The efficacy of antibiotics to prevent collibacilosis in broiler poultry: A protocol for a systematic review and network meta-analysis.

Antibiotics are used in broiler poultry production both for the prevention and treatment of infectious diseases. However, antibiotic use is a driver of antibiotic resistance. The World Health Organization has published numerous reports urging all stakeholders concerned with both food-producing animals and humans to establish recommended steps to enhance the prudent use of antimicrobials (WHO, 2015). Similarly, the World Animal Health Organization has also published recommendations and position statements regarding prudent use and risk management related to antimicrobial use in animals (OIE, 2017). Colibacillosis is an important bacterial pathogen of poultry, and a costly disease for the industry resulting in multimillion dollar losses annually through morbidity, mortality or carcass condemnation at slaughter. Colibacillosis refers to any localized or systemic infection caused entirely or partly by the organism avian pathogenic Escherichia coli (APEC). These bacteria may be isolated as the sole pathogen or contribute to a disease complex with mixed viral and bacterial infections (Guabirara and Schouler, 2015). Two main disease processes important in the broiler industry are early mortality and cellulitis. Early mortality is defined by chicks under a week of age experiencing a higher than normal percentage of deaths in a flock. Early mortality can be caused by many things, for example chilling, overheating, or dehydration, however E.coli infection, or colibacillosis, is one of the main culprits. Colibacillosis can present with omphalitis, yolk sacculitis, enteritis, pasty vents, pericarditis, perihepatitis, polyserositis, congested lungs, splenomegaly and darkened proventriculus or any these combinations (Guabiraba and Schouler, 2015; Geetha and Palanivel, 2018). Many chicks succumb to an early and severe infection or are culled due to excessive morbidity. Antibiotics are typically used to reduce early mortality (Chauvin et al., 2005; Dziva and Stevens, 2008). Those with severe infection are unlikely to survive, however appropriate treatment reduces transmission between birds and improves the suitability of those with a mild infection. Not every labelled drug for E.coli is efficacious, resistance is common (Kabir, 2010) and effectiveness can vary from flock to flock, even within a flock, with more than one strain and more than one treatment. Understanding the efficacy of antibiotics used to prevent colibacillosis in broiler chickens is essential to optimizing their use; ineffective antibiotics should not be used for prevention or, if there are multiple efficacious antibiotics, their importance to human medicine should be considered when making decisions on antibiotic use. Systematic reviews of randomized controlled trials, and network meta-analysis to provide input on relative antibiotic efficacy, will yield the highest level of evidence for efficacy of treatments under field conditions (Sargeant and O’Connor, 2014)

The efficacy of antibiotics to control colibacillosis in broiler poultry: a systematic review

The objective of this systematic review was to evaluate the efficacy of antibiotics to prevent or control colibacillosis in broilers. Studies found eligible were conducted controlled trials in broilers that evaluated an antibiotic intervention, with at least one of the following outcomes: mortality, feed conversion ratio (FCR), condemnations at slaughter, or total antibiotic use. Four electronic databases plus the gray literature were searched. Abstracts were screened for eligibility and data were extracted from eligible trials. Risk of bias was evaluated. Seven trials reported eligible outcomes in a format that allowed data extraction; all reported results for FCR and one also reported mortality. Due to the heterogeneity in the interventions and outcomes evaluated, it was not feasible to conduct meta-analysis. Qualitatively, for FCR, comparisons between an antibiotic and an alternative product did not show a significant benefit for either. Some of the comparisons between an antibiotic and a no-treatment placebo showed a numerical benefit to antibiotics, but with wide confidence intervals. The risk-of-bias assessment revealed concerns with reporting of key trial features. The results of this review do not provide compelling evidence for or against the efficacy of antibiotics for the control of colibacillosis

The efficacy of antibiotics to prevent collibacilosis in broiler poultry: A protocol for a systematic review and network meta-analysis.

Antibiotics are used in broiler poultry production both for the prevention and treatment of infectious diseases. However, antibiotic use is a driver of antibiotic resistance. The World Health Organization has published numerous reports urging all stakeholders concerned with both food-producing animals and humans to establish recommended steps to enhance the prudent use of antimicrobials (WHO, 2015). Similarly, the World Animal Health Organization has also published recommendations and position statements regarding prudent use and risk management related to antimicrobial use in animals (OIE, 2017). Colibacillosis is an important bacterial pathogen of poultry, and a costly disease for the industry resulting in multimillion dollar losses annually through morbidity, mortality or carcass condemnation at slaughter. Colibacillosis refers to any localized or systemic infection caused entirely or partly by the organism avian pathogenic Escherichia coli (APEC). These bacteria may be isolated as the sole pathogen or contribute to a disease complex with mixed viral and bacterial infections (Guabirara and Schouler, 2015). Two main disease processes important in the broiler industry are early mortality and cellulitis. Early mortality is defined by chicks under a week of age experiencing a higher than normal percentage of deaths in a flock. Early mortality can be caused by many things, for example chilling, overheating, or dehydration, however E.coli infection, or colibacillosis, is one of the main culprits. Colibacillosis can present with omphalitis, yolk sacculitis, enteritis, pasty vents, pericarditis, perihepatitis, polyserositis, congested lungs, splenomegaly and darkened proventriculus or any these combinations (Guabiraba and Schouler, 2015; Geetha and Palanivel, 2018). Many chicks succumb to an early and severe infection or are culled due to excessive morbidity. Antibiotics are typically used to reduce early mortality (Chauvin et al., 2005; Dziva and Stevens, 2008). Those with severe infection are unlikely to survive, however appropriate treatment reduces transmission between birds and improves the suitability of those with a mild infection. Not every labelled drug for E.coli is efficacious, resistance is common (Kabir, 2010) and effectiveness can vary from flock to flock, even within a flock, with more than one strain and more than one treatment. Understanding the efficacy of antibiotics used to prevent colibacillosis in broiler chickens is essential to optimizing their use; ineffective antibiotics should not be used for prevention or, if there are multiple efficacious antibiotics, their importance to human medicine should be considered when making decisions on antibiotic use. Systematic reviews of randomized controlled trials, and network meta-analysis to provide input on relative antibiotic efficacy, will yield the highest level of evidence for efficacy of treatments under field conditions (Sargeant and O’Connor, 2014).</p

The efficacy of litter management to prevent disease and/or antibiotic use in broiler poultry: A protocol for a systematic review

To control and prevent major causes of disease in broiler production, it is important that contributing risk factors are identified and managed (USAHA, 2017). A crucial part of broiler production is litter management (Chen and Jiang, 2014), which, if managed improperly, leads to higher incidence of disease (Dunlop et al., 2016). Poor litter management is typically observed as excessively wet or dry litter. The development of wet litter is multifactorial, but the main triggers are improper ventilation, bird illness, equipment malfunction, diet composition, and extreme environmental temperatures and humidity. Wet litter (above 25-35% moisture) provides a better medium for pathogenic organisms to thrive (Lister, 2009), is associated with necrotic enteritis outbreaks (Hermans and Morgan, 2007). Wet litter also is associated with 2 higher ammonia levels, which can damage birds’ respiratory lining, and can cause foot pad dermatitis (Shepherd and Fairchild, 2010). Dry litter can lead to dusty conditions which can be an issue with the bird’s, and people’s, respiratory health (Homidan et al., 2003). Typically, many of these causes of morbidity are treated or prevented with antibiotics. As a result, litter management is linked to the use of antimicrobials, which in turn is a driver of antimicrobial resistance. The World Health Organization is urging all stakeholders concerned with both food-producing animals and humans to establish recommended steps to enhance the prudent use of antimicrobials (WHO, 2015). Similarly, the World Animal Health Organization has also published recommendations and position statements regarding prudent use and risk management related to antimicrobial use in animals (OIE, 2017).</p

The efficacy of antibiotics to control colibacillosis in broiler poultry: a systematic review

The objective of this systematic review was to evaluate the efficacy of antibiotics to prevent or control colibacillosis in broilers. Studies found eligible were conducted controlled trials in broilers that evaluated an antibiotic intervention, with at least one of the following outcomes: mortality, feed conversion ratio (FCR), condemnations at slaughter, or total antibiotic use. Four electronic databases plus the gray literature were searched. Abstracts were screened for eligibility and data were extracted from eligible trials. Risk of bias was evaluated. Seven trials reported eligible outcomes in a format that allowed data extraction; all reported results for FCR and one also reported mortality. Due to the heterogeneity in the interventions and outcomes evaluated, it was not feasible to conduct meta-analysis. Qualitatively, for FCR, comparisons between an antibiotic and an alternative product did not show a significant benefit for either. Some of the comparisons between an antibiotic and a no-treatment placebo showed a numerical benefit to antibiotics, but with wide confidence intervals. The risk-of-bias assessment revealed concerns with reporting of key trial features. The results of this review do not provide compelling evidence for or against the efficacy of antibiotics for the control of colibacillosis.This article is published as Sargeant, Jan M., Michele D. Bergevin, Katheryn Churchill, Kaitlyn Dawkins, Bhumika Deb, Jennifer Dunn, Catherine M. Logue, Anastasia Novy, Annette M. O'Connor, Mark Reist, and Charlotte B. Winder. "The efficacy of antibiotics to control colibacillosis in broiler poultry: a systematic review." Animal Health Research Reviews 20, no. 2 (2019): 263-273. DOI: 10.1017/S1466252319000264. Posted with permission.</p

The efficacy of litter management strategies to prevent morbidity and mortality in broiler chickens: a systematic review and network meta-analysis

A systematic review and network meta-analysis (NMA) were conducted to address the question, ‘What is the efficacy of litter management strategies to reduce morbidity, mortality, condemnation at slaughter, or total antibiotic use in broilers?’ Eligible studies were clinical trials published in English evaluating the efficacy of litter management in broilers on morbidity, condemnations at slaughter, mortality, or total antibiotic use. Multiple databases and two conference proceedings were searched for relevant literature. After relevance screening and data extraction, there were 50 trials evaluating litter type, 22 trials evaluating litter additives, 10 trials comparing fresh to re-used litter, and six trials evaluating floor type. NMAs were conducted for mortality (61 trials) and for the presence or absence of footpad lesions (15 trials). There were no differences in mortality among the litter types, floor types, or additives. For footpad lesions, peat moss appeared beneficial compared to straw, based on a small number of comparisons. In a pairwise meta-analysis, there was no association between fresh versus used litter on the risk of mortality, although there was considerable heterogeneity among studies (I2 = 66%). There was poor reporting of key design features in many studies, and analyses rarely accounted for non-independence of observations within flocks.This article is published as Sargeant, Jan M., Dapeng Hu, Annette M. O’Connor, Chong Wang et al. "The efficacy of litter management strategies to prevent morbidity and mortality in broiler chickens: a systematic review and network meta-analysis." Animal Health Research Reviews 20, no. 2 (2019): 247-262. DOI:10.1017/S1466252319000227. Posted with permission.</p