Relationship between the Metabolic Regulaton of Intestinal Microflora by Feeding Bifidobacterium and Host Hepatic Function

Abstract

We studied the effect of feeding Bifidobacterium breve 4006 on abnormal metabolic activities in intestinal microflora and the alteration of hepatic drug-metabolizing enzyme activity in animals. Abnormal metabolic activities in intestinal microflora were induced by feeding a diet supplemented with 3% L-lysine-1% -L-tryptophan (lys-try diet) or 40% egg white protein in human flora (HF) or conventional (Cv) rats, respectively. Feeding of B. breve 4006 and transgalactosylated oligosaccharide (TOS), a growth factor of B. breve 4006, caused a significant reduction of a number of microbial enzyme activities and metabolites in the urine and the intestinal contents of HF and CV rats. Moreover, feeding of B. breve 4006 to neonate rats showed a significant decrease in the population levels of Enterobacteriaceae and Bacteroidaceae in the gut. Hepatic aniline hydroxylase (AH) and aminopyrine -N-demethylase (AMD) activities decreased significantly below normal values in HF rats fed on a lys-trp diet. In contrast, normal levels of AH and AMD activities were maintained in HF rats fed B. breve and/or TOS. The same situation was also found in overall hepatic function. The development of AH and AMD activities in neonate rats was significantly enhanced by the feeding of B. breve 4006. This enhancement seems to be due to a potent decrease of Gram-negative bacteria in the gut. In agreement with this, AH and AMD activities in gnotobiotic mice associated with Klebsiella pneumoniae and B. breve 4006 were restored to the germ-free level, whereas in mice monoassociated with K. pneumoniae, the activities significantly decreased.