Determination of Fermentation of Four Novel Type 4 Resistant Starches by Sprague Dawley Male Rats (P20-006-19)

The goal of this study was to determine fermentation of four novel resistant starch (RS) type 4 products (RSA, B, C, and D) in Sprague Dawley male rats compared to control (CON). Assessment was by standard measures: empty cecum weight (ECW), cecal contents weight (CCW), cecal contents pH (pH), cecal contents short-chain fatty acids: acetate, propionate and butyrate, cecal contents RS (CCRS), and serum active glucagon-like peptide 1 (GLP-1). Abdominal cavity fat (abfat)/body weight was determined. Forty weanling rats (Envigo), after a week quarantine, were randomly assigned to five groups (n = 8) for a 3-week study. Starches (Ingredion Incorporated) were RS products as 10% of weight of RS diets (equivalent to human fiber requirement) and AMIOCA® starch (100% amylopectin) comprised 53.6% weight of CON and 43.6% weight of the RS diets (RSA – RSD). The RS products varied by % purity and origin (e.g.,potato, tapioca, corn). Other ingredients (DYETS) were used (AIN-93 G). A one-way ANOVA was followed by Tukey post hoc test (P < 0.05). At euthanasia, cecal contents, serum, GI tract, and abfat were collected. Emboweled body weight (EBW) was calculated as body weight minus GI contents. RSB, RSC, and RSD demonstrated greater fermentation than CON and RSA. This was based on pH below 6.5 vs above 8.0, ECW above 0.7 g vs. below 0.54, CCW above 7.5 g vs below 3.86, and cecal contents acetate above 0.36 mmol/cecum vs below 0.21. Cecal contents propionate was increased for RSB and RSC (above 0.08 mmol/cecum vs below 0.06), but cecal contents butyrate and GLP-1 were not statistically significant. Post hoc power analysis for the latter two demonstrated power <80%. All groups had low CCRS. All four RS groups had lower abfat/EBW% than CON, but only RSA had a lower body weight. RSB, RSC, and RSD products were fermented; but it was inconclusive whether fermentation led to increased butyrate and serum GLP-1. Compared to CON all four novel RS groups had reduced abfat% indicating reduced energy density of the RS diets. Estimates of RS disappearance from cecum indicated digestion and/or fermentation of RS products with RSA apparently mainly digested. Ingredion Incorporated, LSU AgCenter.