Title: Spatial and temporal analysis of microbial populations in production broiler house litter in the southeastern U.S. Authors
Submitted to: Journal of Applied Poultry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 11, 2013
Publication Date: N/A
Interpretive Summary: Broiler production is one of the leading agricultural enterprises in the United States. In Mississippi the economic impact from broiler production and processing exceeds that of any other agricultural commodity. Reducing mortality rates is critical in broiler production; therefore, it is vital to reduce bacterial pathogen loads in broilers and broiler houses. Litter is an essential component in production, the primary point of intimate contact between broilers and the house environment, and the common link between successive flocks. The focus of this study was on factors that affect changes in litter microbial populations, including pathogens, which have the potential to increase mortality and decrease production in concentrated broiler feeding operations. Intra-house spatial distributions of bacterial populations were measured across three flocks in one broiler house to determine which bacteria were more or less likely to occur in litter near water lines, feeders, sidewalls, and ends of the house. Litter temperature and moisture data were collected and analyzed to determine their influence on microbial populations. The common foodborne pathogens, Salmonella and Listeria, were isolated and enumerated sporadically, along with staphylococci, enterococci, and Clostridium perfringens (common nuisance pathogens) detected at relatively high frequency late in the flock age. Campylobacter was not detected. Of the spatial factors investigated, only the ends of the house were positively associated with bacterial presence. Broiler age influenced the presence of nuisance bacteria and indicated that particular attention to flock health and litter management must be given to reduce flock mortalities. House ends were noted for high moisture and indicated potential for foodborne pathogens, suggesting location specific treatment to dissipate moisture. Overall, bacterial levels were difficult to predict and require more investigation for adequate reductions.
Technical Abstract: Broiler production is one of the leading agricultural enterprises in the United States. In Mississippi the economic impact from broiler production and processing exceeds that of any other agricultural commodity. Reducing mortality rates is critical in broiler production; therefore, it is vital to reduce bacterial pathogen loads in broilers and broiler houses. The main objectives of this study were to discern intra-house spatial and temporal effects on foodborne and nuisance pathogen bacterial levels. A single broiler concentrated animal feeding operation house litter was monitored throughout 3 consecutive flocks; Salmonella, Staphylococci, Enterococci, Clostridium perfringens, Campylobacter, and Listeria levels were monitored thoughout that time at the wall, feeder, water cup, and house end spatial positions. Nuissance pathogens Clostridium perfringens, staphylococci, and enterococci were consistently present at levels of 4 log10, 9 log10 and 5 log10 colony forming units (cfu) gram-1, respectively; while Salmonella, Campylobacter, and Listeria were present at low levels. Among surveyed bacteria, Salmonella was more consistently detected at the ends of the house, while staphylococci levels were lower near feeder locations. Nearly all measured bacteria were significantly associated with broiler age as Salmonella was found early in the flock, while Clostridium perfringens, staphylococci, and enterococci levels were greater late in the flock. The effect of season was noted only for staphylococci and Listeria which were positively associated with flock 1 (summer). Overall, it appeared that pathogen levels were difficult to predict given house conditions, both spatially and temporally; however it was evident that high moisture supported Salmonella at the ends of the house, and broiler age influenced the presence of most nuisance pathogens as broiler age increased. This suggests review of house management practices with particular attention to high moisture locations and precautions taken as the broilers age.