Associations of Interferon-γ Genotype and Protein Level with Antibody Response Kinetics in Chickens

Although previous studies have demonstrated an association between interferon-gamma (IFN-gamma) promoter genotype and antibody response kinetics in chickens, the protein levels that may mediate such a gene-trait association have not been determined. The objective of this study, therefore, was to determine the correlation of circulating IFN-gamma levels with both the IFN-gammaIFN-gamma promoter polymorphisms and antibody response in order to evaluate the potential role of IFN-gamma protein in mediating genetic control of antibody response in chickens. Antibody response after Salmonella enteritidis (SE) vaccination at day 10, antibody response to sheep red blood cells (SRBCs) and killed Brucella abortus after immunizations at 19 wk and 22 wk, and serum IFN-gamma protein level were measured in an F2 population derived from inbred lines. A single nucleotide polymorphism in the IFN-gamma promoter region was associated with IFN-gamma protein expression as measured by an enzyme-linked immunosorbent assay after both primary and secondary immunizations. Higher IFN-gamma protein level was correlated with higher antibody level to SE and with increased maximum level and decreased time to reach the maximum secondary antibody response to SRBCs. These results suggest that one of the mechanisms by which promoter polymorphism of IFN-gamma affects antibody production in chickens may involve the circulating level of IFN-gamma protein

Effects of Simple and Disposable Chicken Cages for Experimental Eimeria Infections

During experimental Eimeria infections in chickens, facilities are often contaminated by fecal oocysts known to be highly resistant to both chemical and enzymatic treatments. Thus, studies using experimental Eimeria infections have been limited due to the difficulty of complete elimination of residual oocysts from both cages and facilities. To overcome this limitation, simple, inexpensive, and disposable cages were constructed from cardboard boxes and tested during experimental Eimeria maxima infections. The cages were used in animal rooms with only a 1.7% evidence of coccidia contamination between adjacent cages. No significant differences in fecal oocyst output and body weight gain were noted between animals housed in disposable cages and animals housed in wire control cages. This cage design is a useful means for preventing oocyst contamination during experimental conditions, suggesting that this disposable cage design could be used for other avian infectious disease studies

Structural diversity in the type IV pili of multidrug-resistant Acinetobacter

Acinetobacter baumannii is a Gram-negative coccobacillus found primarily in hospital settings that has recently emerged as a source of hospital-acquired infections. A. baumannii expresses a variety of virulence factors, including type IV pili, bacterial extracellular appendages often essential for attachment to host cells. Here, we report the high resolution structures of the major pilin subunit, PilA, from three Acinetobacter strains, demonstrating thatA. baumannii subsets produce morphologically distinct type IV pilin glycoproteins. We examine the consequences of this heterogeneity for protein folding and assembly as well as host-cell adhesion by Acinetobacter. Comparisons of genomic and structural data with pilin proteins from other species of soil gammaproteobacteria suggest that these structural differences stem from evolutionary pressure that has resulted in three distinct classes of type IVa pilins, each found in multiple species

Indole Treatment Alleviates Intestinal Tissue Damage Induced by Chicken Coccidiosis Through Activation of the Aryl Hydrocarbon Receptor

Indoles, as the ligands of aryl hydrocarbon receptor (AhR), have been shown to possess immune-modulating property in terms of the balancing between regulatory T cells (Treg) and T helper 17 cells (Th17) activities. In the present study, we examined the effects of dietary indoles, 3,3′-diindolylmethane (DIM) and indole-3-carbinol (I3C), on CD4+T cell population and functions in chickens. Furthermore, the effects of dietary DIM treatment on chicken coccidiosis caused by an apicomplexan parasite were investigated. Dietary treatment of healthy chickens with DIM and I3C induced increased CD4+CD25+ (Treg) cells and the mRNA expression of IL-10, while decreasing number of CD4+IL-17A+ (Th17) cells and Th17-related cytokines transcripts expression in the intestine. In addition, we explored the role of AhR in indole-treated splenic lymphocytes by using AhR antagonist and our results suggested that DIM is a ligand for chicken AhR. In chicken coccidiosis, treatment of DIM increased the ratio of Treg/Th17 cells and significantly reduced intestinal lesion although no significant changes in body weight and fecal oocyst production were noted compared to non-treated control group. These results indicate that DIM is likely to affect the ratios of Treg/Th17 reducing the level of local inflammatory response induced by Eimeria or facilitate repairing process of inflamed gut following Eimeria infection. The results described herein are thus consistent with the concept that AhR ligand modulates the T cell immunity through the alteration of Treg/Th17 cells with Treg dominance. To our knowledge, present study is the first scientific report showing the effects of dietary indole on T cell immunity in poultry species

Effect of ochratoxin A on the intestinal mucosa and mucosa-associated lymphoid tissues in broiler chickens

The immunotoxic effect of ochratoxin A (OTA) on the intestinal mucosa-associated lymphoid tissue and its cytotoxic action on the intestinal epithelium were studied in broiler chickens experimentally treated with the toxin. From the 7th day of life, 80 male broiler chickens (Ross 308) were randomly divided into four groups of 20 birds each. The three experimental groups (E1-3) were treated with OTA for 28 days (E1: 50 μg/kg body weight [bw]/day; E2: 20 μg/kg bw/day; E3: 1 μg/kg bw/day) and the fourth group served as control. Histological examination of the intestinal mucosa and immunohistochemical staining for identification of CD4+, CD8+, TCR1 and TCR2 lymphocytes in the duodenum, jejunum and ileocaecal junction were performed, and CD4+/CD8+ and TCR1/TCR2 ratios were calculated. OTA toxicity resulted in decreased body weight gain, poorer feed conversion ratio, lower leukocyte and lymphocyte count, and altered intestinal mucosa architecture. After 14 days of exposure to OTA, immunohistochemistry showed a significant reduction of the lymphocyte population in the intestinal epithelium and the lamina propria. After 28 days of exposure, an increase in the CD4+ and CD8+ values in both the duodenum and jejunum of chickens in Groups E1 and E2 was observed, but the TCR1 and TCR2 lymphocyte counts showed a significant reduction. No significant changes were observed in Group E3. The results indicate that OTA induced a decrease in leukocyte and lymphocyte counts and was cytotoxic to the intestinal epithelium and the mucosa-associated lymphoid tissue, altering the intestinal barrier and increasing susceptibility to various associated diseases

Comparing the immune responses of two genetically B-complex disparate Fayoumi chicken lines to Eimeria tenella

The present study was conducted to compare the susceptibility of congenic Fayoumi lines to Eimeria tenella infection and to assess genetic differences in Eimeria egression. Chickens were orally inoculated with 5 × 104 sporulated E. tenella oocysts and challenged with 5 × 106 oocysts on the 10th day after the primary infection. The Fayoumi M5.1 line exhibited higher levels of body weight gain, less oocyst shedding and higher percentages of B and CD4+/CD8+ T cells than the M15.2 chickens. These results demonstrate that M5.1 line is more resistant to E. tenella infection than M15.2 line. Furthermore, the percentage of sporozoite egress from peripheral blood mononuclear cells (PBMCs) was higher in the M5.1 line. The results of this study suggest that enhanced resistance of Fayoumi M5.1 to E. tenella infection may involve heightened cell-mediated and adaptive immunity, resulting in reduced intracellular development of Eimeria parasites

Host-mediated beneficial effects of phytochemicals for prevention of avian coccidiosis

Both in vitro and in vivo studies were conducted to evaluate the beneficial effects of green tea extract (GT), cinnamon oil (CO), and pomegranate extract (PO) on avian coccidiosis. In experiment (EXP) 1, an in vitro culture system was used to investigate the individual effects of GT, CO, and PO on the proinflammatory cytokine response and integrity of tight junction (TJ) in chicken intestinal epithelial cells (IEC), on the differentiation of quail muscle cells and primary chicken embryonic muscle cells, and anticoccidial and antibacterial activities against Eimeria tenella sporozoites and Clostridium perfringens bacteria, respectively. In EXP 2 and 3, in vivo trials were carried out to study the dose-dependent effect of blended phytochemicals (GT, CO, PO) on coccidiosis in broiler chickens infected with E. maxima. For EXP 2, one hundred male broiler chickens (0-day-old) were allocated into the following five treatment groups: Control group for non-infected chickens (NC), Basal diet group for E. maxima-infected chickens (PC), PC group supplemented with phytochemicals at 50 (Phy 50), 100 (Phy 100), and 200 (Phy 200) mg/kg feed diets for E. maxima-infected chickens. For EXP 3, one hundred twenty male broiler chickens (0-day-old) were allocated into the following six treatment groups: NC, PC, PC supplemented with phytochemicals at 10 (Phy 10), 20 (Phy 20), 30 (Phy 30), and 100 (Phy 100) mg/kg feed for E. maxima-infected chickens. Body weights (BW) were measured on days 0, 7, 14, 20, and 22, and jejunum samples were used to measure cytokine, TJ protein, and antioxidant enzyme responses at 8 days post-infection (dpi). Fecal samples for oocyst enumeration were collected from 6 to 8 dpi. In vitro, CO and PO reduced LPS-induced IL-1β and IL-8 in IEC, respectively, and GT enhanced the gene expression of occludin in IEC. PO at 1.0 and 5.0 mg/mL exerted antimicrobial effect against E. tenella sporozoites and C. perfringens bacteria, respectively. In vivo, chickens fed a diet supplemented with phytochemicals showed enhanced BW, reduced oocyst shedding, and decreased proinflammatory cytokines following E. maxima challenge. In conclusion, the combination of GT, CO, and PO in the diet of broiler chickens infected with E. maxima induced enhanced host disease resistance including innate immunity and gut health, which contributed to improved growth and reduced disease responses. These findings provide scientific support for the development of a novel phytogenic feed additive formula that enhances the growth and intestinal health of broiler chickens infected with coccidiosis

Immunogenic Eimeria tenella Glycosylphosphatidylinositol-Anchored Surface Antigens (SAGs) Induce Inflammatory Responses in Avian Macrophages

, but the ability of these proteins to stimulate immune responses in the chicken is unknown. infection. Concomitantly, treatment with rSAGs 4, 5 and 12 suppressed the expression of IL-12 and IFN-γ and elevated that of IL-10, suggesting that during infection these molecules may specifically impair the development of cellular mediated immunity. pathogenicity associated with the endogenous second generation stages

Strategic Priorities for Research on Antibiotic Alternatives in Animal Agriculture—Results From an Expert Workshop

The emergence, spread, and expansion of antibiotic resistance and increasing restrictions on the use of antibiotics in animal agriculture have created a need for efficacious alternatives that remains unmet. Prioritizing research needs in the development of alternatives is key to ensuring that scarce research resources are dedicated to the most promising approaches. However, frameworks to enable a consistent, systematic, and transparent evaluation of antibiotic alternative candidates are lacking. Here, we present such an evaluation framework