Impact of rearing system of Rosa breed laying hens on occurrence and antibiotic resistance of Salmonella spp. isolated from egg shell surface

Abstract

Salmonelloses are among the most common animal-borne infections. The most frequent causes of their occurrence are contaminated chicken eggs. For this reason, the control of bacteria from the Salmonella genus living in the cloaca of laying hens can contribute to the reduction of spreading levels of infections with these bacteria. The most popular methods of rearing laying hens in small agricultural farms comprise run and cage keeping. The aim of the performed studies was to determine the impact of rearing and nutritional systems on the occurrence of egg infections with Salmonella spp. bacteria. Detection by PCR method corroborated presence of bacteria from the Salmonella genus on eggs surface from hens kept in litter system. Latex serotyping test confirmed the presence of Salmonella Enteritidis. Salmonella spp. was not detected on eggs surface from hens kept in cage system. Salmonella spp. isolates from the eggs surface of hens reared on litter were characterized by drug resistance to tetracycline. Addition of EM probiotic failed to show reduction in incidence of Salmonella spp. infection.