Broiler farming practices using new or re-used bedding, inclusive of free-range, have no impact on Campylobacter levels, species diversity, Campylobacter community profiles and Campylobacter bacteriophages

A multi-stage option to address food-safety can be produced by a clearer understanding of Campylobacter's persistence through the broiler production chain, its environmental niche and its interaction with bacteriophages. This study addressed Campylobacter levels, species, genotype, bacteriophage composition/ levels in caeca, litter, soil and carcasses across commercial broiler farming practices to inform on-farm management, including interventions. Broilers were sequentially collected as per company slaughter schedules over two-years from 17 farms, which represented four commercially adopted farming practices, prior to the final bird removal (days 39-53). The practices were conventional full clean-out, conventional litter re-use, free-range-full cleanout and free-range-litter re-use. Caeca, litter and soil collected on-farm, and representative carcases collected at the processing plant, were tested for Campylobacter levels, species dominance and Campylobacter bacteriophages. General community profiling via denaturing gradient gel electrophoresis of the flaA gene was used to establish the population relationships between various farming practices on representative Campylobacter isolates. The farming practice choices did not influence the high caeca Campylobacter levels (log 7.5 to log 8.5 CFU/g), the carcass levels (log 2.5 to log 3.2 CFU/carcass), the C. jejuni/C. coli dominance and the on-farm bacteriophage presence/levels. A principal coordinate analysis of the flaA distribution for farm and litter practices showed strong separation but no obvious farming practice related grouping of Campylobacter. Bacteriophages originated from select farms, were not practice-dependent, and were detected in the environment (litter) only if present in the birds (caeca). This multifaceted study showed no influence of farming practices on on-farm Campylobacter dynamics. The significance of this study means that a unified on-farm risk-management could be adopted irrespective of commercial practice choices to collectively address caeca Campylobacter levels, as well as the potential to include Campylobacter bacteriophage biocontrol. The impact of this study means that there are no constraints in re-using bedding or adopting free-range farming, thus contributing to environmentally sustainable (re-use) and emerging (free-range) broiler farming choices.

Management and environmental factors influence the prevalence and abundance of food-borne pathogens and commensal bacteria in peanut hull-based broiler litter

In this study, we conducted a longitudinal sampling of peanut hull-based litter from a farm under a "no antibiotics ever" program. Our objective was to determine broiler management practices and environmental factors that are associated with the occurrence of food-borne pathogens (Salmonella and Campylobacter) and the abundance of commensal bacteria (Escherichia coli, Enterococcus spp., and Staphylococcus spp.). Litter (n = 288) was collected from 4 broiler houses over three consecutive flocks, starting with a complete house cleanout and fresh peanut hull. Litter was sampled at the beginning of each grow-out cycle and at the end of the cycle. Logistic and linear regression models were used to model the relationships between pathogen prevalence, commensal abundance and management practices, and environmental factors. The number of flocks raised on litter, grow-out period, broiler house, litter pH, litter moisture, and house temperature were associated with the prevalence of pathogens and the abundance of commensal bacteria in litter. The final logistic model for pathogens showed that a higher probability of detecting Salmonella in litter was associated with the number of flocks raised on litter and the grow-out period. A higher probability of detecting Campylobacter in litter was associated with the number of flocks raised on litter, broiler house and the sections of the house, and the pH of litter. Our results suggest that management practices and environmental factors affect Salmonella and Campylobacter differently and suggest that each pathogen will require its own tailored intervention to stop their persistence in broiler litter.