Abstract:

【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.

Key words: conglycinin, conglycinin peptides, DGGE, bacterial community, bifidobacteria