Bacillus licheniformis normalize the ileum microbiota of chickens infected with necrotic enteritis

Efficacy of Bacillus subtilis probiotic in preventing necrotic enteritis in broilers: a systematic review and meta-analysis

Probiotics can enhance broiler chicken health by improving intestinal microbiota, potentially replacing antibiotics. They protect against bacterial diseases like necrotic enteritis (NE) in poultry. Understanding their role is crucial for managing bacterial diseases, including NE. This study conducted a meta-analysis to assess the effects of Bacillus subtilis probiotic supplementation on feed conversion ratio (FCR), NE lesion score, and mortality. Additionally, a systematic review analysed gut microbiota changes in broilers challenged with Clostridium perfringens with or without the probiotic supplementation. Effect sizes from the studies were estimated in terms of standardized mean difference (SMD). Random effect models were fitted to estimate the pooled effect size and 95% confidence interval (CI) of the pooled effect size between the control [probiotic-free + C. perfringens] and the treatment [Bacillus subtilis supplemented + C. perfringens] groups. Overall variance was computed by heterogeneity (Q). The meta-analysis showed that Bacillus subtilis probiotic supplementation significantly improved FCR and reduced NE lesion score but had no effect on mortality rates. The estimated overall effects of probiotic supplementation on FCR, NE lesion score and mortality percentage in terms of SMD were -0.91 (CI = -1.34, -0.49; P < 0.001*); -0.67 (CI = -1.11, -0.22; P = 0.006*), and -0.32 (CI = -0.70, 0.06; P = 0.08), respectively. Heterogeneity analysis indicated significant variations across studies for FCR (Q = 69.66; P < 0.001*) and NE lesion score (Q = 42.35; P < 0.001*) while heterogeneity was not significant for mortality (Q = 2.72; P = 0.74). Bacillus subtilis probiotic supplementation enriched specific gut microbiota including Streptococcus, Butyricicoccus, Faecalibacterium, and Ruminococcus. These microbiotas were found to upregulate expression of various genes such as TJ proteins occluding, ZO-1, junctional adhesion 2 (JAM2), interferon gamma, IL12-β and transforming growth factor-β4. Moreover, downregulated mucin-2 expression was involved in restoring the intestinal physical barrier, reducing intestinal inflammation, and recovering the physiological functions of damaged intestines. These findings highlight the potential benefits of probiotic supplementation in poultry management, particularly in combating bacterial diseases and promoting intestinal health.

Bacillus licheniformis suppresses Clostridium perfringens infection via modulating inflammatory response, antioxidant status, inflammasome activation and microbial homeostasis in broilers

Pathogenic bacteria infection, especially Clostridium perfringens (C. perfringens), markedly threatened the health of animals, and further caused huge economic loss. In this study, Bacillus licheniformis HJ0135 (BL) was used. Oxford cup bacteriostatic test and inhibitory rate test were conducted to evaluate the antibacterial ability of BL. Results showed the strongest inhibitory role of BL on C. perfringens (P < 0.05). Afterwards, 540 one-day-old yellow-feather broilers (32.7 ± 0.2 g) were randomly allocated into 3 groups, including CON group (basal diet), CP group (basal diet + 1 × 109 CFU C. perfringens in gavage), and BL + CP group (basal diet containing 7.5 × 106 CFU/g BL + 1 × 109 CFU C. perfringens in gavage). At d 70, broilers in the CP and BL + CP groups were treated with C. perfringens by continuously oral administration for 5 d. The experiment lasted for 75 d. The serum, immune organs, jejunal mucosa, and cecal contents were collected for analysis. In vivo experiment showed that BL supplementation markedly improved (P < 0.05) BW, ADG, thymus index, serum immunoglobins and antioxidases, reduced feed conversion ratio (FCR) and serum pro-inflammatory cytokines of C. perfringens-infected broilers. Furthermore, the increased jejunal injury and levels of pro-inflammatory cytokines, decreased gene expressions of tight junction proteins in the jejunal mucosa were significantly alleviated (P < 0.05) by BL. More importantly, the activation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome was inhibited (P < 0.05) by BL to further attenuate jejunal damage. Besides, BL supplementation markedly increased (P < 0.05) the cecal isobutyric acid and isovaleric acid. Microbial analysis showed that BL changed the composition and relative abundances of microbiota in the cecal contents (P < 0.05), especially the short chain fatty acids (SCFAs)-producing bacteria including Eubacterium_coprostanoligenes_group, Megamonas, Faecalibacterium, and Lactobacillus, which further protected against C. perfringens-induced jejunal inflammation in broilers. Our study laid a theoretical basis for the application of probiotics in lessening C. perfringens-related diseases in poultry farming.

The effect of supplemental arginine on the gut microbial homeostasis of broilers during sub-clinical necrotic enteritis challenge

Necrotic enteritis (NE) is an enteric disease of poultry that alters the structure of the gut microbial community causing dysbiosis. This 28 day experiment investigated the effects of 125% and 135% arginine diets on the gut microbial diversity and composition of broilers during a subclinical NE challenge. One hundred and twenty one-day-old chicks were randomly allocated to 4 treatments with six replicates each- Uninfected + Basal, NE + Basal, NE + Arg 125%, and NE + Arg 135% diet groups. NE was induced by inoculating 1 × 104 E. maxima sporulated oocysts on day 14 and 1 × 108 CFU C. perfringens on days 19, 20, and 21 of age. The NE challenge significantly decreased the number of observed amplicon sequence variants (p = 0.03), the abundance of the phylum Firmicutes (p < 0.01), and the species Mediterraneibacter cottocaccae (p = 0.01) in the ceca of birds on day 21. The NE challenge significantly increased the Bray-Curtis index (p < 0.01), and the abundance of the phylum Bacteroidota (p < 0.01), family Odoribacteraceae (p < 0.01), genus Odoribacter (p < 0.01), and species O. splanchnicus (p = 0.01) on day 21. During NE, the 125% arginine diet restored the abundance of the phylum Bacteroidota (p = 0.03), family Odoribacteraceae (p = 0.03) and Oscillospiraceae (p = 0.03), genus Odoribacter (p = 0.03), and species O. splanchnicus (p = 0.03) and M. cottocaccae (p < 0.01) on day 21. The 135% arginine diet effectively restored the loss in alpha diversity (p = 0.01) caused by NE, the abundance of the phylum Firmicutes (p = 0.01) and Bacteroidota (p < 0.01), family Oscillospiraceae (p = 0.03) and Odoribacteraceae (p < 0.01), genus Odoribacter (p < 0.01), and species O. splanchnicus (p < 0.01) and M. cottocaccae (p < 0.01) on day 21. On day 28, the treatments had a significant effect on the cecal propionate (p = 0.01), butyrate (p = 0.04), and total SCFA (p = 0.04) concentrations. In conclusion, the 125% and 135% arginine diets restored gut microbial composition during a subclinical NE challenge, but not the cecal SCFA profile. Hence, arginine in combination with other feed additives could be used in restoring gut microbial homeostasis during NE in poultry.

Multi-omic analysis reveals that Bacillus licheniformis enhances pekin ducks growth performance via lipid metabolism regulation

Introduction: Bacillus licheniformis (B.licheniformis) was widely used in poultry feeds. However, it is still unclear about how B.licheniformis regulates the growth and development of Pekin ducks. Methods: The experiment was designed to clarify the effect and molecular mechanism of B. licheniformis on the lipid metabolism and developmental growth of Pekin ducks through multiomics analysis, including transcriptomic and metabolomic analyses. Results: The results showed that compared with the control group, the addition of 400 mg/kg B. licheniformis could significantly increase the body weight of Pekin ducks and the content of triglyceride (p < 0.05), at the same time, the addition of B. licheniformis could affect the lipid metabolism of liver in Pekin ducks, and the addition of 400 mg/kg B. licheniformis could significantly increase the content of lipoprotein lipase in liver of Pekin ducks. Transcriptomic analysis revealed that the addition of B. licheniformis primarily impacted fatty acid and glutathione, amino acid metabolism, fatty acid degradation, as well as biosynthesis and elongation of unsaturated fatty acids. Metabolomic analysis indicated that B. licheniformis primarily affected the regulation of glycerol phospholipids, fatty acids, and glycerol metabolites. Multiomics analysis demonstrated that the addition of B. licheniformis to the diet of Pekin ducks enhanced the regulation of enzymes involved in fat synthesis via the PPAR signaling pathway, actively participating in fat synthesis and fatty acid transport. Discussion: We found that B. licheniformis effectively influences fat content and lipid metabolism by modulating lipid metabolism-associated enzymes in the liver. Ultimately, this study contributes to our understanding of how B. licheniformis can improve the growth performance of Pekin ducks, particularly in terms of fat deposition, thereby providing a theoretical foundation for its practical application. Conclusion: B. licheniformis can increase the regulation of enzymes related to fat synthesis through PPAR signal pathway, and actively participate in liver fat synthesis and fatty acid transport, thus changing the lipid metabolism of Pekin ducks, mainly in the regulation of glycerol phospholipids, fatty acids and glycerol lipid metabolites.

Effects of dietary Nisin on growth performance, immune function, and gut health of broilers challenged by Clostridium perfringens

Nisin (Ni) is a polypeptide bacteriocin produced by lactic streptococci (probiotics) that can inhibit the majority of gram-positive bacteria, and improve the growth performance of broilers, and exert antioxidative and anti-inflammatory properties. The present study investigated the potential preventive effect of Nisin on necrotic enteritis induced by Clostridium perfringens (Cp) challenge. A total of 288 Arbor Acres broiler chickens of 1-d-olds were allocated using 2 × 2 factorial arrangement into four groups with six replicates (12 chickens per replicate), including: (1) control group (Con, basal diet), (2) Cp challenge group (Cp, basal diet + 1.0 × 108 CFU/mL Cp), (3) Ni group (Ni, basal diet + 100 mg/kg Ni), and (4) Ni + Cp group (Ni + Cp, basal diet + 100 mg/kg Ni + 1.0 × 108 CFU/mL Cp). The results showed that Cp challenge decreased the average daily gain (ADG) of days 15 to 21 (P<0.05) and increased interleukin-6 (IL-6) content in the serum (P < 0.05), as well as a significant reduction in villus height (VH) and the ratio of VH to crypt depth (VCR) (P<0.05) and a significant increase in crypt depth (CD) of jejunum (P<0.05). Furthermore, the mRNA expressions of Occludin and Claudin-1 were downregulated (P<0.05), while the mRNA expressions of Caspase3, Caspase9, Bax, and Bax/Bcl-2 were upregulated (P<0.05) in the jejunum. However, the inclusion of dietary Ni supplementation significantly improved body weight (BW) on days 21 and 28, ADG of days 15 to 21 (P<0.05), decreased CD in the jejunum, and reduced tumor necrosis factor-α (TNF-α) content in the serum (P<0.05). Ni addition upregulated the mRNA levels of Claudin-1 expression and downregulated the mRNA expression levels of Caspase9 in the jejunum (P<0.05). Moreover, Cp challenge and Ni altered the cecal microbiota composition, which manifested that Cp challenge decreased the relative abundance of phylum Fusobacteriota and increased Shannon index (P<0.05) and the trend of phylum Proteobacteria (0.05 Collapse

Key Words

• Clostridium perfringens
• broiler
• gut health
• necrotic enteritis
• nisin

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MESH Headings

• Animals
• Clostridium perfringens
• Chickens
• Intestines
• Clostridium Infections/prevention & control
• Clostridium Infections/veterinary
• Clostridium Infections/microbiology
• Nisin/pharmacology
• Claudin-1
• bcl-2-Associated X Protein/pharmacology
• Diet/veterinary
• RNA, Messenger/genetics
• Immunity
• Poultry Diseases/microbiology
• Dietary Supplements
• Animal Feed/analysis

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Affiliation(s)

Hua Yuan College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Guangdong Bai College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China College of Animal Science and Technology, Southwest University, Chongqing 400715, China
Yu Lin College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Xilong Yu College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Qinghui Yang College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Renkai Dou College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Hao Sun College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Zeyu Zhao College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Zhongyu Li College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Zhihui Chen College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
Liangmei Xu College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China

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Effects of Dietary Limosilactobacillus fermentum and Lacticaseibacillus paracasei Supplementation on the Intestinal Stem Cell Proliferation, Immunity, and Ileal Microbiota of Broiler Chickens Challenged by Coccidia and Clostridium perfringens

This study was conducted to investigate effects of dietary Limosilactobacillus fermentum and Lacticaseibacillus paracasei supplementation on the intestinal stem cell proliferation, immunity, and ileal microbiota of broiler chickens challenged by coccidia and Clostridium perfringens. A total of 336 one-day-old Ross 308 chickens were randomly assigned into four groups. Chickens in the control (CTR) group were fed basal diet, and chickens in the three challenged groups were fed basal diets supplemented with nothing (CCP group), 1.0 × 109 CFU/kg L. fermentum (LF_CCP group), and 1.0 × 109 CFU/kg L. paracasei (LP_CCP group), respectively. All challenged birds were infected with coccildia on day 9 and Clostridium perfringens during days 13-18. The serum and intestinal samples were collected on days 13 and 19. The results showed that L. fermentum significantly increased jejunal gene expression of cdxB (one of the intestinal stem cell marker genes) on day 13. Additionally, L. fermentum significantly up-regulated mRNA levels of JAK3 and TYK2 and tended to increase STAT6 mRNA expression in jejunum on day 19. In the cecal tonsil, both L. fermentum and L. paracasei decreased mRNA expression of JAK2 on day 13, and L. fermentum down-regulated JAK1-2, STAT1, and STAT5-6 gene expressions on day 19. Ileal microbiological analysis showed that coccidial infection increased the Escherichia-Shigella, Lactobacillus, and Romboutsia abundance and decreased Candidatus_Arthromitus richness on day 13, which were reversed by Lactobacillus intervention. Moreover, Lactobacilli increased ileal Lactobacillus richness on day 19. In conclusion, Lactobacilli alleviated the impairment of intestinal stem cell proliferation and immunity in coccidia- and C. perfringens-challenged birds via modulating JAK/STAT signaling and reshaping intestinal microflora.

Evaluation of the Immunoprotective Capacity of Five Vaccine Candidate Proteins against Avian Necrotic Enteritis and Impact on the Caecal Microbiota of Vaccinated Birds

Avian necrotic enteritis is an enteric disease of broiler chickens caused by certain pathogenic strains of Clostridium perfringens in combination with predisposing factors. A vaccine offering complete protection against the disease has not yet been commercialized. In a previous study, we produced five recombinant proteins predicted to be surface-exposed and unique to necrotic enteritis-causing C. perfringens and the immunogenicity of these potential vaccine candidates was assessed in broiler chickens. In the current work, the relative contribution of the antibodies raised by these putative antigens to protect broiler chickens was evaluated using an experimental necrotic enteritis induction model. Additionally, the link between the immune response elicited and the gut microbiota profiles in immunized birds subjected to infection with virulent C. perfringens was studied. The ELISA results showed that the IgY antibody titers in vaccinated birds on days 21 and 33 were significantly higher than those on days 7 and 14 and those in birds receiving the adjuvant alone, while the relative contribution of the specific immunity attributed to these antibodies could not be precisely determined using this experimental necrotic enteritis induction model. In addition, 16S rRNA gene amplicon sequencing showed that immunization of birds with recombinant proteins had a low impact on the chicken caecal microbiota.

Osteoimmunology: A Link between Gastrointestinal Diseases and Skeletal Health in Chickens

Bone serves as a multifunctional organ in avian species, giving structural integrity to the body, aiding locomotion and flight, regulating mineral homeostasis, and supplementing calcium for eggshell formation. Furthermore, immune cells originate and reside in the bone marrow, sharing a milieu with bone cells, indicating a potential interaction in functions. In avian species, the prevalence of gastrointestinal diseases can alter the growth and the immune response, which costs a great fortune to the poultry industry. Previous studies have shown that coccidiosis and necrotic enteritis can dramatically reduce bone quality as well. However, possible mechanisms on how bone quality is influenced by these disease conditions have not yet been completely understood, other than the reduced feed intake. On the other hand, several mediators of the immune response, such as chemokines and cytokines, play a vital role in the differentiation and activation of osteoclasts responsible for bone resorption and osteoblasts for bone formation. In the case of Eimeria spp./Clostridium perfringens coinfection, these mediators are upregulated. One possible mechanism for accelerated bone loss after gastrointestinal illnesses might be immune-mediated osteoclastogenesis via cytokines-RANKL-mediated pathways. This review article thus focuses on osteoimmunological pathways and the interaction between host immune responses and bone biology in gastrointestinal diseases like coccidiosis and necrotic enteritis affecting skeletal health.

Impact of a Blend of Microencapsulated Organic Acids and Botanicals on the Microbiome of Commercial Broiler Breeders under Clinical Necrotic Enteritis

Previously, the supplementation of a microencapsulated blend of organic acids and botanicals improved the health and performance of broiler breeders under non-challenged conditions. This study aimed to determine if the microencapsulated blend impacted dysbiosis and necrotic enteritis (NE) in broiler breeders. Day-of-hatch chicks were assigned to non-challenge and challenge groups, provided a basal diet supplemented with 0 or 500 g/MT of the blend, and subjected to a laboratory model for NE. On d 20-21, jejunum/ileum content were collected for microbiome sequencing (n = 10; V4 region of 16S rRNA gene). The experiment was repeated (n = 3), and data were analyzed in QIIME2 and R. Alpha and beta diversity, core microbiome, and compositional differences were determined (significance at p ≤ 0.05; Q ≤ 0.05). There was no difference between richness and evenness of those fed diets containing 0 and 500 g/MT microencapsulated blend, but differences were seen between the non-challenged and challenged groups. Beta diversity of the 0 and 500 g/MT non-challenged groups differed, but no differences existed between the NE-challenged groups. The core microbiome of those fed 500 g/MT similarly consisted of Lactobacillus and Clostridiaceae. Furthermore, challenged birds fed diets containing 500 g/MT had a higher abundance of significantly different phyla, namely, Actinobacteriota, Bacteroidota, and Verrucomicrobiota, than the 0 g/MT challenged group. Dietary supplementation of a microencapsulated blend shifted the microbiome by supporting beneficial and core taxa.

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.

Differential effects of Bacillus subtilis- and Bacillus licheniformis-fermented products on growth performance, intestinal morphology, intestinal antioxidant and barrier function gene expression, cecal microbiota community, and microbial carbohydrate-active enzyme composition in broilers

This study investigated the differential effects of Bacillus subtilis-fermented products (SFPs) and Bacillus licheniformis-fermented products (LFPs) on the growth performance, intestinal morphology, intestinal gene expression, cecal microbiota community, and microbial carbohydrate-active enzyme composition of broilers. In total, 160 one-day-old unsexed Arbor Acres broiler chicks were randomly allocated to 4 treatment groups (with 8 replicates per group and 5 chicks per replicate): control (CON), enramycin (ENM), SFP, and LFP groups, which were fed a basal diet, basal diet supplemented with 10 mg/kg ENM, basal diet supplemented with 10⁸ colony-forming units (CFU) of B. subtilis spores per gram of feed, and basal diet supplemented with 10⁸ CFU of B. licheniformis spores per gram of feed, respectively. LFP treatment resulted in a higher (P < 0.01) body weight at the age of 35 d and higher average daily gain over 15 to 35 (P < 0.05) and 1 to 35 (P < 0.05) d of age than did the CON and SFP treatments. The average villus heights in the jejunum were longer (P < 0.05) in the LFP group than those in the SFP group. Moreover, the LFP group exhibited a higher jejunal barrier function gene expression (mucin 2, zonula occludens-1, and occludin) and cecal antioxidant gene expression (superoxide dismutase) than did the CON group (P < 0.05). A principal coordinate analysis of cecal microbiota and carbohydrate-active enzyme composition demonstrated distinct clustering among the groups. Lactobacillus crispatus abundance in the cecal digesta was higher (P < 0.01) in the SFP group than in the CON and LFP groups. Finally, microbial glycosyltransferase 2 gene expression in the cecal digesta was higher in the LFP group than in the CON and ENM groups. In conclusion, LFPs can improve the growth performance, increase intestinal barrier function and antioxidant gene expression, and modulate cecal microflora composition and carbohydrate-active enzyme composition of broilers. The overall effect of LFPs on growth promotion in broilers was superior to that of SFPs.

A meta-analysis of the effect of Eimeria spp. and/or Clostridium perfringens infection on the microbiota of broiler chickens

Coccidiosis in chickens is caused by Eimeria spp. The infection provides a growth advantage to Clostridium perfringens (CP), frequently leading to necrotic enteritis. One approach to alleviate the negative impacts of the diseases is to improve the bacterial composition in chickens, and many experiments investigating chicken enteric health in recent years include the characterization of the bacterial microbiota. This meta-analysis synthesized the data of studies investigating the intestinal microbiota after infection with coccidia and/or CP to provide a basis for future research. Inclusion criteria were that experiments contained a group infected with one or both pathogens and an uninfected control group, the use of 16SrRNA Illumina sequencing and the availability of raw data. A total of 17 studies could be included. Meta-analyses of 3 different data sets were performed: 1 on data of 9 experiments on chickens infected with coccidia only; the second on data of 4 studies on chickens infected with CP only; the third on raw data of 8 experiments with chickens infected with coccidia and CP. The meta-analysis of relative abundance and alpha diversity of the data sets was performed in R using the SIAMCAT and metafor packages. The number of families of interest identified by the analyses of experiments with infection with coccidia only, CP only and the combined infection were 23, 2, and 29, respectively. There was an overlap of 13 families identified by analyses of experiments with infection with coccidia only and of experiments with the combined infections. Machine learning was not able to find a model to predict changes of the microbiota in either 1 of the 3 analyses. Meta-analyses of functional profiles showed a more uniform reaction to the infections with the relative abundance of many pathways significantly altered. Alpha diversity was not affected by infection with either pathogen or the combination. In conclusion, the heterogeneity of these microbiota studies makes recognizing common trends difficult, although it seems that coccidia infection affects the microbiota more than an infection with CP. Future studies should focus on the bacterial functions that are changed due to these infections using metagenome techniques.

The effects of a Bacillus licheniformis and phytase mixture added to broiler diets on growth performance, nutrient digestibility, and cecal microecosystem

This study aims to evaluate the effects of Bacillus licheniformis and 6-phytase added alone or in combination to broiler chicken diets on the growth performance, apparent ileal digestibility coefficient (AID) of nutrients, microbial activity, and cecal bacterial communities. In total, 400 one-day-old female Ross 308 chicks were randomly allocated to 4 dietary treatments (10 replicate pens, 10 birds each). The following groups were defined: NC (negative control), basal diet without any feed additive supplementation; NC+Pro, basal diet with addition of the B. licheniformis preparation (500 g/t of diet); NC+Phy, basal diet with addition of phytase (200 g/t of diet); and NC+Pro+Phy, basal diet combined with both studied additives. B. licheniformis positively affected (P<0.05) the feed intake (FI) and feed conversion ratio (FCR) in the first 10 d of bird rearing. Moreover, phytase supplementation elevated the FCR from 21 to 35 d. In the entire experiment, an interaction between phytase and probiotic was observed only in terms of decreasing the bird FI (P=0.005) without a negative effect on the FCR (P>0.05). Furthermore, the AID of ether extract was improved by phytase supplementation. In terms of the cecal microecology, both separately administered factors promoted Lactobacillaceae in the ceca. Interactions between probiotic preparation and phytase were noted that indicated a decreased Clostridiales population and favored Ruminococcaceae proliferation. It can be concluded that for the first time in the available literature, the favorable interactions between B. licheniformis and phytase resulted in improved performance and cecal microbiota changes in broilers.

Co-fermented yellow wine lees by Bacillus subtilis and Enterococcus faecium regulates growth performance and gut microbiota in finishing pigs

Fermented yellow wine lees (FYWL) are widely used to increase feed utilization and improve pig performance. Based on the preparation of co-FYWL using Bacillus subtilis and Enterococcus faecalis, the purpose of this study was to investigate the effects of co-FYWL on growth performance, gut microbiota, meat quality, and immune status of finishing pigs. 75 pigs were randomized to 3 treatments (5 replicates/treatment), basal diet (Control), a basal diet supplemented with 4%FYWL, and a basal diet supplemented with 8%FYWL, for 50 days each. Results showed that the 8% FYWL group significantly reduced the F/G and increased the average daily weight gain of pigs compared to the control group. In addition, 8% FYWL improved the richness of Lactobacillus and B. subtilis in the gut, which correlated with growth performance, serum immune parameters, and meat quality. Furthermore, acetate and butyrate in the feces were improved in the FYWL group. Simultaneously, FYWL improved the volatile flavor substances of meat, increased the content of flavor amino acids, and played a positive role in the palatability of meat. In addition, FYWL increased serum IgA, IgM, IL-4 and IL-10 levels. Overall, the growth performance, the gut microbiota associated with fiber degradation, meat quality, and immune status were improved in the 8% FYWL group.

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

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

Bacillus licheniformis PF9 improves barrier function and alleviates inflammatory responses against enterotoxigenic Escherichia coli F4 infection in the porcine intestinal epithelial cells

Background

Enterotoxigenic Escherichia coli (ETEC) F4 commonly colonizes the small intestine and releases enterotoxins that impair the intestinal barrier function and trigger inflammatory responses. Although Bacillus licheniformis (B. licheniformis) has been reported to enhance intestinal health, it remains to be seen whether there is a functional role of B. licheniformis in intestinal inflammatory response in intestinal porcine epithelial cell line (IPEC-J2) when stimulated with ETEC F4.

Methods

In the present study, the effects of B. licheniformis PF9 on the release of pro-inflammation cytokines, cell integrity and nuclear factor-κB (NF-κB) activation were evaluated in ETEC F4-induced IPEC-J2 cells.

Results

B. licheniformis PF9 treatment was capable of remarkably attenuating the expression levels of inflammation cytokines tumor necrosis factor-α (TNF-α), interleukin (IL)-8, and IL-6 during ETEC F4 infection. Furthermore, the gene expression of Toll-like receptor 4 (TLR4)-mediated upstream related genes of NF-κB signaling pathway has been significantly inhibited. These changes were accompanied by significantly decreased phosphorylation of p65 NF-κB during ETEC F4 infection with B. licheniformis PF9 treatment. The immunofluorescence and western blotting analysis revealed that B. licheniformis PF9 increased the expression levels of zona occludens 1 (ZO-1) and occludin (OCLN) in ETEC F4-infected IPEC-J2 cells. Meanwhile, the B. licheniformis PF9 could alleviate the injury of epithelial barrier function assessed by the trans-epithelial electrical resistance (TEER) and cell permeability assay. Interestingly, B. licheniformis PF9 protect IPEC-J2 cells against ETEC F4 infection by decreasing the gene expressions of virulence-related factors (including luxS, estA, estB, and elt) in ETEC F4.

Conclusions

Collectively, our results suggest that B. licheniformis PF9 might reduce inflammation-related cytokines through blocking the NF-κB signaling pathways. Besides, B. licheniformis PF9 displayed a significant role in the enhancement of IPEC-J2 cell integrity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00746-8.

Effects of Bacillus licheniformis on Growth Performance, Diarrhea Incidence, Antioxidant Capacity, Immune Function, and Fecal Microflora in Weaned Piglets

Simple Summary

Bacillus licheniformis has been shown to be safe as a green additive in food and feed. This experiment was conducted to investigate the value of Bacillus licheniformis in the diet of piglets. Our results suggested that dietary Bacillus licheniformis supplementation plays an important role in improving the average daily gain, alleviating diarrhea, improving antioxidant capacity, promoting immune function, and regulating the intestinal microflora of weaned piglets.

Abstract

Bacillus licheniformis (B. licheniformis) is a safe probiotic that can promote animal growth and inhibit pathogenic bacteria. This study aimed to assess the effects of B. licheniformis, one green feed additive, on growth performance, diarrhea incidence, immune function, fecal volatile fatty acids, and microflora structure in weaned piglets. Weaned piglets (n = 180) were randomly divided into three treatment groups and fed a basal diet and a basal diet supplemented with 500 mg B. licheniformis per kg and 1000 mg B. licheniformis per kg, respectively. The dietary 500 mg/kg B. licheniformis inclusion improved the average daily gain, reduced diarrhea incidence, and strengthened antioxidant capacity. Piglets supplemented with B. licheniformis presented increased serum immunoglobulins (IgA, IgM) compared to the CON group. Meanwhile, the expression of anti-inflammation factors was increased, and the levels of pro-inflammation factors were reduced after B. licheniformis administration. Moreover, the levels of volatile fatty acids, including acetic acid, propionic acid, butyric acid, isobutyric acid, and isovaleric acid, in the BL500 and BL1000 groups were increased compared with the CON group, and the concentration of valeric acid was higher in the BL500 group. Furthermore, piglets in the 500 mg/kg B. licheniformis addition group significantly altered fecal microbiota by increasing Clostridium_sensu_stricto_1 and Oscillospira. In conclusion, dietary B. licheniformis relieved diarrhea, enhanced antioxidant capacity, immunity function, and fecal microflora structure in weaned pigs.

Probiotics as Alternatives to Antibiotics for the Prevention and Control of Necrotic Enteritis in Chickens

Necrotic enteritis (NE) in poultry is an economically important disease caused by Clostridium perfringens type A bacteria. A global trend on restricting the use of antibiotics as feed supplements in food animal production has caused a spike in the NE incidences in chickens, particularly in broiler populations. Amongst several non-antibiotic strategies for NE control tried so far, probiotics seem to offer promising avenues. The current review focuses on studies that have evaluated probiotic effects on C. perfringens growth and NE development. Several probiotic species, including Lactobacillus, Enterococcus, Bacillus, and Bacteroides bacteria as well as some yeast species have been tested in chickens against C. perfringens and NE development. These findings have shown to improve bird performance, reduce C. perfringens colonization and NE-associated pathology. The underlying probiotic mechanisms of NE control suggest that probiotics can help maintain a healthy gut microbial balance by modifying its composition, improve mucosal integrity by upregulating expression of tight-junction proteins, and modulate immune responses by downregulating expression of inflammatory cytokines. Collectively, these studies indicate that probiotics can offer a promising platform for NE control and that more investigations are needed to study whether these experimental probiotics can effectively prevent NE in commercial poultry operational settings.

Probiotic Effects of Bacillus licheniformis DSM5749 on Growth Performance and Intestinal Microecological Balance of Laying Hens

This study was conducted to investigate the effects of Bacillus licheniformis DSM5749 on the production performance and intestinal health in laying hens. A total of 32-week-old laying hens (Hyline Brown) were randomly assigned to two dietary groups (10 replicates of 27 laying hens), namely, basal diet and basal diet complemented with 200 g/t B. licheniformis (3.2 × 10⁹ CFU/kg). The trial lasted for 8 weeks, and samples were collected at the last week. Results revealed that B. licheniformis DSM5749 significantly improved laying performance, including an increase in egg production rate and average daily egg yield, and a decrease in the feed-to-egg ratio during the entire 8-week experimental period (P < 0.05). B. licheniformis DSM5749 increased the levels of superoxide dismutase and glutathione peroxidase in the liver and decreased the IL-1 level in the serum (P < 0.05). In addition, the integrity of intestinal morphology (villus height, crypt depth, and villus height/crypt depth), tight junctions (ZO-1, Claudin-1, and Occludin), and lipase vitality in the intestine were potentiated by B. licheniformis DSM5749 in laying hens (P < 0.05). B. licheniformis DSM5749 decreased the Firmicutes/Bacteroidetes ratio (P < 0.05) in the cecum. Furthermore, B. licheniformis DSM5749 modulated the microbiota in the cecum of the laying hens, increased the relative abundance of beneficial bacteria (e.g., Prevotella) at the genus level and decreased the relative abundance of potential pathogens (e.g., Desulfovibrio). In conclusion, B. licheniformis DSM5749 can improve laying performance, promote intestinal health, affect the composition of cecal microorganisms, and regulate the intestinal micro-ecological balance, making B. licheniformis a good probiotic candidate for application in the laying hens industry.

Growth performance, carcass yield and characteristics, meat quality, serum biochemistry, jejunal histomorphometry, oxidative stability of liver and breast muscle, and immune response of broiler chickens fed natural antioxidant alone or in combination with &lt;i&gt;Bacillus licheniformis&lt;/i&gt;

Abstract. In this study, oxidative stability of liver and breast meat, and immune response were evaluated in broiler chickens fed supplemental phytogenic feed additive (PFA) alone or in combination with Bacillus licheniformis. Three experimental groups – control, PFA (60 mg kg−1), and PFA (60 mg kg−1) + 0.5 mg kg−1 B. licheniformis (1.6 × 1012 cfu g−1), each consisting of 5 replicates – were established with 20 one-day-old chickens per replicate (300 birds in total). Growth performance, carcass yield and characteristics, and meat quality remained unaffected. However, supplemental PFA and PFA + B. licheniformis improved the serum biochemistry and jejunal histomorphometry of broiler chickens (P<0.05). PFA and PFA + B. licheniformis groups had lower thiobarbituric acid reacting substances (TBARS) in liver, and freeze–thaw breast meat after 30, 60, and 90 d of storage (P<0.05). PFA and PFA + B. licheniformis supplementation lowered the carbonyl group in fresh and stored breast meat (P<0.05). Antibody titer against infectious bursal disease virus was higher in the PFA + B. licheniformis group than the control group (P<0.05). It can be concluded that PFA or PFA + B. licheniformis in broiler diets improves the health, oxidative stability of liver and breast meat, and immune response of broiler chickens.

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

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

Ileal Microbiota Alters the Immunity Statues to Affect Body Weight in Muscovy Ducks

The ileum is mainly responsible for food absorption and nutrients transportation. The microbes in its intestinal lumen play an essential role in the growth and health of the host. However, it is still unknown how the ileal microbes affect the body weight of the host. In this study, we used Muscovy ducks as an animal model to investigate the relationship between the ileal microbes and body weight and further explore the potential mechanism. The ileum tissue and ileal contents of 200 Muscovy ducks were collected for mRNA extraction and real-time quantitative PCR, as well as DNA separation and 16S rRNA gene sequencing. With body weight being ranked, the bottom 20% (n = 40) and top 20% (n = 40) were set as the low and high groups, respectively. Our results showed that in the ileum of Muscovy ducks, the Bacteroides, Firmicutes, and Proteobacteria were the predominant phyla with the 10 most abundant genera, namely Candidatus Arthromitus, Bacteroides, Streptococcus, Vibrio, Romboutsia, Cetobacterium, Clostridium sensu stricto 1, Terrisporobacter, Escherichia-Shigella, and Lactobacillus. We identified Streptococcus, Escherichia-Shigella, Candidatus Arthromitus, Bacteroides, Faecalibacterium, and Oscillospira were closely correlated to the growth of Muscovy ducks. Streptococcus and Escherichia-Shigella were negatively related to body weight (BW), while Candidatus Arthromitus, Bacteroides, Faecalibacterium, and Oscillospira were positively associated with BW. In addition, we found that the relative expression levels of tight junction proteins (Claudin 1, Claudin 2, ZO-1 and ZO-2) in the high group showed an upward trend, although this trend was not significant (P > 0.05). The expression of pro-inflammatory factors (IL-1β, IL-2 and TNF-α) decreased in the high group, while the anti-inflammatory factor IL-10 increased. Of course, except IL-2, these differences were not significant (P > 0.05). Finally, the correlation analysis showed that Escherichia-Shigella was significantly positively correlated with IL-1β (P < 0.05). These findings may provide fundamental data for the development of next-generation probiotics and assist the development of strategies for changing the gut microbiota to promote the growth performance in the duck industry.

Live Performance and Microbial Load Modulation of Broilers Fed a Direct-Fed Microbials (DFM) and Xylanase Combination

The animal industry, which focuses on producing protein for human consumption, is continuously seeking solutions that can enhance both animal performance and health at a low cost. Several feed additives are currently being used to improve the nutritive value of feed as well as replacing the subtherapeutic levels of antibiotic growth promoters (AGP). This study was designed to investigate the effect of a feed additive that is a blend of multi-strain Bacillus spp. probiotics and a xylanase in a 2 × 2 factorial dietary treatments design, testing two levels of the feed additive blend (0 and 100 g/MT) and two cereal grain types (corn and wheat) on live performance, gut lesions, environmental Clostridium perfringens load, and pathogen load in the digesta of broiler chickens (E. tenella, total aerobic count cells (APC), E. coli, and C. perfringens). Day-old chicks were randomly placed in 10 replicate pens per treatment with 52 birds per replicate and grown to 42 d of age. Data were analyzed by two-way ANOVA. At 42 d, birds fed EnzaPro were heavier (p < 0.0004) than unsupplemented birds. An improvement in FCR (p = 0.03) was observed from 1 to 42 d by approximately two points in both corn- and wheat-based diets supplemented with EnzaPro. In wheat-based diets, supplementing EnzaPro reduced (p < 0.0001) a 21 d lesion score of intestines with a further reduction (p < 0.02) at 42 d. EnzaPro reduced (p < 0.03) litter moisture by approximately 1% compared to non-supplemented EnzaPro in both corn- and wheat-based diets. Pathogen load in digesta (C. perfringens, E. tenella, APC, and E. coli) was reduced (p < 0.0002) when EnzaPro was supplemented in diets. It can be concluded that EnzaPro (a blend of DFM Bacillus spp (1 × 105 CFU/g feed) and xylanase (10 XU/g feed)) may be used in both corn- and wheat-based diets to improve the performance and gut health of broilers.

Effect of Dietary Bacillus licheniformis Supplementation on Growth Performance and Microbiota Diversity of Pekin Ducks

This experiment was conducted to investigate the effects of different concentrations of Bacillus licheniformis (B. licheniformis) on growth performance and microbiota diversity of Pekin ducks. Three hundred 1-day-old healthy Pekin ducks were randomly divided into 5 groups with 6 replicates per group and 10 ducks per replicate. The five treatments supplemented with basal diets containing: either 0 (group CON), 200 (group LLB), 400 (group MLB), and 800 (group HLB) mg/kg B. licheniformis or 150 mg/kg aureomycin (group ANT) for 42 days, respectively, and were sacrificed and sampled in the morning of the 42nd day for detection of relevant indexes. The results showed as follows: The feed conversion ratio of the LLB group and MLB groups were lower than the CON group (P < 0.05). The body weight and average daily feed intake of the MLB group were significantly higher than that of the CON group and ANT group (P < 0.05). Compared with the CON group, the MLB group significantly increased the content of IgA (P < 0.05) and proinflammatory IL-6 were significantly decreased (P < 0.05), besides, the activity of SOD and T-AOC were also significantly increased in the MLB group (P < 0.05). The 16S rRNA analysis showed that B. licheniformis treatments had no effect (P > 0.05) on the alpha diversities of the intestine. The addition of B. licheniformis had a dynamic effect on the abundance of cecal microflora of Pekin ducks, and 1-21 d increased the diversity of microflora, while 21d-42 d decreased it. Compared with the CON group, the relative abundance of Epsilonbacteraeota in the MLB group was significantly increased on Day 21 (P < 0.05), and that of Tenericutes in the LLB group was significantly increased as well (P < 0.05). At 42 d, the relative abundance of Bacteroidetes in LLB, MBL, HBL, and ANT groups was significantly increased (P < 0.05). In addition, the addition of B. licheniformis increased the amount of SCAF-producing bacteria in the intestinal microbiota, such as Lachnospiraceae, Collinsella, Christensenellaceae, and Bilophila. The PICRUSt method was used to predict the intestinal microbiota function, and it was found that lipid transport and metabolism of intestinal microbiota in the MLB group were significantly affected. Overall, these results suggest diet supplemented with B. licheniformis improved growth performance, immune status, antioxidant capacity, and modulated intestinal microbiota in Pekin ducks. The optimal dietary supplement dose is 400 mg/kg.

Effects of Bacillus methylotrophicus SY200 Supplementation on Growth Performance, Antioxidant Status, Intestinal Morphology, and Immune Function in Broiler Chickens

The present study was focused on evaluating the effects of Bacillus methylotrophicus SY200 in broiler production. A total of 120 healthy 7-day-old broiler chicks were randomly assigned to four dietary treatments, which included basal diet supplemented with 0%, 0.10%, 0.25%, or 0.50% (w/w) B. methylotrophicus SY200 preparation (1.0 × 10⁹ cfu/g), regarded as negative control group (NC), low-dose group (BML), medium-dose group (BMM), and high-dose group (BMH), respectively. Each treatment was fed the corresponding experimental diet for 35 days. Results showed that dietary supplementation of B. methylotrophicus SY200 could improve broiler weight gain, especially the finisher phase. Further studies suggested that a certain amount of B. methylotrophicus SY200 enhanced the broiler antioxidant status and improved the morphological development of jejunum. Besides, dietary supplementation of B. methylotrophicus SY200 especially in 0.50% levels significantly increased the relative weight of immune organs and Newcastle disease virus antibody titer, similarly, increased mRNA expression levels of claudin-1, claudin-3, zonula occluden-1, and zonula occluden-2 were observed in the jejunum of BMM group. Moreover, B. methylotrophicus SY200 also showed beneficial effects in improving broilers microbiota homeostasis by increasing the number of beneficial bacteria. Conclusively, B. methylotrophicus SY200 could effectively improve the antioxidant status, modulate the intestinal structure, enhance the intestinal mucosal barrier function, and regulate the immune function of broilers, which finally improves the performance of the chicken in the finisher period.

Bacteremia caused by accidental injection of Bacillus licheniformis microbiota modulator through the central venous catheter: A case report

RATIONALE

Bacillus licheniformis (B licheniformis) is a commonly used microbiota modulator. However, infections are rarely observed in immunocompetent hosts.

PATIENT CONCERNS

A 67-year-old woman who underwent esophagectomy experienced accidental injection of B licheniformis and presented with chills followed by hyperpyrexia.

DIAGNOSIS

The initial diagnosis was B licheniformis bacteremia.

INTERVENTION

Based on our experience, the patient first received levofloxacin and ornidazole. The application of levofloxacin was retained based on the antibiogram results. After discharge, the antibiotics were changed to vancomycin and levofloxacin, based on sensitivity tests, until two consecutive blood cultures were negative.

OUTCOMES

The patient recovered without any severe complications.

LESSONS

This is a rare report of the successful treatment of B licheniformis bacteremia caused by improper drug administration, which will provide a reference for the treatment of B licheniformis bacteremia.

Short and Medium Chain Fatty Acids and Their Derivatives as a Natural Strategy in the Control of Necrotic Enteritis and Microbial Homeostasis in Broiler Chickens

The use of antibiotic growth promoters (AGPs) has historically been the most important prophylactic strategy for the control of Necrotic Enteritis (NE) caused by some Clostridium perfringens toxin types in poultry. During the last five decades, AGPs have also been supplemented in feed to improve body weight gain and feed efficiency as well as to modulate the microbiome (consisting of microbes and their genes both beneficial and potentially harmful) and reduce enteric pathogens, among other benefits. New regulatory requirements and consumer preferences have led to strong interest in natural alternatives to the AGPs for the prevention and control of illnesses caused by enteric pathogens. This interest is not just focused on the direct removal or inhibition of the causative microorganisms but also the improvement of intestinal health and homeostasis using a range of feed additives. A group of promising feed additives is short- and medium-chain fatty acids (SCFA and MCFA, respectively) and their derivatives. The use of SCFA and MCFA, including butyric, caproic, caprylic, capric, and lauric acids, has shown strong effects against NE in broilers both at experimental and commercial levels. These fatty acids also benefit intestinal health integrity and homeostasis. Other effects have also been documented, including increases in intestinal angiogenesis and gene expression of tight junctions. Chemical modifications to improve stability and point of release in the intestine have been shown to improve the efficacy of SCFA and MCFA and their derivatives. The aim of this review is to give an overview of SCFA, MCFA and their derivatives, as an alternative to replace AGPs to control the incidence and severity of NE in poultry.

Effectiveness of Bacillus licheniformis-Fermented Products and Their Derived Antimicrobial Lipopeptides in Controlling Coccidiosis in Broilers

Simple Summary

Coccidiosis is an important health problem in broilers, caused by infection with a highly contagious intestinal parasite of the genus Eimeria. Anti-coccidial drugs are widely used for the prevention of coccidiosis in broilers. However, multi-resistance coccidia is a potential threat to poultry production. In this study, we evaluated the potential of Bacillus licheniformis-fermented products (BLFP) and their derived antimicrobial lipopeptide, surfactin, on the prevention of coccidiosis in broilers. Results demonstrate that BLFPs and their derived antimicrobial lipopeptide, surfactin, exhibit anti-coccidial activity in vitro and in vivo.

Abstract

This study aimed to investigate the potential of Bacillus licheniformis-fermented products (BLFP) and their derived antimicrobial lipopeptide, surfactin, for the prevention of coccidiosis in broilers. Broilers were fed BLFP at 1.25 and 5 g/kg under Eimeria tenella challenge. At the end of experiment (35 days), the growth performance, survival rate, cecal morphology, cecal lesion scores, oocyst-count index, and anti-coccidial index were analyzed. The effects of the BLFP-derived surfactin on oocyst sporulation and sporozoite morphology in Eimeria species were also investigated in vitro. Results showed that BLFP supplementation at 1.25 and 5 g/kg improved cecal morphology and increased the survival rate of broilers under E. tenella challenge. Supplementation with 1.25 g/kg of BLFP reduced the lesion scores in the cecum of E. tenella-challenged broilers, while the oocyst-count index was reduced in broilers given 5 g/kg of BLFP. The anti-coccidial index of the 1.25 g/kg of BLFP-treated group was greater than 160, compared with the E. tenella-challenge-only group. Furthermore, surfactin inhibited Eimeria oocyst sporulation and disrupted sporozoite morphology. These results demonstrate that BLFPs and their derived antimicrobial lipopeptide, surfactin, exhibit anti-coccidial activity in vitro and in vivo. BLFP may be used as a natural feed additive for the prevention of coccidiosis in broilers, and 1.25 g/kg can be considered the optimum dosage.

Supplemental Bacillus subtilis PB6 Improves Growth Performance and Gut Health in Broilers Challenged with Clostridium perfringens

Clostridium perfringens (CP) is the principal pathogenic bacterium of chicken necrotic enteritis (NE), which causes substantial economic losses in poultry worldwide. Although probiotics are known to provide multiple benefits, little is known about the potential effects of Bacillus subtilis (B. subtilis) application in preventing CP-induced necrotic enteritis. In this study, 450 male Arbor Acres broilers were divided into 5 experimental treatments: A: basal diet (control group); B: basal diet and CP challenge (model group); C: CP challenge+10 mg/kg enramycin (positive control group); D: CP challenge+4 × 10⁷ CFU/kg of feed B. subtilis PB6 (PB6 low-dosage group); and E: CP challenge+6 × 10⁷ CFU/kg of feed B. subtilis PB6 (PB6 high-dosage group). There were 6 replicate pens per treatment with 15 broilers per pen. The present research examined the effect of Bacillus subtilis PB6 (B. subtilis PB6) on growth performance, mRNA expression of intestinal cytokines and tight junctions, and gut flora composition in broilers challenged with CP. The entire experiment was divided into two phases: the non-CP challenge phase (d0–18) and the CP challenge phase (d18–26). PB6 did not increase the growth performance during the first stage, but the PB6 high-dosage group was found to have larger body weight gain and ADFI during the CP challenge stage. Feed supplementation with PB6 reduced the lesion score of challenged chicks, with increased tight junction-related gene expression (occludin and ZO-1) and decreased TNF-α expression compared with CP-infected birds. A decrease in the abundance of Clostridium XI, Streptococcus, and Staphylococcus was observed after CP infection (P < 0.05), while supplementation with PB6 restored the ileal microbial composition. In conclusion, administration of B. subtilis PB6 improved growth performance, enhanced intestinal barrier function, and mitigated intestinal inflammation/lesions, which might be due to its restoring effects on the ileal microbial composition in CP-challenged broilers.

Compound Probiotics Improve Body Growth Performance by Enhancing Intestinal Development of Broilers with Subclinical Necrotic Enteritis

The aim of this study is to explore whether or not the combined application of BS15 and H2 is capable to have a more effective control effect on SNE in broilers. A total of 240 1-day-old female chickens were randomly divided into 5 groups: (a) basal diet in negative control group (NC group); (b) basal diet + SNE infection (coccidiosis vaccine + CP) (PC group); (c) basal diet + SNE infection + H2 pre-treatment (BT group); (d) basal diet + SNE infection + BS15 pre-treatment (LT group); and (e) basal diet + SNE infection + H2 pre-treatment + BS15 pre-treatment (MT group). The results showed the MT group had the most positive effect on inhibiting the negative effect of growth performance at 42 days of age. In the detection of the NC, PC, and MT group indicators at 28 days of age, we found that MT group significantly promoted ileum tissue development of broilers, and the ileum of broilers in the MT group formed a flora structure different from NC and PC, although it was found that the MT group had no effect on the butyrate level in the cecum, but it could affect the serum immune level, such as significantly reducing the level of pro-inflammatory cytokine IL-8 and increasing the content of immunoglobulin IgM and IgG. In conclusion, the composite preparation of Lactobacillus johnsonii BS15 and Bacillus licheniformis H2 could effectively improve the growth performance against SNE broilers, which is possibly caused by the improvement of the immune levels, the reduction of inflammation levels, and the promotion of the intestinal development.

Coccidia-Microbiota Interactions and Their Effects on the Host

As a common parasitic disease in animals, coccidiosis substantially affects the health of the host, even in the absence of clinical symptoms and intestinal tract colonization. Gut microbiota is an important part of organisms and is closely related to the parasite and host. Parasitic infections often have adverse effects on the host, and their pathogenic effects are related to the parasite species, parasitic site and host-parasite interactions. Coccidia-microbiota-host interactions represent a complex network in which changes in one link may affect the other two factors. Furthermore, coccidia-microbiota interactions are not well understood and require further research. Here, we discuss the mechanisms by which coccidia interact directly or indirectly with the gut microbiota and the effects on the host. Understanding the mechanisms underlying coccidia-microbiota-host interactions is important to identify new probiotic strategies for the prevention and control of coccidiosis.

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.

Identification of an Intestinal Microbiota Signature Associated With the Severity of Necrotic Enteritis

Necrotic enteritis (NE), an economically devastating disease of poultry caused by pathogenic Clostridium perfringens, is known to induce small intestinal lesions and dysbiosis. However, the intestinal microbes that are associated with NE severity are yet to be characterized. Here, we investigated the link between the ileal microbiota and disease severity in a chicken model of clinical NE using 16S rRNA gene sequencing. Our results indicated that richness and Shannon Index of the ileal microbiota were drastically reduced (p<0.01) as NE was exacerbated. While the relative abundance of C. perfringens increased from 0.02% in healthy chickens to 58–70% in chickens with severe infection, a majority of the ileal microbes were markedly diminished, albeit varying in their sensitivity to NE. Compositionally, a large group of ileal microbes showed a significant correlation with NE severity. Firmicutes, such as group A and B Lactobacillus, Lactobacillus reuteri, Subdoligranulum variabile, Mediterraneibacter, and Staphylococcus as well as two genera of Actinobacteria (Corynebacterium and Kocuria) and two highly related Cyanobacteria were progressively declined as NE was aggravated. Other Firmicutes, such as Weissella, Romboutsia, Kurthia, Cuneatibacter, Blautia, and Aerococcus, appeared much more sensitive and were rapidly abolished in chickens even with mild NE. On the other hand, Enterococcus cecorum and two Escherichia/Shigella species were only enriched in the ileal microbiota of chickens with extremely severe NE, while several other species such as Streptococcus gallolyticus and Bacteroides fragilis remained unaltered by NE. Functionally, secondary bile acid biosynthesis was predicted to be suppressed by NE, while biosynthesis of aromatic and branched-amino acids and metabolism of a majority of amino acids were predicted to be enhanced in the ileum of NE-afflicted chickens. These intestinal microbes showing a strong correlation with NE severity may provide important leads for the development of novel diagnostic or therapeutic approaches to NE and possibly other enteric diseases.

A study on fungal defensin against multidrug-resistant Clostridium perfringens and its treatment on infected poultry

In the present study, we aimed to investigate the antibacterial activity and mechanisms of plectasin-derived peptide NZ2114 in vitro and its therapeutic effects in vivo on broilers challenged with Clostridium perfringens. In vitro assay showed that NZ2114 had potent (minimal inhibitory concentration, 0.91 μM) and rapid antibacterial activity (99.9% reduction within 2 h), and the dual antibacterial mechanisms (including interfering with the cell membrane and intracellular DNA) against C. perfringens CVCC 2030. In vivo study, NZ2114 tended to increase linearly and quadratically the average daily gain as NZ2114 level increased and was the highest at 20 mg/L. NZ2114 at 10 ~ 40 mg/L dramatically reduced jejunal lesion score. Besides, the levels of IL-6, TNF-α, and IL-1β tended to downregulate linearly and quadratically as the NZ2114 level increased and were all the lowest at the dose of 20 mg/L. NZ2114 significantly upregulated those levels of IgA, IgG, IgM, and sIgA with a linear and quadratic dose effect, with the highest IgA, IgG, IgM, and sIgA at 20 mg/L. Finally, NZ2114 tended to linearly and quadratically increase the numerical value of crypt depth, with the lowest value at 40 mg/L. Lincomycin only dramatically reduced the jejunal lesion score and increased the numerical value of crypt depth. These results indicate that NZ2114 has the potential as a new alternative to antibiotics for the treatment of C. perfringens-induced necrotic enteritis infection.Key points• NZ2114 could kill C. perfringens by dual antibacterial mechanisms• Broiler necrotic enteritis model induced by C. perfringens was established• NZ2114 treatment could ameliorate C. perfringens-induced necrotic enteritis.

Comparison of Chicken Cecal Microbiota after Metaphylactic Treatment or Following Administration of Feed Additives in a Broiler Farm with Enterococcal Spondylitis History

Minimizing the clinical signs of Enterococcus cecorum infections causing enterococcal spondylitis in broiler herds is successful when initiated as metaphylaxis in the first week of life. Mechanistically, either the Enterococcus species present at that time are reduced by antibiotic treatment or antibiotic treatment might induce changes in intestinal microbiota composition with an indirect and subsequent influence. The aim of the present study was to examine the cecal microbiota of chickens after administering lincospectin or different additives to evaluate whether these additives have lincospectin-like effects on microbiota. Therefore, 157,400 broiler chickens were reared in four chicken houses (~40,000 birds each) on a broiler farm with history of enterococcal spondylitis. Each flock was treated either with lincospectin or water soluble esterified butyrins, Bacillus (B.) licheniformis or palm oil was added via drinking water during the first days of life. Ten birds per house were dissected at days 11, 20 and 33 of life and cecal microbiota were analyzed (16S rRNA gene sequencing). Lincospectin treatment elicited significant changes in the cecal microbiota composition until slaughter age. Among the tested additives, effects of B. licheniformis on cecal microbiota composition were most similar to those seen after the treatment with lincospectin at day 11.

Poultry Response to Heat Stress: Its Physiological, Metabolic, and Genetic Implications on Meat Production and Quality Including Strategies to Improve Broiler Production in a Warming World

The continuous increase in poultry production over the last decades to meet the high growing demand and provide food security has attracted much concern due to the recent negative impacts of the most challenging environmental stressor, heat stress (HS), on birds. The poultry industry has responded by adopting different environmental strategies such as the use of environmentally controlled sheds and modern ventilation systems. However, such strategies are not long-term solutions and it cost so much for farmers to practice. The detrimental effects of HS include the reduction in growth, deterioration of meat quality as it reduces water-holding capacity, pH and increases drip loss in meat consequently changing the normal color, taste and texture of chicken meat. HS causes poor meat quality by impairing protein synthesis and augmenting undesirable fat in meat. Studies previously conducted show that HS negatively affects the skeletal muscle growth and development by changing its effects on myogenic regulatory factors, insulin growth factor-1, and heat-shock proteins. The focus of this article is in 3-fold: (1) to identify the mechanism of heat stress that causes meat production and quality loss in chicken; (2) to discuss the physiological, metabolic and genetic changes triggered by HS causing setback to the world poultry industry; (3) to identify the research gaps to be addressed in future studies.

Dietary Probiotic Bacillus licheniformis H2 Enhanced Growth Performance, Morphology of Small Intestine and Liver, and Antioxidant Capacity of Broiler Chickens Against Clostridium perfringens-Induced Subclinical Necrotic Enteritis

The reduction in the use of antibiotics in the poultry industry has considerably increased the appearance of Clostridium perfringens (CP)-induced subclinical necrotic enteritis (SNE), forcing researchers to search alternatives to antibiotic growth promoters (AGP) like probiotics. This study aimed to investigate the effect and the underlying potential mechanism of dietary supplementation of Bacillus licheniformis H2 to prevent SNE. A total of 180 1-day-old male broiler chickens (Ross 308) were randomly divided into three groups, with six replicates in each group and ten broilers per pen: (a) basal diet in negative control group(NC group); (b) basal diet + SNE infection(coccidiosis vaccine + CP) (SNE group); (c) basal diet + SNE infection + H2 pre-treatment(BL group). Growth performance, morphology of small intestine and liver, and antioxidant capacity of the serum, ileum, and liver were assessed in all three groups. The results showed that H2 significantly suppressed (P < 0.05) the negative effects on growth performance induced by SNE, including loss of body weight gain, decrease of feed intake, and raise of feed conversion ratio among the different treatments at 28 days. The addition of H2 also increased (P < 0.05) the villus height: crypt depth ratio as well as villus height in the ileum. Chicks fed with H2 diet had lower malondialdehyde (MDA) concentration in the ileum in BL group than that in SNE group (P < 0.05). Moreover, compared with other treatment groups, dietary H2 improved the activities of antioxidant enzymes in the ileum, serum, and liver (P < 0.05). H2 may also prevent SNE by significantly increasing the protein content (P < 0.05) of Bcl-2 in the liver. Dietary supplementation of H2 could effectively prevent the appearance of CP-induced SNE and improve the growth performance of broiler chickens damaged by SNE, of which the mechanism may be related to intestinal development, antioxidant capacity, and apoptosis which were improved by H2.

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

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

Choice of 16S ribosomal RNA primers affects the microbiome analysis in chicken ceca

We evaluated the effect of applying different sets of 16S rRNA primers on bacterial composition, diversity, and predicted function in chicken ceca. Cecal contents from Ross 708 birds at 1, 3, and 5 weeks of age were collected for DNA isolation. Eight different primer pairs targeting different variable regions of the 16S rRNA gene were employed. DNA sequences were analyzed using open-source platform QIIME2 and the Greengenes database. PICRUSt2 was used to determine the predicted function of bacterial communities. Changes in bacterial relative abundance due to 16S primers were determined by GLMs. The average PCR amplicon size ranged from 315 bp (V3) to 769 bp (V4–V6). Alpha- and beta-diversity, taxonomic composition, and predicted functions were significantly affected by the primer choice. Beta diversity analysis based on Unweighted UniFrac distance matrix showed separation of microbiota with four different clusters of bacterial communities. Based on the alpha- and beta-diversity and taxonomic composition, variable regions V1–V3(1) and (2), and V3–V4 and V3–V5 were in most consensus. Our data strongly suggest that selection of particular sets of the 16S rRNA primers can impact microbiota analysis and interpretation of results in chicken as was shown previously for humans and other animal species.

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.

Effects of Clostridium butyricum- and Bacillus spp.-Based Potential Probiotics on the Growth Performance, Intestinal Morphology, Immune Responses, and Caecal Microbiota in Broilers

We aimed to investigate the effects of Clostridium butyricum-, Bacillus subtilis-, and Bacillus licheniformis-based potential probiotics on the growth performance, intestinal morphology, immune responses, and caecal short chain fatty acids (SCFAs) and microbial structure in broiler chickens. Three treatment groups containing a total of 1200 one-day-old AA broilers were included: birds fed with a basal diet only (Con), birds fed with added 10¹⁰ probiotics cfu/kg (ProL), and birds fed with added 10¹¹ probiotics cfu/kg (ProH). The dietary probiotics significantly improved the final and average body weights and serum immunoglobulins A, M, and Y. The probiotics also enhanced the ileal morphology and improved the caecal acetate, butyrate, and propionate contents. Furthermore, 16S rRNA sequencing revealed that dietary compound probiotics modulated the caecal microflora composition as follows: (1) all birds shared 2794 observed taxonomic units; (2) treatment groups were well separated in the PCA and PCoA analysis; (3) the relative abundance of Parabacteroides, Ruminococcaceae_UCG-014, Barnesiella, Odoribacter, [Eubacterium_coprostanoligenes_group], [Ruminococcus]_torques_group, and Butyricimonas significantly varied between treatments. The compound probiotics improved the growth performance, serum immune responses, the ratio of ileal villus height to crypt depth, and major caecal SCFAs in broiler chickens. The dietary C. butyricum-, B. subtilis-, and B. licheniformis-based probiotics improved overall broiler health and would benefit the poultry industry.

Efficacy of probiotic Bacillus licheniformis DSM 28710 on performance and the mitigation of Clostridium perfringens-induced necrotic enteritis in broiler chickens

The aim of this study was to evaluate the impact of a probiotic Bacillus licheniformis strain (DSM 28710; B-Act®) on growth performance and its capacity to mitigate necrotic enteritis (NE; induced via a Clostridium perfringens challenge) in poultry. A broiler trial was conducted, examining three treatments for 42 days under an induced NE challenge; a negative control (basal diet only); an antibiotic treated group (oxytetracycline hydrochloride (OXT), therapeutic dose of 105 mg OXT/litre in drinking water, for three days after C. perfringens challenge); and a B-Act group (500 g B-Act/tonne of feed, equalling 1.6×1012 colony forming units B. licheniformis DSM 28710/tonne of feed, supplemented from start until finish). Despite the induced NE challenge, weight gains of the B-Act and OXT groups were similar to each other but significantly higher compared to the control at the end of the study (P<0.05). Weight gain of the B-Act group was already significantly higher compared to the control on day 21 (P<0.05), indicating a potential benefit of the probiotic even before clinical establishment of NE. Feed conversion ratio (FCR) values followed a similar pattern throughout the study, with a significantly lower overall FCR for the B-Act and OXT groups compared to the control (P<0.05; d0-42). Birds fed B-Act had significantly (P<0.05) lower NE lesions compared to the control and OXT group on day 21, although OXT was not supplemented to the animals at this stage yet. Both B-Act and OXT groups had significantly (P<0.05) lower NE scores than the control on day 28, demonstrating the effectiveness of the antibiotic treatment and the mitigating effect of B-Act on the effects of a Clostridium perfringens induced NE 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.

Preventive Effects of Bacillus licheniformis on Heat Stroke in Rats by Sustaining Intestinal Barrier Function and Modulating Gut Microbiota

Heat stroke (HS) models in rats are associated with severe intestinal injury, which is often considered as the key event at the onset of HS. Probiotics can regulate the gut microbiota by inhibiting the colonization of harmful bacteria and promoting the proliferation of beneficial bacteria. Here, we investigated the preventive effects of a probiotic Bacillus licheniformis strain (BL, CMCC 63516) on HS rats as well as its effects on intestinal barrier function and gut microbiota. All rats were randomly divided into four groups: control (Con) + PBS (pre-administration with 1 ml PBS twice a day for 7 days, without HS induction), Con + BL group (pre-administration with 1 ml 1 × 10⁸ CFU/ml BL twice a day for 7 days, without HS induction), HS + PBS (PBS, with HS induction), and HS + BL (BL, with HS induction). Before the study, the BL strain was identified by genomic DNA analysis. Experimental HS was induced by placing rats in a hot and humid chamber for 60 min until meeting the diagnostic criterion of HS onset. Body weight, core body temperature, survival rate, biochemical markers, inflammatory cytokines, and histopathology were investigated to evaluate the preventive effects of BL on HS. D-Lactate, I-FABP, endotoxin, and tight-junction proteins were investigated, and the fluorescein isothiocyanate-dextran (FD-4) test administered, to assess the degree of intestinal injury and integrity. Gut microbiota of rats in each group were analyzed by 16S rRNA sequencing. The results showed that pre-administration with BL significantly attenuated hyperthermia, reduced HS-induced death, alleviated multiple-organ injury, and decreased the levels of serum inflammatory cytokines. Furthermore, BL sustained the intestinal barrier integrity of HS rats by alleviating intestinal injury and improving tight junctions. We also found that BL significantly increased the ratios of two probiotic bacteria, Lactobacillus and Lactococcus. In addition, Romboutsia, a candidate biomarker for HS diagnosis, was unexpectedly detected. In summary, BL pre-administration for 7 days has preventative effects on HS that may be mediated by sustaining intestinal barrier function and modulating gut microbiota.

Influence of Particle Size and Xylanase in Corn-Soybean Pelleted Diets on Performance, Nutrient Utilization, Microbiota and Short-Chain Fatty Acid Production in Young Broilers

The objective of this study was to investigate the effects of particle size and xylanase supplementation in corn-based pellet diets on the performance and digestive traits in young broilers. A total of 512 male Ross 308 broilers were used in a 21-day study. The treatments were designed in a 4 × 2 factorial arrangement with four levels of geometric mean diameter (Dgw) of corn (540, 660, 1390, and 1700 µm), and two levels of xylanase (0 or 16,000 BXU/kg diet). Feeding coarse corn diets (1390 and 1700 µm Dgw) and xylanase supplementation showed an inferior coefficient of variation of body weight. Higher gizzard weight, microbiome alpha-diversity, and clustered separately beta-diversity (p < 0.05) were observed in birds fed coarse diets. The addition of xylanase promoted changes in relative bacteria abundance, increasing Lachnospiraceae, Defluviitaleaceae, Bacteroidaceae, Bacillaceae, Eggerthellaceae, and Streptococcaceae families in the 1700 µm group, and Christensenellaceae and Lachnospiraceae families in the 540 µm Dgw group. In conclusion, xylanase supplementation and particle size of corn interact in the intestinal environment, showing changes in microbial composition. Coarse diets and xylanase supplementation showed improved body weight homogeneity, which might be related to a better gut development and microbiota modulation.

Modulations of genes related to gut integrity, apoptosis, and immunity underlie the beneficial effects of Bacillus amyloliquefaciens CECT 5940 in broilers fed diets with different protein levels in a necrotic enteritis challenge model

Background

The ban of in-feed antimicrobial additives has negatively affected the poultry industry by causing necrotic enteritis (NE) to emerge in the flocks. Alternatives such as Bacillus probiotics have shown to be effective on eliminating the negative effects of this disease. Two experiments were conducted to investigate the effect of Bacillus amyloliquefaciens CECT 5940 (BA) in broiler chickens under NE challenge and/or fed diets with different protein levels.

Methods

In both experiments, 480 day-old mix-sexed Ross-308 broilers were arranged in a 2 × 2 factorial arrangement of treatments. In experiment 1, the factors were NE challenge (yes or no) and probiotic (yes or no). In experiment 2, the factors were dietary crude protein levels (standard or reduced) and probiotic (yes or no) and were used under NE challenge condition. Oral administration of Eimeria oocysts (day 9) followed by inoculation with Clostridium perfringens (day 14 and 15) was used to induce NE challenge. On day 16, two birds from each treatment were gavaged with fluorescein isothiocyanate-dextran (FITC-d) and blood samples were collected for gut integrity evaluation, and jejunal samples were collected for gene expression assay.

Results

In experiment 1, BA supplementation decreased caspase-3 (CASP3) (P < 0.001) and caspase-8 (CASP8) (P < 0.05) and increased occludin (OCLD) (P < 0.05) expression regardless of the challenge. Additionally, BA supplementation downregulated interfron-γ (IFN-γ) expression (P < 0.01) and upregulated immunoglobulin-G (IgG) (P < 0.01) and immunoglobulin-M (IgM) (P < 0.05) only in challenged birds. In experiment 2, the expression of genes encoding mucin-2 (MUC2) (P < 0.001), tight junction protein-1 (TJP1) (P < 0.05) and OCLD (P < 0.05) were upregulated by the addition of BA in the diet, regardless of the crude protein level. Further, BA supplementation downregulated INF-γ (P < 0.01) and upregulated immunoglobulin-A (IgA) (P < 0.05), IgM (P < 0.05) and IgG (P < 0.01) regardless of the crude protein level.

Conclusion

These findings suggest that supplementation of BA in broiler diets can improve gut health by modulation of genes related to the mucosal barrier, tight junction, and immunity in broilers challenged by unfavourable conditions such as NE challenge.

Clostridium perfringens as Foodborne Pathogen in Broiler Production: Pathophysiology and Potential Strategies for Controlling Necrotic Enteritis

Clostridium perfringens (Cp.) is the cause of human foodborne desease. Meat and poultry products are identified as the main source of infection for humans. Cp. can be found in poultry litter, feces, soil, dust, and healthy birds' intestinal contents. Cp. strains are known to secrete over 20 identified toxins and enzymes that could potentially be the principal virulence factors, capable of degrading mucin, affecting enterocytes, and the small intestine epithelium, involved in necrotic enteritis (NE) pathophysiology, also leading to immunological responses, microbiota modification and anatomical changes. Different environmental and dietary factors can determine the colonization of this microorganism. It has been observed that the incidence of Cp-associated to NE in broilers has increased in countries that have stopped using antibiotic growth promoters. Since the banning of such antibiotic growth promoters, several strategies for Cp. control have been proposed, including dietary modifications, probiotics, prebiotics, synbiotics, phytogenics, organic acids, and vaccines. However, there are aspects of the pathology that still need to be clarified to establish better actions to control and prevention. This paper reviews the current knowledge about Cp. as foodborne pathogen, the pathophysiology of NE, and recent findings on potential strategies for its control.

Evaluation of Bacillus licheniformis-Fermented Feed Additive as an Antibiotic Substitute: Effect on the Growth Performance, Diarrhea Incidence, and Cecal Microbiota in Weaning Piglets

This study investigated the potential of a Bacillus licheniformis-fermented feed additive (BLF) as an antibiotic substitute in weaning piglets. Ninety-six crossbred piglets were randomly allotted into four treatments with three replicate pens per treatment and eight pigs per pen. Piglets were fed diets as follows: a basal diet as control, a basal diet supplemented with bacitracin (30 mg/kg of bacitracin methylene disalicylate), a basal diet supplemented with BLF (1 g/kg of the Bacillus licheniformis-fermented feed additive), and a basal diet supplemented with bacitracin and BLF (15 mg/kg of bacitracin methylene disalicylate and 0.5 g/kg of the Bacillus licheniformis-fermented feed additive). The results showed that replacing all or half the bacitracin with BLF both reduced the incidence of diarrhea in weaning piglets from day 1 to 14. Principal coordinates analysis and a species abundance heat map showed that distinct clusters were formed between groups. Replacing all the bacitracin with BLF reduced bacterial evenness in the cecal digesta of weaning piglets, while the inhibitory effect on bacterial evenness was reversed in the group treated with bacitracin in combination with BLF. These results indicated that the half replacement of bacitracin with BLF was able to decrease the incidence of diarrhea and modify cecal microbiota composition in weaning piglets, suggesting that a Bacillus licheniformis-fermented feed additive has good potential as a suitable alternative to antibiotics use in the swine industry.