Salmonella Infection In Local And Exotic Chicken Breeds

ABSTRACT In Ghana, the local chicken and commercial cohorts are managed under different production systems that appear to expose local chicken usually raised under the extensive system, to higher risk of infectious diseases as compared to the exotic cohorts that are raised in confinement. The key question is, will raising these birds under identical conditions result in corresponding reduction in the prevalence of Salmonella infection in the local chicken to levels prevailing in the exotic chicken usually confined to cages and litter houses? In this study, 450 cloacal swabs were obtained from local and exotic chicken breeds managed under intensive and extensive systems at different locations and investigated for Salmonella infection from January, 2017 to April, 2017. Our analysis revealed that whereas up to 50% of the birds from local chicken managed under extensive system and 38% kept under the intensive system were contaminated with Salmonella, only 16% of the exotic layers kept on deep litter were infected. A total of 156 isolates were tested for motility and 54 were non-motile Salmonellae: 12 from exotic birds on deep litter, 21 from local birds on deep litter and 21 from local unrestricted birds. There were less than two times as many motile salmonellae present in the local chicken tested as compared with the non-motile cohorts. In contrast the number of non-motile and motile organisms in the exotic chicken was essentially the same. PCR analysis of 14 non-motile Salmonella isolates generated 197bp of the fliC gene that serves as a biomarker of prototypical pathogenic strains circulating in the poultry. Successful amplification of this gene has greatly facilitated quantitative analysis of the diversity in number of infected cases within the population of susceptible birds which was previously restricted to biochemical analysis alone. The presence of the fliC gene in these isolates confirms that they are the non-motile strains of salmonellae (Salmonella Gallinarum or Salmonella Pullorum). ix Cross breeding between the exotic and the local chicken must be encouraged to reduce salmonellosis in poultry.