Defining susceptibility of broiler chicks to colibacillosis

Ask, B.; Waaij, E.H. van der; Eck, J. H. H. van; Arendonk, J.A.M. van; Stegeman, J.A.

doi:10.1080/03079450600597998

Cited by 27 publications

(19 citation statements)

References 17 publications

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“…An association has been found between the presence of four or more of the selected APEC VGs in all of the E. coli isolates that were cultured from organs (n = 74) of chicken with colibacillosis. Similarly, Ask et al (2006) reported a direct correlation between the colibacillosis lesions and the occurrence of similar VGs. Of the 74 E. coli isolates cultured from organs, 8% (n = 6; isolates from liver and spleen of chicken 12) were lactose negative and harboured all of the five selected VGs.…”

Section: Page | 106mentioning

confidence: 78%

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Studies on avian pathogenic Escherichia coli in commercial broiler chicken in South East Queensland

Awawdeh¹,

Turni²,

Henning³

et al.

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Avian pathogenic Escherichia coli (APEC) is the causative agent of avian colibacillosis, a localised or systemic infection resulting in clinical diseases such as colisepticemia, chronic respiratory disease and swollen-head syndrome. Globally, avian colibacillosis is the leading cause of morbidity and mortality in poultry, and it has been associated with massive economic losses and welfare problems.This organism is of public health significance as APEC is communicable to humans. The diagnosis of avian colibacillosis relies on clinical signs, typical pathological lesions and culture of E. coli from affected tissue(s). Antimicrobial therapy is often used both for treatment and control. Previous overseas studies have characterised APEC and identified virulence genes (VGs) that can be used as molecular markers for the identification of APEC. Little is known about APEC in broiler chickens in Australia.The aim of this thesis was to gain a better understanding of the epidemiology of APEC in Australian broiler flocks and how factors including presence of VGs and phylogenetic group can improve the identification of this pathotype in Australia. Firstly, three faecal DNA extraction methods were evaluated. Faeces were collected from healthy chickens and chickens with colibacillosis from commercial broiler farms in South East Queensland (SEQ). The extracted DNA was screened by a pentaplex-PCR for five APEC-associated VGs (iroN, iutA, iss, hlyF and ompT). DNA extracted from E. coli isolates cultured from the cloaca and organs of the birds were screened using the same PCR.Repeated bead beating plus column elution was the preferred DNA extraction method, as it yielded good PCR quality and adequate quantity DNA. However, identifying APEC by direct detection of the five VGs from the faecal material was not feasible as all of these genes were also detected in all of the birds. However, the VGs were more commonly detected in E. coli isolates cultured from birds with colibacillosis.A cross-sectional study was performed to estimate APEC farm-level prevalence in healthy broiler chickens in SEQ and to identify potential risk factors associated with the carriage of APEC. At the farm-level, all of the 40 farms sampled were positive for APEC, that is at least one bird per farm carried APEC, while the within-farm prevalence was 63% (95% Confidence Interval: 55.8, 70.2).Higher APEC within-farm bird-level prevalence was significantly associated with the usage of well water as a source of drinking water, failure to disinfect the water line after each flock, farm visitors not showering before entering the shed, distances greater than 20 metres between the car park and the poultry shed and the presence of wild birds within 50 metres of the shed. Chlorinating the drinking water combined with automatic water filtration reduced within-farm bird-level APEC prevalence. Page | 3Therefore, based on the results concluded from the multivariable model, improving biosecurity and water treatments might reduce APEC prevalence, decrease the risk of co...

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Section: Page | 106mentioning

confidence: 78%

“…experimental studies have enhanced the understanding of the APEC pathogenicity mechanisms (Antão et al, 2008;Ask et al, 2006;Musa et al, 2009). However, no single or specific set of VGs have been systematically linked with APEC pathogenicity.…”

Section: Few In Vivomentioning

confidence: 99%

Studies on avian pathogenic Escherichia coli in commercial broiler chicken in South East Queensland

Awawdeh¹,

Turni²,

Henning³

et al.

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“…The E. coli strain 506 (serotype O78K80) used is a flumequine-resistant and doxycycline intermediary sensitive strain isolated from an inflamed pericardium from a commercial broiler suffering from natural colibacillosis (Van Eck & Goren, 1991). Its colibacillosis inducing potency was confirmed experimentally earlier (Matthijs et al, 2003;Velkers et al, 2005;Ask et al, 2006;Dwars et al, 2009). The inocula were prepared from a deep-frozen stock culture (Á708C) of this strain.…”

Section: Fungal Immunomodulatory Proteinmentioning

confidence: 99%

“…Efficacy of treatments was evaluated based on the parameters mortality, mean body weight gain between 8 and 15 days of age, colibacillosis lesion scores and generalized colibacillosis (Velkers et al, 2005;Ask et al, 2006).…”

Section: Fungal Immunomodulatory Proteinmentioning

confidence: 99%

In vivoscreening of five phytochemicals/extracts and a fungal immunomodulatory protein against colibacillosis in broilers

Peek¹,

Halkes²,

Tomassen³

et al. 2013

Avian Pathology

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Five phytochemicals/extracts (an extract from Echinacea purpurea, a b-glucan-rich extract from Shiitake, betaine [Betain TM ], curcumin from Curcuma longa [turmeric] powder, carvacrol and also a recombinant fungal immunomodulatory protein [FIP] from Ganoderma lucidum) cloned and expressed in Escherichia coli were investigated for their anticolibacillosis potential in three chicken experiments, which were conducted in floor pens. Birds that were inoculated with E. coli intratracheally were treated with the phytochemicals/ extracts or the FIP and compared with doxycycline-medicated and non-medicated infected broilers. Nonmedicated and non-infected birds were used as negative controls. Mortality, colibacillosis lesions and body weight gains were used as parameters. Considering the sum of dead birds and chickens with generalized colibacillosis per group, there was no significant difference between the positive control groups and birds treated with phytochemicals/extracts or the FIP. In contrast, doxycycline-treated birds showed significantly lower mortality and generalized colibacillosis. Moreover, none of the phytochemicals/extracts and the FIP improved recovery from colibacillosis lesions, while all doxycycline-treated broilers recovered completely. The negative control birds and doxycycline-treated groups consistently showed the highest weight gains. Pulsed-field gel electrophoresis of reisolates showed that they were genetically indistinguishable from the inoculation strain. In conclusion, none of the tested phytochemicals/extracts and the FIP significantly reduced the E. coli-induced mortality and generalized colibacillosis, and nor did they improve recovery from colibacillosis lesions.

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“…The range of the immunocompetence parameters are the minimum and maximum estimates from 5 longitudinal studies (Kaleta, 1972;Boa-Amponsem et al, 1997;Toro et al, 1997;Sahin et al, 2001;Islam et al, 2002). 2 The benchmark value of the age at challenge is set to 7 d of age because this is a common choice for challenging young chicks (Ask et al, 2006). The challenge age is varied from 0 to 42 d of age.…”

Section: Simulationsmentioning

confidence: 99%

Modeling Variability in Immunocompetence and Immunoresponsiveness

2008

Self Cite

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The purposes of this paper were to 1) develop a stochastic model that would reflect observed variation between animals and across ages in immunocompetence and responsiveness; and 2) illustrate consequences of this variability for the statistical power of genotype comparisons and selection. A stochastic model of immunocompetence development and responsiveness kinetics was developed. This model enabled variability in immunological variables to be taken into account in the evaluation of challenge and measurement strategies for selection. The characteristics of the variation in model output reflect those observed in the literature, to the extent that variation in the literature shows a consistent pattern; knowledge of true variation and patterns of variation in immunological variables is limited. The model created correlations between immunocompetence and immunoresponsiveness components, as well as correlations within each component across time. These correlations were generally in agreement with literature estimates, where available. The model enabled predictions of the effectiveness of selection for improved health through immunocompetence or immunoresponsiveness. It was predicted that effective selection for increased general immunocompetence to improve health should be done only when baseline immunity has matured. Further, the model implied that selection is unlikely to be successful if it is based only on a single measurement. Problems with low statistical power to detect differences between genotypes can be reduced by increasing challenge age in the experimental design, and one should ensure that the effects of maternal immunity are minimal when the challenge is done. The ability to detect differences between different groups of animals differs substantially with measurement timing because of low repeatabilities of immunocompetence and responsiveness across time. In general, the probability of detecting differences becomes higher when the challenge age is increased. Consequently, both the age at selection and the age at which information is gathered for selection must be considered carefully when designing genetic evaluations.

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Defining susceptibility of broiler chicks to colibacillosis

Cited by 27 publications

References 17 publications

Studies on avian pathogenic Escherichia coli in commercial broiler chicken in South East Queensland

Studies on avian pathogenic Escherichia coli in commercial broiler chicken in South East Queensland

In vivoscreening of five phytochemicals/extracts and a fungal immunomodulatory protein against colibacillosis in broilers

Modeling Variability in Immunocompetence and Immunoresponsiveness

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