The objective of this study was to investigate the effect of an elemental diet (ED) on the strength and on the morphology of the small bowel. Male Wistar rats were randomized to two groups to receive during 14 days either standard laboratory rat chow (N=16) or ED (N=16) containing total parenteral nutrition (TPN) solution. After this period they were killed and necropsied. The small bowel was measured and weighted with and without the contents. Bursting pressure (BP) was taken from the jejunum and ileum and histological sections of these two portions was performed to register the crypt depth (CD), vilus height (VH) and wall width (WW). All animals significantly gain weight. The bowel of animals fed with TPN solution had significantly less weight when compared with the controls either with (9.9 ± 1.9g x 7.8 ± 1.5g, p<0.05) or without (8.3 ± 1.3g x 6.5 ± 0.8g; p<0.05) the luminal contents. BP was lower in animals receiving TPN solution compared with controls in both studied segments but the difference only reached significance at the ileum (287 ± 60 x 234 ± 46 mm of Hg; p<0.05). VH, CD and WW were significantly shorter at the ileum in TPN-fed animals when compared to controls (p<0.05). This contrast was also seen at the jejunum though without significant difference. The small bowel looses mass and become less resistant when rats are fed with elemental diet though the nutritional state is maintained. The loss of mass appeared to be not only at the mucosa layer but through all the bowel wall. This occurs predominantly at the terminal part of the small bowel.
Jejunum; Ileum; Animal nutrition; Intestinal mucosa
