Parenteral nutrition with short- and long-chain triglycerides: triacetin reduces atrophy of small and large bowel mucosa and improves protein metabolism in burned rats

The effect of total parcnteral nutrition with combinations of long-chain triglycerides (LCTs) and triacetin, the water-soluble triglyceride of acetate, on structural compo- nents of the gastrointestinal tract and protein metabolism was assessed in burned (30% body surface area) rats. Rats received isovolemic, isocaloric, and isonitrogenous diets that delivered 672 kJ . kg' . d1 (160 kcal#{149} kg' . d'), 9.6 g amino ac- ids . kg' . d', and 30% nonprotein calories as 90% triacetin/ 10% LCTs, 50% triacctin/50% LCTs, or 100% LCTs for 7 d. Daily and cumulative nitrogen balances and whole-body leucine kinetics and fractional protein synthetic rates in rectus muscle and liver were determined on the last day of nutrition. DNA, protein, and total weight were determined in mucosal scrapings from segments ofjejunum and colon. Plasma acetate concen- trations were substantially higher in both triacetin groups. Par- enteral nutrition with 50% triacctin and 50% LCTs promoted a positive nitrogen balance similar to that of 100% LCTs, increased protein in rectus muscle and liver, smaller and more numerous mucosal cells in jejunum and colon, and increased colonic mu- cosal weight compared with the other groups. Triacetin did not appreciably affect whole-body and tissue leucine kinetics. The equicaloric provision of triacctin and LCTs improved protein utilization and structural components of the small and large bowel and reduced the development of intestinal mucosal atro- phy associated with conventional parenteral nutrition in burn injury. Am JClin Nutr 1992;55:1005-l I.