J L McReynolds

University of Arkansas, Fayetteville, Arkansas, United States

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Publications (63)

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    File available · Dataset · Jan 2016
  • C. L. Swaggerty · J. L. McReynolds · J. A. Byrd · [...] · M. H. Kogut
    [Show abstract] [Hide abstract] ABSTRACT: We developed a novel selection method based on an inherently high and low phenotype of pro-inflammatory mediators and produced “high” and “low” line chickens. We have shown high line birds are more resistant to Salmonella enterica serovar Enteritidis and Eimeria tenella compared to the low line. Clostridium perfringens is the fourth leading cause of bacterial-induced foodborne illness, and is also an economically important poultry pathogen and known etiologic agent of necrotic enteritis (NE). The objective of this study was to determine if high line birds were also more resistant to NE than low line birds using an established model. Birds were reared in floor pens and challenges were conducted twice (high line = 25/trial, 50 birds total; low line = 26/trial, 52 birds total). Day-old chicks were provided a 55% wheat-corn-based un-medicated starter diet. A bursal disease vaccine was administered at 10× the recommended dose via the ocular route at 14-d-of-age. Birds were challenged daily for 3 d beginning at 16-d-of-age by oral gavage (3 mL) with 107 colony forming units (cfu) of C. perfringens/mL then necropsied at 21-d-of-age. All birds had sections of the intestine examined and scored for lesions while the first 10 necropsied also had gut content collected for C. perfringens enumeration. Chickens from the high line were more resistant to C. perfringens-induced NE pathology compared to the low line, as indicated by reduced lesion scores. Ninety percent of the high line birds had lesions of zero or one compared to 67% of the low line birds. Wilcoxon rank sum test showed significantly higher lesion scores in the low line birds compared to the high line (P < 0.0001). There were no differences in the C. perfringens recovered (P = 0.83). These data provide additional validation and support selection based on elevated levels of pro-inflammatory mediators produces chickens with increased resistance against foodborne and poultry pathogens.
    Article · Dec 2015 · Poultry Science
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    Si Hong Park · Scot E Dowd · Jack L McReynolds · [...] · Steven C Ricke
    [Show abstract] [Hide abstract] ABSTRACT: The gastrointestinal microbial community in broiler chickens consists of many different species of bacteria, and the overall microbiota can vary from bird to bird. To control pathogenic bacteria in broilers and improve gut health, numerous potential dietary amendments have been used. In this study, we used a pyrosequencing platform to evaluate the effect of sodium bisulfate on microbiota of the crop, cecum, and ileum of broiler chickens grown over several weeks. The diversity information in each digestive organ sample exhibited considerable variation and was clearly separable, suggesting distinct bacterial populations. Although no apparent microbial clustering occurred between the control and the dietary treatments, we did observe shifts in overall microbiota populations in the crop, ileum, and ceca as well as changes in specific microorganisms such as Bacteroides, Clostridium, and Lactobacillus species that were identified as birds became older.
    Full-text available · Article · Oct 2015 · Poultry Science
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    M.H. Kogut · J.L. McReynolds · H. He · [...] · S.D. Pillai
    [Show abstract] [Hide abstract] ABSTRACT: Our laboratories are investigating the use of High Energy (10 MeV) Electron-Beam (E-beam) irradiation for is potential use in vaccine development. Ionizing radiation inactivates microorganisms by “direct and indirect” effects on nucleic acids and other cellular components. Though the cells are inactivated, the surface antigenic properties of the microorganisms remain unaltered. We hypothesized that electron-beam (E-beam) inactivated Salmonella enterica serovars could be used as a potential immune modulator to activate the innate immune response and thus reduce Salmonella intestinal colonization and shedding in neonatal chickens. Three replicate experiments were designed to evaluate the efficacy of a high energy E-beam irradiated Salmonella enterica serovar Typhimurium (ST) administered in ovo to: (a) induce a functional innate immune response and (b) reduce ST colonization in the ceca of chicks three-weeks post-hatch. We have previously shown that unmethylated CpG motifs of bacteria DNA oligodeoxynucleotides (CpG-ODN) given in ovo stimulates innate immune responsiveness of chicken heterophils and increases resistance of young chickens to SE colonization; thus were used as positive controls in these experiments Eighteen-day-old chicken embryos were equally divided into four independent treatment groups: (1) a negative control (sham injected, no challenge) group, (2) an infected control (sham injected, challenged) group, (3) a CpG-ODN injected, challenged positive control, and (4) an E-beam ST-injected, challenged group. All treatment groups contained 100 birds, half of the animals from each treatment group were euthanized on day 4 post-hatch so that peripheral blood granulocytes (heterophils) could be collected to evaluate the functional innate immune response. The remaining birds where reared under normal housing conditions for the remainder of the experiment. On day 18 post-hatch the birds were challenged with the homologous ST strain and five days later (day 23 post-hatch), the experiment was terminated to evaluate the colonization of ST in the ceca of the birds. Differences in the leukocyte function and in the log10 cfu of ST counts among treatment groups were determined by analysis of variance. Significant differences were further separated using Duncan's multiple range tests. Here, heterophil function was measured using in vitro assays for (1) oxidative burst and (2) degranulation. Heterophils from the CpG-ODN and E-beam ST-treated birds exhibited a significant increase (P < 0.05) in both the oxidative response and degranulation when compared to all other treatment groups with no differences in heterophil functions between the CpG-ODN and e-beam-treated groups. ST colonization of the ceca was significantly reduced (P < 0.05) in both the CpG-ODN and the E-beam ST-treated birds when compared to the non-vaccinated control birds. These results demonstrate that in ovo administration of E-beam irradiated Salmonella induced a primed heterophil-mediated innate immune response and provide a protective intestinal colonization-inhibition effect against a homologous Salmonella challenge.
    Full-text available · Article · Jan 2012 · Procedia in Vaccinology
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    [Show abstract] [Hide abstract] ABSTRACT: Populations of Salmonella in animals may be substantially reduced by treatment with a vaccine composition which has been produced by exposing whole, intact cells of a Salmonella species to irradiation with an electron beam under conditions effective to kill the cells. The electron beam irradiated cells of Salmonella are effective for stimulating protective immune response in the animals against the Salmonella. Induction of these immune responses significantly reduces or eliminates the colonization of the animal by the Salmonella, and consequently reduces or eliminates the shedding of Salmonella in the feces of the animals.
    Full-text available · Patent · Jan 2012
  • [Show abstract] [Hide abstract] ABSTRACT: The nursery industry pasteurizes soil with steam and quicklime to reduce plant pathogens. The mechanism of action for quicklime is the resulting exothermic reaction that occurs when the chemical interacts with water and its ability to increase pH levels. These treatments may also reduce pathogens in a commercial poultry house. In this study, a steam sterilization cart simulated conditions used by the nursery industry to treat litter inoculated with Salmonella enterica serovar Typhimurium. A homogenized sample of litter was exposed to steam for 0, 5, 30, or 120 min. Quicklime was used at concentrations of 0 (control), 2.5, 5.0, or 10.0%. All steam treatments, with or without quicklime, significantly reduced Salmonella Typhimurium colonization by at least 3 orders of magnitude. Significant reductions were also observed in the treatments with quicklime alone. Both the steam and the quicklime treatments often reduced colonization to undetectable levels, even when samples were enriched. Therefore, we demonstrated 2 novel techniques for reducing Salmonella Typhimurium in poultry litter. Soil pasteurization potentially offers an environmentally sound means of reducing the pathogens present in used poultry litter.
    Article · Nov 2010 · The Journal of Applied Poultry Research
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    R Thanissery · J L McReynolds · D E Conner · [...] · Y O Fasina
    [Show abstract] [Hide abstract] ABSTRACT: 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.
    Full-text available · Article · Nov 2010 · Poultry Science
  • [Show abstract] [Hide abstract] ABSTRACT: Salmonella is one of the leading causes of human foodborne illness and is associated with swine production. Bacteriophages are naturally occurring viruses that prey on bacteria and have been suggested as a potential intervention strategy to reduce Salmonella levels in food animals on the farm and in the lairage period. If phages are to be used to improve food safety, then we must understand the incidence and natural ecology of both phages and their hosts in the intestinal environment. This study investigates the incidence of phages that are active against Salmonella spp. in the feces of commercial finishing swine. Fecal samples (n = 60) were collected from each of 10 commercial swine finishing operations. Samples were collected from 10 randomly selected pens throughout each operation; a total of 600 fecal samples were collected. Salmonella spp. were found in 7.3% (44/600) of the fecal samples. Bacteriophages were isolated from fecal samples through two parallel methods: (1) initial enrichment in Salmonella Typhimurium; (2) initial enrichment in Escherichia coli B (an indicator strain), followed by direct spot testing against Salmonella Typhimurium. Bacteriophages active against Salmonella Typhimurium were isolated from 1% (6/600) of the individual fecal samples when initially enriched in Salmonella Typhimurium, but E. coli B-killing phages were isolated from 48.3% (290/600) of the fecal samples and only two of these phages infected Salmonella Typhimurium on secondary plating. Collectively, our results indicate that bacteriophages are widespread in commercial swine, but those capable of killing Salmonella Typhimurium may be present at relatively low population levels. These results indicate that phages (predator) populations may vary along with Salmonella (prey) populations; and that phages could potentially be used as a food safety pathogen reduction strategy in swine.
    Article · Mar 2010 · Foodborne Pathogens and Disease
  • L.M. Norberg · J.L. McReynolds · W.-K. Kim · [...] · S.C. Ricke
    [Show abstract] [Hide abstract] ABSTRACT: Introduction Salmonellosis is a foodborne disease that affects over 1.4 million people each year in the United States alone, of which more than 500 cases are fatal (CDC 2004). Frenzen et al. (1999) has estimated the annual cost of foodborne Salmonella infection to be nearly $2.3 billion in the United States. The majority of this cost is due to loss of productivity in the workforce and medical bills (Frenzen et al. 1999). While human Salmonella cases are at their lowest levels since 1987, they are not on the decline (Cogan and Humphrey 2003). The CDC estimates that for every one case that is reported, 37 go unrecognized (CDC 2004), thus the total number of outbreaks is much greater and the cost estimates are quite conservative. While there are estimated to be nearly 2,400 different serovars of Salmonella believed to cause foodborne illness, two are considered to be the most dominant. The two serotypes that cause the majority of the cases are Salmonella subspecies enterica serovar Enteritidis (SE) and serovar Salmonella Typhimurium (ST). SE cases are generally believed to be derived from shell eggs from chickens. These eggs come from hens that appear asymptomatic but carry SE in their gastrointestinal and reproductive tracts, which can potentially be transmitted to the interior of the egg prior to shell formation; in addition, these contaminated eggs are indistinguishable from noncontaminated, normal eggs (Cogan and Humphrey 2003; Wegener et al. 2003). This fact along with undercooking contaminated eggs leads to SE infection. Patrick et al. (2004) estimates that of all the outbreaks of SE from 1985 through 1999, 80% were egg associated. Among this 80%, 28% of the outbreaks were from foods that contained raw eggs such as ice cream, egg nog, and Caesar salad dressing. Of the outbreaks, 27% were attributed to traditional egg dishes such as omelets, French toast, and other foods that use egg batter (Patrick et al. 2004). While the incidence of SE in egg contents is estimated to be 0.005%, it is still a prominent food-safety issue, as approximately 3.2 million eggs are contaminated annually in the United States alone (CDC 2004). Physiological stresses, such as molting, increase the susceptibility of SE infection in the hen (Poppe 1999). Modi - fied molting diets and prebiotics incorporation appear to be alternative approaches to control preharvest SE contamination of layer flocks. Understanding the physiology of the hen and the route of transmission of Salmonella will facilitate the formulation of effective alternative molt diets that benefit the hen while inhibiting Salmonella colonization. © 2010 by The University of Arkansas Press. All rights reserved.
    Article · Jan 2010
  • [Show abstract] [Hide abstract] ABSTRACT: Foodborne disease infections are estimated to afflict more than 76 million people in the United States each year (Mead et al. 1999). Campylobacter and Salmonella are responsible for most cases of the bacterial foodborne disease, causing more than 1.9 and 1.3 million infections, respectively (Mead et al. 1999). Escherichia coli O157 and non-O157 shiga toxin-producing E. coli are estimated to cause more than 62,000 and 31,000 cases of foodborne disease annually (Mead et al. 1999). Costs associated with foodborne illness caused by the bacteria are considerable, exceeding $2.4 billion for Salmonella and $445 million for E. coli O157 (Crutchfield and Roberts 2000; ERS 2007). Cost for foodborne Campylobacter infections are estimated at $1.2 billion annually (Crutchfield and Roberts 2000). Although Listeria monocytogenes is estimated to cause fewer than 2,500 cases of disease, its associated annual cost exceeds $6.9 billion, due largely to the long-term impact of congential and newborn infections (Crutchfield and Roberts 2000). Considerable effort has been and continues to be expended by government agencies and all involved in the production of food to ensure that the food pro - duced is safe and wholesome. Contemporary concepts now recognize that applying preharvest interventions with existing or newly develped postharvest technologies (chemical dehairing, steam pasteurization, steam vacuuming, and hot water and organic acid rinses and irradiation) in a "multi-hurdle" approach could result in the most effective way to minimize contamination of meat products by foodborne pathogens (Acuff et al. 1987; Castell-Perez and Moreira 2004; Cherrington et al. 1991; Dorsa 1997; Farkas 1998; Hardin et al. 1995; Keeton and Eddy 2004; Koohmaraie et al. 2005; Micheals et al. 2004; Ricke 2003). In 2003, for example, the United States Department of Agriculture's Food Safety Inspection Service listed among their research priorities "Development of improved on-farm, feedlot, and antemortem interventions for reducing the incidence and levels of pathogens in raw products" (FSIS 2003). Risk assessments provide support for the concept that preharvest interventions would reduce human exposure to pathogens (Hynes and Wachsmuth 2000; Vugia et al. 2003). Presently, we review some of the research conducted within our laboratory aimed at developing safe and efficacious feed or water supplements to reduce the incidence and survivability of foodborne pathogens in the gut of food animals. © 2010 by The University of Arkansas Press. All rights reserved.
    Article · Jan 2010
  • Article · Jan 2010 · Journal of Dairy Science
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    K Stringfellow · J McReynolds · J Lee · [...] · M Farnell
    [Show abstract] [Hide abstract] ABSTRACT: Clostridium perfringens-associated necrotic enteritis causes significant economic losses. The objective of this study was to evaluate the effect of bismuth citrate, lactose, and organic acid on the development of necrotic enteritis in broilers. The first study was a dose response that evaluated bismuth citrate at 50, 100, or 200 ppm on bacterial intestinal colonization and lesion development associated with our C. perfringens challenge model. The second study evaluated bismuth citrate, lactose, and citric acid on intestinal pH and lesion development. For the third study, we determined if lactose would enhance the efficacy of bismuth citrate against intestinal colonization and lesion development associated with C. perfringens. In study 1, intestinal lesion scores at the 50, 100, and 200 ppm bismuth citrate treatment level were reduced (P < or = 0.05) when compared with the birds fed 0 ppm bismuth citrate. Intestinal C. perfringens colonization of the 100 and 200 ppm bismuth citrate treatment group was significantly reduced when compared with birds fed 0 ppm bismuth citrate. In study 2, we found no significant differences in lesion development, after C. perfringens challenge, between birds fed 100 ppm bismuth citrate or fed a combination of 100 ppm bismuth citrate with dietary lactose or citric acid relative to the controls. The intestinal pH of birds fed 100 ppm bismuth citrate or fed a combination of 100 ppm bismuth citrate with dietary lactose or citric acid was not significantly reduced when compared with the controls. However, a significant reduction in pH was observed in birds fed a combination of 100 ppm bismuth citrate and lactose relative to the negative controls. In study 3, a decrease (P < or = 0.05) in intestinal lesion scores occurred in birds fed lactose with 100 ppm bismuth citrate, compared with the positive controls. There were no significant differences in intestinal bacterial colonization. These preliminary data suggest that bismuth citrate may reduce intestinal lesion development and C. perfringens colonization in broilers infected with necrotic enteritis.
    Full-text available · Article · Nov 2009 · Poultry Science
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    J McReynolds · C Waneck · J Byrd · [...] · D Nisbet
    [Show abstract] [Hide abstract] ABSTRACT: Our laboratory is evaluating the efficacy of direct-fed microbials (DFM) and phytogenic products to control Clostridium perfringens, a gram-positive organism associated with decreased performance and morbidity and mortality associated with necrotic enteritis, as well as some recent human food safety issues. Three experiments were conducted to evaluate a DFM (PoultryStar) and a phytogenic product (PEP125), which were administered to birds from day of hatch until termination (d 25) via the drinking water or through supplementation to a wheat-corn diet, respectively. Each experiment contained a nonchallenged negative control and a positive control wherein birds were immunocompromised with a 10x dosage of infectious bursal disease vaccine at 14 d of age and subsequently gavaged with C. perfringens (10(7) cfu/mL) daily for 3 consecutive days starting on d 17. Intestinal lesions, mortality, and log10 values of C. perfringens in the probiotic and phytogenic treatment groups were found to be lower (P<0.05) than those observed in the positive controls. These experiments suggest that the DFM and the phytogenic product could be used as potential alternatives to help control C. perfringens and necrotic enteritis.
    Full-text available · Article · Oct 2009 · Poultry Science
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    J. L. McReynolds · K. J. Genovese · H. He · [...] · M. H. Kogut
    [Show abstract] [Hide abstract] ABSTRACT: Forced molting of laying hens increases enteric foodborne pathogens in the reproductive tract, leading to contaminated eggs and progeny of infected hens. Currently, we lack a complete understanding of how conditions such as molting affect the immune system. Previous reports have shown that alfalfa is effective in inducing a molt as well as in producing protection against Salmonella Enteritidis organ invasion. Our laboratory has also shown that immune functions are significantly reduced during molting. The present investigation evaluates a specific parameter of immune function, heterophil function, during an induced molt in hens fed alfalfa. Three replicate experiments used hens older than 65 wk of age that were divided into 6 groups of 12 hens each and placed in individual laying cages. Two weeks before dietary changes, hens were placed on an 8L:16D photoperiod that continued for the 12-d experiment. Peripheral blood samples were taken from hens on d 0, 2, 6, and 12 of molt. Hens were randomly placed into 3 treatment groups: nonfed hens, fully fed hens, and alfalfa-fed hens. To evaluate heterophil functions, the production of an oxidative burst as well as cellular degranulation assays were performed. In addition, total and differential peripheral blood leukocyte counts were performed. When compared with the nonfed control, alfalfa-fed birds showed significantly (P < 0.05) higher oxidative burst and degranulation activities. The data confirm previous observations that heterophil functions are significantly decreased in nonfed birds and the data show that birds fed alfalfa had numerically increased heterophil functions over a 12-d molting period when compared with heterophils of nonfed controls. Commercial integrators should consider using alfalfa when developing new molting programs.
    Full-text available · Article · Sep 2009 · The Journal of Applied Poultry Research
  • R. Harvey · K. Nornman · M. Hume · [...] · M. Scott
    Article · Jul 2009 · International Journal of Antimicrobial Agents
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    [Show abstract] [Hide abstract] ABSTRACT: The correct usage of disinfectants is an important component of a successful biosecurity program. The objective of this study was to determine the effect of time, temperature, and organic matter (OM) on disinfectant efficacy. Staphylococcus aureus and Salmonella Typhimurium were used to represent gram-negative and gram-positive bacteria commonly found in commercial poultry housing. The first study evaluated the effect of temperature (4, 20, 32, or 43 degrees C) and time (1, 2, 3, 4, 6, 8, 12, 16, 20, 24, and 30 wk) on the efficacy of disinfectants diluted to working concentrations. The second study determined the effect of OM on the efficacy of working concentrations of freshly prepared disinfectants against the bacteria. For the third study, we compared the bactericidal properties of freshly prepared disinfectants and 30-wk-old disinfectants in the presence of OM. Quaternary ammonium-, chlorhexidine-, phenolic-, and binary ammonium-based solutions represented disinfectants commonly used within the poultry industry. In the first study, all of the disinfectants were effective against S. aureus and Salmonella Typhimurium regardless of treatment. However, the phenolic compound had reduced (P <or= 0.05) efficacy against Salmonella Typhimurium after 6 wk of storage at the highest temperature of 43 degrees C and after 16 wk at the second highest temperature of 32 degrees C. All of the disinfectants were effective against S. aureus regardless of temperature treatment. In the second study, the addition of sterile chicken litter had deleterious effects on all 4 classes of disinfectants against Salmonella Typhimurium. Of the disinfectants tested, the phenolic compound retained efficacy against S. aureus. In the third study, the presence of OM significantly reduced (P <or= 0.05) the efficacy of the 30-wk-old quaternary ammonium and phenolic compound against Salmonella. The fresh quaternary ammonium and binary compound achieved a greater kill (P <or= 0.05) of Staphylococcus, relative to the 30-wk-old disinfectant. These results emphasize the need to use fresh disinfectants and that OM should be removed before disinfection.
    Full-text available · Article · Jun 2009 · Poultry Science
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    [Show abstract] [Hide abstract] ABSTRACT: Laying hens are typically induced to molt to begin a new egg-laying cycle by withdrawing feed for up to 12 to 14 d. Fasted hens are more susceptible to colonization and tissue invasion by Salmonella enterica serovar Enteritidis. Much of this increased incidence in fasted hens is thought to be due to changes in the native intestinal microflora. An alternative to feed withdrawal involves feeding alfalfa meal crumble to hens, which is indigestible by poultry but provides fermentable substrate to the intestinal microbial population and reduces Salmonella colonization of hens compared with feed withdrawal. The present study was designed to quantify differences in the cecal microbial population of hens (n = 12) fed a typical layer ration, undergoing feed withdrawal, or being fed alfalfa crumble by using a novel tag bacterial diversity amplification method. Bacteroides, Prevotella, and Clostridium were the most common genera isolated from all treatment groups. Only the ceca of hens undergoing feed withdrawal (n = 4) contained Salmonella. The number of genera present was greatest in the alfalfa crumble-fed group and least in the feed withdrawal group (78 vs. 54 genera, respectively). Overall, the microbial diversity was least and Lactobacillius populations were not found in the hens undergoing feed withdrawal, which could explain much of these hens’ sensitivity to colonization by Salmonella.
    Full-text available · Article · Mar 2009 · Poultry Science
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    K M Lee · J L McReynolds · C C Fuller · [...] · M Runyon
    [Show abstract] [Hide abstract] ABSTRACT: A multi-state outbreak investigation of Salmonella Typhimurim cases associated with pet snakes and the frozen vacuum-packed rodents used to feed them identified a Texas frozen feeder rodent facility (Supplier A) as the source of the Salmonella-infected frozen rodents. Texas authorities collected samples directly from Supplier A. Seven Salmonella-positive samples out of 49 environmental swabs were found and one adult mouse out of 88 frozen feeder rodents was Salmonella-positive by culture. No Salmonella strains were isolated from rodent feeds. The pulsed-field gel electrophoresis (PFGE) subtype patterns of S. Typhimurium isolates from feeder rodent and environment samples were indistinguishable from the outbreak strain isolated from humans. A follow-up investigation was performed on all additional feeder rodent facilities identified in Texas. Salmonella was isolated at one of four facilities; seven of 100 rodent samples were positive for Salmonella at this facility. The serotype S. I 4,[5],12:i:- was isolated from seven feeder rodent samples, and PFGE patterns of the seven isolates were indistinguishable. As observed in the initial outbreak investigation, no Salmonella were cultured from rodent feeds at any of the facilities. The feeder rodent industry is an insufficiently recognized industry in the United States. Outbreak investigation and testing of additional feeder rodent facilities in Texas indicate that further evaluation of feeder rodent facilities as a source of Salmonella for pet snakes and humans is warranted.
    Full-text available · Article · Nov 2008 · Zoonoses and Public Health
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    [Show abstract] [Hide abstract] ABSTRACT: Induction of the innate immune response in newly hatched chickens is important for limiting infections with bacteria, such as Salmonella enterica serovar Enteriditis (SE). CpG oligodeoxynucleotides (CpG-ODN) can stimulate the innate immune response of young chickens. Therefore, we examined the effectiveness of CpG-ODN administered in ovo on intestinal colonization by SE and the ability to modulate the function of heterophils in young chickens. Heterophils were isolated from 2-day-old chickens and were stimulated with heat-killed SE (HK-SE) or PMA for oxidative burst and HK-SE or live SE for degranulation assays. CpG-ODN treatment had no effect on heterophil oxidative burst when stimulated with HK-SE or PMA. However, HK-SE and live SE increased degranulation (P<0.01) in heterophils from CpG-ODN-treated birds compared to PBS-treated controls. In a second experiment, chickens were orally infected with SE on day 10 post-hatch and cecal contents were collected 6 days later for assessment of SE intestinal colonization. CpG-ODN treatment reduced SE colonization by greater than 10-fold (P<0.001) compared to PBS-injected control birds. Overall, we show for the first time that CpG-ODN given in ovo stimulates innate immune responsiveness of chicken heterophils and increases resistance of young chickens to SE colonization.
    Full-text available · Article · Oct 2008 · Veterinary Immunology and Immunopathology
  • J A Byrd · M R Burnham · J L McReynolds · [...] · D J Nisbet
    [Show abstract] [Hide abstract] ABSTRACT: A study was conducted to evaluate the effect of experimental chlorate product (ECP) feed supplementation on Salmonella Typhimurium (ST) in the crop and ceca of market-age broilers. In trial 1, 160 market-age broilers were randomly assigned to 8 treatment groups and replicated twice, with 20 broilers per pen for 1 wk. Trial 2 used the same design, but used 80 market-age broilers with 10 broilers per pen. Treatments were as follows: 1) control feed + double-distilled drinking water (dd H2O); 2) control + 18.5% experimental zeolite carrier with dd H2O; 3 to 7) control feed supplemented with 0.5, 1.0, 5.0, 10.0, or 18.5% of a feed grade ECP + dd H2O; 8) control feed + 1× ECP (0.16% w/v; containing 15 mM chlorate ion equivalent) added to dd H2O. Seven-week-old broilers were provided experimental treatments for 7 d, killed, and then ceca and crops were removed and evaluated for ST. Broilers fed 5 to 18.5% ECP or water ECP had a significantly lower (P < 0.05) incidence of ST in the crop (36 to 38% and 14%, respectively) when compared with the control (60%). Broilers fed 10% ECP or water ECP had significantly lower ST crop concentrations (1.03 log10 and 0.38 log10 ST/g, respectively) when compared with broilers fed a control diet (1.54 log10 ST/g). Crop and ceca ST incidence (32 to 48%) and concentration (1.00 to 1.82 log10 ST/g) were significantly lower in broilers fed 5 to 18.5% ECP as compared with the control (78%; 2.84 log10 ST/g). Broilers fed 5% or greater ECP had significantly higher water consumption (380 to 580 mL water/d) and litter moisture (31 to 56%) when compared with the control (370 mL water/d; 23% moisture). Only broilers fed 18.5% ECP had significantly lower 7-wk BW (2.77 kg of BW) when compared with the controls (3.09 kg of BW). Average daily gains were significantly depressed in broilers fed 10 or 18.5% ECP compared with the controls. These results indicate broilers supplemented with feed ≤ 5% ECP or water ECP 7 d before slaughter reduced ST without affecting growth parameters.
    Article · Oct 2008 · Poultry Science