Background: The efficacy of different fat emulsions as components of a total parenteral nutrition (TPN) regimen on the integrity of the gut was assessed in traumatized rats. With the release of the short-chain fatty acids butyric or propionic acid during the hydrolysis of a structured triglyceride containing butyric acid (C4-L-C4-TG) or the beta-oxidation of nonanoic acid from trinonanoin (C9TG), respectively, the infusion of these two triglycerides was supposed to reveal positive effects against the TPN-induced atrophy of the intestine.
Methods: After 3 days of fiber-free liquid diet, rats were traumatized (laparotomy) and catheterized. Afterwards they received equicaloric TPN that delivered 1008 kJ (241 kcal)/kg of body weight per day and 30% nonprotein calories as fat emulsion. The four fat emulsions tested in four groups of six animals contained either long-chain triglycerides (LCT), medium-chain triglycerides (MCT)-LCT (1:1), C9TG/LCT (1:1) or C4-L-C4-TG. Animals of a control group were infused with isovolemic 0.9% NaCl solution and were offered oral standard chow.
Results: After 7 days of MCT/LCT administration, the mass-to-length ratio of the total small bowel as well as the masses of mucosa/submucosa and muscularis/serosa in 10-cm segments of the distal half of the small bowel were significantly higher than that found in the other TPN groups or not different from controls. Histometric measurement of the villus height in the ileum revealed no statistically significant differences from controls for the rats of the MCT/LCT and C4-L-C4-TG groups. In the colon, no statistically significant differences between TPN groups were found for either parameter.
Conclusions: Within the tested fatty substrates the MCT/LCT fat emulsion revealed less structural impairments in the distal half of the small bowel regarding mucosa/submucosa (mass and villus height), but also muscularis/ serosa (mass).