Several 30-day feeding substudies were conducted in order to evaluate different immunotoxic effects. At termination, all animals were anaesthetized by carbon dioxide inhalation and killed by exsanguinations. The parameters of immunopathology, humoral immunity, cellular immunity, non-specific immunity were measured in the four groups with 10 mice per group. The study was approved by the Animal Ethics Committee of National Institute for Nutrition and Food Safety, Chinese Center for Disease Control and Prevention.