Maternal antibody decay and antibody-mediated immune responses in chicken pullets fed prebiotics and synbiotics.

Three experiments were conducted to evaluate the effect of yeast-derived carbohydrates (YDC), and a blend of probiotics and YDC (synbiotic, SNB) on serum IgG concentration, maternal-derived antibody (MDA) decay, and specific antibody-mediated immune response in chick pullets following immunization with T-cell dependent antigens. A total of 300 day-old pullet chicks were randomly assigned to 3 dietary treatments including: a basal diet (Control), and diets containing YDC, and SNB (Lactobacillus acidophilus, L. casei, Streptococcus faecium, and Bacillus subtilis, and YDC). In experiment one, on d 1 and wk 3, 4, 5, and 6, blood samples were collected and serum were analyzed by ELISA for total IgG (Y), and MDA against Newcastle disease virus (NDV) and infectious bursal disease virus (IBDV). The second experiment examined the specific antibody against infectious bronchitis virus (IBV) in pullet chicks following vaccination against IBV at d 1. Finally, in experiment 3, on d 21 and 28 posthatch, 10 birds per treatment were immunized intramuscularly with both sheep red blood cells (SRBC) and bovine serum albumin (BSA), and 11 after immunization serum samples were analyzed by hemagglutination assay for antibody response to SRBC, and by ELISA for serum IgM and IgG response to BSA. The results demonstrated that diet containing SNB increased serum IgG at wk 3 posthatch. However, the decay rate of MDA against NDV and IBDV were not affected by dietary treatments. Birds fed YDC showed higher specific antibody response against IBV in wk 4, while both diets containing YDC and SNB decreased antibody response to IBV in wk 6. In addition, specific antibody response against SRBC and BSA was not affected by diets. In conclusion, supplementation of diet with SNB improved humoral immunity by increasing IgG concentration in serum, and modulated the adaptive antibody-mediated immune response against IBV.

Organic trace mineral supplementation enhances local and systemic innate immune responses and modulates oxidative stress in broiler chickens.

The effect of organic trace mineral supplementation on performance, intestinal morphology, immune organ weights (bursa of Fabricius and spleen), expression of innate immune response related genes, blood heterophils/lymphocytes ratio, chemical metabolic panel, natural antibodies (IgG), and oxidative stress of broiler chickens was studied. A total of 1,080 day-old male broilers were assigned to 1 of 3 dietary treatments, which included basal diet with Monensin (control), control diet supplemented with bacitracin methylene disalicylate (BMD), and BMD diet supplemented with organic trace minerals (OTM). No difference in feed conversion ratio was observed among treatments; ileum histomorphological analysis showed a lower crypt depth, higher villi height/crypt depth ratio, and lower villi width in the OTM treatment compared to control. Furthermore, OTM treatment resulted in higher uric acid and lower plasma malondehaldehyde (MDA), indicating lower oxidative stress. Gene expression analysis showed that OTM treatment resulted in up-regulations of TLR2 bin the ileum, and TLR2b, TLR4, and IL-12p35 in the bursa of Fabricius, and down-regulation of TLR2b and TLR4 in the cecal tonsils. In the spleen, OTM treatment resulted in up-regulation of IL-10. In conclusion, OTM supplementation to broiler diets may have beneficial effects on intestinal development, immune system status, and survival by improving ileum histomorphological parameters, modulation of Toll-like receptors and anti-inflammatory cytokines, and decreasing level of MDA, which in conjunction could enhance health status.

Impact of combined ß-glucanase and xylanase enzymes on growth performance, nutrients utilization and gut microbiota in broiler chickens fed corn or wheat-based diets.

The effects of a xylanase and ß-glucanase (XB) blend (2,500 U of xylanase and 250 U of ß-glucanase per kg of complete feed) on growth performance, nutrients utilization and digesta microbiota in broiler chickens were investigated. A total of 140 day-old male Ross 308 broiler chicks were randomly assigned to 7 replicate cages and fed experimental diets. Diets were based on either corn or wheat without or with supplemental XB. Performance was monitored weekly and excreta were collected from d 17 to 20 for nutrients digestibility and AMEn measurements. On d 21, jejunal contents were collected for viscosity determination whereas ileal and cecal contents were obtained for microbial analysis by Illumina sequencing. Microbial data were analyzed using QIIME and PLS-DA whilst other data were analyzed using SAS. Birds fed wheat diets had higher (P < 0.001) BWG (3.4%) than birds fed corn-based diet whilst birds fed XB had better BWG (4%) and FCR (7%) than birds fed non-XB diets. Birds fed wheat diet had higher (P < 0.001) NDF (46.5%) and less (P = 0.01) CP (-5.4%) digestibility compared to birds fed corn-based diet. XB reduced (P < 0.001) jejunal digesta viscosity to a greater extent in wheat diet (-31%) than in corn-based diet (-10%). Birds fed wheat-based diet with XB had higher (3.5%) starch digestibility than birds fed this diet without XB. Janthinobacterium was associated with non-XB corn-based diet, whereas Ruminococcus, Lachnospiraceae, Lactobacillaceae, Peptostreptococcaceae, Clostridiales, Acidovorax and Blautia were associated with XB corn-based diet in the ileum. A relatively similar microbiome clustering was observed in wheat-based treatments in the cecum. There were no significant (P ≥ 0.05) correlations between selected ileal or cecal bacterial taxa and AMEn. Diet impacted growth performance but XB was efficacious across diet types, implying that degradation of dietary fibrous components by feed enzymes may stimulate performance in young birds. Data provided significant insight on ileal and cecal microbial profile associated with the dietary types and XB; however their functional roles require further investigations.

Innate immune response of pullets fed diets supplemented with prebiotics and synbiotics.

Prebiotics and synbiotics are considered to be among the most promising replacements for in-feed antibiotic growth promoters (AGP) in poultry feed. The current study was designed to study the effect of Bacitracin methylene disalicylate (BMD) (Control), yeast-derived carbohydrates (YDC), and a blend of YDC and probiotics [Lactobacillus acidophilus, Lactobacillus casei, Streptococcus faecium, Bacillus subtilis, and YDC] (SNB) in the performance and innate immune response of pullets. Feed intake and BW were measured on a weekly basis. At the end of the study (d 21), 10 birds/treatment were sacrificed by cervical dislocation and ileum, cecal tonsil, and spleen samples were collected for gene expression analysis. No significant difference (P > 0.05) in feed intake and G:F was observed among treatments. In the second and third wk age, higher BW gain was observed in SNB treatment compared to control and both control and YDC treatments, respectively. Expression of TLR2b was upregulated in YDC and SNB in the ileum, and in SNB in the spleen (P < 0.05). Expression of TLR4 was downregulated in SNB in the cecal tonsil. Expression of TLR21 was downregulated in YDC in the ileum, while it was upregulated in SNB in the spleen (P < 0.05). In the ileum, YDC resulted in downregulated IL-12p35, CxCLi2, and IL-13, and SNB resulted in upregulated IL-6, interferon (IFN)-γ, and IL-4 (P < 0.05). In the cecal tonsil, YDC resulted in upregulated IL-12p35, IL-2, IL-13 and IL-10, and SNB resulted in downregulated IL-2 and upregulated IL-13 and IL-10 (P < 0.05). In the spleen, YDC resulted in dowregulated IL-2 and CxCLi2, and SNB resulted in upregulated IL-6, IFN-γ, IL-4, and IL-10 (P < 0.05). In conclusion, no change in performance was observed. Innate immune response analysis showed SNB with a more potent effect compared to YDC where the former showed a balanced T-helper (Th)-1/Th-2 response locally and a more Th-2-dependent response systemically; SNB might provide a more beneficial immune modulation with maintaining immune homeostasis, which was observed in a strong IL-10 response.

Effect of crowding stress and Escherichia coli K88+ challenge in nursery pigs supplemented with anti-Escherichia coli K88+ probiotics.

Under commercial conditions and during production periods, pigs are generally exposed to a number of stressors that may have direct or indirect influence on their performance and general health. As a result, environmental stressors can influence the productivity as well as the onset and severity of infectious diseases. The aim of this study was to investigate the effects of crowding stress on performance and some immunological responses in piglets challenged with enterotoxigenic Escherichia coli (ETEC) K88(+) and fed diets containing anti-ETEC probiotic strains derived from E. coli in a 3-wk trial. Ninety-six piglets at 20 ± 1 d of age were randomly assigned to 6 experimental treatments with 3 pigs/pen and 5 replicates/treatment and fed a basal mash diet. To model stress, piglets were housed in 2 kinds of pens: standard floor allowance (SFA; no stress) and half standard floor allowance (HSFA; stressed). The treatments were 1) control pigs with SFA, 2) control pigs with HSFA, 3) pigs with SFA and challenged with ETEC (ESFA), 4) pigs with HSFA and challenged with ETEC (EHSFA), 5) pigs with ESFA and supplemented with a cocktail of E. coli probiotics (PSFA), and 6) pigs with EHSFA and supplemented with a cocktail of E. coli probiotics (PHSFA). After 4 d acclimatization, crowding stress was started on d 5, E. coli probiotics were given daily from d 5, and ETEC challenge was administered on d 8 and 10. Body weight and feed disappearance were determined weekly and severity of diarrhea was characterized daily. Blood samples were collected for biochemistry and inflammatory analysis and pigs were euthanized to obtain digesta for bacterial enumeration. The ADG and ADFI decreased (P < 0.05) in stressed and ETEC-challenged pigs 5 d after ETEC challenge. The ETEC population was higher in both ileal and colon digesta of stressed pigs whereas ETEC-challenged and probiotic-fed pigs had higher fecal consistency scores 96 h and 7 d after ETEC challenge. Stressed pigs had higher (P < 0.001) levels of neutrophils, neutrophil:lymphocyte ratio, albumin:globulin ratio, fibrinogen, total protein:fibrinogen ratio, and cortisol. Generally, the levels of cortisol, interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) differed over time among some treatment groups. In conclusion, reduced space allowance stress and ETEC challenge depressed certain aspects of performance and immunological responses and increased E. coli counts; however, probiotics feeding had little positive effects on these measures suggesting further research.

Performance, serum biochemical responses, and gene expression of intestinal folate transporters of young and older laying hens in response to dietary folic acid supplementation and challenge with Escherichia coli lipopolysaccharide.

The present study was conducted to investigate the effects of dietary folic acid (FA) supplementation on performance, serum biochemical indices, and mRNA abundance of intestinal folate transporters in young and older laying hens after acute lipopolysaccharide (LPS) challenge. Two experiments were conducted separately involving 48 Shaver White young laying hens (24 wk of age) in experiment 1 and 48 Shaver White older laying hens (58 wk of age) in experiment 2. Birds were fed 2 diets in a complete randomized design. The diets were wheat-soybean meal based, with or without supplemental 4 mg of FA/kg of diet. Birds were fed for 8 wk, during which time feed consumption and egg production were monitored. At the end of each feeding experiment, 6 hens from each dietary treatment were injected intravenously with 8 mg/kg of BW of either Escherichia coli LPS or sterile saline. Four hours after injection, blood and intestinal samples were collected for further analysis. Compared with the control, dietary FA supplementation increased egg weight and egg mass and decreased serum glucose levels in the young laying hens, and reduced serum uric acid in the older laying hens (P < 0.05). Relative to saline injection, plasma homocysteine, serum calcium, and phosphorus levels were found to be lower in both young and older laying hens after LPS challenge (P < 0.05). Other serum biochemical variables and the mRNA expression of 2 folate transport genes in the small and large intestine were differentially affected by LPS challenge, and some of those responses varied with the age of the birds. Additionally, interactions between diet and LPS challenge were specifically found in the older laying hens. In summary, in addition to improving production performance, there were effects of dietary FA supplementation and its interaction with LPS challenge on biochemical constituents, and age played a role in the development of responses to diet and bacterial LPS infections.

Performance, histomorphology, and toll-like receptor, chemokine, and cytokine profile locally and systemically in broiler chickens fed diets supplemented with yeast-derived macromolecules.

The turnover of intestinal epithelial cells is a dynamic process that includes adequate cell proliferation and maturation in the presence of microbiota and migration and seeding of immune cells in early gut development in chickens. We studied the effect of yeast-derived macromolecules (YDM) on performance, gut health, and immune system gene expression in the intestine of broiler chickens. One thousand eighty 1-d-old birds, with 60 birds per pen and 6 pens per treatment, were randomly assigned to 3 treatment diets; a diet containing monensin (control), control diet supplemented with bacitracin methylene disalycylate (BMD), and BMD diet supplemented with YDM. Feed intake, BW, mortality, ileum histomorphology, and gene expression of Toll-like receptors (TLR2b, TLR4, and TLR21), cytokines [interferon (IFN)-γ, IFN-ß, IL-12p35, IL-1ß, IL-6, IL-10, IL-8, IL-2, IL-4, and transforming growth factor (TGF)-ß4], and cluster of differentiation (CD)40 in the ileum, cecal tonsil, bursa of Fabricius, and spleen were assessed. No significant overall difference in performance in terms of feed intake, BW gain, and G:F was observed among treatments (P > 0.05). The YDM diet resulted in significantly higher villi height and villi height:crypt depth ratio compared with BMD and control diets (P < 0.05). A significantly lower mortality was observed in the YDM treatment compared with both control and BMD treatments. Compared with the control, gene expression analysis in YDM treatment showed no major change in response in the ileum, whereas higher CD40, IFN-ß, IL-ß, IL-6, TGF-ß4, IL-2, and IL-4 in the cecal tonsil; TLR2b, TLR4, TLR21, and TGF-ß4 in the bursa of Fabricius; and TLR4, IL-12p35, IFN-γ, TGF-ß4, and IL-4 in the spleen was observed (P < 0.05). In conclusion, supplementation of YDM supports pro- and anti-inflammatory cytokine production via T helper type 1 and 2 (Th1 and Th2) cell-associated pathways both locally and systemically with a stronger additive effect in the cecal tonsil in the presence of BMD in the diet of chickens.

Response of older laying hens to an Escherichia coli lipopolysaccharide challenge when fed diets with or without supplemental folic acid.

Folic acid plays a key role in nucleic acids and protein synthesis, and has been associated with anti-inflammatory effects in LPS-induced infections. To this end, a study was conducted to investigate the effects of dietary folic acid (FA) supplementation in older laying hens (58 to 66 wk of age) challenged with Escherichia coli lipopolysaccharide (LPS). A total of 24 Shaver White laying hens at 58 wk were fed 2 diets. The diets were wheat-soybean-based, with either 0 or 4 mg of supplemental FA per kg of diet. After 8 wk of feeding and at 66 wk, the hens were injected intravenously with 8 mg of LPS or saline per kg of BW. Four hours after injection, blood was collected and hens were euthanized to obtain spleen and cecal tonsils. The T cell subsets in the blood and the spleen (CD4+ and CD8+), total IgG, and biochemical constituents (total protein, albumin, globulin, and fibrinogen) were not influenced (P > 0.05) by dietary FA supplementation. However, LPS injection decreased (P < 0.05) biochemical constituents, CD4+, and CD8+ cells in the blood, whereas CD4+:CD8+ ratio and total IgG increased (P < 0.05), and fibrinogen was not influenced. Gene expression in the spleen and cecal tonsils was not influenced by dietary FA supplementation except a diet × challenge interaction for interleukin (IL)-8 in the spleen; IL-8 decreased in FA-fed hens that were treated with LPS. Also, FA supplementation decreased the expression of IL-8 in cecal tonsils. Relative to saline-injected hens, expression of IL-1ß, interferon-γ, and IL-10 increased in the LPS-injected hens in the spleen and cecal tonsils, IL-8 increased in LPS-injected hens only in the cecal tonsils, whereas Toll-like receptor 4, IL-4, IL-17, and IL-18 increased in the LPS-injected hens only in the spleen; however, LPS decreased expression of IL-13 in the cecal tonsils. In conclusion, FA did not affect inflammatory responses in older laying hens; more studies are required to investigate possible protective effects of FA in laying hens.

Immunomodulation in young laying hens by dietary folic acid and acute immune responses after challenge with Escherichia coli lipopolysaccharide.

We investigated the effects of dietary folic acid (FA) supplementation on immunological parameters in young laying hens under acute conditions of lipopolysaccharide (LPS) challenge. Twenty-four Shaver White laying hens at 24 wk were fed 2 diets in a completely randomized design. The diets were wheat-soybean based, with either 0 or 4 mg of supplemental FA per kilogram of diet. At 32 wk of age, 6 hens from each dietary treatment were injected intravenously with 8 mg/kg of BW of either LPS or saline. Four hours after injection, blood was collected and the hens were euthanized to obtain spleen and cecal tonsils. Heterophil:lymphocyte ratio, CD3+, CD4+, CD8+ T cells, and CD4+:CD8+ cells in the blood and spleen were not affected by dietary FA. Relative to saline-injected hens, LPS-injected hens had fewer (P < 0.05) CD3+, CD4+, CD8+, and CD4+:CD8+ cells in the blood, and no difference was found in the spleen. Total protein, albumin, and globulin were found to be higher (P < 0.05) in FA-supplemented hens compared with the control. However, total protein, albumin, and globulins decreased (P < 0.05) in the LPS-injected hens compared with the saline control. Expression of interleukin (IL)-1ß in cecal tonsils decreased (P < 0.05) in FA-supplemented hens, but no dietary influence was found on the expression of other genes in both the spleen and cecal tonsils. Lipopolysaccharide upregulated (P < 0.05) expression of IL-10 and interferon (IFN)-γ in the spleen, and IL-1ß, IL-10, and IFN-γ in the cecal tonsils, whereas the expression of Toll-like receptor (TLR)-4 and IL-8 was not influenced by LPS in the spleen and cecal tonsils. There was a diet × challenge interaction for total IgG, and cytokines IL-1ß and IL-18 in the spleen as well as IL-18 in the cecal tonsils. In conclusion, there were few interactions of dietary FA and LPS; however, FA increased biochemical constituents, enhanced generation of total IgG, as well as exhibiting pleoitropic effects in inflammatory responses.

Local and systemic innate immunity in broiler chickens supplemented with yeast-derived carbohydrates.

A study was conducted to assess the effect of yeast-derived carbohydrates (YDC) on performance and innate immune responses of broiler chickens. In total, 1,080 one-day-old birds were randomly assigned to one of 3 dietary treatments (n = 360): a standard broiler diet containing monensin (control), control + bacitracin methylene disalycylate (BMD), and YDC treatment (control + YDC at 0.02%, 0.01%, and 0.005% for starter, grower, and finisher, respectively). Weekly BW, feed intake (FI), and feed conversion ratio (FCR) were recorded. Immune organ weights, gut morphology, gene expression, heterophil:lymphocyte (H:L), and serum IgG were determined at d 42. No significant difference in FCR, FI, and mortality was observed among treatments. However, BW gain in starter phase was higher in control and YDC treatments compared with BMD treatment. Ileal villi height, crypt depth, and their ratio were not significantly different among treatments, whereas villi width was lower in control and YDC treatments compared with BMD treatment. The number of goblet cells per unit area in the ileum was lower in BMD treatment compared with control and YDC treatments. Expression of TLR2b and IL-6 in the ileum and cecal tonsils was not significantly different among treatments (P > 0.05). Expression of TLR4 was downregulated in YDC treatment compared with control in the ileum. Expression of IL-12p35 and IFN-γ were downregulated in the YDC treatment only in the cecal tonsils. Compared with the control, the expression of IL-10 in both the ileum and the cecal tonsils was downregulated in YDC treatment. Serum IgG and H:L ratio were lower and higher, respectively, in the YDC treatment compared with control and BMD treatments. In conclusion, dietary inclusion of YDC affected intestinal cytokines anti-inflammatory profile on a gut location associated immune pathways manner, suggesting different immune pathways that require further studies in this field.