Poultry CRC has commenced three new projects in conjunction with partners The University of Sydney, The University of Melbourne and Queensland’s Department of Agriculture, Fisheries and Forestry (QLD DAFF). These projects, which aim to reduce AI risk for the free-range layer sector, investigate a cause of lameness in broilers, and try a new approach to controlling food-pathogens in broilers, are outlined as follows:
Sub-Project 1.5.7 – Avian Influenza Risk Mitigation for the Free-Range sector of the Australian Poultry Industry
This project, led by Jenny-Ann Toribio and Peter Groves at The University of Sydney, will undertake research and extension with the aim of safeguarding the Australian chicken industry from avian influenza virus (AIV H5 or H7) outbreaks. This will be a timely contribution to Poultry CRC activities, aiming to maintain poultry health and improve bird welfare by directly addressing a critical infectious disease threat for industry. The focus is on AI H5 and H7 virus subtypes, as all naturally occurring highly pathogenic strains of AI (causing acute disease in chickens) have been identified as one of these.
While current chicken industry practice in Australia is world-class, increasing demand for free-range produce requires a more detailed and scientific approach to assessing AI risk. This project will collect new data and build stochastic models of disease risk designed to estimate the probability of AI virus entry and establishment on farms, and the probability of AI virus spread from one infected farm to other farms. On farm visits will conduct camera surveillance of wild bird activity and gather data on farm structure and management practices relevant to AI risk. The level of AI risk will be compared between farm types in the layer sector (caged, cage-free, and free-range) and in the broiler sector (barn and free-range); between free-range farms in the layer sector and the broiler sector; and between geographic regions of New South Wales.
This is a two-phase research project. Phase 1 will focus on discovery of new knowledge while phase 2 will focus on extension of this knowledge including revision of biosecurity guidelines for free-range farms in both the layer and broiler sectors. Discussion of the findings and guidelines shall be disseminated to a range of industry players at a national forum and regional workshops.
In light of the outbreaks of highly pathogenic AI in NSW in 2012 and 2013, which appeared to originate in free range flocks, research that will provide industry with a reliable and quantifiable assessment of risk is strongly desired. There is great support for this project from many industry representatives.
An investigation into the epidemiology and pathogenesis of femoral head necrosis in broilers in Australia (1.5.8)
Lameness in the broiler industry accounts for a large proportion of bird mortality culls, and femoral head necrosis (FHN) has repeatedly been shown to be the most common cause of broiler lameness in other countries. While data on the incidence in Australia is scarce, it appears that condition occurs in broiler flocks here. Implementation of management strategies that reduce the incidence of the disease, even by a small margin, has the potential to greatly increase both farm profitability and bird welfare.
The main objectives for this project, led by Dr Andrew Stent from The University of Melbourne, are therefore to:
- determine the incidence and aetiological agents involved in FHN amongst birds in Australian broiler flocks;
- assess the influence of epidemiological factors on the incidence of the disease (including age, genotype, hatchery conditions, nutrition, grower management practices and concurrent disease processes); and
- formulate and trial strategies to reduce the incidence of FHN in commercial flocks.
The Australian Chicken Meat Federation estimated that 628.3 million broiler birds were raised to slaughter in 2013/14, and so as little as 0.1% reduction in the incidence of femoral head necrosis has the potential to spare hundreds of thousands of birds each year that would otherwise be culled. Furthermore, as this condition is a worldwide phenomenon, development of practical measures to reduce the impact of this disease would have ramifications for the broiler industry globally.
Depending on the risk factors identified during the study, it is possible that preventative measures may be able to be implemented immediately or the research may identify areas that need further investigation for their impact on the development of FHN.
A “proof of concept” study to control Campylobacter using bacteriophages (3.1.6)
The hypothesis underpinning this research, led by Dr Nalini Chinivasagam at QLD DAFF in collaboration with researchers at the University of Nottingham in the United Kingdom, is that an appropriate cocktail of phages delivered via the drinking water immediately before pick-up has the potential to lower the levels of Campylobacter in the caeca of treated chickens. Further, it is hypothesised that such a treatment can contribute to a reduction in Campylobacter levels in the carcass of the treated chickens and, therefore, a reduction in the number of cases of human food poisoning.
The aims of the work are to:
- perform laboratory studies to establish a collection of characterised bacteriophages of known capacity to kill Campylobacter;
- establish the suitability of water delivery of the selected phage or phages; and
- perform farm/processing plant trials that will evaluate the performance of the phage/phages administered in reducing the levels of Campylobacter in the chicken caecum and at two points in the processing plant to assess what is being delivered to the consumer.
If the phage bio-control process proves an effective on-farm control, then both the industry and Australian society in general will benefit. Concerns about food safety are one of the major negative images that the Australian public has about chicken meat. The phages have been sourced from the chicken thus this bio-control process aims to exploit the natural dynamics that already exist between Campylobacter and Campylobacter bacteriophage in poultry environments. This option can contribute towards reducing the levels of a major food-borne pathogen such as Campylobacter will be a considerable boost to the image of the chicken meat industry. Additionally, the ability to demonstrate an improved level of food safety is highly likely to boost acceptance of chicken meat, potentially increasing levels of consumption.
It has been estimated that Campylobacter causes 223,000 cases of gastroenteritis a year in Australia with over 50,000 of these being associated with chicken meat. European studies indicate that on-farm interventions can be very effective; a 2-log reduction in faecal Campylobacter counts will reduce human infections by 75%. A 1-log reduction in faecal count supported by a 1-log reduction in contamination of the exterior of chickens during processing would result in a 90% reduction of human infections. Hence, the development and validation on-farm of tools for reducing Campylobacter levels by 1 to 2 logs can realistically result in a lowering of human infections from 50,000 to 5,000 case per year if all production systems adopt the techniques.
