In vitro characterization and analysis of probiotic species in the chicken intestine by real-time polymerase chain reaction

Bacillus subtilis KC1 prevents Mycoplasma gallisepticum-induced lung injury by enhancing intestinal Bifidobacterium animalis and regulating indole metabolism in chickens

It has been reported that dietary administration of Bacillus subtilis KC1 is effective in alleviating lung injury induced by Mycoplasma gallisepticum (MG) infection in chickens. However, the underlying molecular mechanism of B. subtilis KC1 against MG infection is still unclear. The purpose of this study was to determine whether B. subtilis KC1 could alleviate MG infection-induced lung injury in chickens by regulating their gut microbiota. The results of this study indicate that B. subtilis KC1 supplementation has the potential to alleviate MG infection-induced lung injury as reflected by reduced MG colonization, reduced pathologic changes, and decreased production of pro-inflammatory cytokines. In addition, B. subtilis KC1 supplementation was partially effective in alleviating the gut microbiota disorder caused by MG infection. Importantly, B. subtilis KC1 enriched the beneficial Bifidobacterium animalis in gut and thus reversed indole metabolic dysfunction caused by MG infection. B. subtilis KC1 supplementation increased levels of indole, which enhanced aryl hydrocarbon receptor activation, improving barrier function and alleviating lung inflammation caused by MG. Overall, this study indicates that B. subtilis KC1 has a "gut-lung axis" mechanism that can reduce the severity of MG infection by enriching intestinal B. animalis and regulating indole metabolism.

Short-term exposure to fumonisins and deoxynivalenol, on broiler growth performance and cecal Salmonella load during experimental Salmonella Enteritidis infection

Fumonisins (FUM) and deoxynivalenol (DON) are two common mycotoxins in poultry feed. Salmonella enterica ser. Enteritidis (S. Enteritidis) is a primary foodborne bacterium in broilers. This trial was conducted to evaluate the effects of naturally occurring FUM and DON and their combination at subclinical doses on broiler performance during a S. Enteritidis challenge. The experiment consisted of five treatments: NCC, no-challenge no-mycotoxin treatment; CC, Salmonella challenge + no-mycotoxin treatment; DON, DON 0.6 mg/kg + Salmonella challenge; FUM, FUM 14 mg/kg + Salmonella challenge; DON + FUM + T-2 + neosolaniol, DON 0.6 mg/kg + FUM 14 mg/kg + T-2 toxin 0.6 mg/kg + 0.8 mg/kg neosolaniol + Salmonella challenge. On d 4, birds were challenged with either 0 or 1 × 10⁹ CFU/mL S. Enteritidis orally. There were no significant effects on growth performance among treatments at 0, 3, 7, and 14 d of post-inoculation (dpi). On 14 dpi, the combined DON + FUM + T-2 + neosolaniol significantly increased the Salmonella load by 1.5 logs compared to the control groups (P < 0.05). FUM significantly increased the cecal tonsil IL-10 gene expression by 1.2-fold at 7 dpi (P < 0.05) and downregulated TNF-α by 1.8-fold on 14 dpi compared to the control, nonchallenge groups (P < 0.05). On 7 dpi, the combined DON + FUM + T-2 + neosolaniol reduced occludin by 4.4-fold (P < 0.05) when compared to the control groups. Similarly, combined DON + FUM+ T-2 + neosolaniol decreased zona-occluden transcription by 2.3 and 7.6-fold on 3 and 14 dpi, respectively (P < 0.05). Furthermore, combined DON + FUM + T-2 + neosolaniol decreased Claudin-1 by 2.2-fold and Claudin-4 by 5.1-fold on 14 dpi when compared to the control groups (P < 0.05). In conclusion, short-term exposure to a subclinical dose of combined DON + FUM + T-2 + neosolaniol had an impact on broiler intestinal tight junction proteins and cecal Salmonella abundance under experimental Salmonella challenge.

Subclinical Doses of Combined Fumonisins and Deoxynivalenol Predispose Clostridium perfringens–Inoculated Broilers to Necrotic Enteritis

Fumonisins (FB) and deoxynivalenol (DON) are mycotoxins which may predispose broiler chickens to necrotic enteritis (NE). The objective of this study was to identify the effects of subclinical doses of combined FB and DON on NE. A total of 480 day-old male broiler chicks were divided into four treatment groups; 1) control group (basal diet + Clostridium perfringens); 2) necrotic enteritis group (basal diet + Eimeria maxima + C. perfringens); 3) FB + DON group (basal diet + 3 mg/kg FB + 4 mg/kg DON + C. perfringens); and 4) FB + DON + NE group (basal diet + 3 mg/kg FB + 4 mg/kg DON + E. maxima + C. perfringens). Birds in NE and FB + DON + NE groups received 2.5 × 10³E. maxima on day 14. All birds were inoculated with C. perfringens on days 19, 20, and 21. On day 35, birds in the NE, FB + DON, and FB + DON + NE groups had 242, 84, and 339 g lower BWG and a 19-, 2-, and 22-point increase in FCR respectively, than in the control group. Subclinical doses of FB + DON increased (p < 0.05) the NE lesion scores compared to the control group on day 21. On day 21, birds in the NE, FB + DON, and FB + DON + NE groups had increased (p < 0.05) serum FITC-D, lower (p < 0.05) jejunal tight junction protein mRNA, and increased (p < 0.05) cecal tonsil IL-1 mRNA compared to control group. On day 21, birds in the NE group had decreased (p < 0.05) villi height to crypt depth ratio compared to the control group and the presence of FB + DON in NE-induced birds further decreased the villi height to crypt depth ratio. Birds in the NE, FB + DON, and FB + DON + NE groups had increased (p < 0.05) C. perfringens, lower (p < 0.05) Lactobacillus loads in the cecal content, and a lower (p < 0.05) CD8⁺: CD4⁺ cell ratio in the cecal tonsils compared to the control group. It can be concluded that subclinical doses of combined FB and DON predispose C. perfringens-inoculated birds to NE, and the presence of FB + DON in NE-induced birds exacerbated the severity of NE.

Gastrointestinal Microbiota and Their Manipulation for Improved Growth and Performance in Chickens

The gut of warm-blooded animals is colonized by microbes possibly constituting at least 100 times more genetic material of microbial cells than that of the somatic cells of the host. These microbes have a profound effect on several physiological functions ranging from energy metabolism to the immune response of the host, particularly those associated with the gut immune system. The gut of a newly hatched chick is typically sterile but is rapidly colonized by microbes in the environment, undergoing cycles of development. Several factors such as diet, region of the gastrointestinal tract, housing, environment, and genetics can influence the microbial composition of an individual bird and can confer a distinctive microbiome signature to the individual bird. The microbial composition can be modified by the supplementation of probiotics, prebiotics, or synbiotics. Supplementing these additives can prevent dysbiosis caused by stress factors such as infection, heat stress, and toxins that cause dysbiosis. The mechanism of action and beneficial effects of probiotics vary depending on the strains used. However, it is difficult to establish a relationship between the gut microbiome and host health and productivity due to high variability between flocks due to environmental, nutritional, and host factors. This review compiles information on the gut microbiota, dysbiosis, and additives such as probiotics, postbiotics, prebiotics, and synbiotics, which are capable of modifying gut microbiota and elaborates on the interaction of these additives with chicken gut commensals, immune system, and their consequent effects on health and productivity. Factors to be considered and the unexplored potential of genetic engineering of poultry probiotics in addressing public health concerns and zoonosis associated with the poultry industry are discussed.

Effects of Salmonella enterica ser. Enteritidis and Heidelberg on host CD4+CD25+ regulatory T cell suppressive immune responses in chickens

Poultry infected with Salmonella mount an immune response initially, however the immune responses eventually disappear leading the bird to be a carrier of Salmonella. The hypothesis of this study is that Salmonella infection induces T regulatory cell numbers and cytokine production and suppress host T cells locally in the gut to escape the host immune responses. An experiment was conducted to comparatively analyze the effect of S. enterica ser. Enteritidis (S. Enteritidis) and S. enterica ser. Heidelberg (S. Heidelberg) infection on CD4⁺CD25⁺ T regulatory cell properties in chickens. A total of 144 broiler chicks were randomly distributed into three experimental groups of non-infected control, S. Enteritidis infected and S. Heidelberg infected groups. Chickens were orally inoculated with PBS (control) or 5x10⁶ CFU/mL of either S. Enteritidis or S. Heidelberg at 3 d of age. Each group was replicated in six pens with eight chickens per pen. Chickens infected with S. Enteritidis had 6.2, 5.4, and 3.8 log₁₀ CFU/g, and chickens infected with S. Heidelberg had 7.1, 4.8, and 4.1 log₁₀ CFU/g Salmonella in the cecal contents at 4, 11, and 32 dpi, respectively. Both S. Enteritidis and S. Heidelberg were recovered from the liver and spleen 4 dpi. At 4, 11, and 32 dpi, chickens infected with S. Enteritidis and S. Heidelberg had increased CD4⁺CD25⁺ cell numbers as well as IL-10 mRNA transcription of CD4⁺CD25⁺ cells compared to that in the control group. CD4⁺CD25⁺ cells from S. Enteritidis- and S. Heidelberg-infected chickens and restimulated with 1 μg antigen in vitro, had higher (P < 0.05) IL-10 mRNA transcription than the CD4⁺CD25⁺ cells from the non-infected controls Though at 4dpi, chickens infected with S. Enteritidis and S. Heidelberg had a significant (P < 0.05) increase in CD4⁺CD25^- IL-2, IL-1β, and IFNγ mRNA transcription, the CD4⁺CD25^- IL-2, IL-1β, and IFNγ mRNA transcription, were comparable to that in the control group at 11 and 32dpi identifying that the host inflammatory response against Salmonella disappears at 11 dpi. It can be concluded that S. Enteritidis and S. Heidelberg infection at 3 d of age induces a persistent infection through inducing CD4⁺CD25⁺ cells and altering the IL-10 mRNA transcription of CD4⁺CD25⁺ cell numbers and cytokine production in chickens between 3 to 32 dpi allowing chickens to become asymptomatic carriers of Salmonella after 18 dpi.

Lactobacillus salivarius and Lactobacillus agilis feeding regulates intestinal stem cells activity by modulating crypt niche in hens

Previously, we found that Lactobacillus salivarius, Lactobacillus agilis, and Lactobacillus aviarius were associated with excellent egg nutrition in native chicken. Next, the optimal Lactobacillus combination is worth studying. Here, a total of 120 HyLine hens (30 hens per group contained 3 replicate cells, 10 hens/cell) in the laying peak period were randomly divided into (1) control, (2) L. salivarius + L. agilis, (3) L. salivarius + L. aviarius, and (4) L. agilis + L. aviarius groups, fed with diet only or with corresponding Lactobacilli (10⁸ colony-forming units/hen/day) for 30 days. As a result, L. salivarius + L. agilis feeding could (1) improve egg-laying rate, egg weight, and albumen's amino acid levels; (2) increase Lactobacillus abundance, decrease Escherichia coli abundance, upregulate the tryptophan metabolism pathway-related molecules, and downregulate the primary bile acid biosynthesis pathway-related molecules in intestinal contents; and (3) upregulate oxidative-phosphorylation pathway-related genes, reactive oxygen species levels, and mRNA abundance of Wnt3a, Dll1, Lgr5, CCDN1, and CDK2 in the crypt. Collectively, L. salivarius + L. agilis feeding in hens could improve intestinal microflora and metabolism profile, promote crypt's local energy metabolism and reactive oxygen species levels, and thus enhance Paneth cells and intestinal stem cells activity.Key points• Lactobacilli co-feeding could improve laying performance and egg nutrition.• Lactobacilli co-feeding could improve intestinal microflora and metabolism profile.• Lactobacilli co-feeding could enhance Paneth cells and intestinal stem cells activity.

Transplantion of predominant Lactobacilli from native hens to commercial hens could indirectly regulate their ISC activity by improving intestinal microbiota

In poultry, HyLine (HL) Hens are known for their excellent laying performance. However, ZhenNing (ZN) Hens, a native chicken breed in China, are known for their unique flavour. The intestinal mucosa, which is the main organ for nutrient absorption, could affect livestock product quality. In ZN Hens’ intestinal mucosa, we found more villus wrinkles, larger villus circumference and higher amino acid transporters mRNA abundance compared with HL Hens. Among three laying periods of ZN Hens, in the intestinal lumen, Lactobacillus salivarius (L. sa.), Lactobacillus agilis (L. ag.) and Lactobacillus aviarius were the predominant species in the laying peak period. Furthermore, multiple‐antibiotics feeding in ZN Hens and predominant Lactobacillus feeding in HL Hens suggested that these Lactobacilli could indeed increase villus wrinkles and improve intestinal absorption. In HL Hens, L. sa. + L. ag. treatment could promote organoids budding in vitro, and promote epithelial proliferation in vivo. Collectively, the unique intestinal mucosa morphology in ZN Hens was due to the high abundance of intestinal L. sa. and L. ag. Transplant these Lactobacilli to HL Hens could increase their intestinal probiotics abundance, fine adjust the intestinal stem cell function and promote the epithelial proliferation, in turn, increase villus winkles and mucosal absorption area.

Potential role of important nutraceuticals in poultry performance and health - A comprehensive review

Antibiotics use in poultry as a growth promoter leads to the propagation of antibiotic-resistant microorganisms and incorporation of drug residues in foods; therefore, it has been restricted in different countries. There is a global trend to limit the use of antibiotics in the animal products. Prevention of the antibiotics use in the poultry diets led to the reduction in the growth performance. Consequently, there is a high demand for natural substances that lead to the same growth enhancement and beneficially affect poultry health. These constituents play essential roles in regulating the normal physiological functions of animals including the protection from infectious ailments. Nutraceuticals administration resulted beneficial in both infectious and noninfectious diseases. Being the natural components of diet, they are compatible with it and do not pose risks associated with antibiotics or other drugs. Nutraceuticals are categorized as commercial additives obtained from natural products as an alternative feed supplement for the improvement of animal welfare. This group includes enzymes, synbiotics, phytobiotics, organic acids and polyunsaturated fatty acids. In the present review, the summary of various bioactive ingredients that act as nutraceuticals and their mode of action in growth promotion and elevation of the immune system has been presented.

Characterizing the immune response of chickens to Campylobacter jejuni (Strain A74C)

Campylobacter is one of the major foodborne pathogens causing bacterial gastroenteritis worldwide. The immune response of broiler chickens to C. jejuni is under-researched. This study aimed to characterize the immune response of chickens to Campylobacter jejuni colonization. Birds were challenged orally with 0.5 mL of 2.4 x 10⁸ CFU/mL of Campylobacter jejuni or with 0.5 mL of 0.85% saline. Campylobacter jejuni persisted in the ceca of challenged birds with cecal colonization reaching 4.9 log10 CFU/g on 21 dpi. Campylobacter was disseminated to the spleen and liver on 7 dpi and was cleared on 21 dpi from both internal organs. Challenged birds had a significant increase in anti-Campylobacter serum IgY (14&21 dpi) and bile IgA (14 dpi). At 3 dpi, there was a significant suppression in T-lymphocytes derived from the cecal tonsils of birds in the challenge treatment when compared to the control treatment after 72 h of ex vivo stimulation with Con A or C. jejuni. The T-cell suppression on 3 dpi was accompanied by a significant decrease in LITAF, K60, CLAU-2, IL-1β, iNOS, and IL-6 mRNA levels in the ceca and an increase in nitric oxide production from adherent splenocytes of challenged birds. In addition, on 3 dpi, there was a significant increase in CD4+ and CD8+ T lymphocytes in the challenge treatment. On 14 dpi, both pro and anti-inflammatory cytokines were upregulated in the spleen, and a significant increase in CD8+ T lymphocytes in Campylobacter-challenged birds’ ceca was observed. The persistence of C. jejuni in the ceca of challenged birds on 21 dpi was accompanied by an increase in IL-10 and LITAF mRNA levels, an increase in MNC proliferation when stimulated ex-vivo with the diluted C. jejuni, an increase in serum specific IgY antibodies, an increase in both CD4+ and CD8+ cells, and a decrease in CD4+:CD8+ cell ratio. The balanced Th1 and Th2 immune responses against C. jejuni might explain the ceca’s bacterial colonization and the absence of pathology in Campylobacter-challenged birds. Future studies on T lymphocyte subpopulations should elucidate a pivotal role in the persistence of Campylobacter in the ceca.

Probiotic and synbiotic in broiler diet: performance and Enterobacteriaceae

ABSTRACT The objective of this study was to evaluate the effects of probiotics and synbiotics on the performance and Enterobacteriaceae count of broiler chickens. A total of 640 one-day-old male broiler chicks were distributed in a completely randomized design with four treatments and eight replicates with 20 birds each. The treatments were: ration with performance enhancer (zinc bacitracin; positive control); ration without performance enhancer and probiotic/synbiotic (negative control); ration with probiotics; and ration with synbiotics. At 35 days, five birds from each treatment were euthanized and intestinal contents were harvested for determining the Enterobacteriaceae count. The performance data and average colony-forming units (CFUs) transformed as log CFU/g were subjected to analysis of variance and Tukey’s test. The effects of probiotics and synbiotics were observed in the initial phase, with supplemented birds exhibiting comparable weight gain to those supplemented with bacitracin. No effect of the treatment on broiler performance was observed after 42 days. The enterobacterial count was comparable among all experimental treatments. Supplementation with probiotics and synbiotics did not compromise the performance of broilers and did not alter the Enterobacteriaceae count.

Efficacy of chitosan-based nanoparticle vaccine administered to broiler birds challenged with Salmonella

Two experiments were conducted to evaluate the immune response of broilers vaccinated with Salmonella chitosan-nanoparticle (CNP) vaccine and challenged with Salmonella. The Salmonella CNP vaccine was synthesized with Salmonella enterica outer membrane proteins (OMPs) and flagellin proteins. In Experiment I, birds were orally gavaged with PBS or 500, 1000, or 2000μg of CNP vaccine 1 and 7d-of-age. At 14d-of-age, birds were orally challenged with 1 X 10⁵ CFU/bird of live S. Enteritidis (SE). Macrophage-nitrite production 11d-post-challenge was higher (P<0.05) in the 500μg group when compared to the control. At d14 (8h-post-challenge), broilers vaccinated with 1000μg CNP had higher (P<0.05) serum anti-OMPs IgG and IgA and cloacal anti-OMP IgA amounts. At 11d-post-challenge, birds vaccinated with 1000μg CNP vaccine had greater (P<0.05) bile anti-OMP and anti-flagellin IgA amounts. At 11d-post-challenge, birds administered 1000μg CNP vaccine has increased (P<0.05) IL-1β and IL-10 mRNA in cecal tonsils. In Experiment II, birds were orally gavaged with PBS or 1000μg CNP or a live commercial vaccine at 1 and 7d-of-age. At 14d-of-age, birds were orally challenged with 1 X 10⁵ CFU/bird of live SE or S. Heidelberg (SH). Birds vaccinated with CNP showed higher (P<0.05) serum anti-OMPs IgG amounts at 8h-post-challenge. At 4d-post-SH challenge, birds vaccinated with CNP had higher (P<0.05) bile anti-flagellin IgA amounts. CNP decreased (P<0.05) anti-OMPs IgG levels in serum at 2d-post-SE challenge and 4d-post-SH or SE challenge. Salmonella Enteritidis loads in cecal content at 2d-post-challenge was decreased (P<0.05) by 65.9% in birds vaccinated with CNP, when compared to the control. Chitosan-nanovaccine had no adverse effects on bird’s production performance. In conclusion, 1000μg CNP vaccine can induce a specific immune response against Salmonella and has the potential to mitigate SE cecal colonization in broiler birds.

Research Note: Effect of synbiotic supplementation on caecal Clostridium perfringens load in broiler chickens with different necrotic enteritis challenge models

Studies were conducted to determine the efficacy of synbiotic applications to combat the negative effects of necrotic enteritis (NE). An in vitro study was conducted to test the effect of probiotics species supernatants to decrease Clostridium perfringens (CP) proliferation. Lactobacillus reuteri, Enterococcus faecium, Bifidobacterium animalis, and Pediococcus acidilactici culture supernatants decreased the proliferation of CP at 1:1 supernatant-to-pathogen dilution in vitro. Two in vivo studies were conducted to determine the in vivo response of synbiotic supplementation containing the aforementioned probiotic strains on broiler production performance and caecal CP load in broilers induced with NE infection. In experiment 1, 75 broiler chicks were randomly allotted to 3 treatment groups, control (basal diet), ionophore (Salinomycin), and synbiotic (PoultryStar me), from day of hatch, and NE was induced in all birds. There were no significant treatment effects on BW, feed consumption, and feed gain ratio. However, at 35 D, ionophore or synbiotic supplementation increased (P < 0.05) villi height and decreased interleukin (IL)-1 mRNA abundance, while synbiotic supplementation increased (P < 0.05) IL-10 mRNA abundance compared with the control group, respectively. In experiment 2, 360 broiler chicks were randomly allotted to 3 treatments, an unchallenged negative control (control; basal diet), challenged positive control (NE; basal diet), or NE + synbiotic group (synbiotic). At both 21 and 42 D of age, NE birds had decreased (P < 0.05) BW, feed conversion, and jejunal villi height compared with control, while NE + synbiotic birds were not different from control groups. At 42 D of age, NE birds had 2.2 log/g increased CP in the ceca contents compared with control, while synbiotic birds had CP load that was not different than that of the control group. NE + synbiotic birds had significantly greater amounts of bile anti-CP IgA than the control and NE groups. It can be concluded that synbiotic supplementation decreased CP proliferation in vitro and caecal CP load in vivo while improving production parameters during an NE infection in broilers.

Synbiotic supplementation to decrease Salmonella colonization in the intestine and carcass contamination in broiler birds

In vitro and in vivo experiments were conducted to study the effects of synbiotic supplementation on Salmonella enterica ser. Enteritidis (SE) proliferation, cecal content load, and broiler carcass contamination. Lactobacillus reuteri, Enterococcus faecium, Bifidobacterium animalis, and Pediococcus acidilactici culture supernatants decreased (P < 0.05) the in vitro proliferation of SE at 1:1 supernatant: pathogen dilution. A total of 240 Cobb-500 broiler chicks were randomly allotted to three treatment groups (8 replicates/group with 10 birds/replicate): control (basal diet), antibiotic (Virginiamycin at 20 mg/kg feed), synbiotic (PoultryStar® ME at 0.5 g/kg feed containing L. reuteri, E. faecium, B. animalis, P. acidilactici and a Fructooligosaccharide) from day of hatch. At 21 d of age, all birds in experimental groups were orally inoculated with 250 μl of 1 X 109 CFU SE. Antibiotic supplementation increased (P < 0.05) body weight and feed consumption, compared to the control group. Birds in the synbiotic supplementation had intermediate body weight and feed consumption that were not significantly different from both the control and antibiotic group at 42 d of age in SE infected birds. No significant effects were observed in feed efficiency at 42 d of age among the groups. Antibiotic and synbiotic supplementation decreased (P < 0.05) SE load in cecal contents by 0.90 and 0.85 log units/ g and carcass SE load by 1.4 and 1.5 log units/mL of rinsate compared to the control group at 42 d of age (21 dpi). The relative abundance of IL-10, IL-1, TLR-4, and IFNγ mRNA was decreased (P < 0.05) in the antibiotic and synbiotic supplementation groups compared to the control birds at 42 d of age (21 dpi). It can be concluded that synbiotic supplementation decreased SE proliferation in vitro and decreased SE load in the cecal contents and broiler carcass.