The health and management of poultry production

AbstractThe poultry industry in the USA is a fully integrated system of animal agriculture. Each company has control over the bird husbandry and health management aspects of production, including the use of antimicrobial agents. The three segments of the industry—broiler chickens, turkeys, and layer chickens—have few antibiotics available for the therapeutic treatment of bacterial diseases. Prior to approval of the fluoroquinolones, tetracyclines were the major antibiotics approved for the treatment of the most economically important disease in broiler chickens and turkeys, Escherichia coli airsacculitis. This resulted in levels of resistance to the tetracyclines in clinical E. coli isolates in excess of 90%.The integrated nature of the poultry industry lends itself well to preventive medicine utilizing the tools of biosecurity and vaccination. Therefore, very few flocks of birds require antibiotic therapy. When a flock must be treated, the poultry veterinarian will usually base the recommendation of the drug to use on culture and antibiogram results

Jaagsiekte Sheep Retrovirus Biology and Oncogenesis

Jaagsiekte sheep retrovirus (JSRV) is the causative agent of a lung cancer in sheep known as ovine pulmonary adenocarcinoma (OPA). The disease has been identified around the world in several breeds of sheep and goats, and JSRV infection typically has a serious impact on affected flocks. In addition, studies on OPA are an excellent model for human lung carcinogenesis. A unique feature of JSRV is that its envelope (Env) protein functions as an oncogene. The JSRV Env-induced transformation or oncogenesis has been studied in a variety of cell systems and in animal models. Moreover, JSRV studies have provided insights into retroviral genomic RNA export/expression mechanisms. JSRV encodes a trans-acting factor (Rej) within the env gene necessary for the synthesis of Gag protein from unspliced viral RNA. This review summarizes research pertaining to JSRV-induced pathogenesis, Env transformation, and other aspects of JSRV biology

Complex Spatial Dynamics of Oncolytic Viruses In Vitro: Mathematical and Experimental Approaches

Oncolytic viruses replicate selectively in tumor cells and can serve as targeted treatment agents. While promising results have been observed in clinical trials, consistent success of therapy remains elusive. The dynamics of virus spread through tumor cell populations has been studied both experimentally and computationally. However, a basic understanding of the principles underlying virus spread in spatially structured target cell populations has yet to be obtained. This paper studies such dynamics, using a newly constructed recombinant adenovirus type-5 (Ad5) that expresses enhanced jellyfish green fluorescent protein (EGFP), AdEGFPuci, and grows on human 293 embryonic kidney epithelial cells, allowing us to track cell numbers and spatial patterns over time. The cells are arranged in a two-dimensional setting and allow virus spread to occur only to target cells within the local neighborhood. Despite the simplicity of the setup, complex dynamics are observed. Experiments gave rise to three spatial patterns that we call “hollow ring structure”, “filled ring structure”, and “disperse pattern”. An agent-based, stochastic computational model is used to simulate and interpret the experiments. The model can reproduce the experimentally observed patterns, and identifies key parameters that determine which pattern of virus growth arises. The model is further used to study the long-term outcome of the dynamics for the different growth patterns, and to investigate conditions under which the virus population eliminates the target cells. We find that both the filled ring structure and disperse pattern of initial expansion are indicative of treatment failure, where target cells persist in the long run. The hollow ring structure is associated with either target cell extinction or low-level persistence, both of which can be viewed as treatment success. Interestingly, it is found that equilibrium properties of ordinary differential equations describing the dynamics in local neighborhoods in the agent-based model can predict the outcome of the spatial virus-cell dynamics, which has important practical implications. This analysis provides a first step towards understanding spatial oncolytic virus dynamics, upon which more detailed investigations and further complexity can be built

Rapid screening of Salmonella enterica serovars Enteritidis, Hadar, Heidelberg and Typhimurium using a serologically-correlative allelotyping PCR targeting the O and H antigen alleles

<p>Abstract</p> <p>Background</p> <p>Classical <it>Salmonella </it>serotyping is an expensive and time consuming process that requires implementing a battery of O and H antisera to detect 2,541 different <it>Salmonella enterica </it>serovars. For these reasons, we developed a rapid multiplex polymerase chain reaction (PCR)-based typing scheme to screen for the prevalent <it>S. enterica </it>serovars Enteritidis, Hadar, Heidelberg, and Typhimurium.</p> <p>Results</p> <p>By analyzing the nucleotide sequences of the genes for O-antigen biosynthesis including <it>wb</it>a operon and the central variable regions of the H1 and H2 flagellin genes in <it>Salmonella</it>, designated PCR primers for four multiplex PCR reactions were used to detect and differentiate <it>Salmonella </it>serogroups A/D1, B, C1, C2, or E1; H1 antigen types i, g, m, r or z₁₀; and H2 antigen complexes, I: 1,2; 1,5; 1,6; 1,7 or II: e,n,x; e,n,z₁₅. Through the detection of these antigen gene allele combinations, we were able to distinguish among <it>S. enterica </it>serovars Enteritidis, Hadar, Heidelberg, and Typhimurium. The assays were useful in identifying <it>Salmonella </it>with O and H antigen gene alleles representing 43 distinct serovars. While the H2 multiplex could discriminate between unrelated H2 antigens, the PCR could not discern differences within the antigen complexes, 1,2; 1,5; 1,6; 1,7 or e,n,x; e,n,z₁₅, requiring a final confirmatory PCR test in the final serovar reporting of <it>S. enterica</it>.</p> <p>Conclusion</p> <p>Multiplex PCR assays for detecting specific O and H antigen gene alleles can be a rapid and cost-effective alternative approach to classical serotyping for presumptive identification of <it>S. enterica </it>serovars Enteritidis, Hadar, Heidelberg, and Typhimurium.</p

Supplementation of Protected Sodium Butyrate Alone or in Combination With Essential Oils Modulated the Cecal Microbiota of Broiler Chickens Challenged With Coccidia and Clostridium perfringens

The objective of this study was to determine the effects of protected sodium butyrate (SB), and protected sodium butyrate plus essential oils (carvacrol and ginger; SBEO) on the cecal microbiota of broilers challenged with Eimeria maxima and Clostridium perfringens. Birds were assigned to 4 treatments (8 replicates pens of 58 birds/pen): unchallenged control; challenged control; challenged and supplemented with SB; challenged and supplemented with SBEO. On d 13, challenged birds were orally inoculated with ~5,000 Eimeria maxima oocysts. On d 18–19, the same birds were exposed to Clostridium perfringens via drinking water (~8 log CFU/ml). Cecal excreta was collected at d 12, 18, 21, and 28 for microbiota analysis through 16s rRNA sequencing using Illumina MiSeq platform and analyzed using QIIME v. 1.9.1 The cecal microbiota was analyzed over time within each experimental group. The inclusion of SB alone or in combination with EO contributed to larger variations in the cecal microbiota over time than the unsupplemented treatments, as shown by the diversity indices. The community structure and abundance of the cecal microbiota were significantly different across ages, especially in the groups supplemented with SB and SBEO. As shown in the PCoA analysis, the supplementation of SB led to a more stable microbial community and lower between-sample variability over time. In the unchallenged control birds, Ruminococcus decreased (p = 0.006), whereas Bacteroides and Clostridiales increased (p ≤ 0.02) as the birds aged. In the challenged control group, however, the frequency of Coprococcus and Blautia decreased as birds aged (p ≤ 0.01), and, Clostridiales did not increase. Supplementation of SB, but not SBEO, increased the frequency of Lactobacillus (p = 0.01) on d 12 compared to d 18 and d 28, and prevented the reduction in the frequency of Blautia as the birds aged. Nevertheless, supplementation of SB and SBEO contributed to unique changes in the predicted functions of the cecal microbiota over time, which was not observed in the unsupplemented birds. SB and SBEO modulated the diversity, composition, and predictive function of the cecal microbiota which may have lowered the negative impact of necrotic enteritis (NE)

Antimicrobial Resistant Salmonella enterica Typhimurium Colonizing Chickens: The Impact of Plasmids, Genotype, Bacterial Communities, and Antibiotic Administration on Resistance

The rise in Salmonella resistance to cephalosporins and fluoroquinolones has become a significant threat to public health. At issue, is whether agricultural use of antimicrobials is selecting antibiotic resistance in Salmonella and the degree to which large antimicrobial resistance gene reservoirs, present in animal manures, contribute to this resistance. Two in vivo studies were performed to address these questions. In the first study, chickens were administered Salmonella and commensals, including an Escherichia coli strain with a mobile, ceftiofur-resistance plasmid, in order to determine how antibiotic administration impacted resistance in E. coli and Salmonella. All antibiotics administered to chickens increased streptomycin resistance in E. coli. However, only ceftiofur administration increased resistance in Salmonella and specifically to extended-spectrum β-lactams and cephalosporins (ESBL). There was no significant increase in ESBL-resistant Salmonella in chickens administered a ceftiofur-resistance plasmid donor. In the second study, chickens were administered two different isolates of S. enterica Typhimurium and a chicken resistome to serve as a gene donor. Birds were subsequently administered chlortetracycline or streptomycin. Antimicrobial administration significantly altered aminoglycoside and tetracycline resistance in the Enterobacteriaceae population. However, there was no significant increase in antimicrobial resistant Salmonella. Administration of a chicken resistome had no significant impact on prevalence of resistance in Enterobacteriaceae populations, including Salmonella. Evident, from both studies, was that these treatments had minimal effect on increasing the prevalence of resistance in Salmonella, suggesting that other factors may be more important in dissemination of antimicrobial resistant Salmonella in chickens

How Visitors and Locals at a Sport Event Differ in Motives and Identity

Although the literature on events differentiates between locals, casual attendees, and those who have travelled specifically to attend the event, little is known about how the types of attendee differ. This study compared the fan motivation, leisure motivation, and identification with the subculture of athletics reported by a sample (N = 777) of attendees at the 2005 Pan American Junior Athletics Championships. Age, gender, and income were also included. Regression analyses were used to determine the structure of relations among the variables, and to ascertain whether the levels of motivation or identity varied among the three types of attendee. Tests for linear restrictions were used to determine whether the structure of relations among the variables differed by type of attendee. The structure of relations among the variables did not differ among the three types of attendee, but attendees who had travelled specifically to attend the event reported substantially higher identification with the subculture of athletics, and slightly higher fan motivation. Identification with the subculture of athletics mediated much of the effect. Females reported higher fan motivation and higher leisure motivation than did males. Age had a small but significant relationship with fan motivation, and income had a small but significant relationship with leisure motivation. Findings are generally consistent with predictions derived from theories of motivation, subculture, and gender roles. It is suggested that marketing communications directed out-of-town should highlight opportunities to strengthen, parade, and celebrate, while those in the local trading radius should underscore the entertainment, aesthetics, and vicarious achievement featured at the event