Could chicken movement indicate Campylobacter infection risk?

By Joseph James Whitworth

- Last updated on GMT

Previous work found 71.2% of EU broiler chicken flocks remained Campylobacter-positive at slaughter during 2008
Previous work found 71.2% of EU broiler chicken flocks remained Campylobacter-positive at slaughter during 2008

Related tags Chicken

Monitoring chicken behavior can give an indication of which flocks are likely to become Campylobacter positive within seven to 10 days of life, according to a study.

Using cameras and analysing the ‘optical flow’ patterns made by flock movements can identify at risk flocks earlier than conventional on-farm microbiological methods, said Oxford University scientists.

Almost three-quarters of chickens tested positive for Campylobacter, according to results of a year-long study by the FSA last year​, and 19% tested positive within the highest band of contamination – more than 1,000 colony forming units per gram (>1,000 cfu/g).

Behaviour as a clue?

The Oxford team tested the hypothesis that flocks colonised with Campylobacter might be distinguishable by behaviour.

“This early warning has the potential to lead to a more targeted approach to Campylobacter control and also provides new insights into possible sources of infection that could transform the control of this globally important foodborne pathogen​,” said the researchers.

“Farm managers able to access such information in real time would have an early warning of which of their flocks were most at risk of health and welfare problems, enabling them to intervene before these became serious and helping them to produce higher-quality, healthier food with better welfare.”​ 

Campylobacter is the most common cause of food poisoning in the UK, making an estimated 280,000 people ill every year, said the FSA

‘Optical flow’ works by detecting the rate of change of brightness in different parts of visual images both temporally and spatially and does not require tagging or marking individual animals.

The team collected optical flow data for 31 commercial broiler flocks and faecal samples from the same flocks and tested them for Campylobacter at different ages (day 21, 28 and 35 of age) using standard laboratory methods to get a direct comparison.

Positive flock findings

They found Campylobacter-positive flocks showed lower mean optical flow than flocks not detected as shedding the pathogen, as early as the first 10 days of life.

“Flocks shedding Campylobacterhave a lower mean optical flow (less average movement) and higher kurtosis (less uniform movement) than flocks not detected as shedding Campylobacter​,” said the study.

“This link is independent of external temperature and cannot be explained by a direct effect of temperature on the behaviour of a flock.”

The data was collected between October 2010 and November 2014 from three UK sites belonging to two different producers. 

All samples were cultured using standard methods for both direct culture using mCCDA (PO0119 Oxoid) and enrichment culture using Exeter broth (Bolton Broth CM0983, defibrinated horse blood SR0050 and Campylobacter growth supplement SR0232, Oxoid; and Exeter Campylobacter enrichment-selective supplement SV59, Mast Group) and sub-culture onto mCCDA.

Researchers said it is not clear whether the lower mean and higher kurtosis of optical flow associated with Campylobacter infection is the result of a direct effect of the bug on chicken behaviour or whether the optical flow is detecting other signs of reduced welfare (such as poorer walking ability) that indicate a general reduction in the birds' overall health.

“We also do not know whether the optical flow differences that were apparent in very young birds (less than 10 days old) were due to their already being infected but not shedding sufficiently for infection to be detected or whether they were still uninfected but had slightly reduced overall condition that would make them vulnerable to later infection.”

Source: Proceedings of the Royal Society B

DOI: 10.1098/rspb.2015.2323

“Monitoring chicken flock behaviour provides early warning of infection by human pathogen Campylobacter”

Authors: Frances M. Colles, Russell J. Cain, Thomas Nickson, Adrian L. Smith, Stephen J. Roberts, Martin C. J. Maiden, Daniel Lunn, Marian Stamp Dawkins 

Related topics Food Safety & Quality

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