Role Of Diet On Intestinal Metabolites And Appetite Control Factors In SD Rats

Background:With the development of social economy and culture and lifestyle changes, the prevalence of obesity in the developed and developing countries continues to increase. Obesity is a major public health challenge today that grows into a global epidemic. The human gut is home to a vast number of the microbiota, whose genomes complement our own set of genes. The gut microbiota functions at the intersection between host genotype and diet to modulate host physiology and metabolism. It has been seen as a potential factor contributing to the patho genes is of obesity.Objective:To explore the role of diet in obesity occurring and glucose and lip id metabolism, also we analyze the differences of the intestinal metabolites and appetite control factors expression causing by different diets, to research the roles of metabolites and appetite control factors in the pathogenesis of obesity in SD rats.Methods:35just weaned male SD ratswere randomly assigned into five groups, separately received different diets including high fat, high sugar, high protein, high fiber and normal diet for4weeks. The weight, Lee’s index, serum biochemical parameters and serum leptin and ghrelin levels were followed. We also analysed the SCFAs and amino acids content in serum, feces and cecum contents samples using HPLC method, and leptin and ghrelin mRNA expression in gastrointestinal, adipose and hypothalamus tissues using real-time PCR.Results:1. The effect of diet on body weight and glucolipid metabolism in SD rats:High-fat diet increased weight gain, Lee’s index, adipose tissue mass, triglyceride content, LDL-C level, and decreased HDL-C level. However high-protein had an opposite effect. High-fat diet caused obvious sugar metabolic disorder, high-protein, high fibre and high sugar also induced different levels of abnormal glucose tolerance. 2. The effect of diet on the production of SCFAs and amino acids in SD rats:The high-fat diet primarily reduced formation of SCFAs in feces and blood samples, and high-protein diet increased the formation of SCFAs. When analyse the proportion among acetic, prop ionic and butyric acid, we found there is no difference of propionic/butyric acid ratio between high-fat diet group and the other groups, but acetic/butyric acid ratio and acetic/propionic acid ratio significantly reduced, high-protein diet had an opposite effect. The amino acid content in feces and cecum contents was higher than the other groups when feeding high-protein diet, but the content in blood is lower. While noticeably that of the contents of all kinds of amino acids were highest with the high-sugar and high-fiber diet.3. The effect of diet on the expression of leptin and ghrelin in SD rats:In our study, we found there were different levels of expression of leptin, ghrelin and related receptor mRNA in gastrointestinal, adipose and hypothalamus tissues. The expression level of leptin and leptin receptor is associated with the adipose tissue mass. The expression of ghrelin increased in hypothalamus tissues when with high-protein diet. And the expression of ghrelin receptor mRNA was significantly increased in hypothalamus, adipose and small intestinal tissues.Conclusion:The present study provides further evidence of the role of diet on obesity occurring and prevention. It also highlights the role of intestinal metabolites and appetite control factors expression in the pathogenes is of obesity in SD rats.