Y. O. Fasina

Intestinal Cytokine Response of Commercial Source Broiler Chicks to Salmonella Typhimurium Infection

Development of molecular-based immunotherapeutic strategies for controlling Salmonella Typhimurium (ST) infection in poultry requires a better understanding of intestinal and cecal cytokine responses. Accordingly, an experiment was conducted to measure changes in intestinal cytokine expression when commercial source broiler chickens were challenged with a nalidixic acid-resistant ST. Ross broiler chicks were nonchallenged with ST (control treatment) or challenged by orally giving 7.8 x 10(6) cfu at 4 d of age (STC treatment). Each treatment consisted of 4 replicate pens with 14 chicks per pen. Expression levels of proinflammatory cytokines, interferon-gamma, and antiinflammatory interleukin (IL)-10 were determined at 5 and 10 d postchallenge (PC). Intestinal flushes were also collected from each treatment at 7 d PC to estimate IgA and IgG. Results showed an upregulation in IL-1beta mRNA in STC chicks at 5 d PC. By 10 d PC, the expression of IL-1beta was further increased and accompanied by an upregulation of IL-6 and interferon-gamma mRNA, whereas IL-10 mRNA expression decreased. It was concluded that ST induced an intestinal mucosal inflammatory response in commercial source broiler chicks less than 2 wk of age.

Influence of Salmonella enterica Serovar Typhimurium Infection on Intestinal Goblet Cells and Villous Morphology in Broiler Chicks

Abstract Live broiler chickens are important in the transmission of Salmonella to humans. Reducing Salmonella levels in the intestine of broiler chickens, in part, requires understanding of the interactions between Salmonella and the intestinal barriers that represent the first line of defense. Such barriers include the mucus layer (composed of mucins secreted by goblet cells) and the underlying epithelium. Two experiments were conducted to evaluate the effect of Salmonella Typhimurium infection on intestinal goblet cell dynamics (density and size) and villous morphology in broiler chicks. In Experiment 1, broiler chicks were either challenged with sterile media (control treatment) or orally given 7.4 × 107 colony-forming units (CFU) at 3 days of age (termed the CST treatment). Treatments were similar in Experiment 2, except that chicks in the CST treatment were challenged with 7.8 × 106 CFU at 4 days of age. Duration of each experiment was 14 days. At 7 days postchallenge (PC) in Experiment 1, jejunal tissue sections were collected, formalin-fixed, and routinely processed for histologic measurement of villous morphometric indices. In Experiment 2, at 10 days PC, jejunal tissue sections were collected and processed for histologic determination of goblet cell numbers and size, in addition to villous measurements. Results showed that Salmonella Typhimurium infection increased goblet cell density, reduced villous surface area, increased the incidence of epithelial exfoliation, and increased the incidence of heterophil influx into the lamina propria (P < 0.05). It was concluded that Salmonella Typhimurium infection impacts goblet cell biology and exerts morphopathologic changes in the jejunum of broiler chicks.

Evaluation of the efficacy of yeast extract in reducing intestinal Clostridium perfringens levels in broiler chickens

The etiological agent of necrotic enteritis is Clostridium perfringens. Traditionally, necrotic enteritis is controlled with in-feed antibiotics. However, increasing consumer demand for drug-free poultry has fostered the search for nonantibiotic alternatives. Yeast extract contain nucleotides that are immunomodulatory and also essential for cellular functions. An experiment was conducted to evaluate the efficacy of NuPro yeast extract (Alltech Inc., Nicholasville, KY) in reducing intestinal C. perfringens levels in broiler chickens. One hundred ninety-two 1-d-old male broiler chicks were obtained and randomly assigned to 6 treatments in a battery cage trial. Treatment 1 consisted of chicks fed a corn-soybean meal basal diet (BD) without added bacitracin methylene disalicylate or NuPro. Treatment 2 consisted of chicks fed BD into which bacitracin methylene disalicylate was added at 0.055 g/kg. Treatment 3 consisted of chicks fed BD supplemented with NuPro at a 2% level for the first 10 d of the experiment. Treatments 4 (PX), 5, and 6 (PN) consisted of chicks that were challenged with 3 mL of the C. perfringens inoculum (~10(7) cfu/mL) on d 14, 15, and 16 of the experiment and fed diets similar to treatments 1, 2, and 3, respectively. On d 1 and 7 postchallenge, intestinal C. perfringens levels, lesion scores, and alkaline phosphatase activity were assessed. On d 1 postchallenge, C. perfringens level in treatment 5 (2.09 log(10) cfu/g) was lower (P < 0.05) compared with the PX treatment (4.71 log(10) cfu/g) but similar to the PN treatment (2.98 log(10) cfu/g). A similar trend was observed on d 7 postchallenge. NuPro supplementation enhanced alkaline phosphatase activity (P < 0.05) in C. perfringens-challenged chicks and appeared to reduce intestinal lesion scores. Although dietary supplementation of NuPro in the PN treatment reduced C. perfringens levels by 1.73 and 0.68 log(10) cfu/g compared with the PX treatment on d 1 and 7 postchallenge, respectively, these reductions were not significant. Extending the period of NuPro supplementation beyond the first 10 d of life should be considered for achieving significant reduction in intestinal C. perfringensg levels.

Effect of dietary glutamine supplementation on Salmonella colonization in the ceca of young broiler chicks

Live poultry is an important vehicle for transmitting Salmonella Typhimurium to humans that have salmonellosis. It is therefore imperative to reduce Salmonella Typhimurium levels in the gastrointestinal tract of live chickens. Glutamine is an established immunonutrient that is capable of alleviating disease conditions in humans and rats. Thus, 2 experiments that used Ross broiler chicks were conducted to evaluate the effect of glutamine supplementation at 1% level of the diet on cecal Salmonella Typhimurium levels in young broiler chicks. Experiment 1 consisted of i) treatment 1 (control, CN), in which chicks were given an unmedicated corn-soybean meal basal starter diet without glutamine supplementation or Salmonella Typhimurium challenge; ii) treatment 2 (CST), in which chicks were given the same diet as CN but challenged with 3.6 x 10(6) cfu Salmonella Typhimurium/mL at 3 d of age; and iii) treatment 3 (GST), in which chicks were given the unmedicated corn-soybean meal basal starter diet supplemented with glutamine at 1% level, and challenged with 3.6 x 10(6) cfu at 3 d of age. Experiment 2 used similar treatments (CN, CST, and GST), except that chicks in CST and GST were challenged with 7.4 x 10(7) cfu Salmonella Typhimurium/mL, and a fourth treatment was added. The fourth treatment consisted of chicks that were not challenged with Salmonella Typhimurium but given the same diet as in GST. Duration of each experiment was 14 d. Growth performance of chicks was monitored weekly, and cecal Salmonella Typhimurium concentration was microbiologically enumerated on d 4, 10, or 11 postchallenge. Results showed that glutamine supplementation improved BW and BW gain in experiment 2 (P < 0.05) but did not reduce cecal Salmonella Typhimurium levels in either experiment (P > 0.05). The optimum supplemental level of glutamine that will enhance intestinal resistance to Salmonella Typhimurium colonization should be determined.

Effect of Clostridium perfringens infection and antibiotic administration on microbiota in the small intestine of broiler chickens

The etiological agent of necrotic enteritis (NE) is Clostridium perfringens (CP), which is an economically significant problem for broiler chicken producers worldwide. Traditional use of in-feed antibiotic growth promoters to control NE disease have resulted in the emergence of antibiotic resistance in CP strains. Identification of probiotic bacteria strains as an alternative to antibiotics for the control of intestinal CP colonization is crucial. Two experiments were conducted to determine changes in intestinal bacterial assemblages in response to CP infection and in-feed bacitracin methylene disalicylate (BMD) in broiler chickens. In each experiment conducted in battery-cage or floor-pen housing, chicks were randomly assigned to the following treatment groups: 1) BMD-supplemented diet with no CP challenge (CM), 2) BMD-free control diet with no CP challenge (CX), 3) BMD-supplemented diet with CP challenge (PCM), or 4) BMD-free control diet with CP challenge (PCX). The establishment of CP infection was confirmed, with the treatment groups exposed to CP having a 1.5- to 2-fold higher CP levels (P < 0.05) compared to the non-exposed groups. Next-generation sequencing of PCR amplified 16S rRNA genes, was used to perform intestinal bacterial diversity analyses pre-challenge, and at 1, 7, and 21 d post-challenge. The results indicated that the intestinal bacterial assemblage was dominated by members of the phylum Firmicutes in all treatments before and after CP challenge, especially the Lactobacillaceae and Clostridiales families. In addition, we observed post-challenge emergence of members of the Enterobacteriaceae and Streptococcaceae in the non-medicated PCX treatment, and emergence of the Enterococcaceae in the medicated PCM treatment. This study highlights the bacterial interactions that could be important in suppressing or eliminating CP infection within the chicken intestine. Future studies should explore the potential to use commensal strains of unknown Clostridiales, Lactobacillaceae, Enterobacteriaceae, Streptococcaceae, and Enterococcaceae in effective probiotic formulations for the control of CP and NE disease.

Comparative efficacy of a yeast product and bacitracin methylene disalicylate in enhancing early growth and intestinal maturation in broiler chicks from breeder hens of different ages

The intestine of the newly hatched chick is immature at hatch. Yeast contains nucleotides and β-glucans that enhance intestinal development and chick growth. Accordingly, a 14-d experiment was conducted to evaluate the efficacy of a novel yeast product and bacitracin methylene disalicylate in enhancing early growth and intestinal maturation in chicks obtained from young (26-27 wk old) and old (58 to 59 wk old) breeder hens. Chicks (384) were randomly assigned to 8 dietary treatments. Treatment 1 (YH) consisted of chicks, from young hens, fed corn-soybean meal (SBM) diet alone. Treatment 2 (YHB) consisted of chicks, from young hens, fed corn-SBM basal into which BMD was added at 0.055 g/kg. Treatment 3 (YHE) consisted of chicks, from young hens, fed corn-SBM basal into which yeast extract (YE) was added at 0.075% level. Treatment 4 (YHED) consisted of chicks, from young hens, fed corn-SBM basal into which YE was added at 0.15% level. Treatments 5 (OH), 6 (OHB), 7 (OHE), and 8 (OHED) consisted of chicks from old hens fed diets similar to those given to YH in treatments 1, 2, 3, and 4, respectively. Growth performance (body weight gain and feed conversion ratio) was evaluated on d 7 and 14. Intestinal tissue samples were also analyzed for alkaline phosphatase (ALP) activity as an indicator of intestinal maturation on d 4 and 13 of experiment. Results showed that by d 14 of experiment, only BMD treatments (YHB and OHB) improved body weight gain (P < 0.05). However, the body weight gains of chicks in the yeast-supplemented treatments (YHE, YHED, OHE, and OHED) were statistically similar (P > 0.05) to those of the BMD treatments. Ileal ALP activity was consistently enhanced by BMD and yeast product supplemented at 0.075% of the diet. It was concluded that antibiotic BMD and our novel yeast product supplemented at 0.075% of the diet improved early chick growth and maturation of the ileal segment of the small intestine.

Whole canola/pea and whole canola/canola meal blends in diets for broiler chickens 2. Determination of optimal inclusion levels

Whole canola/pea (WCP, 1:1 wt/wt) or whole canola/canola meal (WCC, 3:1 wt/wt) were heat-processed using a commercial pellet mill prior to incorporation in broiler starter (0–20 d) and finisher diets (20–40 d). The pelleted blends readily disintegrated in the preparation of the mash diets. Body weight gain of broilers (0–40 d) fed WCP (0, 10, 20, or 30%) or WCC (0, 5, 10, or 15%) declined linearly with level of dietary inclusion (P < 0.01). Feed intake declined curvilinearly (P < 0.01) with both blends, with lower intake most apparent at the higher inclusion levels. Feed/gain increased for broilers fed WCP or WCC (P < 0.01). Overall broiler mortality declined incrementally with inclusion of WCP (P < 0.07) or WCC (P < 0.03) in the diet. Although there was no distinct limitation on the dietary inclusion levels of either blend, the low feed intake with broilers fed 15% WCC indicated that its level should not exceed 10% of the diet. Key words: Canola seed, canola meal, peas, broiler chickens

Characterization of intestinal immune response to Clostridium perfringens infection in broiler chickens

&NA; Necrotic enteritis toxin B (NetB)‐producing Clostridium perfringens (CP) type A is the etiological agent of necrotic enteritis (NE) ‐ an economically significant disease in broiler chickens. Understanding the immune response to CP infection in broiler chickens is becoming important to develop effective vaccines against NE. An experiment was conducted to determine the expression levels of selected cytokine genes in the intestine and cecal tonsil of CP‐challenged broiler chickens. In a floor‐pen housing, broiler chickens were randomly assigned to the following treatment groups: 1) bacitracin methylene disalicylate (BMD)‐free control diet with no CP challenge (CX), 2) BMD‐supplemented diet with no CP challenge (CM), 3) BMD‐free control diet with CP challenge (PCX), or 4) BMD‐supplemented diet with CP challenge (PCM). The establishment of CP infection was confirmed, with the treatment groups exposed to CP having a 1.5 to 2‐fold higher CP levels (P < 0.05) compared to the non‐exposed groups. On day 1 and 7 post‐challenge, jejunal segments and cecal tonsils were collected from experimental chickens for quantitative real‐time RT‐PCR analysis to determine the expression levels of interleukin (IL)‐1&bgr;, interferon‐&ggr; (IFN‐&ggr;), IL‐2, IL‐13, IL‐17, IL‐10, and transforming growth factor (TGF)‐&bgr; genes. Levels of antibodies to CP recombinant proteins were also determined in the plasma of experimental chickens. Results indicated that on day 7 post‐challenge, IL‐1&bgr; (proinflammatory cytokine), IL‐13 (Th2 cytokine), and IL‐17 (Th17 cytokine) were upregulated (P < 0.05) in CP‐challenged PCX and PCM treatments, compared to the unchallenged (control) CX and CM treatments. A reverse trend was observed for TGF‐&bgr; (anti‐inflammatory cytokine), while no change was observed in IFN‐&ggr; (Th1 cytokine). Levels of plasma antibodies (IgY) to CP recombinant proteins were higher in CP‐challenged treatments (PCX and PCM; P < 0.05), compared to their corresponding controls (CX and CM). It was concluded that CP infection induced inflammatory response in the intestine of broiler chickens, and the mechanisms of inflammation are probably mediated via Th2 and Th17 cells.

Whole canola/pea and whole canola/canola meal blends in diets for broiler chickens 1. Evaluation of steam-pelleting or expansion processing

Whole canola blended with whole peas (1:1; WCP) or canola meal (3:1; WCC) provide complementary high energy-protein supplements for poultry feeding. Both WPC and WCC blends were fed with or without processing (steam-pelleting or expansion) to broiler chicks in a 14-d feeding trial. Pelleted WCP supported higher body weight gain and feed efficiency than the untreated blend (P   0.05), with notable exception of the expanded WCC which had a lower feeding value. With the pelleted or expanded blends, protein digestibility, N-retention, fat digestibility, and AMEN were comparable or improved over the unprocessed blends, again with the exception of the expanded WCC. The processed blends had higher gelatinized starch, and lower protein solubility and myrosinase activity index. Protein solubility was very low for the expanded WCC, which is indicative of excessive heat...