Suppression of Feed Intake in Response to Rice Bran Oil Supplementation in Normal Rat

ABSTRACT

@#Introduction: Rice bran oil (RBO) is used in Asian countries as a daily dietary supplement. RBO is known in particular for its hypolipidemic effect. There has been increasing interest recently in the use of RBO as a means to maintain body weight and prevent obesity, though the mechanism of how this happens is still not well understood. We have investigated the effect of RBO on expression of genes that might influence energy homeostasis and feed intake. Methods: This study assessed Sprague-Dawley male rats at 12-weeks that were split into three groups over a 28-day period. A control group was fed a diet of standard rat chow, a standard group was fed standard rat chow with Orlistat (10.8 mg/kg bw/day), and a treatment group was fed standard rat chow with RBO (57.6 mg oryzanol/day). All supplementation was given by oral gavage. Possible adiposity was investigated through a histological analysis of adipocytes size measurement of intra-abdominal white adipose tissue in the rats. Changes in gene expression in the liver were determined by microarray. Results: The data suggest that RBO supplementation of a regular diet did not result in excess body weight and adiposity. A microarray analysis of the rats’ livers found that RBO altered the expression of genes related to energy homeostasis and feeding behavior, by upregulating genes such as Olr522, RGD1561231 and Rgs16. Conclusion: It is suggested that RBO supplementation can be used to maintain body weight by lowering appetite.