Effect of dietary selenium on the response of stressed and unstressed chickens to Escherichia coli challenge and antigen

Selenium was added to the feed of White Leghorn type chickens 1 day prior to challenge with either Escherichia coli or sheep erythrocyte antigen. The incidence of death or lesions was reduced from 86% to 21% at the optimal dose of selenium (0.4 mg/kg resulting in feed concentration of 0.45 mg/kg). After the chickens were stressed by chilling, selenium was ineffective against E. coli. Dietary additions of selenium between 0.1 and 0.8 mg/kg resulted in an antibody titer increase from 2.2 to 3.9 to the log(2) against sheep erythrocytes (SRBC). Following chilling, antibody titer response was reduced from 4.9 to 2.4 to the log(2). This titer reduction could be prevented with dietary additions of selenium between 0.1 and 1.2 mg/kg. The effects of a nitrofuran and selenium were additive against E. coli challenge infection.