Summary

This study will evaluate the Campylobacter jejuni and coli dynamics (and levels) within two farming systems, i.e. free-range and conventional grow-out, both with and without re-using litter. The current RIRDC study, looking at Campylobacter over six cycles in conventional partial and full re-use has shown a sequential increase in the percentages of C. coli, reaching an overall dominance of 60% (when compared with C. jejuni) across treatments. More so, a 100% dominance of C. coli (in caeca) was observed during the sixth cycle which was run as free-range due to commercial reasons. Whether this was specifically linked to free-range or the re-use practices adopted or both are un-clear. Overseas studies have also shown a similar dominance of C. coli with free-range production (El-Shibiny et al. 2005). These outcomes clearly showing that the farming system (and related litter and /or soil environments) seems to influence species dominance of Campylobacter. Majority of the human gastroenteritis (~ 95%) is attributed to C. jejuni (D’Lima et al. 2007) than C. coli, though somewhat a risk. The natural dominance of C. coli could have an indirect impact on the human disease burden. This study will explore the Campylobacter dynamics that naturally occur within free-range, re-use and conventional grow-out farming conditions. The outcomes of the study will provide a scientific basis for the industry to control C. jejuni by exploiting the natural microbial interactions that potentially occur within these various farming systems.

Program

Chicken Meat

Research Organisation

The State of Queensland acting through the Department of Agriculture and Fisheries

Objective Summary

This study will build on the outcomes of the work in progress (RIRDC project on re-use litter).
The key R & D objectives of the study are:
1.To compare the levels of Campylobacter in the litter, caeca and carcasses of chicken from conventional and free-range farming both with and with-out re-use. (The re-use being the Australian practice of re-using through either one or two cycles following a push-up process)
2.To enumerate (and isolate) Campylobacter-phages that may prevail within the various farming systems with special emphasis on both free-range and re-use environments, i.e. litter, soil and caeca
3.To study 1 and 2 from farms belonging to two major companies
4.To evaluate (within different ecological settings) the C. jejuni and C. coli dynamics attributed to the different farming systems
5.To provide the industry with the knowledge (and options) to manage C. jejuni by exploiting the merits attributed to already adopted farming practices