Variations in the efficacy of resistant maltodextrin formula on body fat reduction in rats fed different high-fat models

• Main Authors: Hui-Fang Chu, 朱慧芳
• Other Authors: 周志輝
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/23780660041658482670

博士 === 國立中興大學 === 食品暨應用生物科技學系所 === 105 === The prevalence of obesity in the world has been increasing along with an improvement in the living quality of general public. Obesity may increase the risk of many chronic diseases. Many scientists dedicated themselves to the study of body fat-lowering effect. However, the types of high-fat diet used to induce obesity in animal models are highly variable. Little is known about the effects of fat content in diet on high-fat diet-induced obesity in animal models. For this reason, this study was divided into three parts. In part I, rats were fed diets with different fat contents (23% and 40%) with or without condensed milk in order to compare different formula combinations to induce obesity in animal models. In part II, the body fat-lowering effects of several fiber formulations were evaluated. In part III, the body fat-lowering effects of the comparatively effective fiber formulation in different dosages were evaluated. These experiments were conducted to determine the most appropriate fat content in the diet to induce obesity in animal models, and also to evaluate the body fat-lowering effects of water-soluble dietary fiber in this model. In part I, total energy intake and body weight gain were increased significantly in both groups (23% and 40% fat contents) with condensed milk addition. This result showed that adding condensed milk into diets could increase the palatability of the diets. The presence of resistant maltodextrin in the diet, either in low dose or high dose, could significantly lower total crude body fats in the group fed 23% fat diet with condensed milk addition (23 M-C) as compared with high-fat control group (HF). However, the body fat-lowering effects were not noticeable in the group fed 40% fat diet with condensed milk addition (40 M-C). It was concluded that 23 M-C was the most appropriate fat content of high-fat diet to induce obesity, and therefore it was applied in part II. In part II, resistant maltodextrin (F), inulin (I), and polymethoxylated flavones (F) were combined in different ratios to develop three formulations: FI (F+I with a 1 to 1 ratio, w/w), FP (F+P with a 1 to 1 ratio, w/w), and F2P (F+2P with a 1 to 2 ratio, w/w). The total crude body fats and hepatic triglycerides of rats in groups FI, FP, and F2P were significantly (p < 0.05) decreased compared with those in group HF. From the results, FI was considered as the best formulation among the three groups. Part III was conducted according to the evaluation method of body fat-lowering effects announced by Ministry of Health and Welfare with formulation FI as the sample. In part III, formulation FI was further divided into three dosages: low (HF1X), medium (HF2X), and high (HF3X), then evaluation was done to determine their body-fat lowering effects. Group HF and experimental groups had higher final weights and weight gains than control group, once again proving that 23% fat diet had successfully induced obesity in rats. The feed efficiency of groups HF2X and HF3X were significantly lower than that of HF group, showing that the samples have a better capacity for suppressing body weight gain, with group HF3X demonstrating the best effect among the three groups. Compared with group HF, the visceral fat in groups HF2X and HF3X decreased significantly (p < 0.05) in a dose-dependent manner. Total crude body fats of groups HF2X and HF3X were significantly lower by 9.3% and 13.7%, respectively, compared with that of group HF. Moreover, a negative correlation was observed between dosage and degree of reduction. The lipid concentrations of liver in animals fed HF2X and HF3X diets were lower than those with HF diet significantly (p < 0.05). Fecal fat excretions in groups HF2X and HF3X were also found to be higher than that in group HF. It was inferred that the sample might assist fat excretion through feces so that body fat generation was reduced. In conclusion, diets containing 23% fat and condensed milk could be used as an experimental model to induce obesity in rats. This study demonstrated that this model could be an effective way to evaluate the potential ability of water-soluble dietary fiber formula in body fat reduction.