Effects of modified rice bran on serum lipids and taste preference in streptozotocin-induced diabetic rats

The present study was designed to determine whether or not the administration of modified rice bran could improve streptozotocin (STZ)-induced diabetes. Taste preferences were also compared in diabetic and control rats. Male Sprague-Dawley rats were divided into control and diabetic groups. A single STZ injection, 65 mg per kg body mass i.p., induced diabetes. Rats were given free access to commercial diet and water for 2 months and modified rice bran (0.5 g per kg body mass) was administered daily by stomach tube. Two-bottle-choice preference tests between aqueous solutions of either 5 mM citric acid, 27 mM monosodium glutamate, 0.016 mM quinine, or 0.82 mM saccharin in deionized water were conducted in the experimental period. Blood was collected and serum levels of glucose, insulin, triglycerides, total cholesterol, HDL-cholesterol, urea nitrogen, total protein, albumin, and zinc were measured. Serum triglycerides and total cholesterol decreased with the administration of modified rice bran, although serum insulin and glucose remained low and high, respectively. Water intake was also reduced by the modified rice bran, which suggests that polyuria induced by STZ improved. Diabetic rats showed significant aversion to citric acid and quinine when compared with control rats. Modified rice bran can be useful as a dietary fiber supplement for the treatment of diabetes. In addition, high taste sensitivity for sourness and/or bitterness is a characteristic of STZ-induced diabetes.