Changes in Immunological Factors Induced by H9N2 Avian Influenza Challenge in Broilers

Abstract

Avian influenza virus infection, one of the most important diseases recognized in the poultry industry, is known to cause changes in cytokine and serum protein levels. However, the normal ranges and/or age-dependent changes in important cytokines and serum proteins associated with influenza infection have not been fully elucidated. In this study, the levels of cytokines (interleukin-1β, interleukin-6, and interferon-γ) and serum proteins (vitamin D binding protein and ovotransferrin) were determined in 1-week-to 4-week-old broilers at 1-week intervals after challenge with a low pathogenic influenza virus. The results showed that the physiological levels of cytokines and serum proteins varied with aging during the 4 weeks. The levels of interleukin-1β and interleukin-6 increased from 20% to 35% after influenza infection compared to those in the negative control group, indicating that these cytokines may be used to monitor disease progression.