Caecal microbiota composition of experimental laying hens differs according to genetic line and vaccination to IBV

The project evaluated the association between the caecal microbiota composition and the vaccine response against IBV in layer lines with different MHC haplotypes. We wanted to decipher whether:(1) vaccination has an effect on the caecal microbiota composition;(2) the level of the response to IBV vaccination is correlated with the caecal microbiota composition;(3) MHC lines display distinct microbiota compositions.(4) variations in immune parameters are correlated with variations in the caecal microbiota composition.We thus wonder if the MHC line divergence regarding immune response to IBV vaccination could be due to variations in caecal microbiota composition potentially contributing to differences in immune phenotypes.