Influence of Pediococcus pentosaceus GT001 on Performance, Meat Quality, Immune Function, Antioxidant and Cecum Microbial in Broiler Chickens Challenged by Salmonella typhimurium

This study evaluated the effects of Pediococcus pentosaceus GT001 on Salmonella typhimurium (S. typhimurium)-challenged broiler chickens. Two hundred Ross 708 broiler day-old chicks with comparable weight were distributed at random into four treatments with five replicates and ten chicks per replicate. The following were the treatment groups: (B) basal diet (control); (B + S) basal diet and birds were challenged with S. typhimurium at 1.0 × 107 cfu/g; (B + P) basal diet + Pediococcus pentosaceus GT001 at 4.0 × 108 cfu/g; (B + P + S) basal diet + P. pentosaceus GT001 at 4.0 × 108 cfu/g and birds were challenged with S. typhimurium at 1.0 × 107 cfu/g. There was a significant reduction (p < 0.05) in the body weight of the Salmonella-infected birds compared to the other treatment groups. However, the FCRs of the broilers were comparable among the different treatment groups (p > 0.05). The lipid profile and liver function indices measured were significantly enhanced in the P. pentosaceus GT001-supplemented groups (B + P and B + P + S) compared to the group that was Salmonella-challenged (p < 0.05) but were similar to those in the control group. The serum antioxidant activities, such as the T-AOC, SOD, CAT, GHS-Px and MDA, were significantly improved in the P. pentosaceus GT001-supplemented groups (B + P and B + P + S) (p < 0.05). The MDA was similar in the B + P and B + P + S groups, but both were significantly lower than the control and the Salmonella groups. The administration of P. pentosaceus GT001 enhanced the lipase and amylase levels in both the serum and intestine of the broilers (p < 0.05). The immunoglobin (IgA, IgG, IgM) and cytokine (IL-10 and IL-6) levels in the serum were significantly higher in the B, B + P and B + P + S treatment groups (p < 0.05). The immune-related organs (bursa and spleen) were significantly influenced in the birds fed with P. pentosaceus GT001. No significant variation was noted among all the dietary treatments in terms of the measured meat quality indices. The small intestinal digesta content of the Salmonella load was below a detectable range after 14 days of infection (p < 0.05). No significant differences were observed among the different treatment groups in terms of the breast pH, drip loss and meat color (p > 0.05). The inclusion of P. pentosaceus GT001 also modified the community structure in the cecum. This indicates that it has health benefits and could be incorporated in the broiler diet.

Mitigation Potential of Herbal Extracts and Constituent Bioactive Compounds on Salmonella in Meat-Type Poultry

Herbal extracts have been widely evaluated in poultry production for their beneficial effects and potential substitute for antibiotics, which contribute to AMR and risks to human health through the consumption of infected meat. Salmonellosis is a systemic infection caused by Salmonella, an intracellular bacterium with the ability to cause systemic infections with significant implications for both the health and safety of farmers and consumers. The excessive use of antibiotics has escalated the incidence of antibiotic resistance bacteria in the poultry and livestock industry, highlighting the urgent need for alternatives especially in meat-type poultry. Both in vivo usage and in vitro studies of bioactive compounds from herbal extracts have demonstrated the effective antimicrobial activities against pathogenic bacteria, showing promise in managing Salmonella infections and enhancing poultry performance. Phytobiotic feed additives have shown promising results in improving poultry output due to their pharmacological properties, such as stimulating consumption, and enhancing antioxidant properties and preventing the increasing antimicrobial resistance threats. Despite potential for synergistic effects from plant-derived compounds, a further investigation into is essential to fully understand their role and mechanisms of action, for developing effective delivery systems, and for assessing environmental sustainability in controlling Salmonella in poultry production.

Assessing the effects of microencapsulated Lactobacillus salivarius and cowpea seed supplementation on broiler chicken growth and health status

This study aimed to assess the nutritional quality of cowpea seeds (cv. Doljana - CSD) and the impact of partially replacing soybean meal with CSD, along with the supplementation of microencapsulated Lactobacillus salivarius (LS), on the growth performance, selected carcass traits, biochemical plasma profile, tibia bone quality, and microbial populations in the ceca and excreta of broiler chickens aged 1 to 35 days. A total of 432 mixed-sex Ross 308 broiler chickens, aged one day, were randomly allocated to four groups, with 108 birds in each group, further divided into 6 pens containing 18 birds each. The experimental design featured a 2 × 2 factorial arrangement, with two cowpea seed levels (CSD0 and CSD15%) and the presence or absence (Yes/No) of microencapsulated LS probiotic (0 and 1 g/kg feed). The experimental diets did not significantly influenced (p > 0.05) production performances. However, the production efficiency factor was notably higher in the CSD0 (336.8%) and CSD15 (332.2%) groups with LS compared to CSD0 (322.4%) and CSD15 (320.6%) groups without LS supplementation. Regarding carcass traits, the CSD15 group with LS supplementation exhibited higher dressing (70.69%) and liver (2.47%) percentages compared to the other groups. Plasma profile analysis revealed significant reductions (p < 0.05) in total cholesterol (from 115 mg/dL to 105 mg/dL) and triglycerides (from 54.80 mg/dL to 46.80 mg/dL) in the CSD15 group with LS supplementation compared to the CSD0 group, with or without LS supplementation. Moreover, the CSD15 group with LS had significantly higher total protein, albumin, and calcium levels and significantly lower (p < 0.05) uric acid levels compared to the CSD0 group, irrespective of LS supplementation. Tibia bone traits and minerals showed no significant effects. However, the pH exhibited a linear decrease from 6.90 in the CSD0 group without LS to 6.69 in the CSD15 group with LS supplementation. In terms of cecal microbial populations, Coliforms decreased from 7.14 CFU/g in the CSD15 group without LS to 5.48 CFU/g in the CSD15 group with LS. Significant alterations were also observed in Clostridium spp., E. coli, Enterococcus spp., and Staphylococcus spp. in the ceca and excreta of the CSD15 group with LS supplementation compared to the CSD0 group, with or without LS supplementation. Beneficial bacteria, specifically Lactobacillus spp., significantly increased in the cecal content of CSD0 (9.06 CFU/g) and CSD15 (9.01 CFU/g) groups with LS compared to CSD0 (8.41 CFU/g) and CSD15 (8.11 CFU/g) groups without LS. In summary, this study suggests that cowpea seeds can be used as a partial replacement for soybean meal in broiler chicken diets, and microencapsulated Lactobacillus salivarius can be employed as a probiotic supplement.

Applications of Enteroendocrine Cells (EECs) Hormone: Applicability on Feed Intake and Nutrient Absorption in Chickens

This review focuses on the role of hormones derived from enteroendocrine cells (EECs) on appetite and nutrient absorption in chickens. In response to nutrient intake, EECs release hormones that act on many organs and body systems, including the brain, gallbladder, and pancreas. Gut hormones released from EECs play a critical role in the regulation of feed intake and the absorption of nutrients such as glucose, protein, and fat following feed ingestion. We could hypothesize that EECs are essential for the regulation of appetite and nutrient absorption because the malfunction of EECs causes severe diarrhea and digestion problems. The importance of EEC hormones has been recognized, and many studies have been carried out to elucidate their mechanisms for many years in other species. However, there is a lack of research on the regulation of appetite and nutrient absorption by EEC hormones in chickens. This review suggests the potential significance of EEC hormones on growth and health in chickens under stress conditions induced by diseases and high temperature, etc., by providing in-depth knowledge of EEC hormones and mechanisms on how these hormones regulate appetite and nutrient absorption in other species.

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.

Probiotic Lactobacilli Do Not Protect Chickens against Salmonella Enteritidis Infection by Competitive Exclusion in the Intestinal Tract but in Feed, Outside the Chicken Host

Lactobacilli are commonly used as probiotics in poultry to improve production parameters and to increase chicken resistance to enteric infections. However, lactobacilli do not efficiently colonise the chicken intestinal tract, and also, their anti-infection effect in vivo is sometimes questionable. In this study, we therefore evaluated the potential of a mixture of four Lactobacillus species (L. salivarius, L. reuteri, L. ingluviei and L. alvi) for the protection of chickens against Salmonella Enteritidis infection. Whenever the chickens were inoculated by lactobacilli and S. Enteritidis separately, there was no protective effect of lactobacilli. This means that when lactobacilli and S. Enteritidis are exposed to each other as late as in the crop of chickens, lactobacilli did not influence chicken resistance to S. Enteritidis at all. The only positive effect was recorded when the mixture of lactobacilli and S. Enteritidis was used for the inoculation of feed and the feed was anaerobically fermented for 1 to 5 days. In this case, chickens fed such a diet remained S. Enteritidis negative. In vitro experiments showed that the protective effect was caused by acidification of feed down to pH 4.6 due to lactobacilli fermentation and was associated with S. Enteritidis inactivation. The probiotic effect of lactobacilli was thus expressed in the feed, outside the chicken host.

Zeolite-based nanocomposite as a smart pH-sensitive nanovehicle for release of xylanase as poultry feed supplement

Xylanase improves poultry nutrition by degrading xylan in the cell walls of feed grains and release the entrapped nutrients. However, the application of xylanase as a feed supplement is restricted to its low stability in the environment and gastrointestinal (GI) tract of poultry. To overcome these obstacles, Zeozyme NPs as a smart pH-responsive nanosystem was designed based on xylanase immobilization on zeolitic nanoporous as the major cornerstone that was modified with L-lysine. The immobilized xylanase was followed by encapsulating with a cross-linked CMC-based polymer. Zeozyme NPs was structurally characterized using TEM, SEM, AFM, DLS, TGA and nitrogen adsorption/desorption isotherms at liquid nitrogen temperature. The stability of Zeozyme NPs was evaluated at different temperatures, pH, and in the presence of proteases. Additionally, the release pattern of xylanase was investigated at a digestion model mimicking the GI tract. Xylanase was released selectively at the duodenum and ileum (pH 6-7.1) and remarkably preserved at pH ≤ 6 including proventriculus, gizzard, and crop (pH 1.6-5). The results confirmed that the zeolite equipped with the CMC matrix could enhance the xylanase thermal and pH stability and preserve its activity in the presence of proteases. Moreover, Zeozyme NPs exhibited a smart pH-dependent release of xylanase in an in vitro simulated GI tract.

Xylanase impact beyond performance: A microbiome approach in laying hens

Anti-nutritional compounds such as non-starch polysaccharides (NSP) are present in viscous cereals used in feed for poultry. Therefore, exogenous carbohydrases are commonly added to monogastric feed to degrade these NSP. Our hypothesis is that xylanase not only improves laying hen performance and digestibility, but also induces a significant shift in microbial composition within the intestinal tract and thereby might exert a prebiotic effect. In this context, a better understanding on whether and how the chicken gut microbial population can be modulated by xylanase is required. To do so, the effects of dietary supplementation of xylanase on performance, apparent total tract digestibility (ATTD) and cecal microbiome in laying hens were evaluated in the present study. A total of 96 HiSex laying hens were used in this experiment (3 diets and 16 replicates of 2 hens). Xylanase was added to the diets at concentrations of 0, 45,000 (15 g/t Xygest^TM HT) and 90,000 U/kg (30 g/t Xygest HT). The diets were based on wheat (~55%), soybean and sunflower meal. The lowest dosage, 45,000 U/kg, significantly increased average egg weight and improved feed efficiency compared to the control treatment (P<0.05). Egg quality parameters were significantly improved in the experiment in response to the xylanase addition. For example, during the last 28 days of the trial, birds receiving the 45,000 U/kg and the 90,000 U/kg treatments exhibited an increase in Haugh units and albumin heights (P<0.05). Compared with the control, the ATTD of organic matter and crude protein were drastically improved in the 45,000 U/kg treatment group (P<0.05). Furthermore, gross energy and the ATTD of crude fat were improved significantly for birds fed 90,000 U/kg group compared to the control. Importantly, 16S rRNA gene analysis revealed that xylanase at 45,000 U/kg dosage can exert a change in the cecal microbiome. A significant increase in beneficial bacteria (Bacilli class; Enterococcaceae and Lactobacillales orders; Merdibacter, Enterococcus and Nocardiopsis genera; Enterococcus casseliflavus species) was documented when adding 45,000 U/kg xylanase to the diet of laying hens. In conclusion, dietary supplementation of xylanase 45,000 U/kg significantly improved laying hen performance and digestibility. Furthermore, microbiome data suggest that xylanase modulates the laying hen bacterial population beneficially, thus potentially exerting a prebiotic effect.

Xylanase and Direct-Fed Microbials (DFM) Potential for Improvement of Live Performance, Energy Digestibility, and Reduction of Environmental Microbial Load of Broilers

The challenge of identifying alternatives to subtherapeutic levels of antibiotic growth promoters (AGP) in animal feed has led to increased interest in feed additives such as exogenous enzymes and direct-fed microbials (DFM). Six corn soy-based dietary treatments were designed to investigate the effect of high-efficiency xylanase alone, Bacillus spp. probiotics alone, and their combination vs. a commonly used antibiotic growth promoter (bacitracin methylene disalicylate; BMD) on live performance and environmental Clostridium perfringens load of broiler chickens with eight replicate pens per treatment. Diets were as follows: standard diet (positive control; PC); 130 kcal/kg reduced-energy diet (negative control; NC); NC with xylanase (NC + Xy); NC with probiotics (NC + Pro); NC with xylanase and probiotics mix (NC + XyPro); and NC with BMD (NC + BMD). Data were analyzed as one-way ANOVA. At 35 and 42 days, birds fed with NC + XyPro and NC + BMD were heavier (P < 0.05) than birds fed with NC. Improvement in feed conversion ratio (FCR) (P = 0.0001) was observed from 1 to 42 days by ~3 points in both NC + XyPro and NC + BMD compared to NC. The NC + XyPro reduced lesion scores by 66% compared to PC and NC. Litter C. perfringens cell count was reduced by ~16% with supplementation of XyPro or BMD. It can be concluded that a blend of xylanase (10 XU/g feed) and Bacillus spp. [1 × 10⁵ colony forming units (CFU)/g feed] can be used as an alternative to AGP in low-energy broiler diets.

The Systemic Zinc Homeostasis Was Modulated in Broilers Challenged by Salmonella

Salmonella challenge leads to systemic responses that induce the hypozincaemia in mice, which is considered a vital strategy against Salmonella invasion. However, it is not yet known if this phenomenon occurs in broilers. To investigate the change in zinc homeostasis of broilers against Salmonella challenge, 1-day-old male broilers were fed with the basal diet for 7 days. Afterwards, broilers were orally inoculated with either 0 or 0.5 × 108 CFU Salmonella Typhimurium (ST). The serum and selected tissues of Salmonella-challenged and non-challenged broilers were collected at 1, 3 and 7 days post-challenge for zinc homeostasis analysis. Our results showed that Salmonella challenge results in hypozincaemia (serum zinc decrease and liver zinc increase) via modulating the systemic zinc homeostasis of broilers. A profound, zinc transporter-mediated zinc absorption and redistribution affecting zinc homeostasis provided a mechanistic explanation for this phenomenon. In addition, we found that the zinc importers Zip5, Zip10, Zip11, Zip12, Zip13 and Zip14 were mainly downregulated in Salmonella-challenged broilers to reduce zinc absorption in the duodenum, while the Zip14 mRNA expression was upregulated to redistribute zinc into the liver. Collectively, these findings reveal that broilers counteract Salmonella infection via modulating their systemic zinc homeostasis.

Impact of Dietary Manganese on Intestinal Barrier and Inflammatory Response in Broilers Challenged with Salmonella Typhimurium

Growing concern for public health and food safety has prompted a special interest in developing nutritional strategies for removing waterborne and foodborne pathogens, including Salmonella. Strong links between manganese (Mn) and intestinal barrier or immune function hint that dietary Mn supplementation is likely to be a promising approach to limit the loads of pathogens in broilers. Here, we provide evidence that Salmonella Typhimurium (S. Typhimurium, 4 × 10⁸ CFUs) challenge-induced intestinal injury along with systemic Mn redistribution in broilers. Further examining of the effect of dietary Mn treatments (a basal diet plus additional 0, 40, or 100 mg Mn/kg for corresponding to Mn-deficient, control, or Mn-surfeit diet, respectively) on intestinal barrier and inflammation status of broilers infected with S. Typhimurium revealed that birds fed the control and Mn-surfeit diets exhibited improved intestinal tight junctions and microbiota composition. Even without Salmonella infection, dietary Mn deficiency alone increased intestinal permeability by impairing intestinal tight junctions. In addition, when fed the control and Mn-surfeit diets, birds showed decreased Salmonella burdens in cecal content and spleen, with a concomitant increase in inflammatory cytokine levels in spleen. Furthermore, the dietary Mn-supplementation-mediated induction of cytokine production was probably associated with the nuclear factor kappa-B (NF-κB)/hydrogen peroxide (H₂O₂) pathway, as judged by the enhanced manganese superoxide dismutase activity and the increased H₂O₂ level in mitochondria, together with the increased mRNA level of NF-κB in spleen. Ingenuity-pathway analysis indicated that acute-phase response pathways, T helper type 1 pathway, and dendritic cell maturation were significantly activated by the dietary Mn supplementation. Our data suggest that dietary Mn supplementation could enhance intestinal barrier and splenic inflammatory response to fight against Salmonella infection in broilers.

Effect of Antimicrobial Peptide Microcin J25 on Growth Performance, Immune Regulation, and Intestinal Microbiota in Broiler Chickens Challenged with Escherichia coli and Salmonella

Simple Summary

Antimicrobial peptides are thought to be ideal candidates, owing to their antimicrobial properties, broad spectrum of activity, and low propensity for development of bacterial resistance. Microcin J25 (MccJ25) is an antimicrobial peptide produced by a fecal strain of Escherichia coli (E. coli) containing 21 Arbor Acres (AA) broilers, and has a strong inhibition on E. coli and Salmonella. This study was performed primarily to evaluate the effects of MccJ25 on growth performance and gut health in broilers challenged with E. coli and Salmonella, as a potential substitute for antibiotics. The results showed that MccJ25 promoted growth performance, improved intestinal morphology, and influenced fecal microbiota composition.

Abstract

The purpose of this study was to investigate the effects of antimicrobial peptide microcin J25 (MccJ25) on growth performance, immune regulation, and intestinal microbiota in broilers. A total of 3120 one-day-old male Arbor Acres (AA) broilers were randomly allocated to five groups (12 replicates, 52 chickens per replicate). The treatments were control, challenge (0 mg/kg MccJ25), different dosages of antimicrobial peptide (AMP) (0.5 and 1mg/kg MccJ25), and antibiotic groups (20 mg/kg colistin sulfate). The MccJ25 groups increased the body weight gain (starter and overall) that was reduced in the challenge group. The overall (day 1 to day 42) feed-to-gain ratio (G:F) was significantly decreased in AMP groups compared with the challenge group. Birds fed AMP had a decreased population of total anaerobic bacteria (day 21 and day 42) and E. coli (day 21 and day 42) in feces, as well as a lower Salmonella infection rate (day 21 and day 42) compared with birds in the challenge group. The villus height of the duodenum, jejunum, and ileum, as well as the villus height/crypt depth of the duodenum and jejunum were greater in AMP groups than birds in the challenge group. Moreover, MccJ25 linearly improved the villus height of the duodenum and jejunum. The addition of MccJ25 decreased the concentration of TNF-α, IL-1β, and IL-6 compared with challenge group. At d 21, MccJ25 linearly reduced the level of IL-6. In conclusion, dietary supplemented MccJ25 effectively improved performance, systematic inflammation, and improved fecal microbiota composition of the broilers.

Effects of multi-strain probiotic supplementation on intestinal microbiota, tight junctions, and inflammation in young broiler chickens challenged with Salmonella enterica subsp. enterica

Objective

This study assessed the effects of probiotics on cecal microbiota, gene expression of intestinal tight junction proteins, and immune response in the cecal tonsil of broiler chickens challenged with Salmonella enterica subsp. enterica.

Methods

One-day-old broiler chickens (n = 240) were randomly allocated to four treatments: negative control (Cont), multi-strain probiotic-treated group (Pro), Salmonella-infected group (Sal), and multi-strain probiotic-treated and Salmonella-infected group (ProSal). All chickens except those in the Cont and Pro groups were gavaged with 1×10⁸ cfu/mL of S. enterica subsp. enterica 4 days after hatching.

Results

Our results indicated that body weight, weight gain, and feed conversion ratio of birds were significantly reduced (p<0.05) by Salmonella challenge. Chickens challenged with Salmonella decreased cecal microbial diversity. Chickens in the Sal group exhibited abundant Proteobacteria than those in the Cont, Pro, and ProSal groups. Salmonella infection downregulated gene expression of Occludin, zonula occludens-1 (ZO1), and Mucin 2 in the jejunum and Occludin and Claudin in the ileum. Moreover, the Sal group increased gene expression of interferon-γ (IFN-γ), interleukin-6 (IL-6), IL-1β, and lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF) and reduced levels of transforming growth factor-β4 and IL-10 compared with the other groups (p<0.05). However, chickens receiving probiotic diets increased Lactobacillaceae abundance and reduced Enterobacteriaceae abundance in the ceca. Moreover, supplementation with probiotics increased the mRNA expression of Occludin, ZO1, and Mucin 2 in the ileum (p<0.05). In addition, probiotic supplementation downregulated the mRNA levels of IFN-γ (p<0.05) and LITAF (p = 0.075) and upregulated IL-10 (p = 0.084) expression in the cecal tonsil.

Conclusion

The administration of multi-strain probiotics modulated intestinal microbiota, gene expression of tight junction proteins, and immunomodulatory activity in broiler chickens.

Effects of Pediococcus acidilactici, mannan-oligosaccharide, butyric acid and their combination on growth performance and intestinal health in young broiler chickens challenged with Salmonella Typhimurium

This study compared the efficacy of Pediococcus acidilactici, mannan-oligosaccharide, butyric acid, and their combination on growth performance and intestinal health in broiler chickens challenged with S. Typhimurium. Ross 308 male broilers (n = 420) were randomly assigned to one of the 6 treatments, resulting in 5 replicate pens of 14 chicks per treatment. The treatments included a negative control [(NC), no additive, not challenged]; positive control [(PC), no additive, but challenged with S. Typhimurium at d 3 posthatch], and 4 groups whereby birds were challenged with S. Typhimurium at d 3 posthatch and fed diets supplemented with either probiotic [0.1 g/kg Pediococcus acidilactici (PA)], prebiotic [2 g/kg mannan-oligosaccharides (MOS)], organic acid [0.5 g/kg butyric acid (BA)], or a combination of the 3 additives (MA). The S. Typhimurium challenge decreased feed intake, body weight gain and increased feed conversion ratio and reduced jejunum villus height (VH) and VH to crypt depth (CD) ratio (P < 0.05). Birds on the MA treatment exhibited similar performance to birds on the NC treatment (P > 0.05) and had a lower population of Salmonella in the ceca compared with birds on the PC treatment, at d 14 and 21 post-challenge (P < 0.05). The lowest heterophil to lymphocyte ratio was observed in birds on the MA and NC treatments (P < 0.05). Birds fed diets supplemented with MA or PA had greater VH and VH: CD ratio than birds on the PC treatment at d 7, 14 and 21 d post-challenge (P < 0.05). Suppressed amylase and protease activity was observed as a result of the S. Typhimurium challenge; the enzyme levels were restored in birds fed the additive-supplemented diets, when compared to the birds on the PC treatment, particularly at d 21 post-challenge (P < 0.05). These results indicate that dietary supplementation with a combination of PA, BA, and MOS in broiler chickens could be used as an effective tool for controlling S. Typhimurium and promoting growth performance.

Effects of direct-fed microorganisms and enzyme blend co-administration on intestinal bacteria in broilers fed diets with or without antibiotics

Direct-fed microorganisms (DFM) and exogenous enzymes have been demonstrated to improve growth performance in poultry and are potentially important alternatives to antibiotic growth promoters (AGP). We investigated the administration of a feed additive composed of a DFM product containing spores of 3 Bacillus amyloliquefaciens strains and an enzyme blend of endo-xylanase, α-amylase, and serine-protease in diets with or without sub-therapeutic antibiotics in broiler chickens over a 42-d growth period. Evaluation of growth performance determined feed efficiency of broiler chickens which were administered the feed additive was comparable to those fed a diet containing AGPs. Characterization of the gastrointestinal microbiota using culture-dependent methods determined administration of the feed additive increased counts of total Lactic Acid Bacteria (LAB) relative to a negative control and reduced Clostridium perfringens to levels similar to antibiotic administration. Additionally, greater counts of total LAB were observed to be significantly associated with reduced feed conversion ratio, whereas greater counts of C. perfringens were observed to be significantly associated with increased feed conversion ratio. Our results suggest the co-administration of DFMs and exogenous enzymes may be an important component of antibiotic free poultry production programs and LAB and C. perfringens may be important targets in the development of alternatives to AGPs in poultry production.

The role of probiotics, prebiotics and synbiotics in animal nutrition

Along with the intensive development of methods of livestock breeding, breeders' expectations are growing concerning feed additives that would guarantee such results as accelerating growth rate, protection of health from pathogenic infections and improvement of other production parameters such as: absorption of feed and quality of meat, milk, eggs. The main reason for their application would be a strive to achieve some beneficial effects comparable to those of antibiotic-based growth stimulators, banned on 01 January 2006. High hopes are being associated with the use of probiotics, prebiotics and synbiotics. Used mainly for maintenance of the equilibrium of the intestinal microbiota of livestock, they turn out to be an effective method in fight against pathogens posing a threat for both animals and consumers. This paper discusses definitions of probiotics, prebiotics and synbiotics. Criteria that have to be met by those kinds of formulas are also presented. The paper offers a list of the most commonly used probiotics and prebiotics and some examples of their combinations in synbiotic formulas used in animal feeding. Examples of available study results on the effect of probiotics, prebiotics and synbiotics on animal health are also summarised.

Effect of laboratory-isolated Lactobacillus plantarum LGFCP4 from gastrointestinal tract of guinea fowl on growth performance, carcass traits, intestinal histomorphometry and gastrointestinal microflora population in broiler chicken

The study aimed to investigate the effect of feed supplements, viz Lactobacillus plantarum LGFCP4 (laboratory isolate from GIT of Guinea fowl), Lactobacillus acidophilus (NCDC, Karnal) and in-feed antibiotic bacitracin methylene disalicylate (BMD) on growth performance, FCR, carcass traits and immune organs weight, intestinal histomorphometry and gastrointestinal microflora population in broiler chickens. In a completely randomized design, CARIBRO-Dhanraja broiler chicks (n = 160) were used with four treatment groups. During the entire experimental duration of 35 days, treatment groups were provided with different dietary treatments (T1 - basal diet (negative control), T2 - antibiotic growth promoter BMD 20 g/100 kg feed (positive control), T3 - 1 × 10⁸  cfu of L. acidophilus/gm-fermented feed +MOS 1 g/kg feed and T4 - 1 × 10⁸  cfu of laboratory-isolated L. plantarum LGFCP4/gm-fermented feed+ MOS 1 g/kg feed. After 35 days of experimental period, no significant results have been observed in different growth performance traits among treatment groups. Cut-up parts and edible organs' weight remained unaffected by dietary supplementation, whereas weight of immune organs were significantly higher (p < 0.05) in L. plantarum LGFCP4-supplemented group. At the end of feeding trial, significantly (p < 0.05) lower E. coli count was observed in crop of T4 birds, while in ileum, T2 and T3 showed lower count. In caeca, T2 group showed lowest E. coli count. Salmonella count in crop and ileum was significantly (p < 0.05) low in T3 and T4, while in caeca, T2 group showed lowest count. In terms of histomorphometry, duodenal villous height (VH), crypt depth (CD) and VH:CD ratio were higher for T3 and T4 and lowest values were obtained for T2 group. The results of the study showed that L. plantarum LGFCP4 isolated from GIT of guinea fowl can effectively replace in-feed antibiotic growth promoters in broiler diets by altering intestinal villi morphology and improving the gut health by reducing the pathogenic microbial load.

Managing gut health without reliance on antimicrobials in poultry

It is well established that antimicrobials in animal feed enhance feed efficiency, promote animal growth and improve the quality of animal products. However, resistance development in bacterial populations, and hence consumer demand for products free of antimicrobial residues, has prompted efforts to develop alternatives that can replace antimicrobials without causing loss of productivity or product quality. One of the key barriers to complete withdrawal from antimicrobial use is microbial infection, for example, necrotic enteritis. There is much interest in using in-feed nutraceuticals such as prebiotics, probiotics, organic acids and plant extracts as alternatives to antimicrobials to create a healthy gastrointestinal environment and to prevent and treat enteric infections. Enzymes are generally used to alleviate anti-nutritional factors in feed, but there is growing awareness of their beneficial effects on the gastrointestinal environment, and consequently on gut health. An example of this is production of prebiotic xylo-oligosaccharides when xylanase is added to feed. This review discusses developments in alternatives to antimicrobials that can aid in managing gut health in a post-antimicrobial era, with particular reference to recent nutritional strategies.

Effect of Dietary Bacillus Subtilis C14 and RX7 Strains on Growth Performance, Blood Parameter, and Intestinal Microbiota in Broiler Chickens Challenged with Salmonella Gallinarum

Sixty broilers (initially 1.6 kg and 35 d-old) were used to determine the effect of Bacillus subtilis C14 and RX7 strains on growth performance, blood parameter, and intestinal microbiota in response to experimental challenge with Salmonell gallinarum. Broilers were distributed to 4 treatment groups include: C1 (control group; no challenge, no B. subtilis), C2 (Salmonella-challenged group; S. gallinarum 10⁸ cfu/bird), T1 (C2+supplemented with of B. subtilis C14 (1.0×10⁹ cfu/g) at 0.1% in diet) and T2 (C2+supplemented with of B. subtilis RX7 (1.0×10⁹ cfu/g) at 0.1% in diet). Results indicated that inclusion of B. subtilis (T1, T2) in the diet increased (P<0.05) the weight gain and feed intake, and improved feed conversion of challenged broilers compared with no B. subtilis supplementation diet (C2). Improvements (P<0.05) in the immunoglobulin A concentration were observed by the addition of B. subtilis compared with C2 treatment, whereas tumor necrosis factor-α was decreased (P<0.05). Latobacillus number in small and large intestines was higher (P<0.05) by B. subtilis additon than C2 treatment but Salmonella numbers were lower (P<0.05). The results suggested that dietary supplementation of B. subtilis C14 and RX7 improved the growth performance, and affected the blood profiles and intestinal microbiota of broilers against S. gallinarum infection. Therefore, B. subtilis C14 and RX7 may have beneficial effects, in relieving the stress of broilers infected with S. gallinarum.

The effects of the supplementation of Bacillus subtilis RX7 and B2A strains on the performance, blood profiles, intestinal Salmonella concentration, noxious gas emission, organ weight and breast meat quality of broiler challenged with Salmonella typhimurium

An experiment was conducted to evaluate the effects of B. subtilis RX7 and B. subtilis B2A on growth performance, blood profiles, intestinal Salmonella population, noxious gas emission, organ weight and breast meat quality of broilers under S. typhimurium challenge. A total of 120, one-day-old Ross 308 male broiler chicks were assigned to four dietary treatments, composed of six replications, with five birds per replication, for 10 day. The dietary treatment groups were negative control (NC; no antibiotic, no B. subtilis), positive control (PC; NC + 0.1% virginiamycin), B. subtilis RX7 (NC + 0.1% B. subtilis RX7 1.0 × 10(9) cfu/g) and B. subtilis B2A (NC + 0.1% B. subtilis 1.0 × 10(9) cfu/g). All birds were orally challenged with 2 ml suspension, containing 10(4) cfu/ml of S. typhimurium KCCM 40253. Results indicated that the body weight gain, feed intake and feed conversion did not differ, among all comparative treatments. Serum haptoglobin concentration was lower in Bacillus treatments (RX7 + B2A) than the NC treatment (p < 0.05). Intestinal and excreta Salmonella number, and excreta ammonia gas emission in the PC treatment or Bacillus treatments, was lower than the NC treatment (p < 0.05). Breast pH, colour and water-holding capacity were not affected by supplementation of B. subtilis RX7 and B2A. However, drip loss at 1 day post-slaughter from birds fed with B. subtilis RX7 and B2A decreased, compared with the positive control birds (p < 0.05). Relative gizzard weights of birds fed B. subtilis RX7 and B2A were significantly higher than the NC birds under S. typhimurium challenge. It is concluded from the results that B. subtilis RX7 and B2A increased the gizzard weight and decreased the intestinal and excreta Salmonella population and excreta ammonia gas, and drip loss of breast meat after being stored for 1 day, under stress caused by the S. typhimurium challenge.

Zinc prevents Salmonella enterica serovar Typhimurium-induced loss of intestinal mucosal barrier function in broiler chickens

The study was carried out to evaluate the beneficial effects of supplemental zinc (Zn) on the intestinal mucosal barrier function in Salmonella enterica serovar Typhimurium-challenged broiler chickens in a 42-day experiment. A total of 336 1-day-old male Arbor Acres broiler chicks were assigned to eight treatment groups. A 4×2 factorial arrangement of treatments was used in a completely randomized experimental design to study the effects of levels of supplemental Zn (0, 40, 80 and 120 mg/kg diet), pathogen challenge (with or without S. Typhimurium challenge), and their interactions. S. Typhimurium infection caused reduction of growth performance (P<0.05) and intestinal injury, as determined by reduced (P<0.05) villus height/crypt depth ratio and sucrase activity in the ileum, increased (P<0.05) plasma endotoxin levels, and reduced (P<0.05) claudin-1, occludin and mucin-2 mRNA expression in the ileum at day 21. Zn pre-treatment tended to improve body weight gain (P=0.072) in the starter period, to increase the activity of ileal sucrase (P=0.077), to reduce plasma endotoxin levels (P=0.080), and to significantly increase (P<0.05) the villus height/crypt depth ratio and mRNA levels of occludin and claudin-1 in the ileum at day 21. The results indicated that dietary Zn supplementation appeared to alleviate the loss of intestinal mucosal barrier function induced by S. Typhimurium challenge and the partial mechanism might be related to the increased expression of occludin and claudin-1 in broiler chickens.

Effects of Xylanase Supplementation on Growth Performance, Nutrient Digestibility and Non-starch Polysaccharide Degradation in Different Sections of the Gastrointestinal Tract of Broilers Fed Wheat-based Diets

This experiment was performed to investigate the effects of exogenous xylanase supplementation on performance, nutrient digestibility and the degradation of non-starch polysaccharides (NSP) in different sections of the gastrointestinal tract (GIT) of broilers fed wheat-based diets. A total of 120 7-day-old Arbor Acres broiler chicks were randomly allotted to two wheat-based experimental diets supplemented with 0 or 1.0 g/kg xylanase. Each treatment was composed of 6 replicates with 10 birds each. Diets were given to the birds from 7 to 21 days of age. The results showed that xylanase supplementation did not affect feed intake, but increased body weight gain of broiler at 21 day of age by 5.8% (p<0.05) and improved feed-to-gain ratio by 5.0% (p<0.05). Xylanase significantly increased (p<0.05) ileal digestibilities of crude protein (CP) by 3.5%, starch by 9.3%, soluble NSP by 43.9% and insoluble NSP by 42.2% relative to the control group, respectively. Also, compared with the control treatment, xylanase addition increased (p<0.05) total tract digestibilities of dry matter by 5.7%, CP by 4.1%, starch by 6.3%, soluble NSP by 50.8%, and had a tendency to increase (p = 0.093) insoluble NSP by 19.9%, respectively. The addition of xylanase increased the concentrations of arabinose and xylose in the digesta of gizzard, duodenum, jejunum, and ileum (p<0.05), and the order of their concentration was ileum>jejunum>duodenum>>gizzard> caecum. The supplementation of xylanse increased ileal isomaltriose concentration (p<0.05), but did not affect the concentrations of isomaltose, panose and 1-kestose in the digesta of all GIT sections. These results suggest that supplementation of xylanase to wheat-based diets cuts the arabinoxylan backbone into small fragments (mainly arabinose and xylose) in the ileum, jejunum and duodenum, and enhances digestibilites of nutrients by decreasing digesta viscosity. The release of arabinose and xylose in the small intestine may also be the important contributors to the growth-promoting effect of xylanase in broilers fed wheat-based diets.

The role of added feed enzymes in promoting gut health in swine and poultry

The value of added feed enzymes (FE) in promoting growth and efficiency of nutrient utilisation is well recognised in single-stomached animal production. However, the effects of FE on the microbiome of the gastrointestinal tract (GIT) are largely unrecognised. A critical role in host nutrition, health, performance and quality of the products produced is played by the intestinal microbiota. FE can make an impact on GIT microbial ecology by reducing undigested substrates and anti-nutritive factors and producing oligosaccharides in situ from dietary NSP with potential prebiotic effects. Investigations with molecular microbiology techniques have demonstrated FE-mediated responses on energy utilisation in broiler chickens that were associated with certain clusters of GIT bacteria. Furthermore, investigations using specific enteric pathogen challenge models have demonstrated the efficacy of FE in modulating gut health. Because FE probably change the substrate characteristics along the GIT, subsequent microbiota responses will vary according to the populations present at the time of administration and their reaction to such changes. Therefore, the microbiota responses to FE administration, rather than being absolute, are a continuum or a population of responses. However, recognition that FE can make an impact on the gut microbiota and thus gut health will probably stimulate development of FE capable of modulating gut microbiota to the benefit of host health under specific production conditions. The present review brings to light opportunities and challenges for the role of major FE (carbohydrases and phytase) on the gut health of poultry and swine species with a specific focus on the impact on GIT microbiota.

Effect of xylanase and a blend of essential oils on performance and Salmonella colonization of broiler chickens challenged with Salmonella Heidelberg

The present experiment examined the influence of xylanase supplementation and a blend of essential oils (EO; cinnamaldehyde and thymol) on performance and Salmonella horizontal transmission in broiler chickens challenged with Salmonella. Two thousand 1-d-old broiler chicks were randomly assigned to 5 dietary treatments (8 pens/treatment of 50 male broilers each). Four dietary treatments were challenged with Salmonella: 1) control, 2) basal diets supplemented with EO, 3) basal diet supplemented with xylanase (2,000 U/kg of feed), and 4) basal diet supplemented with a combination of EO and xylanase (2,000 U/kg of feed). One treatment served as an unchallenged control and was not supplemented with either additive. Broiler starter and finisher diets, based on wheat and soybean meal, were formulated, pelleted, and fed ad libitum. At d 1, before placement, half of the birds from each pen were tagged and dosed with Salmonella enterica serovar Heidelberg (5 × 10(5) cfu/mL). On d 42, 5 random untagged birds from each pen were killed and their ceca removed and tested for Salmonella. Performance data were analyzed as a completely randomized design using GLM. The frequency of positive Salmonella in the untagged birds was compared between treatments by using a chi-squared test of homogeneity. Challenging the birds with Salmonella had no effect (P > 0.05) on any of the measured performance parameters. Xylanase and EO supplementation improved (P < 0.05) the 42-d BW gain and feed efficiency, with no effect (P > 0.05) on feed intake, compared with that of the control treatment. Xylanase supplementation improved (P < 0.05) BW gain and feed efficiency compared with the results of EO supplementation. The combination treatment of xylanase and EO numerically improved BW gain and feed efficiency compared with the xylanase treatment. Xylanase and EO supplementation reduced (P < 0.05) the incidence of horizontal transmission of Salmonella infection between birds by 61 and 77%, respectively, compared with the control. The results of the current study suggested that dietary addition of EO and xylanase could improve broiler performance and contribute to food safety by lowering the incidence of horizontal transmission of Salmonella infection.

A Bifidobacterium-based synbiotic product to reduce the transmission of C. jejuni along the poultry food chain

With the ban of dietary antimicrobial agents, the use of probiotics, prebiotics and synbiotics has attracted a great deal of attention in order to improve intestinal health and control food-borne pathogens, which is an important concern for the production of safe meat and meat products. Recently, Campylobacter jejuni has emerged as a leading bacterial cause of food-borne gastroenteritis in humans, and epidemiological evidences indicate poultry and poultry products as the main source of human infection. This work aimed at the development of a synbiotic mixture capable of modulating the gut microbiota of broiler chickens to obtain an increase of the beneficial bacteria (i.e. bifidobacteria, lactobacilli) and a competitive reduction of C. jejuni. The prebiotic compound used in the mixture was chosen after an in vivo trial: a fructooligosaccharide and a galactooligosaccharide were separately administered to broilers mixed with normal feed at a concentration of 0.5% and 3%, respectively. Quantitative PCR on DNA extracted from fecal samples revealed a significant (p<0.05) increase of Bifidobacterium spp. in broilers treated with the galactooligosaccharide, coupled to a decrease (p<0.05) of Campylobacter spp. The galactooligosaccharide was then combined with a probiotic Bifidobacterium strain (B. longum subsp. longum PCB133), possessing in vitro antimicrobial activity against C. jejuni. The strain was microencapsulated in a lipid matrix to ensure viability into the feed and resistance to stomach transit. Finally, the synbiotic mixture was administered to broiler chickens for 14 days mixed with normal feed in order to have an intake of 10(9)CFU of PCB133/day. Bifidobacterium spp., Lactobacillus spp., Campylobacter spp., B. longum subsp. longum and C. jejuni were quantified in fecal samples. PCB133 was recovered in feces of all animals. C. jejuni concentration in poultry feces was significantly (p<0.05) reduced in chickens administered with the synbiotic mixture. This study allowed to highlight the positive effect of the synbiotic approach for C. jejuni reduction in broiler chickens, which is of fundamental importance for the safety of poultry meat consumers.

Probiotics and prebiotics in animal feeding for safe food production

Recent outbreaks of food-borne diseases highlight the need for reducing bacterial pathogens in foods of animal origin. Animal enteric pathogens are a direct source for food contamination. The ban of antibiotics as growth promoters (AGPs) has been a challenge for animal nutrition increasing the need to find alternative methods to control and prevent pathogenic bacterial colonization. The modulation of the gut microbiota with new feed additives, such as probiotics and prebiotics, towards host-protecting functions to support animal health, is a topical issue in animal breeding and creates fascinating possibilities. Although the knowledge on the effects of such feed additives has increased, essential information concerning their impact on the host are, to date, incomplete. For the future, the most important target, within probiotic and prebiotic research, is a demonstrated health-promoting benefit supported by knowledge on the mechanistic actions. Genomic-based knowledge on the composition and functions of the gut microbiota, as well as its deviations, will advance the selection of new and specific probiotics. Potential combinations of suitable probiotics and prebiotics may prove to be the next step to reduce the risk of intestinal diseases and remove specific microbial disorders. In this review we discuss the current knowledge on the contribution of the gut microbiota to host well-being. Moreover, we review available information on probiotics and prebiotics and their application in animal feeding.