Observations on the structure of the small intestine on foetal, neo-natal and sucklings pigs

Abstract

Light and electronmicroscopic observations of changes throughout the small intestine of foetal, and both suckled and unsuckled newborn pigs are reported. Foetal animals between 73 days gestation and term showed vacuolation in the terminal ileum. This was most extensive between 90 and 100 days when the terminal 30% of the small intestine contained vacuolated cells. The apical region of such cells contained a system of smooth tubes and vesicles, some of which showed evidence of a characteristic surface pattern. The vacuoles contained material of variable electron density and were sometimes seen apparently discharging their contents into the dilated intercellular spaces. Unsuckled newborn animals showed most of the features described above, but, in addition, the vacuolated cells contained large numbers of electron dense inclusions. In suckled animals from birth to 70 h of age there were considerable variations in cellular structure, which could be related to the position in the small intestine, the position on the villus and the age of the animal. The structural features described are discussed in relation to the transfer of colostrum immunoglobulins into the circulation. Keywords: swine, foetus, newborn, small intestine, structure.