Complications associated with the overfeeding of infected animals.

The effect of overfeeding on survival from peritoneal infection as well as changes in protein metabolism was evaluated. Rats were randomly divided into two groups and given for 6 days different quantities of a liquid diet containing 18% of the energy supplied as protein and 82% as carbohydrate and lipid via an implanted gastric tube. The control group received 301 +/- 4 kcal/kg/day which was equivalent to their mean voluntary intake and the overfeeding group received 528 +/- 8 kcal/kg/day (P less than 0.001). Following 6 days of enteral feeding, all rats received a jugular vein cannulation and cecal ligation with enterotomies. The overfeeding group showed a significantly (P less than 0.05) higher mortality rate to experimental peritonitis, a 24% lower leucine incorporation into whole body protein (P less than 0.05), and a 28% lower fractional synthetic rate of serum albumin (P less than 0.05). Although overfeeding in the rat increased body weight gain and was associated with significantly (P less than 0.001) greater nitrogen balance before infection, it can be concluded that such diets increase mortality to peritonitis and reduce whole body protein and serum albumin synthesis in response to such infections.