. We could show that adjuvanted vaccines containing the same antigenic dose as the
unadjuvanted commercial vaccine could significantly improve the resistance to challenge (length of
hyperthermia and lung lesions) despite similar antibody titers compared to the commercial nonadjuvanted
reference. Lung lesions are a good indicator of vaccine performance as they are strongly
linked to the body weight gain of the animals. It should also be noted that the challenge was highly
discriminative for the vaccines (experimental as well as commercial). Indeed, the virulent strain of virus
we used presents 95% of genetic homology to the 2006/2007 Chinese strain which induced more than
40% of mortality in field condition.