Dietary menhaden oil and resistant starch interact to increase fermentation in large intestine

Abstract

Dietary resistant starch (RS) and fish oil (FO) have been shown independently to reduce body fat in rats. RS may produce this effect through mechanisms and hormone secretions related to colonic fermentation pathways. The objective of this study was to determine additive or synergistic effects when combining Hi‐Maize© RS and Novomega© encapsulated menhaden FO (National Starch). Forty, 5‐week old female rats were free fed for a 4 week weight gain period. Prior to the next feeding period, rats were stratified by weight and placed in 4, energy balanced diet treatment groups: FO, RS, RS/FO, and control. Each group was meal fed for a 2 week restricted feeding period followed by an 8 week free feeding rebound period. Analysis was a 2x2 factorial with significance at p<0.05. The FO showed significantly higher food intake, body weight, and retroperitoneal fat pad weight. Menhaden oil is low in DHA and EPA, which may be necessary for FO to be effective at reducing body fat. RS and RS/FO had larger ceca and lower pH levels in cecal contents indicating increased fermentation. RS/FO had the greatest cecal weight and lowest pH indicating a synergistic interaction between RS and FO which enhanced fermentation to higher levels within the large intestine than RS alone. This combination may benefit the health of the colon. Supported by the LSU AgCenter.