A total of 20 duodenum samples were obtained for a morphometric analysis of villus height. Immediately after slaughter, samples of 2 cm of the duodenum were collected and fixed for 48 h
in a 10% formalin solution. The samples were then dehydrated in an ethyl alcohol battery at increasing concentrations (70%, 80%, 90%, and absolute), followed by diaphanization with xylol and inclusion in paraffin.