Type 4 resistant starch diminishes Citrobacter rodentium induced diarrhea in C3H mice

Purpose: The purpose of this study was to examine the effects of a chemically modified resistant starch, RS4, on diarrhea and inflammation induced by Citrobacter rodentium. We hypothesized that a diet supplemented with RS4, contributing to 25% resistance of the total starch in the diet (55% starch diet), would significantly improve stool consistency and provide protection against the inflammation associated with the pathogen, including inflammation score, mucosal height, ulceration, goblet cell loss, edema, and hyperplasia. Design: 36 mice (18 male, and 18 female) were randomly assigned four treatment groups: uninfected mice fed the control starch diet, uninfected mice fed the RS4 supplemented diet, C. rodentium infected mice fed the control starch diet, and C. rodentium infected mice fed the RS4 supplemented diet. After inoculation with C. rodentium, mice were be subjected to the diets for two weeks, and daily food intake, body weight, and stool consistency were measured. At the completion of the two weeks, mice were euthanized and blood was collected via cardiac puncture for serum glucose, insulin, and lipid analysis. Colon and cecum contents were collected and analyzed for pH, stool fat, and water content; and the tissues were sent for histopathology scoring. Expected results: C. rodentium infected mice fed the RS4 supplemented diet were expected to show a significant increase in stool consistency compared to the infected mice the fed the control starch diet. The infected mice fed the RS4 diet were also expected to have a less severe inflammatory response due to the C. rodentium compared to the infected mice fed the control diet, which would be seen in the histopathology scores. Body weight loss and decreased food intake due to the C. rodentium pathogen were expected to be less severe in mice fed the RS4 supplemented diet, due to its expected protection against inflammation and diarrhea