Morphometry of the intestine of the pig. I. A method for complete circumsection analysis.

A method and scheme are described to improve precision for quantitation of functional aspects of the intestine by morphometric evaluation of a representative sample hereafter called a circumsection. A circumsection is defined as: all tissue lying within the total circumference of a slice of the intestinal wall transected at a righ angle to the long axis of the intestine tube. The quantitative values obtained from these substantial specimens therefore provide a basis for reliable estimations of the organ content of specified cellular masses or of functional surfaces, ie, villi volume, epithelial surface, crypt mass, muscle mass, etc. The volume, mass, or area of specialized cells can be compared with physiological functions and capacities. These comparisons and relationships are important to investigate the causes and effects of digestion-absorption parameters on performance output of healthy animals--growth, development, reproduction, lactation, work output, etc. The data can also describe responses of the digestive organs (tissues) to various inputs--dietary, environmental, chemical, and physical. The method involves analysis of a montage of photomicrographs of the circumsection. The method was successful; the data collected demonstrated that the small intestine of the pig has lateral symmetry (left vs right) but is asymmetrical in the opposite plane (mesenteric vs antimesenteric). The asymmetry is especially clear in the ileum and jejunum where significant differences between opposite halves ranged from 7% to 90% of the mean value.