Main Salmonella serotypes in free-range Amazon broiler chicken farms: Comparison between collection methods and seasonal period in tropical regions.

Abstract

Broiler chicken raised in semi-closed or completely free-range systems are challenged by more environmental variables that can compromise the biosecurity and microbiological quality and safety of the final product from this type of production. This study investigated Salmonella serotypes in Brazilian Amazon free-range broiler chicken farms in a tropical climate region, comparing the efficacy of the official collection methods of poultry sheds (drag swabs, footpads, and cecal feces) and the rainy and dry seasons typical of the region. Specific qualitative microbiological cultures, confirmation of identity by genus-specific PCR (invA), and determination of Salmonella serotypes by real-time PCR were performed on all free-range poultry farms in Tocantins, North Brazil. In total, 935 suggestive isolates were recovered using the three collection methods in both seasons, of which 90 (9.5 %) were positive for invA. There were no significant differences (p > 0.05) between the collection methods or between the rainy and dry seasons. Salmonella Mbandaka, S. Panama, and S. Javiana were identified on different free-range poultry farms. Although the main serotypes of importance in poultry and public health were not identified, according to Brazilian regulations, the results did not compromise the processing of batches for fresh trade, reinforcing the need to support surveillance programs, animal health defense, and epidemiological measures of a one-health approach to control the pathogen in the chain of free-range broiler chickens raised in tropical climate regions.