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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, neutrophihlymphocyte ratio, albumimglobulin ratio, fibrinogen, total proteimfibrinogen 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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-I-), to-tal 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 con-stituents, 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 di-etary FA supplementation except a diet x challenge interaction for interleukin (IL)-8 in the spleen; IL-8 de-creased 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-lß, 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 in-flammatory responses in older laying hens; more studies are required to investigate possible protective effects of FA in laying hens. [ABSTRACT FROM AUTHOR]

We investigated the effects of dietary fo-lic acid (FA) supplementation on immunological pa-rameters 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 supple-mental FA per kilogram of diet. At 32 wk of age, 6 hens from each dietary treatment were injected intra-venously 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 com-pared with the saline control. Expression of interleukin (IL)-1(3 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)-7 in the spleen, and IL-1/3, IL-10, and IFN-7 in the cecal ton-sils, 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 x challenge interaction for total IgG, and cytokines IL-1/3 and IL-18 in the spleen as well as IL-18 in the cecal tonsils. In con-clusion, 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. [ABSTRACT FROM AUTHOR]

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 antiinflammatory profile on a gut location associated immune pathways manner, suggesting different immune pathways that require further studies in this field. [ABSTRACT FROM AUTHOR]