Abstract B136: Inhibition of azoxymethane-induced mucin depleted foci in the rat colon by a novel resistant starch

Abstract

Abstract B136 The purpose of this study was to test the inhibitory effects of a novel resistant starch on azoxymethane (AOM)-induced colon carcinogenesis in rats. The novel resistant starch was processed from a commercial high amylose cornstarch(patent pending). Three groups of 5-week-old male Fischer 344 rats including 15 animals each were injected with AOM and fed normal cornstarch diet, high amylose cornstarch diet, and novel resistant starch diet respectively. Another three groups of male Fischer 344 rats with 5 animals in each group were injected with saline and fed the same three kinds of diets as control groups. Two injections were performed one week apart. Each of the 3 diets contained 55% water boiled high moisture starch, together with 45% of other ingredients necessary for rats’ nutritive requirements. The rats were fed with the above diets for 9 weeks after the second injection and then killed. Liver weight, caecal fermentation (caecum weight and pH), and a predictor of carcinogenicity - Mucin Depleted Foci (MDF) - were investigated. MDF were only seen with AOM treatment and were significantly reduced in rats fed novel resistant starch diet in comparison with rats fed the other two diets. Increased caecum weight and decreased caecum pH were also observed in the novel resistant starch diet group in comparison with the other two diet groups. No significant difference was found comparing liver weights. These results suggested that the novel resistant starch, which is less digestible than regular cornstarch or commercial high amylose cornstarch, may inhibit colonic carcinogenesis, and the inhibition might be related to increased caecal fermentation. Citation Information: Cancer Prev Res 2008;1(7 Suppl):B136.