Bacillus subtilis and yeast cell wall improve the intestinal health of broilers challenged by Clostridium perfringens

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.

Cell-Free Supernatant of Bacillus subtilis G2B9-Q Improves Intestinal Health and Modulates Immune Response to Promote Mouse Recovery in Clostridium perfringens Infection

Clostridium perfringens is one of the critical causative agents causing diarrhea in piglets, with significant economic losses to the pig industry. Under normal gut microbiota homeostasis and well-managed barns, diarrhea caused by C. perfringens could be controlled. Some reports show that probiotics, such as Bacillus subtilis, are beneficial in preventing necrotic enteritis (NE) in chickens, but few reports on piglets. Clostridium perfringens was found in the piglets' diarrhea with intestinal microbiota dysbiosis in our survey. Bacillus subtilis G2B9-Q, which was isolated from the feces of healthy pigs, was found to have anti-Clostridium activity after screening. Clostridium perfringens was used to challenge mice by intraperitoneal injection for modeling to evaluate the anti-infective activity of cell-free supernatant (CFS) of B. subtilis G2B9-Q and different concentrations of B. subtilis G2B9-Q by oral administration. The results showed that G2B9-Q can mitigate intestinal lesions caused by C. perfringens infection, reduce inflammatory reactions, and modulate intestinal microbiota. The CFS of G2B9-Q can alleviate the pathological damage of intestinal tissues caused by C. perfringens infection, reduce the concentration of TNF-α and IL-10 in the sera of mice, as well as the relative expression levels of alpha toxin (CPA), perfringolysin O (PFO) toxin, IL-10, IL-22, and TNF-α in the jejunum and colon tissues, and alleviate the changes in gut microbiota structure caused by C. perfringens infection, which showed better therapeutic effects and indicated that the metabolites of G2B9-Q are essential mediators for their beneficial effects. Therefore, the CFS of G2B9-Q could potentially replace antibiotics in treating C. perfringens infection.

Dietary supplementation of prebiotic yeast Saccharomyces cerevisiae cell wall promotes growth performance and intestinal health in broiler chickens challenged with Clostridium perfringens

1. This study evaluated the effectiveness of yeast (Saccharomyces cerevisiae) cell wall (YCW) supplementation on the growth performance, carcase characteristics, serum biomarkers, liver function, ileal histology and microbiota of broiler chickens challenged with Clostridium perfringens (C. perfringens).2. In a 35-d trial, 240 chicks aged 1-d-old were randomly assigned to one of four treatment groups, each with 10 replicates:   control (CON) with no challenge or additives, challenged with C. perfringens (CHAL), CHAL and supplemented with YCW at either 0.25 g/kg (YCW0.25) or 0.5 g/kg (YCW0.5).3. In comparison to CON, the CHAL birds had reduced growth performance, survival rate, dressing percentage, breast meat yield, levels of total protein (TP), globulin (GLO), glucose (GLU), total antioxidant capacity (T-AOC) and total superoxide dismutase (T-SOD), as well as a decreased Lactobacillus population (P < 0.01). Additionally, this group showed elevated levels of glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), and C. perfringens count (P < 0.01). Compared to CHAL, the YCW0.25 or YCW0.5 groups had improved growth performance, survival rate, dressing percentage, breast meat yield, levels of TP, GLO, GLU, and T-AOC, as well as the activities of T-SOD, GOT, and GPT, villus height, villus surface area, villus height to crypt depth ratio, and the populations of both Lactobacillus and C. perfringens; (P < 0.01).4. The data suggested that YCW supplementation at either 0.25 or 0.50 g/kg can restore the growth performance of broiler chickens during a C. perfringens challenge.

Efficacy of Bacillus subtilis to replace in-feed antibiotics of broiler chickens under necrotic enteritis-challenged experiments: a systematic review and meta-analysis

Necrotic enteritis (NE) and coccidiosis are among the most prevalent infectious diseases in broiler chickens, contributing to large profitability losses. Bacillus subtilis is a promising direct-fed probiotic to counter various pathogens infection in broiler chickens. Here, we performed a meta-analysis to investigate the effects of B. subtilis on broiler chickens performance. A total of 28 studies were selected according to a PRISMA checklist. Random-effect model and mixed-effect model of meta-analysis were fitted to estimate the overall effects of B. subtilis (BS) treatment compared to either the control group (CON) or NE-infected group (NEinf) as a baseline. Hedges' g effect size and its variance were used as estimators of standardized mean difference (SMD) calculation where the results were presented at a 95% confidence interval (95% CI) of the SMD. Overall, NEinf broiler chickens depressed (P < 0.01) body weight (BW), average daily gain (ADG), and feed intake, and elevated (P < 0.01) feed conversion ratio (FCR). Treatment with BS improved ADG and final BW of NEinf with no difference (P = 0.15) between BS and antibiotics (AB), indicating that they had comparable efficacy to treat NE in broiler chickens. BS supplemented to uninfected CON (BSS) improved (P < 0.01) final BW, ADG, and FCR. Compared to CON, BS, and AB failed to recover the FCR but these treatments decreased (P < 0.01) FCR when compared to the NEinf group with similar efficacy (P = 0.97). As expected, NEinf birds had a higher mortality rate (P < 0.01) and higher lesion score (P < 0.01) compared to CON, and treatment using AB and BS successfully decreased (P < 0.01) the mortality rate and lesion score. Compared to BS, AB was more effective to lower (P = 0.01) mortality rate, but comparable (P = 0.65) to minimize lesion score. To conclude, B. subtilis could be an effective natural additive to replace in-feed antibiotics in broiler chickens challenged with C. perfringens. However, the efficacy to reduce mortality rate was better with antibiotics treatment.

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

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

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.

The Combined Effect of Potential Probiotic Bacillus licheniformis MCC 2514 and Bifidobacterium breve NCIM 5671 Towards Anti-inflammatory Activity on HT-29 Cell Lines

Probiotics are considered a natural source for treating many intestinal disorders, which deliver health benefits in different ways. The study aims to evaluate the immunomodulatory gene expression on HT-29 cell line using Bacillus licheniformis MCC 2514 and Bifidobacterium breve NCIM 5671 as a single culture and in combination. Upon inflammation induced by LPS, the combination of bacteria downregulated the pro-inflammatory cytokines IL-1α (13.4), IL-12 (14.6), IL-8 (2.6), and IL-6 (1.9), and in contrast, TNF-α (21.2) folds has upregulated. However, anti-inflammatory genes such as IL-4 (0.6), IL-10 (2.9), TGF-2 (92.2), and TGF-3 (85.8) folds were upregulated. The combination of bacteria against oxidative stress downregulated the pro-inflammatory cytokines such as IL-1α & β, IL-6, IL-8, IL-12, and IL-18, and upregulated the anti-inflammatory cytokines IL-10, IL-4, TGF-2, and TGF-3. On the introduction of Kocuria rhizophila, the pro-inflammatory cytokines were upregulated. On supplementation of B. licheniformis and B. breve, the upregulated pro-inflammatory cytokines were decreased, and anti-inflammatory cytokines such as IL-4 (6.2), IL-10 (23.5), TGF-2 (166), and TGF-3(28.4) folds were increased. However, gene expression of toll-like receptor-2 was found high (26 folds) upon introducing probiotic bacteria. ELISA results of Interferon-γ found that the expression was higher (7.19 ng/mL) on the introduction of both the bacteria in combination. The higher anti-inflammatory activity was observed when potential probiotic bacteria were used in combination compared to a single culture. Overall study indicates that the combination of aerobic B. licheniformis and anaerobic B. breve has an anti-inflammatory activity that can sustain an excellent gastrointestinal environment during pathogen invasion and inflammation.

Effects of three different probiotics of Tibetan sheep origin and their complex probiotics on intestinal damage, immunity, and immune signaling pathways of mice infected with Clostridium perfringens type C

Tibetan sheep have unique intestinal microorganisms in their intestines that are adapted to the highland alpine and anoxic environment. To further clarify the probiotic properties of Tibetan sheep-derived probiotics, we selected three Tibetan sheep-derived probiotic isolates (Enterococcus faecalis EF1-mh, Bacillus subtilis BS1-ql, and Lactobacillus sakei LS-ql) to investigate the protective mechanisms of monocultures and their complex strains against Clostridium perfringens type C infection in mice. We established a model of C. perfringens type C infection and used histology and molecular biology to analyze the effects and mechanisms of different probiotic treatments on mice after C. perfringens type C infection. After supplementation with either probiotics or complex probiotics, mice were improved in terms of weight reduction and reduced the levels of cytokines in serum and increased the levels of intestinal sIgA, and supplementation with complex probiotics was effective. In addition, both probiotic and complex probiotic supplementation effectively improved the damage of intestinal mucosa and spleen tissue. The relative expressions of Muc 2, Claudin-1, and Occludin genes were increased in the ileum. The three probiotics and the compound probiotics treatment significantly reduced the relative mRNA expression of toll-like/MyD88/NF-κB/MAPK. The effect of probiotic treatment was similar to the results of engramycin treatment, but the effect of engramycin treatment on intestinal sIgA was not significant. Our results clarify the immunomodulatory effects of the three probiotic isolates and the complex probiotics on C. perfringens infection, and the repair of the intestinal mucosal barrier.

Effects of Different Nutritional Zinc Forms on the Proliferation of Beneficial Commensal Microorganisms

This study compared the minimal inhibition concentrations (MICs) and their effects on the growth kinetics of seven different types of zinc (Zn) compounds and Na2EDTA in the case of three typical commensal beneficial microorganisms (Bacillus subtilis, Lactococcus lactis, and Saccharomyces cerevisiae). The seven Zn compounds included ZnSO4, four Zn–amino acid chelates, and two Zn–EDTA complexes. Both MICs and growth kinetic parameters indicated that different microorganisms show different sensitivities; for example, B. subtilis, L. lactis, and S. cerevisiae were most sensitive to ZnSO4, Na2EDTA, and Zn(NH3)2(Gly)2, respectively. Both ZnEDTA and Zn(NH3)2(Lys)2 improved the growth rate of all beneficial commensal intestinal microorganisms at low concentrations (5–10 mg/L) and showed low toxicity towards all tested strains. At higher concentrations (100–500 mg/L), all compounds decreased the growth rate and increased the lag phase. In conclusion, both growth kinetic parameters and MICs tested effectively measured the inhibitory effects of the test materials; however, growth kinetics provides a more detailed picture of the concentration-dependent effects and those on the mechanisms of microbial growth inhibition.

Yeast cell wall upregulated cell-mediated immune responses to Newcastle disease virus vaccine

A recent study has suggested that yeast cell wall product (YP) enhanced serum hemagglutination inhibition (HI) titers and intestinal sIgA responses in chickens immunized with Newcastle disease virus (NDV) vaccine. In the present study, the cell-mediated immune responses elicited by NDV and YP were investigated in commercial broilers. Broilers were fed 0 or 0.1% YP and immunized with a live NDV vaccine via an intraocular-and-intranasal route at 14 and 28 days old. After that, blood samples were collected for determination of HI titer, cytokine content, and blood analysis. Eight chickens were randomly selected from each group and sacrificed. Lymphocytes were harvested from the spleens for lymphocyte proliferation and flow cytometry analysis. Total RNA was extracted from spleen and jejunum for RT-qPCR analysis. The results showed that YP significantly increased serum concentration of IL-4, IL-6, IFN-γ, TNF-β, as well as promoted lymphocytes proliferation in broilers immunized with NDV vaccine. The enhanced cell-mediated immunity is correlated with the upregulated mRNA expression of TGF-β, IL-6, TLR5, GATA-3, and T-bet in the spleen and upregulated mRNA expression of CCR-9, J-chain, pIgR, and TLR3 in the jejunum of chickens. It is noteworthy that no significant side effect was observed after the administration of YP. Therefore, YP could be safely used as potential immunopotentiator assisting NDV vaccine for chickens.

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

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

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.

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.

Role of Yeast and Yeast-Derived Products as Feed Additives in Broiler Nutrition

Antibiotic resistance is looming problem in broiler production globally and there has been an increasing interest to look for sustainable alternatives to antibiotics. Yeast and its derived products are recognized as potential feed additives because of their beneficial impacts on poultry. Particularly, yeast exhibited positive effects on the humoral immunity by increasing serum immunoglobulin (Ig) A levels. Moreover, yeast and its products showed immune adjuvant-like properties that helped the broilers chicken to develop faster and stronger innate immune response under pathogenic challenges. Use of yeast and its products as prebiotic/probiotic improves the gut architecture mainly by improving the gut development and gut microbiome, reduction in colonization of pathogens through competitive exclusion, binding of toxins and enhancing digestion and absorption of nutrients. These unique properties of yeast and yeast products enhance animal welfare and productivity; warrant them to be used as a promising feed additive. This article, therefore, provides insights into the functional role of yeast and its products in the broiler diets and highlights its importance as a commercially viable alternative of synthetic antibiotic growth promoters in the broiler feed industry.

Effects of a yeast-derived product on growth performance, antioxidant capacity, and immune function of broilers

Yeast culture plus enzymatically hydrolyzed yeast cell wall (YC-EHY) contains crude protein, mannan-oligosaccharide, β-glucan and yeast culture. This study was carried out to explore the effects of dietary YC-EHY at different levels on growth performance, antioxidant capacity, and immune function of broiler chickens. A total of 320 one-day-age male broiler chicks were allocated into 4 groups and were fed with a basal diet supplemented with 0 mg/kg (the control group), 50 mg/kg, 100 mg/kg, 150 mg/kg YC-EHY for 42 d. Dietary YC-EHY improved average daily gain and feed efficiency during the starter, grower, and overall periods as well as average body weight of broiler chickens on 42 d (linear and quadratic, P < 0.05). Broiler chickens fed with YC-EHY quadratically increased jejunal sucrase activity on 21 d (quadratic, P < 0.05), and linearly and quadratically enhanced maltase activity on 21 and 42 d (linear and quadratic, P < 0.05). Supplementing YC-EHY linearly and quadratically enhanced jejunal superoxide dismutase (SOD) activity on 21 and 42 d and glutathione peroxidase (GPX) activity on 42 d whereas decreased malonaldehyde (MDA) concentration on 42 d (linear and quadratic, P < 0.05). Consistently, the jejunal genes expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and SOD1 on 21 and 42 d, heme oxygenase-1 (HO-1) and GPX1 on 42 d were enhanced by YC-EHY supplementation (linear and quadratic, P < 0.05). The concentrations of jejunal immunoglobulin G (IgG) on 21 and 42 d and secreted immunoglobulin A (SIgA) on 42 d were linearly and quadratically elevated by supplementing YC-EHY (linear and quadratic, P < 0.05). Dietary YC-EHY quadratically increased jejunal IgG and IgM genes expression on 21 d (quadratic, P < 0.05), and linearly and quadratically enhanced the genes expression of IgG and IgM on 42 d (linear and quadratic, P < 0.05). Overall, this study indicated that supplementing YC-EHY could exert beneficial effects on growth performance, intestinal antioxidant capacity and immune function in broiler chickens.

Dietary fiber in poultry nutrition and their effects on nutrient utilization, performance, gut health, and on the environment: a review

Dietary fiber (DF) was considered an antinutritional factor due to its adverse effects on feed intake and nutrient digestibility. However, with increasing evidence, scientists have found that DF has enormous impacts on the gastrointestinal tract (GIT) development, digestive physiology, including nutrient digestion, fermentation, and absorption processes of poultry. It may help maintain the small and large intestine's integrity by strengthening mucosal structure and functions and increasing the population and diversity of commensal bacteria in the GIT. Increasing DF content benefits digestive physiology by stimulating GIT development and enzyme production. And the inclusion of fiber at a moderate level in diets also alters poultry growth performance. It improves gut health by modulating beneficial microbiota in the large intestine and enhancing immune functions. However, determining the source, type, form, and level of DF inclusion is of utmost importance to achieve the above-noted benefits. This paper critically reviews the available information on dietary fibers used in poultry and their effects on nutrient utilization, GIT development, gut health, and poultry performance. Understanding these functions will help develop nutrition programs using proper DF at an appropriate inclusion level that will ultimately lead to enhanced DF utilization, overall health, and improved poultry growth performance. Thus, this review will help researchers and industry identify the sources, type, form, and amount of DF to be used in poultry nutrition for healthy, cost-effective, and eco-friendly poultry production.

Protective Effects of Lactobacillus plantarum 16 and Paenibacillus polymyxa 10 Against Clostridium perfringens Infection in Broilers

This study aimed to investigate the protective effects of Lactobacillus plantarum 16 (Lac16) and Paenibacillus polymyxa 10 (BSC10) against Clostridium perfringens (Cp) infection in broilers. A total of 720 one-day-old chicks were randomly divided into four groups. The control and Cp group were only fed a basal diet, while the two treatment groups received basal diets supplemented with Lac16 (1 × 10⁸ cfu·kg^-1) and BSC10 (1 × 10⁸ cfu·kg^-1) for 21 days, respectively. On day 1 and days 14 to 20, birds except those in the control group were challenged with 1 × 10⁸ cfu C. perfringens type A strain once a day. The results showed that both Lac16 and BSC10 could ameliorate intestinal structure damage caused by C. perfringens infection. C. perfringens infection induced apoptosis by increasing the expression of Bax and p53 and decreasing Bcl-2 expression and inflammation evidence by higher levels of IFN-γ, IL-6, IL-1β, iNOS, and IL-10 in the ileum mucosa, and NO production in jejunal mucosa, which was reversed by Lac16 and BSC10 treatment except for IL-1β (P < 0.05). Besides, the two probiotics restored the intestinal microbiota imbalance induced by C. perfringens infection, characterized by the reduced Firmicutes and Proteobacteria and the increased Bacteroidetes at the phyla level and decreased Bacteroides fragilis and Gallibacterium anatis at the genus level. The two probiotics also reversed metabolic pathways of the microbiota in C. perfringens-infected broilers, including B-vitamin biosynthesis, peptidoglycan biosynthesis, and pyruvate fermentation to acetate and lactate II pathway. In conclusion, Lac16 and BSC10 can effectively protect broilers against C. perfringens infection through improved composition and metabolic pathways of the intestinal microbiota, intestinal structure, inflammation, and anti-apoptosis.

Effects of Spirulina (Arthrospira) platensis and Bacillus subtilis PB6 on growth performance, intestinal microbiota and morphology, and serum parameters in broiler chickens

Context The use of microalgae as prebiotics in poultry diets may improve production efficiency by modifying the gastrointestinal ecosystem. Prebiotic properties of the cyanobacterium Spirulina (Arthrospira) platensis have been confirmed, but effects of its combination with probiotics on broiler chicken performance are unclear. Aims This experiment was designed to study the effects of different levels of a microalga (Spirulina platensis) and a probiotic (Bacillus subtilis PB6, BSPB) on performance, intestinal microbiota and morphology, and blood parameters in broiler chickens. Methods One-day-old Ross 308 broiler chickens (300 in total) were allocated to six treatments in a completely randomised design with 3 × 2 factorial arrangement including three levels of Spirulina (0%, 0.05% or 0.1% of diet) and two levels of BSPB (0% or 0.05% of diet) and were reared for 42 days. Key results Individual use of Spirulina and BSPB improved bodyweight gain and feed conversion ratio of broiler chickens. The relative weight of the breast cut was greater in broilers treated with 0.05% Spirulina than in those receiving Spirulina-free treatments. The count of lactic acid bacteria was higher in the ileum of birds receiving only BSPB than in those receiving diets without BSPB. The use of 0.1% Spirulina in the diet decreased the pH and coliform population in the ileum compared with 0% Spirulina. There was an interaction between Spirulina and BSPB on villus height (VH) and the VH:crypt depth ratio in the small intestine. Co-supplementation with 0.1% Spirulina and BSPB increased VH and the VH:crypt depth ratio in the duodenum compared with diets supplemented, respectively, with 0.1% Spirulina and BSPB alone. Broiler chickens fed diets with BSPB had higher activities of superoxide dismutase and glutathione peroxidase and lower concentrations of cholesterol and triglyceride in serum. Conclusions The results show that supplementation with Spirulina and BSPB had a positive effect on performance and carcass quality of broiler chickens. The synergistic interaction between these supplements leads to enhancement of epithelial morphology in the small intestine. Implications Because of the potential of Spirulina and BSPB to create beneficial changes in the intestinal ecosystem and serum parameters, these dietary additives could be recommended for improving the quantity and quality of meat products and health status in broiler chickens.

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

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

Prospects of yeast based feed additives in poultry nutrition: Potential effects and applications

Yeast and its derivatives are extensively utilized as feed additives in poultry industry owing to their desirable health and growth promoting effects. Exhaustive number of studies had reported positive effects of yeast based additives on growth, meat quality, immunity, antioxidant status, and gastrointestinal functions in poultry birds. Owing to their prebiotic/probiotic properties, they also play significant role in gut development and modulation of gut microbiome by favouring beneficial microbes while reducing colonization of pathogenic microbes by competitive exclusion. They also possess effective potential for binding of dietary toxins in addition to improving digestion and utilization of nutrients. Moreover, yeast based additives have exhibited desirable effects on humoral immunity by increasing serum immunoglobulin (Ig) A levels. These additives have been also used as immune adjuvants to boost innate immune response under any pathogenic challenges in birds. Due to their diverse biological activities, yeast products are potentially capable for immune hemostasis by mediating balance between pro- and anti-inflammatory activities. These unique properties of yeast based products make them promising feed additive to promote health and productivity leading to efficient poultry production. Yeast can be supplemented in poultry diets @ 5.0–10.0 g/kg of feed. Numerous studies had reported significant improvement in body weight gain (3 to 8%) and FCR (1.6 to 12%) in broilers in response to supplementation of yeast based additives. Moreover, yeast supplementation also improved hemoglobin (Hb g/dl) levels up to 2.59 to 6.62%, total protein (>0.69%) while reducing serum cholesterol (mg/dl) up to 3.68 to 13.38%. Despite the potential properties and beneficial effects, use of yeast and its derivatives as feed additives in poultry industry is not matching its inherent potential due to many reasons. This review aims to highlight the importance and potential role of yeast and its products as natural growth promoter to replace in feed antibiotics to address the issues of antibiotic residues and microbial resistance. This article provides insights on functional role of yeast based additives in poultry diets and their importance as commercially viable alternatives of antibiotic growth promoters in poultry feed industry.

Dietary hydrolysed yeast cell wall extract is comparable to antibiotics in the control of subclinical necrotic enteritis in broiler chickens

1. The aim of this study was to examine the effect of yeast cell wall (YCW) on performance and physiological responses of broiler chickens under subclinical necrotic enteritis challenge.2. Six treatments in a 2 × 3 factorial arrangement (non-challenged or challenged plus no supplement, YCW or antibiotics (AB)) was used. Each treatment was replicated eight times with 12 birds per replicate. The treatments included: (1) Positive control (PC; no additive, not challenged); (2) Negative control (NC; no additive, with challenge); (3) YCWN = yeast cell wall (2.0 g/kg diet, not challenged; (4) YCWC = yeast cell wall (2.0 g/kg diet, challenged); (5) ABN = zinc bacitracin 50 ppm + Salinomycin 60 ppm, not challenged); (6) ABC = zinc bacitracin 50 ppm + Salinomycin 60 ppm, challenged).3. Eimeria challenge at 9 d of age did not affect feed intake (FI), body weight gain (BWG), FCR or liveability at 10 d. The BWG and FCR at 10 d were greater (P < 0.05) in birds fed YCW or AB (AB) diets relative to the PC or NC groups. On 24 and 35 d, FI, BWG, FCR and flock uniformity (28 d) were greater (P < 0.05) in the challenged groups fed YCW or AB diets compared to NC group.4. Supplementation with YCW ameliorated the negative effects of NE on liver, spleen and bursa weight of birds.5. Necrotic enteritis challenge decreased (P < 0.05) caecal Lactobacillus and Bifidobacterium spp. counts, and increased ileum lesion score and caecal Clostridium perfirngens counts. This was reversed by the addition of either YCW or AB.6. Supplementation with YCW and AB resulted to a greater (P < 0.05) dressing percentage and meat yield (35 d).7. The results indicated that YCW plays a vital role in improving the physiological response and performance of broiler chickens under subclinical necrotic enteritis challenge.

Xylanase and Fermented Polysaccharide of Hericium caputmedusae Reduce Pathogenic Infection of Broilers by Improving Antioxidant and Anti-Inflammatory Properties

Background

Pathogenic infection in broilers has become an important issue in the development of poultry industry. Xylooligosaccharides released from xylan via xylanase and fermented polysaccharide of Hericium caputmedusae (FPHC) have antimicrobial potential against many pathogens.

Objective

We aimed to explore the effects of xylanase and FPHC on pathogenic infection in the broilers (Gallus gallus domesticus).

Methods

Three hundred and thirty 21-day male broilers were assigned into four groups: control group (CG, basic diet), xylanase group (XG, basic diet + xylanase), FPHC group (HG, basic diet + FPHC), and XHG group (basic diet + xylanase + FPHC). Average daily feed intake (ADFI) and daily gain (ADG) were measured. Microflora from broiler feces was analyzed using 16S rRNA sequencing. Serum tumor necrosis factor- (TNF-) α, interleukin-1β (IL-1β), IL-1 receptor antagonist (IL-1ra), IL-10, total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) contents were detected using kits. The variables were compared using the Student t-test between two groups.

Results

Microbiological investigations showed that 75% of broilers were affected by bacterial pathogens in the CG group, most notably by coagulase-negative staphylococci. Comparatively, 15%, 26%, and 5% of broilers were affected by bacterial pathogens in the XG, HG, and XHG groups, respectively. Xylanase and FPHC treatment increased the ratio of ADG to ADFI and antioxidant capacity by increasing the levels of T-AOC, SOD, and GSH-Px and reducing the levels of MDA (P < 0.05). Xylanase and FPHC treatment improved anti-inflammatory capacity by increasing serum levels of IL-1ra and IL-10 and reducing the levels of IL-1β and TNF-α. On the other hand, the treatment increased probiotic concentration of Bacillus licheniformis, Bacillus subtilis, and Lactobacillus plantarum (P < 0.05), which were also proved in cell culture.

Conclusions

Xylanase and FPHC ameliorate pathogen infection by increasing antioxidant and anti-inflammatory activities of broilers via the increase of probiotics.

Optimization of surfactin production from Bacillus subtilis in fermentation and its effects on Clostridium perfringens-induced necrotic enteritis and growth performance in broilers

Bacillus species are commonly used as probiotics in the poultry feed industry for preventing infectious diseases and improving productivity by altering gastrointestinal microbiota. The growth parameters of Bacillus subtilis for surfactin production in fermentation and the benefits of surfactin on broiler chickens remain unclear. In this study, we examined the growth parameters of B. subtilis in fermentation and evaluated the effects of surfactin from B. subtilis-fermented products on Clostridium perfringens-induced necrotic enteritis and growth performance in broilers. Results showed that the highest viable biomass of B. subtilis was observed at 10% molasses and 2% yeast supplementation during fermentation. The 4- and 6-day fermented B. subtilis products were heat-, acid- and bile-resistant. Furthermore, the 4-day fermented B. subtilis products with the highest surfactin concentration showed the maximal antimicrobial activity against pathogens, including Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and C. perfringens. Dietary B. subtilis-fermented product supplementation in broilers significantly improved intestinal morphology and necrotic lesions under C. perfringens challenge. Bacillus subtilis treatments could enhance broiler productivity, as well as promote bone quality and intestinal morphology. These results together indicate that B. subtilis-fermented products containing surfactin have potential for the development as feed additives and use as possible substitutes for antibiotics to treat C. perfringens in the poultry industry.