Hematoxylin and eosin staining
The partial heart, liver, spleen, lung and small intestine tissues of
each group were removed and fixed with 10% formalin, were then
dehydrated, and embedded in paraffin. To evaluate the pathological
changes, the paraffin-embedded tissues were sliced into 5 μm thin
sections to conduct hematoxylin and eosin staining, and then observed by
a light microscope.
Viscera index measurement
After APEC infection for 24 h, the chickens of each group were
euthanatized and obtain the weight. The complete heart, liver, spleen,
lung, kidney and bursa of fabricius were harvested and weighed. The
viscera index was calculated as each viscera weight divided by chicken
weight.
16S
rDNA