Studying the sources of infection of broiler chickens by salmonella using ERIC-PCR and agglutination reaction with fluorescencelabeled antigens (FLA).

Abstract

The study aims to develop diagnostic algorithms for using ERIC-PCR and IRA, which make it possible to identify the routes of Salmonella introduction into a poultry farm. The authors studied the genetic differences of 15 isolates of Salmonella spp., isolated from pathological material, feed raw materials and swabs from poultry houses of broiler poultry farms (parent stock and replacement young animals) in the West Siberian region. The species of Salmonella cultures were confirmed by sequencing and using biochemical tests and agglutination sera. Bacterial DNA was isolated using the standard silicosorption method. Analysis of the genomic DNA of the studied collection of Salmonella using the ERIC-PCR method allowed us to group the resulting strains and isolates into three genotypes that differ in amplicon patterns on polyacrylamide gel electrophoresis. Comparison of IRA results with blood sera of birds from the parent flock and replacement young animals of poultry farm No. 1 made it possible to identify antibodies to both Salmonella genotype one and Salmonella genotype 2 in most of the examined poultry flocks. Analysis of the correlation of antibody titers to Salmonella antigens of the 1st and 2nd genotypes made it possible to exclude a cross-reaction in some poultry houses. The correlation was negative. It was positive in two poultry houses, and there was no correlation in one. The immunofluorescence agglutination reaction system makes it possible to precisely distinguish the seroprevalence of different Salmonella strains at individual agricultural enterprises. The totality of data from serological analysis suggests that some birds have an increased susceptibility to infection with Salmonella of both genotypes, which means that these individuals have genetic characteristics or characteristics of the intestinal microbiota associated with exposure to infection with Salmonella.