Evaluation of bacterins containing three predominant phage types of Salmonella enteritidis for prevention of infection in egg-laying chickens.

Six Salmonella enteritidis bacterin formulations differing in adjuvant content and whole-cell inactivation procedures were evaluated in egg-laying chickens. Chickens given S enteritidis bacterins containing modified Freund's incomplete adjuvant had greater humoral immune responses to S enteritidis than did birds given other bacterin formulations (P < 0.05). Better protection against infection by S enteritidis phage types 8, 13a, and 23 was obtained in birds vaccinated with bacterin 5. Bacterin 5 contained S enteritidis cells inactivated by 20% acetone and modified Freund's incomplete adjuvant.