Vaccination of chickens with a temperature-sensitive mutant of Salmonella enteritidis

One-day old chickens were inoculated with temperature-sensitive mutant E/1/ 3 of S. enteritidis. Two routes of inoculation were used: oral and intraper itoneal (ip). One group of chickens were given two oral inoculations (oral- oral). A second group received two ip inoculations (ip-ip). A third group r eceived the first dose orally and the second ip (oral-ip) and the fourth gr oup was given the first dose ip and the second dose orally (ip-oral). The v accine strain was safe even when inoculated at high doses, and induced stro ng protection against virulent S. enteritidis strain after oral challenge. Results show that vaccination with mutant E/1/3 reduced the number of anima ls shedding the pathogen after challenge. Furthermore, animals immunized or al-oral and oral-ip showed a significant reduction in cecal and spleen colo nization by virulent Salmonella. (C) 2000 Elsevier Science Ltd. All rights reserved.