| Objective:To investigate the effects of diets with different percentage of energy from fat,carbohydrate and protein on indexes related to obesity and chronic diseases in rats,we fed rats by different diets with different percentage of energy from fat,carbohydrate and protein for 10 weeks.During the experiment,food intake,body weight and other physiological states of rats were recorded.At the same time,blood pressure,blood biochemical indexes,adipocyte factors,appetite regulatory factors,the expression of related genes and the categories of the intestinal flora were tested to explore the difference among these groups and lay a foundation for the relationship between dietary pattern and obesity and help people choose a scientific and adequate diet.Methods:1.Effects of ad libitum feeding diets with different percentage of energy from fat,carbohydrate and protein on blood biochemical indexes and the expression of related genes in ratsAfter feeding the rats with maintenance fodder for 3 weeks,70 healthy male Sprague Dawley rats were randomly divided into 7 groups by their growth rates.Feeding the rats in 7 groups with low fat-high carbohydrate diet,low fat-high protein diet,normal diet,medium fat-low carbohydrate diet,medium fat-low protein diet,high fat-low carbohydrate diet and high fat-low protein diet respectively and separately for 10 weeks.The rats took food and water freely during the experiment.Body weight and body length were measured every week.Blood pressure were measured at the 0,5th,10th week after the beginning of formal test.Orbital venous blood collection were carried and used for detection of blood glucose,blood lipids,free fatty acids,insulin,adiponectin,leptin,lipolysaccharide binding protein(LBP),ghrelin and obestatin at the 0,5th,10th week.The perirenal fat pad,epididymal fat pad and omental adipose tissue were separated and weighed at the end of the 10th week.Part of the epididymal fat pad and stomach were kept for mRNA extraction,inverse transcription,PCR and real-time PCR to detect the expression of adiponectin,leptin in the fat tissues and Growth Hormone Secretagogue Receptor(GHSR),G Protein-coupled Receptor 39(GPR39)in the stomaches.2.Effects of ad libitum feeding diets with different percentage of energy from fat,carbohydrate and protein on intestinal flora in ratsSix rats of every group were chosen for collecting 1.0 g faeces in a germ-free environment twice after the group division and at the end of the experiment.Extracting the whole genome DNA,detecting the quality of DNA,amplifying DNA by PCR,purifying DNA and amplifying DNA by PCR a second time.After quality testing,DNA was sequenced through high throughput sequencing technology on Illumina Miseq platform by 2×300 bp reads.The sequences were matched,filtered and compared with the 16S rDNA database to proceed a diversity analysis,? diversity analysis and principal component analysis.Results:1.Effects of ad libitum feeding diets with different percentage of energy from fat,carbohydrate and protein on blood biochemical indexes and the expression of related genes in ratsAt the end of the 10th week,the level of insulin and HOMA-IR of rats in high fat-low carbohydrate group,high fat-low protein group was higher than that of low fat-high carbohydrate group.The level of total cholesterol and low density lipoprotein cholesterol of rats in medium fat-low protein group were lower than that of normal group.The level of high density lipoprotein cholesterol of rats in medium fat-low protein group,high fat-low carbohydrate group and high fat-low protein group were lower than that of normal group.The ratio of ghrelin and obestatin in low fat-high carbohydrate group was lower than that of medium fat-low protein group and high fat-low protein group.At the end of the 10th week,the expression of adiponectin mRNA of adipose tissue in low fat-high carbohydrate group was higher than that of medium fat-low carbohydrate group and low fat-high protein group was higher than that of medium fat-low carbohydrate group and normal group.The expression of GHSR mRNA of stomach in high fat-low protein group was higher than that of low fat-high protein group.The expression of GPR39 mRNA of stomach in normal group was lower than that of other groups except low fat-high protein group and low fat-high protein group was lower than that of high fat-low carbohydrate group.During the experiment,there were no significant differences among 7 groups in average daily energy intake,body weight,body length,Lee's index,body fat rate,blood pressure,blood glucose,triglyceride,free fatty acids,leptin,adiponectin,ghrelin,obestatin and the expression of leptin mRNA of the adipose tissue.2.Effects of ad libitum feeding diets with different percentage of energy from fat,carbohydrate and protein on intestinal flora in ratsComparing with the beginning,the relative abundance of Firmicutes and Proteobacteria increased and Bacteroidetes decreased in intestinal flora at the end of 10th week.At the end of 10th week,there is no statistically significant difference among 7 groups on diversity and species richness.The relative abundance of Bacteroidetes was lowest in medium fat-low protein group.The relative abundance of Firmicutes in medium fat-low protein group was higher than that of low fat-high protein group,medium fat-low carbohydrate group and high fat-low carbohydrate group.The ratio of Bacteroidetes and Firmicutes in medium fat-low protein group was lower than that of low fat-high protein group and medium fat-low carbohydrate group.The relative abundance of S24-7 in low fat-high carbohydrate group was higher than that of medium fat-low protein group.The relative abundance of Defluviitaleaceae in low fat-high protein group was higher than that of high fat-low carbohydrate group.The relative abundance of VadinBB60 in medium fat-low protein group was higher than that of other groups expect high fat-low protein group.The relative abundance of Incertae_Sedis in low fat-high carbohydrate group was higher than that of medium fat-low carbohydrate group and high fat-low carbohydrate group.Conclusion:1.When the rats took food and water freely,there were no significant differences among diets with different percentage of energy from fat,carbohydrate and protein in Lee's index,body fat rate,blood pressure,blood glucose,triglyceride,free fatty acids,leptin,adiponectin,ghrelin,obestatin and the expression of leptin mRNA of the adipose tissue.2.High-fat diet may cause the decline of the high density lipoprotein cholesterol and the formation of insulin resistance.It may change the metabolism of blood glucose and lipids and make rats be in glycolipid metabolic disorders.3.High-carbohydrate diet may increase the expression of adiponectin mRNA of adipose tissue.The mechanism is unclear and to be studied.4.There were no significant differences among diets with different percentage of energy from fat,carbohydrate and protein in diversity and species richness.5.Comparing to the high fat diet,high carbohydrate diet can help increase the abundance of S24-7,Defluviitaleaceae and Incertae_Sedis better.The biological function of these bacteria are unclear and to be studied. |
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