Segments measuring approximately 2 cm were
collected from the duodenum, jejunum, and cecum
and immersed in Bouin solution for 24 h, according
to the specifications of McManus & Mowry (1960).
After being fixed and sectioned, the material was
dehydrated by immersion in graded series of alcohol,
cleared by three passages in xylol, and embedded
in Polyfinparaplast. Tissues were cut with the aid of
an automatic microtome (Leica, RM-2145) to obtain
4-µm thick cuts in a semi-serial sequence of a 30µm
cut. Tissue sections were stained with periodic acid
Schiff (PAS) and Masson trichrome stains, according to
the methodology of McManus & Mowry (1960) and
Behmer et al. (2003). Mucosa, submucosa, muscularis
mucosa (circular internal and longitudinal external
layers) and serosa thickness of the collected intestinal
segments were determined by image analysis with
the aid of an image-capture software program (Leica
Qwin Lite 3.0). Five measurements were performed
per layer