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The vast capacity for maintenance and dissemination in the environment are major challenges for the control of Salmonella spp. in poultry farms. The aim of this study was to assess environmental contamination by nontyphoidal Salmonella in successive broiler flocks in nine commercial broiler farms integrated with three companies in the south of Brazil, for a twelve-month production period. Recycled broiler litter, feed and swabs from the evaporative cooling system pads were analyzed, and the total enterobacteria count in the litter samples was ascertained. Positive broiler houses were identified in two of the three broiler companies studied, in which nontyphoidal Salmonella were detected for the first time in the first or second flock, and recurred in the recycled litter of subsequent flocks. Feed and evaporative cooling pad swab samples were also positive in at least one of the assessed flocks. The majority of the isolates (87.5%) originating from different flocks, broiler houses and companies that were sampled were identified as S. Heidelberg, with the prevalence of one single genotype. The total enterobacteria levels in the litter diminished as the flocks progressed, but the presence of Salmonella spp. was constant over the course of time, indicating that the litter management procedures were not capable of interrupting the cycle of residual contamination. The predominance of S. Heidelberg highlights its emergence and dissemination in this region, as well as its resistance and maintenance in the environment, and reinforces the need to improve prevention and recycled litter management measures. Made available in DSpace on 2019-11-04T18:11:46Z (GMT). No. of bitstreams: 1 final9057.pdf: 1748574 bytes, checksum: 8d934aa119670b291408db1f1fbc6c90 (MD5) Previous issue date: 2019

Made available in DSpace on 2019-11-07T18:09:25Z (GMT). No. of bitstreams: 1 final9217.pdf: 1544314 bytes, checksum: 55d5f9e4381eb1a955ce043038cc02ce (MD5) Previous issue date: 2019

The granulomatous lymphadenitis (GL) in pigs is mainly caused by Mycobacterium avium hominissuis (MAH), who belongs to the Mycobacterium avium Complex (MAC), considered non-tuberculous mycobacteria (NTM). Although GL does not affect swine zootecnical performance, economic losses occur during the slaughter line by condemning viscera and carcasses. The lesion is characterized by one or more foci of granuloma, which most frequently affect the organs of the digestive tract and peripheral lymph nodes. The main differential diagnosis encompasses Mycobacterium bovis (M. bovis) and Mycobacterium tuberculosis (M. tuberculosis), who belongs to the Mycobacterium tuberculosis Complex (MTbC), of relevant zoonotic potential. Nevertheless macroscopic examinations and histopathology are insufficient to determine the etiologic agent involved. Federal Meat Inspection had registered the frequency of 0,81 % of lymphadenitis in Brazil from 2012 to 2014. The aim of this study was to investigate the etiology of the granulomatous lesions for validation of the national data of inspection and build a database to further risk analysis. Made available in DSpace on 2020-09-17T04:41:05Z (GMT). No. of bitstreams: 1 final9436.pdf: 671691 bytes, checksum: 67aa8f9948f0d9730438802e8c73b6f6 (MD5) Previous issue date: 2019