伴大豆球蛋白胃蛋白酶水解肽对大鼠肠道细菌区系变化的影响

Effects of Conglycinin Peptides on Development of Bacterial Community in Faeces of Rats

【目的】在分子水平上探讨伴大豆球蛋白水解肽对肠道双歧杆菌生长的影响。【方法】选取21日龄健康清洁级雄性SD大鼠,随机分为4个处理,每个处理3只,基础日粮预饲1周后,分别灌胃生理盐水(对照组)、伴大豆球蛋白液(Conglycinin组)、伴大豆球蛋白酶水解肽P2组分(P2-PTC组)、伴大豆球蛋白盐酸彻底水解液(HCl-FHC组),各0.5ml,1次/天。除对照组外,各处理组灌胃液体总含氮量相等(折合蛋白含量为0.5mg·ml-1),试验共21d。应用PCR-DGGE技术分析灌胃伴大豆球蛋白酶解肽对大鼠粪样细菌区系变化的影响,并采用连续稀释PCR的方法半定量研究伴大豆球蛋白酶解肽对大鼠肠道双歧杆菌数量的影响。【结果】灌胃伴大豆球蛋白酶解肽的大鼠在试验后第1周,其粪样微生物区系变化迅速,而后缓慢,最终形成稳定的体系,提示酶解肽在一定程度上影响了肠道细菌的组成,与对照组和蛋白盐酸彻底水解液组比较,肠道双歧杆菌数量明显增加。【结论】本试验在分子水平证明了伴大豆球蛋白水解肽对肠道双歧杆菌的生长有促进作用。

【Objective】 The objective of this experiment is to investigate the effect of conglycinin peptides on bifidobacteria in vivo under the molecular level.【Method】 Twelve male SD rats were randomly assigned into 4 groups,and each group was administered for 21d intragastrically with physiological saline （control group）,conglycinin （conglycinin group）,the most active fraction which isolated from pepsin-treated conglycinin （P2-PTC group） and HCl-full hydrolysis of conglycinin （HCl-FHC group） respectively,0.5 ml volume of administration with equal amount of nitrogen （0.5 mg·ml^-1） for each rat. PCR and denaturing gradient gel electrophoresis （DGGE） were used to monitor the development of bacterial community in faeces of rats which were administered intragastrically with conglycinin peptides. The regions V6 to V8 of the 16S rDNA of faecal bacteria were amplified. DGGE profiles of the PCR amplicons were compared by similarity analysis. 【Result】 Rats administered with conglycinin peptides,DGGE similarity analysis showed that the bacterial community in the faeces developed fast at the first week of experiment and relatively slow later. It suggested that conglycinin peptides were capable of modifying the bacterial composition of the caecal content in rats. To investigate the effect of conglycinin peptides on bifidobacteria in vivo,16S rDNA gene sequence specific for Bifidobacterium in fecal digesta were quantitatively detected by series dillution PCR. It was found that the number of bifidobacteria was increased in conglycinin peptides group compared with the control and HCl-FHC groups. 【Conclusion】 The results showed that conglycinin peptides can increase the growth of bifidobacteria in vivo.