Rats consuming bran from black and brown sorghums have lower short chain fatty acid concentrations and fewer aberrant colonic crypts

Abstract

Diets containing bran isolated from brown and black sorghum grain produce fewer (68 and 38%, respectively, P < 0.04) high multiplicity aberrant crypt foci (HMACF) in azoxymethane‐ (AOM) injected rats, relative to a cellulose diet. Because of the potential for short chain fatty acids (SCFA) to influence colon carcinogenesis, we determined SCFA concentrations in feces (reported as µM/g wet feces) from rats (n=10/diet) consuming diets containing 6% fiber from either cellulose or bran isolated from white, brown (contains tannins), or black (contains anthocyanins) sorghum. Diets were fed for 10 wk, with two AOM injections (15 mg/kg BW) given in wk 3 and 4. Total SCFA were affected (P < 0.0001) by diet; greatest for white sorghum bran (32.0 µM), intermediate for cellulose (22.6 µM), and lowest for black or brown sorghum bran (15.4 or 14.7 µM, respectively). Butyrate concentrations were affected (P < 0.0001) by diet; highest for white sorghum bran (7.8 µM), lowest for brown sorghum bran (1.07 µM), while concentrations were intermediate and similar for black sorghum bran and cellulose (2.7 and 3.6 µM, respectively). Differences among diets were the same when butyrate was expressed as a percentage of SCFA. These data suggest that there are significant changes either in the microbiota within the lumen or in the transport of SCFA into colonocytes, both of which can influence colon carcinogenesis. Funded by USDA 58‐5430‐5‐339 and NIEHS P30‐ES09106.