and intestinal health of broilers by constructing an NE model with C. perfringens infection and determining the appropriate dosage of tannic acid with regard to NE.

RESULTS

Challenged birds showed significant reduction in body weight, villus height, and the ratio of villus height to crypt depth (P < 0.05) and increase in the feed consumption gain ratio, intestinal lesion score, and crypt depth (P < 0.05). The infection significantly reduced the relative Bacteroidota and Ligilactobacillus abundance (P < 0.05) and increased the ratio of Firmicutes/Bacteroidota and cecal content of C. perfringens (P < 0.05). Challenged birds fed diets supplemented with tannic acid showed significantly increased mRNA expression of nutrient transport carriers and intestinal barrier genes and growth performance and reduced serum zonulin and endotoxin levels (P < 0.05). Addition of tannic acid to the diet inhibited the inflammatory response by reducing the number of coccidia oocysts in feces and the content of C. perfringens in the cecum. Specifically, tannic acid reduced the serum levels of C reactive protein, myeloperoxidase, and specific IgY and ileal mucosal secretory immunoglobulin A levels in the ileal mucosa compared with those in the NE-infected birds. NE-infected birds fed diets supplemented with tannic acid also showed significantly increased relative Anaerocolumna, Thermoanaerobacterium, and Thermosinus abundance (P < 0.05); their microbial composition and functional predictions were similar to those of the NC group.

CONCLUSIONS

Tannic acid in the diet alleviated NE by enhancing the intestinal barrier and absorption function. The recommended dietary tannic acid additive level is 500-750 mg/kg. Our study findings would be useful in reducing related economic losses in the broiler industry.

Effects of Vitamin A on Immune Responses and Vitamin A Metabolism in Broiler Chickens Challenged with Necrotic Enteritis

Necrotic enteritis (NE) is an important enteric inflammatory disease of poultry, and the effects of vitamin A (VitA) on NE birds are largely unknown. The present study was conducted to investigate the effects of VitA on the immune responses and VitA metabolism of NE broilers as well as the underlying mechanisms. Using a 2 × 2 factorial arrangement, 336 1-day-old Ross 308 broiler chicks were randomly assigned to 4 groups with 7 replicates. Broilers in the control (Ctrl) group were fed a basal diet without extra VitA supplementation. Broilers in the VitA group were fed a basal diet supplemented with 12,000 IU/kg of VitA. Birds in NE and VitA + NE groups were fed corresponding diets and, in addition, co-infected with Eimeria spp. and Clostridium perfringens on days 14 to 20. Samples of the blood, jejunum, spleen and liver were obtained on day 28 for analysis, and meanwhile, lesion scores were also recorded. The results showed that NE challenge increased lesion score in the jejunum and decreased serum glucose, total glyceride, calcium, phosphorus and uric acid levels (p < 0.05). VitA supplementation reduced the levels of serum phosphorus, uric acid and alkaline phosphatase in NE-challenged birds and increased serum low-density lipoprotein content and the activity of aspartate aminotransferase and creatine kinase (p < 0.05). Compared with the Ctrl group, the VitA and NE groups had higher mRNA expression of interferon-γ in the jejunum (p < 0.05). NE challenge up-regulated mRNA expression of interleukin (IL)-13, transforming growth factor-β4, aldehyde dehydrogenase (RALDH)-2 and RALDH-3 in the jejunum, while VitA supplementation increased jejunal IL-13 mRNA expression and hepatic VitA content, but down-regulated splenic IL-13 mRNA expression (p < 0.05). The VitA + NE group had higher serum prostaglandin E₂ levels and the Ctrl group had higher splenic RALDH-3 mRNA expression than that of the other three groups (p < 0.05). NE challenge up-regulated jejunal retinoic acid receptor (RAR)-β and retinoid X receptor (RXR)-α as well as splenic RAR-α and RAR-β mRNA expression (p < 0.05). VitA supplementation up-regulated jejunal RAR-β expression but down-regulated mRNA expression of RXR-α, RXR-γ, signal transducers and activators of transcription (STAT) 5 and STAT6 in the spleen (p < 0.05). Moreover, compared with the Ctrl group, the VitA and NE groups had down-regulated mRNA expression of jejunal and splenic Janus kinase (JAK) 1 (p < 0.05). In conclusion, NE challenge induced jejunal injury and expression of Th2 and Treg cell-related cytokines and enhanced RALDH and RAR/RXR mRNA expression, mainly in the jejunum of broilers. VitA supplementation did not alleviate jejunal injury or Th2 cell-related cytokine expression; however, it improved hepatic VitA deposition and inhibited the expression of RALDH-3, RXR and the JAK/STAT signaling pathway in the spleen of broilers. In short, the present study suggested the modulatory effects of vitamin A on the immune responses and vitamin A metabolism in broiler chickens challenged with necrotic enteritis.

Recent Trends on Mitigative Effect of Probiotics on Oxidative-Stress-Induced Gut Dysfunction in Broilers under Necrotic Enteritis Challenge: A Review

Gut health includes normal intestinal physiology, complete intestinal epithelial barrier, efficient immune response, sustained inflammatory balance, healthy microbiota, high nutrient absorption efficiency, nutrient metabolism, and energy balance. One of the diseases that causes severe economic losses to farmers is necrotic enteritis, which occurs primarily in the gut and is associated with high mortality rate. Necrotic enteritis (NE) primarily damages the intestinal mucosa, thereby inducing intestinal inflammation and high immune response which diverts nutrients and energy needed for growth to response mediated effects. In the era of antibiotic ban, dietary interventions like microbial therapy (probiotics) to reduce inflammation, paracellular permeability, and promote gut homeostasis may be the best way to reduce broiler production losses. The current review highlights the severity effects of NE; intestinal inflammation, gut lesions, alteration of gut microbiota balance, cell apoptosis, reduced growth performance, and death. These negative effects are consequences of; disrupted intestinal barrier function and villi development, altered expression of tight junction proteins and protein structure, increased translocation of endotoxins and excessive stimulation of proinflammatory cytokines. We further explored the mechanisms by which probiotics mitigate NE challenge and restore the gut integrity of birds under disease stress; synthesis of metabolites and bacteriocins, competitive exclusion of pathogens, upregulation of tight junction proteins and adhesion molecules, increased secretion of intestinal secretory immunoglobulins and enzymes, reduction in pro-inflammatory cytokines and immune response and the increased production of anti-inflammatory cytokines and immune boost via the modulation of the TLR/NF-ĸ pathway. Furthermore, increased beneficial microbes in the gut microbiome improve nutrient utilization, host immunity, and energy metabolism. Probiotics along with biosecurity measures could mitigate the adverse effects of NE in broiler production.

Effect of fermented heat-treated rice bran on performance and possible role of intestinal microbiota in laying hens

Rice bran is a high-quality and renewable livestock feed material rich in nutrients and bioactive substances. To investigate the effects of dietary supplementation with fermented heat-treated rice bran on the performance, apparent digestibility of nutrients, cecal microbiota and metabolites in laying hens, a total of 128 18-week-old Hy-Line brown layers were randomly assigned to four treatment groups: 2.5% HRB (basal diet contained 2.5% heat-treated rice bran), 5.0% HRB (5.0% heat-treated rice bran), 2.5% FHRB (2.5% fermented heat-treated rice bran), 5.0% FHRB (5.0% fermented heat-treated rice bran). Results showed that FHRB supplementation significantly increased the average daily feed intake (ADFI) during 25-28 weeks, and improved apparent digestibility of dry matter (DM), crude protein (CP), ether extract (EE) and crude fiber (CF) in laying hens. Moreover, feeding 5.0% of HRB and FHRB resulted higher egg production (EP) and average egg weight (AEW) during the feeding period, and decreased the feed conversion ratio (FCR) during 21 to 28 weeks. The alpha and beta diversity indices indicated that FHRB altered the cecal microbiota. In particular, dietary supplementation with FHRB significantly increased the relative abundances of Lachnospira and Clostridium. Compared with the 2.5% level of supplementation, supplementing 5.0% HRB and 5.0% FHRB increased the relative abundances of Firmicutes, Ruminococcus and Peptococcus, and lowered the relative abundance of Actinobacteria. Furthermore, dietary FHRB supplementation significantly increased the concentration of short-chain fatty acids in cecum and changed the overall metabolome. The results of correlation analysis showed a close interaction between cecal microbiota, metabolites and apparent digestibility of nutrients. Taken together, we revealed that FHRB supplementation can induce characteristic structural and metabolic changes in the cecal microbiome, which could potentially promote nutrient digestion and absorption, and improve the production performance of laying hens.

Application of Weizmannia coagulans in the medical and livestock industry

Purpose

Products enriched with probiotics have always been fashionable. Weizmannia coagulans has become a hot research topic in the academic community due to their multiple functional properties and high resistance to stress, which can retain their activity in a variety of harsh environments. This review aims to evaluate the probiotic effects of different strains of Weizmannia coagulans in animals and humans and to inspire better exploitation of the value of this strain.

Methods

This review summarizes the latest research progress of Weizmannia coagulans from two major applications in animal breeding and human health.

Results

The functional properties of Weizmannia coagulans are extensively recognized. In animals, the strain can promote nutrient absorption, reduce mortality, and enhance the slaughter rate in livestock and poultry. In humans, the strain can be used to treat gastrointestinal disorders, immunomodulation, depressive symptoms, and non-alcoholic fatty liver. Weizmannia coagulans is projected as an ideal substitute for antibiotics and other chemical drugs.

Conclusion

Despite the outstanding functional properties of Weizmannia coagulans, there are numerous strains of Weizmannia coagulans and significant differences between strains in functional and physiological properties. Currently, there are few literature reports on the probiotic mechanism and functional gene identification of Weizmannia coagulans, which is crucial for the commercialization of Weizmannia coagulans and the benefit of human society.

Dietary supplementation of Macleaya cordata extract and Bacillus in combination improve laying performance by regulating reproductive hormones, intestinal microbiota and barrier function of laying hens

BACKGROUND

This study aimed to investigate whether the combination of Macleaya cordata extract (MCE) and Bacillus could improve the laying performance and health of laying hens better.

METHODS

A total of 360 29-week-old Jingbai laying hens were randomly divided into 4 treatments: control group (basal diet), MCE group (basal diet + MCE), Probiotics Bacillus Compound (PBC) group (basal diet + compound Bacillus), MCE + PBC group (basal diet + MCE + compound Bacillus). The feeding experiment lasted for 42 d.

RESULTS

The results showed that the laying rate and the average daily egg mass in the MCE + PBC group were significantly higher than those in the control group (P < 0.05) and better than the MCE and PBC group. Combination of MCE and Bacillus significantly increased the content of follicle-stimulating hormone (FSH) in the serum and up-regulated the expression of related hormone receptor gene (estrogen receptor-β, FSHR and luteinizing hormone/choriogonadotropin receptor) in the ovary of laying hens (P < 0.05). In the MCE + PBC group, the mRNA expressions of zonula occluden-1, Occludin and mucin-2 in jejunum was increased and the intestinal epithelial barrier detected by transmission electron microscopy was enhanced compared with the control group (P < 0.05). In addition, compared with the control group, combination of MCE and Bacillus significantly increased the total antioxidant capacity and catalase activity (P < 0.05), and down-regulated the mRNA expressions of inflammation-related genes (interleukin-1β and tumor necrosis factor-α) as well as apoptosis-related genes (Caspase 3, Caspase 8 and P53) (P < 0.05). The concentration of acetic acid and butyric acid in the cecum content of laying hens in the MCE + PBC group was significantly increased compared with the control group (P < 0.05).

CONCLUSIONS

Collectively, dietary supplementation of 600 μg/kg MCE and 5 × 10⁸ CFU/kg compound Bacillus can improve laying performance by improving microbiota to enhance antioxidant capacity and intestinal barrier, regulate reproductive hormones and the concentration of cecal short-chain fatty acids of laying hens, and the combined effect of MCE and Bacillus is better than that of single supplementation.

Stimbiotic supplementation modulated intestinal inflammatory response and improved boilers performance in an experimentally-induced necrotic enteritis infection model

Background

Two experiments were conducted to establish an optimal NE challenge model and evaluate the efficacy of stimbiotic (STB) supplementation in necrotic enteritis (NE) challenged broilers. In Exp. 1, a total of 120 Arbor Acres (AA) broilers (45.0 ± 0.21 g) were randomly assigned to 6 treatments in a 3 × 2 factorial arrangement. Vaccine treatments included non-challenge (0), × 10 the recommended dose (× 10) or × 20 the recommended dose (× 20) by the manufacturer. Clostridium perfringens (CP) treatments were non-challenge (No) or 3 mL of 2.2 × 10⁷ CFU CP challenge (Yes). In Exp. 2, a total of 72 AA broilers (40.17 ± 0.27 g) were randomly assigned to 6 treatments in a 3 × 2 factorial arrangement. Dietary treatments included non-additive (CON), 100 mg/kg STB (STB) and 100 mg/kg STB on top of a typical commercial blend including an essential oil, probiotics, and enzyme (CB). Challenge treatments included non-NE challenge (No) and NE challenge (Yes) as established in Exp. 1.

Results

In Exp. 1, CP and vaccine challenge decreased (P < 0.05) body weight (BW), body weight gain (BWG) and feed intake (FI), and increased (P < 0.05) the number of broilers with diarrhea and intestinal lesions. The oral administration of × 20 recommended dose of vaccines coupled with 3 mL of 2.2 × 10⁷ CFU CP resulted in (P < 0.01) a significantly increased incidence of wet litter and intestinal lesions. Thus, this treatment was chosen as the challenge model for the successful inducement of NE in Exp. 2. In Exp. 2, the NE challenge negatively affected (P < 0.01) growth performance, ileal morphology, immunoglobulin contents in blood, caecal microbiota in the caecum, footpad dermatitis, intestinal lesion scores, tumour necrosis factor (TNF-α) and endotoxin in the serum compared with the non-NE challenged birds. The supplementation of STB and CB in diets enhanced (P < 0.05) growth performance, intestinal microbiota, and blood profiles by stimulating ileal morphology (VH and VH:CD) and propionate production in the cecum, and there were no differences in measured variables between STB and CB supplemented birds.

Conclusion

Overall, these results indicate that STB supplementation was able to reduce the inflammatory response and improve the performance of NE challenged birds, and the supplementation of STB alone was as effective as a typical commercial blend containing a number of other additives.

The Effect of Supplementation with Weizmannia coagulans Strain SANK70258 to Coccidia-Infected Broilers Is Similar to That of a Coccidiostat Administration

To determine whether it could also improve the production performance of Eimeria-infected broilers, Weizmannia coagulans strain SANK70258 (WC) supplementation was compared with coccidiostat lasalocid-A sodium (AM) administration. First, to determine the optimum WC dose, newly hatched broiler chick groups (n = 10) were untreated or consecutively given WC (0.005%, 0.01%, 0.03%, and 0.1%) and AM until slaughter (31 days of age). At day 21, all chicks were infected with coccidia. From the economical and practical viewpoints, 0.03% WC supplementation was the best dose. Second, newly hatched broiler chick groups (n = 10) were untreated or given 0.03% WC and AM. Each group was run in triplicate. At day 21, two chicks/pen with the farthest body weights as per the group’s mean body weight were spared, and the remaining inoculated with coccidia. At days 42 and 49, the WC and AM groups had significantly greater body weights and daily weight gains. Intestinal lesion scores were lower in 29-day-old AM and WC. Oocyst numbers were lower in 29- and 49-day-old AM and WC, but only 29- and 49-day-old AM had higher Escherichia coli levels. To conclude, although WC and AM induced similar growth performance in coccidium-infected chicks, unlike AM, the E. coli levels did not increase with WC.

Effect of dietary Bacillus coagulans on the performance and intestinal microbiota of weaned piglets

The performance of weaned piglets suffers from severe limitations resulting from diarrhoea. Therefore, this trial was performed to investigate the effects of Bacillus coagulans as an alternative to antibiotics on piglet growth performance and intestinal health. Ninety (initial BW = 7.70 ± 0.17 kg, weaning age of 26 days) healthy weaned piglets with similar BWs were selected and randomised into three treatment groups. Pigs in the negative control (NC) group were fed a basal diet, pigs in the positive control (PC) group were fed the basal diet plus antibiotics, and pigs in the test group (BC) were fed the basal diet plus Bacillus coagulans at 600 g/t; the trial lasted for 28 days. The results showed that the ratios of feed to gain (F:G) of both the BC and PC groups from 1 to 21 days were significantly lower (P < 0.05), and the average daily weight gain (ADG) of the BC group from 22 to 28 days was significantly higher (P < 0.05) than that of the NC group in terms of growth performance. The diarrhoea index was lowest in the PC group, followed by the BC group, and highest in the NC group. The BC group had a lower diarrhoea index at the later stage. We performed 16S rRNA sequencing to measure the intestinal bacteria and found that the BC group had a higher intestinal bacteria diversity than the NC and PC groups (P < 0.05). From days 1 to 21, the main differential species were Ruminococcaceae_UCG-014 and Faecalibacterium (P < 0.05); from days 22 to 28, the main differential species were Prevotella_9, unclassified_f__Lachnospiraceae, Anaerovibrio, and Ruminococcaceae_UCG-002 (P < 0.05). The correlation analysis between growth performance and species revealed specific gut microorganisms responsible for variation in F:G, ADG, and diarrhoea index, such as Prevotellaceae, Clostridium_sensu_stricto_1, Ruminococcaceae, Phascolarctobacterium, and Anaerovibrio. In conclusion, Bacillus coagulans changed the microbial composition in the faeces of weaned piglets, which had positive effects on growth performance and the diarrhoea index. Therefore, our study provided new insight into the future application of Bacillus coagulans as an additive.

Bacillus Probiotics as Alternatives to In-feed Antibiotics and Its Influence on Growth, Serum Chemistry, Antioxidant Status, Intestinal Histomorphology, and Lesion Scores in Disease-Challenged Broiler Chickens

In commercial poultry production, chickens are reared under intensive conditions, which may allow infections to spread quickly. Antibiotics are used at sub-therapeutic doses in livestock and poultry feed to prevent diseases and improve productivity. However, restrictions on the use of antibiotics at sub-therapeutic concentrations in livestock feed due to growing concerns of antimicrobial resistance (AMR), together with antibiotic residues in meat and eggs has prompted poultry researchers and feed producers to look for viable alternatives. Thus, there is increasing interest in developing natural alternatives to in-feed antibiotics to improve chicken productivity and health. Probiotics, specifically from the genus Bacillus have proven to be effective due to their spore-forming capabilities. Furthermore, their ability to withstand heat during feed processing and be stored for a long time without losing viability as well as their potential to function in the acidic medium of the chicken gut, provide them with several advantages over conventional probiotics. Several studies regarding the antimicrobial and antioxidant activities of Bacillus probiotics and their positive impact in chicken nutrition have been documented. Therefore, the present review shields light on the positive effect of Bacillus probiotics as alternatives to in-feed antibiotics on growth performance, serum chemistry, antioxidant status, intestinal histomorphology and lesion scores of disease-challenged broiler chickens and the mechanisms by which they exert their actions. It is concluded that Bacillus probiotics supplementation improve growth, health and productive indices of disease-challenged broiler chickens and can be a good alternative to in-feed antibiotics. However, more studies are required on the effect of Bacillus probiotics supplementation in broiler chickens to maximize productivity and achieve the ultimate goal of stopping the usage of antibiotics at sub-therapeutic doses in broiler chicken feed to enhance performance.

Dietary ellagic acid ameliorated Clostridium perfringens-induced subclinical necrotic enteritis in broilers via regulating inflammation and cecal microbiota

Background

Subclinical necrotic enteritis (SNE), a common intestinal disease of broiler caused by Clostridium perfringens, could reduce production performance of broilers by chronic intestinal damage and poor absorption of nutrients. Ellagic acid (EA) has been reported to present antioxidant and anti-inflammatory properties on human and animals in many aspects. This study was conducted to evaluate the effect and mechanism of EA in relieving SNE in broilers induced by C. perfringens.

Results

C. perfringens challenge decreased body weight (BW), average daily gain (ADG), jejunal villi height/crypt depth (V/C) ratio, the activity of catalase (CAT) and the mRNA expression of zonula occludens 1 (ZO-1) in jejunal mucosa of broilers. While feed conversion ratios (FCR), jejunal crypt depth (CD), the activities of myeloperoxidase (MPO) and diamine oxidase (DAO), as well as the concentrations of interleukin 6 (IL-6), C-reactive protein (CRP) and procalcitonin (PCT) in serum, the activities of inducible nitric oxide synthase (iNOS) and lysozyme (LZM), the concentration of malondialdehyde (MDA), and the mRNA expressions of claudin-2, TNF-α, IL-1β, TLR-4, TLR-2, NF-κB, JAK3, STAT6 and iNOS in jejunal mucosa of broilers were increased by C. perfringens challenge. Dietary EA supplement relieved these adverse effects, and heightened jejunal villi height (VH), the concentration of D-xylose in plasma, activity of superoxide dismutase (SOD), and the mRNA expression of occludin in jejunal mucosa of broilers. The alpha diversity of cecal microbiota indicated that dietary EA supplement increased observed species and Shannon index. C. perfringens challenge increased the relative abundance of Firmicutes and decreased the relative abundance of Desulfobacterota in cecal microbiota. EA increased the relative abundance of Firmicutes in cecal microbiota. LEfSe analysis showed that C. perfringens challenge triggered the imbalance of cecal microbiota in broilers, dietary EA supplementation led to a small beneficial effect on microbiota, while the simultaneous effect of them seemed to stimulate the immune function of broilers by improving the microbiota balance.

Conclusions

Dietary EA ameliorated C. perfringens-induced SNE in broilers via regulating jejunal inflammation signaling pathways TLR/NF-κB and JAK3/STAT6, relieving jejunal oxidative stress and balancing cecal microbiota to inhibit intestinal barrier damage, prevent systemic inflammatory response and improve nutrient absorption capacity, finally protect and enhance growth performance of broilers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00694-3.

Effects of Dietary Astragalus Polysaccharide Supplementation on the Th17/Treg Balance and the Gut Microbiota of Broiler Chickens Challenged With Necrotic Enteritis

This study aimed to investigate the effects of dietary astragalus polysaccharide (APS) supplementation on the immune function, gut microbiota and metabolism of broiler chickens challenged with necrotic enteritis (NE). Two hundred forty Arbor Acres broiler chicks (one day old) were randomly assigned using a 2 × 2 factorial arrangement into two groups fed different levels of dietary APS (0 or 200 ppm of diet) and two disease challenge groups (control or NE challenged). The results showed that NE infection significantly increased FCR, mortality rate, Th17/Treg (Th17 cells% in blood and ileum, Th17/Treg, IL-17 and IL-17/IL-10 in blood), NO, lysozyme activity and IL-1β in blood, intestinal immune cell proportion and activity (Tc%, Treg% and monocyte phagocytic activity in ileum), intestinal inflammatory cytokines (TLR2, NF-κB, TNF-α and IL- 6) gene expression levels, and the number of Clostridium perfringens in cecum. NE infection significantly reduced body weight gain, thymus index, lymphocyte proliferation activity in blood and ileum, villus height and V/C in jejunum, Th cells% and Mucin2 gene expression in ileum. Dietary APS supplementation significantly increased body weight, feed intake, proportion of immune cells (T cells in blood and Tc, Treg in ileum), lymphocyte proliferation activity, V/C in jejunum, and ZO-1 gene expression in ileum. Dietary APS supplementation significantly reduced FCR and mortality rate, Th17/Treg, Th17%, intestinal pathology scores, intestinal inflammatory cytokine gene expression levels, and the number of Clostridium perfringens in cecum. In addition, broilers challenged with NE significantly increased Staphylococcus and Turicibacter and reduced α diversity of microbiota in ileum. Dietary APS supplementation significantly increased α diversity, Romboutsia, Halomonas, propionic acid, butyric acid, formononetin, taurine, cholic acid and equol and downregulated uric acid, L-arginine and serotonin in ileum. Spearman’s correlation analysis revealed that Romboutsia, Turicibacter, Staphylocpccus, Halomonas, Streptococcus, Escherichia-Shigella, Prevotella, uric acid, L-arginine, jerivne, sodium cholate and cholic acid were related to inflammation and Th17/Treg balance. In conclusion, APS alleviated intestinal inflammation in broilers challenged with NE probably by regulating intestinal immune, Th17/Treg balance, as well as intestinal microbiota and metabolites.

Probiotic Bacillus subtilis LF11 Protects Intestinal Epithelium Against Salmonella Infection

Enteric diseases caused by Salmonella are prevalent in poultry farming. With the forbiddance of antibiotics in feedstuff industry, Bacillus subtilis (B. subtilis) preparation as antibiotic alternatives against Salmonella infection has gained increasing attention recently. However, the protection modes of B. subtilis against Salmonella infection in broilers are strain-specific. In this study, probiotic B. subtilis LF11 significantly reduced diarrhea and mortality of broilers caused by Salmonella braenderup (S. braenderup) in spite of no inhibition effect on it in vitro. Here, the intestinal epithelial cells NCM460 were incubated to explore the protection of B. subtilis LF11 on intestinal epithelium against Salmonella. The results revealed that B. subtilis LF11 showed obvious exclusion activity with the decrease of adhesion and invasion of S. braenderup to NCM460 cells, accordingly with the increase of NCM460 cell survival compared with S. braenderup challenge alone. Meanwhile, RT-PCR and Western blot proved that the gene transcription and expression levels of four tight junction proteins in NCM 460 cells were upregulated, which was further confirmed by immunofluorescence observation. Besides, B. subtilis LF11 downregulated the gene transcription levels of the proinflammatory cytokines IL-6, IL-8, and TNF-α induced by S. braenderup H9812. ELISA analysis also verified that B. subtilis LF11 reduced the IL-8 production significantly. In general, B. subtilis LF11 has the ability to protect the intestinal epithelium against Salmonella infection by reducing the Salmonella adhesion and invasion, enhancing the intestinal barrier and attenuating the enterocyte inflammatory responses, and has the potential as probiotics to prevent enteric diseases in broilers.

Bacillus coagulans TL3 Inhibits LPS-Induced Caecum Damage in Rat by Regulating the TLR4/MyD88/NF-κB and Nrf2 Signal Pathways and Modulating Intestinal Microflora

Background

Bacillus coagulans has been widely used in food and feed additives, which can effectively inhibit the growth of harmful bacteria, improve intestinal microecological environment, promote intestinal development, and enhance intestinal function, but its probiotic mechanism is not completely clear.

Aim

The aim of this study is to discuss the effect and mechanism of Bacillus coagulans TL3 on oxidative stress and inflammatory injury of cecum induced by LPS.

Method

The Wistar rats were randomly divided into four groups, each containing 7 animals. Two groups were fed with basic diet (the LPS and control, or CON, groups). The remaining groups were fed with basic diet and either a intragastric administration high or low dose of B. coagulans, forming the HBC and LBC groups, respectively. The rats were fed normally for two weeks. On the 15th day, those in the LPS, HBC, and LBC groups were injected intraperitoneally with LPS—the rats in the CON group were injected intraperitoneally with physiological saline. After 4 hours, all the rats were anesthetized and sacrificed by cervical dislocation, allowing samples to be collected and labeled. The inflammatory and antioxidant cytokine changes of the cecum were measured, and the pathological changes of the cecum were observed, determining the cecal antioxidant, inflammation, and changes in tight junction proteins and analysis of intestinal flora.

Result

The results show that LPS induces oxidative damage in the cecal tissues of rats and the occurrence of inflammation could also be detected in the serum. The Western blot results detected changes in the NF-κB- and Nrf2-related signaling pathways and TJ-related protein levels. Compared with the LPS group, the HBC group showed significantly downregulated levels of expression of Nrf2, NQO1, HO-1, GPX, and GCLC. The expression of TLR4, MYD88, NF-κB, IL-6, TNFα, and IL-1β was also significantly downregulated, while the expression of other proteins (ZO-1, occludin, and claudin-1) increased significantly. Bacillus coagulans TL3 was also found to increase the relative abundance of the beneficial bacterium Akkermansia muciniphila in the intestines. There is also a significant reduction in the number of harmful bacteria Escherichia coli and Shigella (Enterobacteriaceae).

Conclusion

Bacillus coagulans TL3 regulates the TLR4/MyD88/NF-κB and Nrf2 signaling pathways in the cecal tissue of rats, protects the intestine from inflammation and oxidative damage caused by LPS, and inhibits the reproduction of harmful bacteria and promotes beneficial effects by regulating the intestinal flora bacteria grow, thereby enhancing intestinal immunity.

The Impact of Pre- and Probiotic Product Combinations on Ex vivo Growth of Avian Pathogenic Escherichia coli and Salmonella Enteritidis

Due to the global spread of antibiotic resistance, there is a strong demand to replace antimicrobial growth promotors in livestock. To identify suitable additives that inhibit the growth of avian pathogenic Escherichia coli O1/O18 and Salmonella enterica serotype Enteritidis strains, an ex vivo screening was performed. Inulin and fructooligosaccharides (FOS) were investigated as prebiotics. Enterococcus faecium and Bacillus coagulans served as probiotic strains. Firstly, the pathogen was anaerobically incubated in caecal digesta from different broiler breeder flocks with the addition of feed additives. Secondly, subsamples of these suspensions were incubated in an antibiotic medium for selective growth of the pathogen. During this step, turbidity was recorded, and lag times were calculated for each pathogen as readout of growth inhibition. Combinations of E. faecium with inulin or FOS significantly extended the lag time for E. coli compared to control. Moreover, older age was a significant factor to enhance this inhibitory effect. In contrast, the combination of FOS and B. coagulans showed shorter lag times for S. Enteritidis. Our results indicate that the E. faecium strain with prebiotics may inhibit the pathogen proliferation in the studied poultry flocks. Furthermore, our results suggest that prophylactic treatments should be assigned by feed additive, age and animal origin.

Effect of blending encapsulated essential oils and organic acids as an antibiotic growth promoter alternative on growth performance and intestinal health in broilers with necrotic enteritis

The effects of a blend of encapsulated organic acids with essential oils (EOA) as an alternative to antimicrobial growth promoter (AGP) on growth performance and gut health of Eimeria spp./Clostridium perfringens (C. perfringens) in chickens infected with necrotic enteritis (NE) broilers was investigated. A total of 432 male Arbor Acres broilers (1-day-old) were randomly distributed into 6 treatment groups, namely noninfected negative control (A); NE-infected positive control (D); NE-infected broiler chickens fed a basal diet supplemented with 250 mg/kg bacitracin methylene disalicylate (BMD) plus 90 mg/kg monensin; and NE-infected broiler chicken fed 200; 500; and 800 mg/kg EOA (E, F, G, and H group). Feeding EOA at 200 and 500 mg/kg considerably improved the feed conversion ratio, reduced gut lesions, serum fluorescein isothiocyanate dextran level, and C. perfringens load in the caecum and liver of the NE-infected broiler chickens. This feed was similar to AGP. Furthermore, the increased villous height-to-crypt depth ratio and goblet cells counts, upregulated claudin-1, glucagon-like peptide-2 (GLP-2), insulin-like growth factor-2 (IGF-2) mRNA gene expression, downregulated occludin, zonula occludens-1 (ZO-1), toll-like receptor (TLR-4), interleukin (IL-1β), interferon γ (IFN-γ), TNF receptor-associated factor 6 (TRAF-6), tumor necrosis factor superfamily member 15 (TNFSF15), and Toll-interacting protein (Tollip) genes expression in the jejunum were observed in the NE-infected broiler chickens that received EOA at 200 and 500 mg/kg compared with those of the single NE-challenged groups without EOA supplementations (P < 0.05). The 16S analysis revealed that EOA supplemented with 200 or 500 mg/kg enriched relative abundance of Lactobacillus, unclassified_Lachnospiraceae, and Enterococcus, and carbohydrate metabolic pathways but suppressed unclassified_Erysipelotrichacease and organismal systems involved in the immune system (P < 0.05). Feeding EOA could alleviate NE-induced gut impairment and growth depression and modulate cecal microbiota composition, which has potential as antimicrobial alternatives.

Bacillus coagulans protect against Salmonella enteritidis-induced intestinal mucosal damage in young chickens by inducing the differentiation of goblet cells

Bacillus coagulans (B. coagulans) have proven to be effective in improving the development of gut immunity and microbiome, and offering protection against pathogens, especially in young animals. The newborn chicks are highly vulnerable to the foodborne pathogenic Salmonella infections, leading to high mortality and economic loss. However, whether B. coagulans can protect young chickens from Salmonella-induced intestinal mucosal damage by modulating the development of intestinal epithelium remains unclear. In this study, B. coagulans with excellent anti-Salmonella property was selected and used. The results showed that B. coagulans alleviated the morphological damage, intestinal inflammation and body weight loss caused by Salmonella enteritidis (S. enteritidis) infections. B. coagulans significantly increased the crypt depth. Furthermore, the goblet cell loss and downregulating of mucin 2 induced by S. enteritidis were all relieved by B. coagulans treatment. Consistently, the expression of the related genes of Notch signaling pathway was also upregulated in the S. enteritidis group but inhibited by B. coagulans. In addition, B. coagulans improved the levels of immunoglobulin A, superoxide dismutase, total antioxidant capacity, and avian beta-defensin 2 in the intestinal mucosa. This study demonstrated that B. coagulans could regulate the development of intestinal epithelium, protect the intestinal barrier, thus relieve infections with S. enteritidis in chicks, which can be used as alternatives to antibiotics in poultry feed.

Immunomodulatory and ameliorative effects of probiotic in combination with diclazuril on broilers under coccidia infection

AIM

This study aimed to determine the potential prophylactic efficacy of probiotic individually and/or in combination with anti-coccidial drug on the performance and immunity of broilers under an induced coccidial infection over a 28-day of experimental trial.

METHODS

One hundred and eighty 1-day-old Cobb broiler chicks were randomly divided into five groups, included control group (CG), control positive group (CPG), probiotic-treated group (Prob), diclazuril-treated group (Dic), and probiotic + diclazuril-treated group (Prob + Dic). On day 21 of age, all birds, except group CG, were orally inoculated with 1 ml of tap water containing 25,000 Eimeria tenella sporulated oocysts.

RESULTS

Our results showed that the probiotic treatment did not influence pre-challenge body weight, feed intake and feed conversion ratio (FCR). During the post-challenge period, chickens in groups probiotic and diclazuril individually and in combination exhibited higher body weight and lower (better) FCR, reduced oocyst shedding (throughout the day four, five, six and seven post-infection), cecal lesions and mortality compared with control positive chickens. Moreover, Compared to CPG group, Prob + Dic group showed increased (p < 0.05) serum levels of interleukin-10 (IL-10) and immunoglobulin M (IgM) and decreased the concentrations of interferon gamma (IFN-γ). On the other hand, individual treatment with probiotic exhibited highest serum levels of IL-10 and IgM, while diclazuril alone increased the blood concentrations of IL-10 and decreased the levels of IFN-γ compared to control positive group; however, there was no significant effect of Prob on IFN-γ, Dic on IgM and all groups on interleukin-17.

CONCLUSION

In conclusion, supplementation of probiotic, with and/or without anti-coccidial drug, enhances immunity and inhibits the negative effects of Eimeria infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study reveals the anti-coccidial mechanisms of probiotic in the presence and absence of anti-coccidial drug in preventing the coccidia infection.

Dietary Supplementation With Lactobacillus plantarum Ameliorates Compromise of Growth Performance by Modulating Short-Chain Fatty Acids and Intestinal Dysbiosis in Broilers Under Clostridium perfringens Challenge

Clostridium perfringens is an important zoonotic pathogen associated with food contamination and poisoning, gas gangrene, necrotizing enterocolitis or necrotic enteritis in humans and animals. Dysbacteriosis is supposedly associated with the development of C. perfringens infection induced necrotic enteritis, but the detailed relationship between intestinal health, microbiome, and C. perfringens infection-induced necrotic enteritis remains poorly understood. This research investigated the effect of probiotics on the growth performance and intestinal health of broilers, and the involved roles of intestinal microbiota and microbial metabolic functions under C. perfringens infection. Results showed that subclinical necrotic enteritis was successfully induced as evidenced by the significant lower body weight (BW), suppressed feed conversion ratio (FCR), decreased ileal villus height and mucosal barrier function, and increased ileal histopathological score and bursal weight index. Lactobacillus plantarum or Paenibacillus polymyxa significantly attenuated C. perfringens-induced compromise of growth performance (BW, FCR) and ileal mucosa damage as illustrated by the increased ileal villus height and villus/crypt ratio, the decreased ileal histopathological score and the enhanced ileal mucosal barrier function. L. plantarum also significantly alleviated C. perfringens-induced enlarged bursa of fabricius and the decreased levels of ileal total SCFAs, acetate, lactate, and butyrate. Furthermore, dietary L. plantarum improved C. perfringens infection-induced intestinal dysbiosis as evidenced by significantly enriched short-chain fatty acids-producing bacteria (Lachnospiraceae, Ruminococcaceae, Oscillospira, Faecalibacterium, Blautia), reduced drug-resistant bacteria (Bacteroides, Alistipes) and enteric pathogens (Escherichia coli, Bacteroides fragilis) and bacterial metabolic dysfunctions as illustrated by significantly increased bacterial fatty acid biosynthesis, decreased bacterial lipopolysaccharide biosynthesis, and antibiotic biosynthesis (streptomycin and vancomycin). Additionally, the BW and intestinal SCFAs were the principal factors affecting the bacterial communities and microbial metabolic functions. The above findings indicate that dietary with L. plantarum attenuates C. perfringens-induced compromise of growth performance and intestinal dysbiosis by increasing SCFAs and improving intestinal health in broilers.

Effect of organic acids on growth performance, intestinal morphology, and immunity of broiler chickens with and without coccidial challenge

A total of 360-day-old broiler chicks were allocated into six groups in 2 (Coccidial challenge or not) × 3 (dietary treatments) factorial design. Three dietary treatments including: basic diet, basic diet plus organic acids (OAs) in drinking water, and basic diet plus OAs in the feed with and without coccidial challenge. The OAs in water or feed improved (P < 0.01) average body weight (ABW), average body weight gain (ABWG), and feed conversion ratio (FCR) as compared with the control diet during starter, grower, and whole experimental period. Coccidial challenge decreased BW, ABWG, and average feed intake (AFI), as well as resulted in poor FCR during the starter and whole experimental period (P < 0.05). Though there was no interaction between OAs supplementation and coccidial challenge, the OAs supplementation improved the overall performance with and without coccidial challenge birds on 21 d and 35 d. IgG was found higher (P = 0.03) in broilers fed OAs in feed without the coccidial challenge group. On 18 d, OAs supplementation in feed increased TNF-γ (P = 0.006), whereas the coccidial challenge decreases TNF-γ (P = 0.01) and IL-10 (P =  < .0001), and increases IgM (P = 0.03), IgG (P = 0.04) and IgA (P = 0.02). On 29 d, the coccidial challenge increases IgM and IgA. On 18 d, jejunal lesion score was found significantly higher in the coccidial challenged group as compared to OAs supplementation with coccidial challenged groups on 18 d (P < 0.0001) and 29 d (P = 0.03). Crypt depth was higher, and Villus-height to Crypt depth ratio was lower in the coccidial challenge group on 18 and 29 d. The Goblet cells were found higher in the non-coccidial challenge on 18 d. After 18 d, 16S rDNA gene sequence analysis of ileal chyme has shown that coccidial challenge decreases Lactobacillus_reuteri species as compared to the non-challenged group (P = 0.02). After 29, Cyanobacteria abundance reduced (P = 0.014) in the challenged group than the non-challenged group at the phylum level. At the genus level, Lactobacillus (P = 0.036) and unidentified Cyanobacteria (P = 0.01) were found higher in the non-challenged group than the coccidial challenge group. The results indicate that the OAs supplementation showed improved responses in a pattern similar to the non-challenged control group by neutralizing the negative effects of the coccidial challenge.

Clostridium butyricum Supplement Can Ameliorate the Intestinal Barrier Roles in Broiler Chickens Experimentally Infected With Clostridium perfringens

Necrotic enteritis (NE), caused by Clostridium perfringens, is an economically important disease in the broiler. Among normal flora in the broiler intestinal region, Clostridium butyricum has been identified as a probiotic agent that reduces the susceptibility of broilers to C. perfringens. However, the effects of C. butyricum supplement on broiler intestinal integrity during NE are largely unknown. In this study, we investigated the effects of C. butyricum on the growth performance, intestinal morphology and barrier function, and the functions of immune-related cytokines under NE in broilers. Chickens were divided into five groups: control group (NC), supplement C. butyricum only group (CB), NE-infected group (PC), supplement C. butyricum from Day 14 (NECB1) to Day 22 NE-infected group, and supplement C. butyricum from Day 1 (NECB2) to Day 22 NE-infected group. The results showed that there were significantly decreased average daily weight gain and increased feed conversion rate in the infected group (PC) compared with the C. butyricum-supplemented groups (NECB1 and NECB2) through the diet. Histopathological observation on the Hematoxylin–Eosin staining avian small intestine sections revealed that supplementation of C. butyricum (NECB1 and NECB2) could increase the intestinal villus height/crypt depth and lessen the intestinal damage under NE. ELISA and Limulus test showed that broilers infected with NE (PC) had higher serum IgA and lipopolysaccharide content; however, after C. butyricum supplementation (NECB1 and NECB2), they returned to a normal level. Furthermore, real-time PCR and Western blot results indicated that compared with PC, supplementing C. butyricum (NECB1 and NECB2) could initialize the expressions of genes related to the intestinal barrier-associated molecules (such as CLDN-1, CLDN-3, OCLN, MUC2, ZO-1, and CLDN5), cytokines (such as IL-10, IL-6, and TGFB1), and C. perfringens plc gene expression. Moreover, the results detected by the Ussing chamber suggested that C. butyricum (NECB1 and NECB2) could amend the decrease in conductivity value and short-circuit current value caused by NE. In addition, NECB2 significantly reduced the upregulation of fluorescein isothiocyanate–dextran flux caused by the NE disease. In conclusion, these findings suggest that dietary supplementation of C. butyricum in broilers with NE improved chicken growth performance, intestinal integrity and barrier function, and immunological status. Notably, no statistical difference was observed with the addition of C. butyricum on day 1 or day 14.

Bacillus subtilis DSM29784 Alleviates Negative Effects on Growth Performance in Broilers by Improving the Intestinal Health Under Necrotic Enteritis Challenge

Along with banning antibiotics, necrotic enteritis (NE), especially subclinical enteritis (SNE), poses a significant threat to the chicken industry; however, probiotics are a potentially promising intervention. We aimed to investigate the beneficial effects of Bacillus subtilis DSM29784 (BS) on the treatment of Clostridium perfringens (CP)-induced SNE in broilers. A total of 360 1-day-old broiler chicks were divided into three treatment groups, namely control (Ctr), SNE, and BS treatment (BST) groups, all of which were fed with a basal died for 21days, and then from day 22 onward, only the BST group had a BS supplemented diet (1×10⁹ colony-forming units BS/kg). On day 15, all chicks, except the Ctr group, were challenged with a 20-fold dose coccidiosis vaccine and 1ml CP (2×10⁸) on days 18–21 for SNE induction. Beneficial effects were observed on growth performance in BST compared to SNE broilers. BST treatment alleviated intestinal lesions and increased the villus height/crypt depth ratio. Further, BST broilers showed increased maltase activity in the duodenum compared with SNE chicks, and a significantly decreased caspase-3 protein expression in the jejunum mucosa. Moreover, an increased abundance of Ruminococcaceae and Bifidobacterium beneficial gut bacteria and an altered gut metabolome were observed. Taken together, we demonstrate that the manipulation of microbial gut composition using probiotics may be a promising prevention strategy for SNE by improving the composition and metabolism of the intestinal microbiota, intestinal structure, and reducing inflammation and apoptosis. Hence, BS potentially has active ingredients that may be used as antibiotic substitutes and effectively reduces the economic losses caused by SNE. The findings of this study provide a scientific foundation for BS application in broiler feed in the future.

Effects of Lactobacillus acidophilus on the growth performance, immune response, and intestinal barrier function of broiler chickens challenged with Escherichia coli O157

We studied the effects of Lactobacillus acidophilus (L. acidophilus) on the growth performance, intestinal morphology, barrier function, and immune response of broilers challenged with Escherichia coli O157 (E. Coli). A total of 360 1-day-old Cobb male broilers were tested in a 3 × 2 factorial arrangement with 3 dietary L. acidophilus levels (0, 5 × 108 CFU/kg, and 10 × 108 CFU/kg of diet) and 2 disease challenge treatments (control or E. coli challenged). Results showed that E. coli challenge decreased the ADG, ADFI, and BW of broilers from 15 to 21 d (P < 0.05), increased the jejunum intestinal wall thickness, and significantly increased the mortality rate. E. coli challenge significantly (P < 0.05) decreased the serum IgA and IgM contents and peripheral blood CD3+ T cell counts (P < 0.05), increased the serum CRP, DAO, and LPS levels at 21 d; upregulated the mRNA expression of iNOS, IL-8, IL-1β in the jejunum and iNOS in the spleen, and downregulated the occludin and ZO-1 mRNA expression in the ileum at 21 d compared with uninfected birds (P < 0.05). Dietary L. acidophilus supplementation consistently showed higher BW, ADG, ADFI, and jejunum and ileum V:C ratio at 14 d and 21 d in the presence and absence of E. coli challenge (P < 0.05). L. acidophilus supplementation reduced the mortality rate caused by E. coli challenge (P < 0.05), decreased the serum CRP, DAO, and LPS levels at 14 d and 21 d; upregulated the mRNA expression of occludin and ZO-1 in the jejunum and ileum, and downregulated the mRNA expression of iNOS, IL-8, and IL-1β in the jejunum in E. coli challenged birds at 21 d (P < 0.05). Dietary supplementation with L. acidophilus can improve the growth performance, intestinal health, and survival of broilers challenged with E. coli.

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 Dietary Bacillus coagulans and Different Forms of Zinc on Performance, Intestinal Microbiota, Carcass and Meat Quality of Broiler Chickens

A total of 288-day-old male broilers were allocated to six dietary treatments to evaluate the effects of zinc source and Bacillus coagulans supplements and their interaction on growth, intestinal microbial population, carcass traits and meat quality in broiler chickens. Three levels of dietary supplemental Zn source (100 mg/kg of DM diet zinc oxide, 25 and 50 mg/kg of diet zinc oxide nanoparticles (Zn-nan)) and two levels of B. coagulans (0 and 100 mg/kg of diet) were combined as a completely randomised design with a 3 × 2 factorial arrangement. B. coagulans increased the body weight gain, body weight and feed conversion ratio. The lactic acid producing bactereia of ileal were increased by B. coagulans supplementation, and its coliform count was decreased by Zn-nan in a dose-dependent manner. The B. coagulans increased the relative weights of legs and proventriculus and reduced weights of livers, abdominal fat and meat thiobarbituric acid (TBA) value. Likewise, dietary B. coagulans increased pH, yellowness and lightness values of leg muscles. Birds fed Zn-nan50 had lower liver weight, TBA and cooking loss and higher yellowness values than chicks fed ZnO-100. In conclusion, the dietary supplementation with B. coagulans improved broiler performance, microbial population and meat quality. The Zn-nan in lower dose could be a good substitution in mineral premix instead of zinc oxide. In addition, the Zn-nan improved intestinal microbial population, carcass characteristics and oxidative stability of chicken meat; however, the combination of two levels of Zn-nan with B. coagulans did not vary the measured parameters.

Dietary Lactobacillus fermentum and Bacillus coagulans Supplementation Modulates Intestinal Immunity and Microbiota of Broiler Chickens Challenged by Clostridium perfringens

Preventative effects of Lactobacillus fermentum and Bacillus coagulans against Clostridium perfringens infection in broilers have been well-demonstrated. The present study was conducted to investigate the modulation of these two probiotics on intestinal immunity and microbiota of C. perfringens-challenged birds. The 336 one-day-old broilers were assigned to four groups with six replicates in each group. Birds in the control were unchallenged and fed a basal diet, and birds in the three challenged groups were dietary supplemented with nothing (Cp group), 1 × 10⁹ CFU/kg of L. fermentum (Lf_Cp group), or 1 × 10¹⁰ CFU/kg of B. coagulans (Bc_Cp group). Challenge was performed from days 14 to 20, and samples were collected on days 21 and 28. Challenge upregulated interleukin (IL)-1β and transforming growth factor (TGF)-β4 mRNA expression in jejunum on day 21, which was downregulated by B. coagulans and L. fermentum, respectively (P < 0.05). Both probiotic groups upregulated jejunal IL-1β, interferon (IFN)-γ, IL-17, and TGF-β4 on day 28 as well as IFN-γ on day 21 (P < 0.05). The Bc_Cp group increased CD3⁺ T cell counts in the jejunal crypt on day 21 (P < 0.05). Challenge decreased the ileal ACE index on day 21 and cecal microbial richness on day 28, which were increased by probiotic treatments, and ileal bacterial richness decreased in the Bc_Cp group on day 28 (P < 0.05). Only ileal microbiota on day 21 was distinctly affected with an R-value at 0.3116 by ANOSIM analysis (P < 0.05). Compared with the control, ileal Firmicutes increased on day 21, and ileal Bacteroidetes and cecal Proteobacteria decreased on day 28 in challenged groups (P < 0.05). Challenge increased Romboutsia spp. in the ileum as well as unclassified f_Lachnospiraceae and Ruminococcus_torques group in the cecum, and decreased Lactobacillus spp. in the ileum on day 21, which were all conversely modulated by L. fermentum (P < 0.05). Challenge increased amino acid metabolism of ileal microbiota and membrane transport of cecal microbiota, and decreased amino acid metabolism of cecal microbiota on day 21, which were conversely regulated by both probiotics (P < 0.05). In conclusion, L. fermentum and B. coagulans attenuated the intestinal inflammation and microbial dysbiosis soon after C. perfringens challenge.

Probiotics Bacillus licheniformis Improves Intestinal Health of Subclinical Necrotic Enteritis-Challenged Broilers

Necrotic enteritis infection poses a serious threat to poultry production, and there is an urgent need for searching effective antibiotic alternatives to control it with the global ban on in-feed antibiotics. This study was conducted to investigate the effects of dietary Bacillus licheniformis replacing enramycin on the growth performance and intestinal health of subclinical necrotic enteritis (SNE)-challenged broilers. In total, 504 1-day-old Arbor Acres male chickens were selected and subsequently assigned into three treatments, including PC (basal diet + SNE challenge), PA (basal diet extra 10 mg/kg enramycin + SNE challenge), and PG (basal diet extra 3.20 × 109 and 1.60 × 109 CFU B. licheniformis per kg diet during 1-21 days and 22-42 days, respectively + SNE challenge). Results showed that B. licheniformis significantly decreased the intestinal lesion scores and down-regulated the Claudin-3 mRNA levels in jejunum of SNE-infected broilers on day 25, but increased the mucin-2 gene expression in broilers on day 42. In addition, B. licheniformis significantly up-regulated the mRNA levels of TRIF and NF-κB of SNE-challenged broilers compared with the control group on day 25 and TLR-4, TRIF compared with the control and the antibiotic group on day 42. The mRNA expression of growth factors (GLP-2 and TGF-β2) and HSPs (HSP60, HSP70, and HSP90) were up-regulated in B. licheniformis supplementary group on days 25 and 42 compared with group PC. LEfSe analysis showed that the relative abundance of Lachnospiraceae_UCG_010 was enriched in the PG group; nevertheless, Clostridiales_vadinBB60 and Rnminococcaceae_NK4A214 were in PA. PICRUSt analysis found that the metabolism of cofactors and vitamins, amino acid metabolism, and carbohydrate metabolism pathways were enriched, whereas energy metabolism, membrane transport, cell motility, and lipid metabolism were suppressed in B. licheniformis-supplemented groups as compared with the PC control. In conclusion, dietary supplementation of B. licheniformis alleviated the intestinal damage caused by SNE challenge that coincided with modulating intestinal microflora structure and barrier function as well as regulating intestinal mucosal immune responses.

Bacillus coagulans R11 consumption influenced the abundances of cecum antibiotic resistance genes in lead-exposed laying hens

Bacillus coagulans is regarded as a clean, safe and helpful probiotic additive in the production of livestock and poultry breeds. Some studies have also shown that Bacillus coagulans can adsorb heavy metals in water, even in the gut of animals. However, whether Bacillus coagulans feeding influences antibiotic resistance gene (ARG) abundance in the gut of lead-exposed laying hens is unknown. To better apply such probiotics in the breeding industry, the present study employed Bacillus coagulans R11 and laying hens in model experiments to test ARG changes in the cecum of laying hens under lead exposure and B. coagulans R11 feeding. The results showed that there was the trend for ARG abundance decreasing in feeding B. coagulans R11 without lead exposure to laying hens in the cecum; however, feeding B. coagulans R11 to laying hens exposed to lead obviously increased the abundances of aminoglycoside and chloramphenicol ARGs. Further experiment found that hydroquinone, dodecanedioic acid, gibberellin A14, alpha-solanine, jasmonic acid and chitin were involved in the abundances of ARGs in the cecum, in addition the abundances of these compounds were also significantly enhanced by lead exposure or combination effects of lead and B. coagulans R11. As a result, the ARG hazards increased with feeding B. coagulans R11 to laying hens exposed to lead, and the key compounds which influenced by the combination effects of lead and B. coagulans R11 might influence the ARGs abundance.

Transversal gene expression panel to evaluate intestinal health in broiler chickens in different challenging conditions

There is a high interest on gut health in poultry with special focus on consequences of the intestinal diseases, such as coccidiosis and C. perfringens-induced necrotic enteritis (NE). We developed a custom gene expression panel, which could provide a snapshot of gene expression variation under challenging conditions. Ileum gene expression studies were performed through high throughput reverse transcription quantitative real-time polymerase chain reaction. A deep review on the bibliography was done and genes related to intestinal health were selected for barrier function, immune response, oxidation, digestive hormones, nutrient transport, and metabolism. The panel was firstly tested by using a nutritional/Clostridium perfringens model of intestinal barrier failure (induced using commercial reused litter and wheat-based diets without exogenous supplementation of enzymes) and the consistency of results was evaluated by another experiment under a coccidiosis challenge (orally gavaged with a commercial coccidiosis vaccine, 90× vaccine dose). Growth traits and intestinal morphological analysis were performed to check the gut barrier failure occurrence. Results of ileum gene expression showed a higher expression in genes involved in barrier function and nutrient transport in chickens raised in healthy conditions, while genes involved in immune response presented higher expression in C.perfringens-challenged birds. On the other hand, the Eimeria challenge also altered the expression of genes related to barrier function and metabolism, and increased the expression of genes related to immune response and oxidative stress. The panel developed in the current study gives us an overview of genes and pathways involved in broiler response to pathogen challenge. It also allows us to deep into the study of differences in gene expression pattern and magnitude of responses under either a coccidial vaccine or a NE.

Bacillus amyloliquefaciens CECT 5940 improves performance and gut function in broilers fed different levels of protein and/or under necrotic enteritis challenge

Two studies were conducted to investigate the effect of Bacillus amyloliquefaciens CECT 5940 (BA) as a probiotic on growth performance, amino acid digestibility and bacteria population in broiler chickens under a subclinical necrotic enteritis (NE) challenge and/or fed diets with different levels of crude protein (CP). Both studies consisted of a 2 × 2 factorial arrangement of treatments with 480 Ross 308 mix-sexed broiler chickens. In study 1, treatments included 1) NE challenge (+/-), and 2) BA (1.0 × 10⁶ CFU/g of feed) supplementation (+/-). In study 2, all birds were under NE challenge, and treatments were 1) CP level (Standard/Reduced [2% less than standard]) and 2) BA (1.0 × 10⁶ CFU/g of feed) supplementation (+/-). After inducing NE infection, blood samples were taken on d 16 for uric acid evaluation, and cecal samples were collected for bacterial enumeration. In both studies, ileal digesta was collected on d 35 for nutrient digestibility evaluation. In study 1, the NE challenge reduced body weight gain (BWG), supressed feed conversion ratio (FCR) and serum uric acid levels (P < 0.001). Supplementation of BA increased BWG (P < 0.001) and reduced FCR (P = 0.043) across dietary treatments, regardless of challenge. Bacillus (P = 0.030) and Ruminococcus (P = 0.029) genomic DNA copy numbers and concentration of butyrate (P = 0.017) were higher in birds fed the diets supplemented with BA. In study 2, reduced protein (RCP) diets decreased BWG (P = 0.010) and uric acid levels in serum (P < 0.001). Supplementation of BA improved BWG (P = 0.001) and FCR (P = 0.005) and increased Ruminococcus numbers (P = 0.018) and butyrate concentration (P = 0.033) in the ceca, regardless of dietary CP level. Further, addition of BA reduced Clostridium perfringens numbers only in birds fed with RCP diets (P = 0.039). At d 35, BA supplemented diets showed higher apparent ileal digestibility of cystine (P = 0.013), valine (P = 0.020), and lysine (P = 0.014). In conclusion, this study suggests positive effects of BA supplementation in broiler diets via modulating gut microflora and improving nutrient uptake.

Over-processed meat and bone meal and phytase effects on broilers challenged with subclinical necrotic enteritis: Part 2. Inositol phosphate esters hydrolysis, intestinal permeability, hematology, jejunal gene expression and intestinal morphology

This study investigated the hypothesis that feeding broilers over-processed meat and bone meal (MBM) would impair gut health in the absence of phytase and in turn, affect inositol phosphate (inositol x-phosphate, IPx: IP3, IP4, IP5 and IP6) ester hydrolysis, intestinal permeability, hematology, jejunal gene expression and intestinal morphology during necrotic enteritis (NE). Ross 308 male broilers (n = 768) were assigned to one of 8 dietary treatments in a 2 × 2 × 2 factorial arrangement, with 6 replicate pens per diet and 16 birds per pen in a completely randomized design. Factors were: NE challenge (no or yes), phytase level (500 or 5,000 FTU/kg) and MBM processing (as-received or over-processed). For the NE challenge, half of the birds were challenged with field strains of Eimeria spp. on d 9 and 10⁸ CFU/mL of Clostridium perfringens strain EHE-NE18 on d 14 and 15. A 3-way challenge, phytase and MBM processing interaction was detected for IP5 (P < 0.05) and IP6 (P < 0.05) levels in the ileum. Birds fed low phytase had increased IP5 and IP6 in unchallenged birds only when diets contained over-processed MBM. Challenge with NE increased intestinal permeability as measured by serum fluorescein isothiocyanate dextran (FITC-d; P < 0.001), increased white blood cells (WBC; P < 0.001), decreased mean corpuscular volume (MCV; P < 0.001) and mean corpuscular hemoglobin (MCH; P < 0.05), and decreased crypt-to-villi ratio (P < 0.05). The over-processed MBM reduced the villi-to-crypt ratio (P < 0.05). A 3-way challenge × phytase × MBM processing interaction was detected for mucin 2 (MUC-2) expression (P < 0.05) where only in unchallenged birds fed over-processed MBM did high phytase reduce MUC-2 expression. A lower expression of aminopeptidase N (APN; P < 0.001) and vitamin D receptor (VDR; P < 0.001) were recorded in NE challenged birds. In conclusion, NE has a negative impact on the gut and hematology of broilers, but its effect on phytate hydrolysis is minimal.

Pretreatment with probiotics ameliorate gut health and necrotic enteritis in broiler chickens, a substitute to antibiotics

Necrotic enteritis (NE) is being considered as one of the most important intestinal diseases in the recent poultry production systems, which causes huge economic losses globally. NE is caused by Clostridium perfringens, a pathogenic bacterium, and normal resident of the intestinal microflora of healthy broiler chickens. Gastrointestinal tract (GIT) of broiler chicken is considered as the most integral part of pathogen's entrance, their production and disease prevention. Interaction between C. perfringens and other pathogens such as Escherichia coli and Salmonella present in the small intestine may contribute to the development of NE in broiler chickens. The antibiotic therapy was used to treat the NE; however European Union has imposed a strict ban due to the negative implications of drug resistance. Moreover, antibiotic growth promoters cause adverse effects on human health as results of withdrawal of antibiotic residues in the chicken meat. After restriction on use of antibiotics, numerous studies have been carried out to investigate the alternatives to antibiotics for controlling NE. Thus, possible alternatives to prevent NE are bio-therapeutic agents (Probiotics), prebiotics, organic acids and essential oils which help in nutrients digestion, immunity enhancement and overall broiler performance. Recently, probiotics are extensively used alternatives to antibiotics for improving host health status and making them efficient in production. The aim of review is to describe a replacement to antibiotics by using different microbial strains as probiotics such as bacteria and yeasts etc. having bacteriostatic properties which inhibit growth of pathogens and neutralize the toxins by different modes of action.