On d 21, the chickens were weighed and 6 from each
of the replicate cages were bled by cardiac puncture;
the blood was collected in Vaccutainer tubes containing
EDTA for hematology and clot accelerator for serum
clinical chemistry analyses. The chickens were killed
by cervical dislocation and the weights of liver, heart,
spleen, and bursa recorded, and calculated as percentage
of BW. The blood with clot accelerator were kept
at room temperature for 2 h, centrifuged at 2,500 × g to
separate serum, and stored in aliquots at −20◦C until
the assays were done.