本文研究了香蕉抗性淀粉对高脂饮食菌群人源化小鼠(HFA)肠道菌群的调控效果。将30只肠道菌群人源化昆明小鼠随机分为3组(10只/组),分别饲喂普通饮食、高脂饮食和高脂饮食+抗性淀粉。提取第0周和第8周新鲜粪便DNA,比较用16S r DNAV6-V8区段特异性引物扩增产物,以PCR-DGGE技术手段检测抗性淀粉组、高脂饮食组和普通饮食组肠道菌群差异。第0周,三组小鼠菌群总菌丰富度,多样性指数和均匀度无显著差异(p>0.05),小鼠和粪便供者之间菌群相似性为36%;三组小鼠肠道菌群相似性达到60-93%,PCA分析显示三组小鼠的数据点都聚在一起,说明在干预前无明显差异,适用于分析抗性淀粉对肠道菌群的影响;膳食干涉第8周后小鼠肠道菌群的多样性指数和丰富度数值,抗性淀粉组都极显著低于高脂组和普通饲料组(p<0.01),PCA分析也显示三组小鼠肠道菌群各组的数据点都分布在不同区域,说明抗性淀粉对高脂饮食HFA小鼠肠道菌群结构产生显著影响。
Short chain fatty acids(SCFA)are the main products of indigestible carbohydrates undergoing bacterial fermentation in the hindgut,which are related to some physiological functions.This study was designed to investigate the effects of SCFA infusion by ileum on the carcass traits,meat quality and lipid meta-bolism of growing pigs.In a 28-day study,24 growing barrows fitted with a T-cannula in distal ileum were divided into 4 treatments:1)Control,2)antibiotics(AB),3)AB+300 mL of SCFA1 solution(ABS1),4)AB+300 mL of SCFA2 solution(ABS2).The concentrations of acetate,propionate and butyrate in SCFA1 solution were respectively 61.84,18.62 and 12.55 mmol/L,and in SCFA2 were respectively 40.08,15.41 and 9.78 mmol/L The results showed that the SCFA infusion increased the average daily feed intake and average daily gain of pigs(P<0.05).Meanwhile,the SCFA treatments increased longissimus dorsi area(P<0.05)and carcass weight(P=0.058),decreased the drip loss of longissimus dorsi(P=0.059),and reduced serum concentrations of triglyceride,total cholesterol and urea nitrogen(P<0.05).Besides,the SCFA administration inhibited the mRNA expressions of fatty acid synthase(FAS)and acetyl-CoA carboxylase in longissimus dorsi(P<0.05),the mRNA expression of FAS in the liver(P<0.05),and the mRNA expression of hormone-sensitive lipase in abdominal fat(P<0.05).Short chain fatty acid infusion also enhanced the mRNA expression of carnitine palmitoyltransferase-1αin the liver(P<0.05),the mRNA expressions of peroxisome proliferator activated receptor gamma and lipoprotein lipase in abdominal fat(P<0.05),and the mRNA expressions of free fatty acid receptor 2,glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon(P<0.05).These results suggested that SCFA administration in the ileum could improve the carcass traits and meat quality of growing pigs,which was possibly due to the fact that SCFA modulated lipid metabolism.
