EFFECT OF HIGH-AMYLOSE STARCH ON CARBOHYDRATE DIGESTIVE CAPABILITY AND LIPOGENESIS IN EPIDIDYMAL ADIPOSE-TISSUE AND LIVER OF RATS

This study was conducted to clarify whether feeding high-amylose corns tarch would delay digestion and absorption of the starch and lead to a decrease in lipogenesis in epididymal adipose tissue and liver Two gr oups of five or six male Wistar rats were fed defined diets ad libitum for 14 days. The control group received a diet containing 53.7% stand ard cornstarch rich in amylopectin (control diet) and the experimental group received a diet containing 53.7% high-amylose cornstarch (70% a mylose). Food intake during the experimental period did not differ bet ween the two groups. Feeding the high-amylose diet resulted in signifi cantly lower activities of sucrase, isomaltase, and maltase in the upp er jejunum than in the animals fed the control diet. However in the lo wer part of small intestine, disaccharidase activities were significan tly elevated in the rats fed the high-amylose diet compared with those fed control diet. The activities of lipogenic enzymes, i.e., fatty ac id synthetase, malic enzyme, and glucose-6-phosphate dehydrogenase wer e significantly lower in the liver as well as in the adipose tissue of the animals fed the high-amylose diet compared with the control group . The weights of both epididymal and mesentery adipose tissues were re duced by 30% in rats fed the high amylose diet, and the serum concentr ation of triglycerides was also reduced in rats fed the high-amylose d iet. These results suggest that digestion and absorption of high-amylo se starch may be slower than low-amylose starch and feeding a diet ric h in amylose might produce lower glycemic response, consequently leadi ng to declined lipogenesis in adipose tissue and liver.