| ObjectiveTo investigate the influence of dietary fat intake on obesity related indexes on energy balance status in rats, two studies- a restriction feed study and a half-restriction feed study were employed to evaluate the effects of different dietary fat intake on blood glucose, blood fat, BP, body fat and factors in regulating energy, which can provide the basis and foundation for guiding the suitable diets and prevention and control of non-communicable chronic diseases.Methods1. Restriction Feed StudyForty male SD rats were randomly assigned to four groups based on their weight, 10 rats for each group. Rats in four groups were fed equal energy diets of low fat diet, normal diet, medium fat diet and high fat diet respectively. Rats were fed once every two days at the same time, body weight of each rat was recorded to ensure they are in energy balance status. Food intake was adjusted to keep their weight unchanged.Blood pressure was measured at 0,5 and 10 weeks. Blood glucose, lipids, serum FFA and insulin were analyzed at 0,5 and 10 weeks. The level of serum adiponectin, leptin, LBP, ghrelin and obestatin was tested at 0 and 10 weeks. At the end of 10 weeks, the rats were sacrificed, the perirenal and periepididymis fat were separated and weighed. The mRNA of adiponectin and leptin in fat tissues and the ones of ghrelin and obestatin in gastric tissues were determined by realtime PCR.2. Half-restriction feed studyForty male SD rats were assigned to ten blocks based on their weight and weight increase. Every four rats in one block were randomly assigned to four groups and fed equal energy diets of low fat diet, normal diet, medium fat diet and high fat diet respectively according to the free food intake of rats in low fat group. Rats were also fed once every two days.Blood pressure was measured at 0,5 and 10 weeks. Blood glucose, lipids, serum FFA and insulin were analyzed at 0,5 and 10 weeks. The level of serum adiponectin, leptin, LBP, ghrelin and obestatin was tested at 0 and 10 weeks.5 rats were randomly selected from each group for feces collection at 0 and 10 weeks. The effect of different fat intake on intestinal micro flora of rats was studied by denaturing gradient gel electrophoresis (DGGE) based on sequencing of 16SrDNA. At the end of 10 weeks, the rats were sacrificed, the perirenal and periepididymis fat were separated and weighed. The mRNA of adiponectin and leptin in fat tissues and the ones of ghrelin and obestatin in gastric tissues were determined by realtime PCR.Results1. Restriction Feed StudyAfter the 5 and 10 weeks, the levels of serum triglyceride of rats in medium fat group and high fat group were lower than those in low fat group and normal fat group. At the end of 10 weeks, the expression of adiponectin mRNA in fat tissues in medium fat group was lower than those in low fat group, the expression of ghrelin mRNA in gastric tissues in medium fat group and high fat group were higher than those in low fat group. There were no significant differences among four groups in body fat, blood glucose, serum cholesterol, FFA, insulin, LBP, adiponectin and leptin, the expression of leptin mRNA in fat tissues and of.Gpr39 mRNA in gastric tissues.2. Half-restriction Feed StudyAfter the 5 and 10 weeks, the levels of blood glucose of rats in medium fat group and high fat group were higher than those in low fat group and normal fat group, while the levels of serum cholesterol, triglyceride and HDL-C in medium fat group and high fat group were lower than those in low fat group and normal fat group. There were no significant differences among four groups in weight, body fat, Lee’s index, serum LDL-C, FFA, insulin, LBP, adiponectin, leptin, ghrelin and obestatin.PCR-DGGE polyacrylamide gel electrophoresis bands of intestinal microflora showed there were no significant differences among the four groups. DGGE maps by UPGMA cluster analysis indicated that the similarity of these four groups were>74% at the beginning of the experiment. After 10 weeks, there are some differences among blocks, while the similarity of the four groups>57%.Conclusions1. In energy balance status, different dietary fat intake had no effects on body fat, blood glucose, serum cholesterol, FFA, insulin, LBP, adiponectin and leptin,in rats..High fat diet may have function in lowering the level of serum triglyceride and the expression of adiponectin mRNA in fat tissues, also can increase the expression of ghrelin mRNA in gastric tissues.2. In positive energy balance status with the same energy intake, different dietary fat intake had no effects on body weight, body fat, Lee’s index, serum LDL-C, FFA, insulin, LBP, adiponectin, leptin, ghrelin and obestatin。High fat diet may do harm such as increase blood glucose or reduce the level of HDL-C. On the other hand, high fat diet may do good like lowering the level of serum FFA and cholesterol.3. Different energy intake had some effects on intestinal microflora in rats, and the effects disappeared when energy intake became the same. |
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