Influence of production system on the rate of onset of Campylobacter colonisation in chicken flocks reared extensively in the United Kingdom.Report as inadecuate




Influence of production system on the rate of onset of Campylobacter colonisation in chicken flocks reared extensively in the United Kingdom. - Download this document for free, or read online. Document in PDF available to download.

* Corresponding author 1 Clinical Veterinary Science 2 Department of Food and Environmental Safety 3 Clinical Veterinary Science 4 Centre for Epidemiology and Risk Analysis

Abstract : Because thermophilic Campylobacter spp. are known to be common in chicken flocks reared extensively, cross-sectional and longitudinal studies were carried out on organic and free-range farms to determine the onset of colonisation lag phase and likely sources of flock infection. For 14 organic and 14 free range flocks, there was a statistically significant P < 0.01 difference in lag phases, with the former being colonised at a mean of 14.1 days in comparison with 31.6 days for the latter. Whereas most free-range flocks became colonised when released onto pasture, those reared organically were usually colonised at the housed brooding stage. Further study of organic flocks on three farms over seven successive crop cycles confirmed that colonisation was strongly influenced by the prevailing husbandry conditions and was not a consequence of the length of the rearing period. Molecular epidemiological investigations on a farm showing the shortest lag phase, using PFGE typing with two different restriction enzymes SmaI and KpnI and flaA SVR sequence typing, revealed that potential sources of colonisation for organic chickens were already present on the farm at the time of chick placement. Such sources included the ante area of the brooding house, surrounding pasture and other livestock being kept on the farm. Overall, the study demonstrated that, under UK conditions, the prevalence of colonisation was greater in extensive flocks 95 - 100% than it was for conventional broilers 55%, similar to the situation in other countries, but all three management systems showed comparable levels of caecal carriage in positive birds log10-g 6.2 - 6.7.

Mots-clés : Life Sciences





Author: Vivien Allen - Anne Mcalpine Ridley - Jillian Anne Harris - Diane Georgina Newell - Laura F Powell -

Source: https://hal.archives-ouvertes.fr/



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