Phenotypic and molecular detection of Salmonella sp. on growing, rearing and production phases in a commercial group of laying hens

Abstract: This present study was developed with the objective of detect Salmonella sp. by conventional bacteriology and qPCR techniques in samples of flooring material from transport crates (meconium); raising environment (swab of cages and drinking fountains); cloacal swab; food and insects from growing, rearing and production phases in a commercial group of laying hens. A total of 864 samples were collected, among whom 248 originated from growing, 392 from rearing and 224 from production phase. Among the 864 samples, 2,8% where positives in bacteriologic technique and 15.3% in qPCR. Contamination was higher in growing and rearing phases and declined in production phase. Twenty four isolations of Salmonella where typified as Salmonella Agona (41.7%), Salmonella Livingstone (33.3%), Salmonella Cerro (16.7%), Salmonella Senftenberg (4.2%) and Salmonella Schwarzengrund (4.2%). During growing phase Salmonella Livingstone was identified. These findings suggest vertical contamination in the group. During rearing and production phases, isolated materials belong to serovars Agona, Cerro, Senftenberg and Schwarzengrund, pointing to horizontal contamination. It is possible to conclude that both vertical and horizontal contaminations are important during the cycle of commercial egg production and contamination in rearing phase is higher than in growing and production phases.