Improvement in Intestinal Flora Regulation and Laxative Function to Lactobacillus paracasei K56

Objective:To study the regulatory effect of a Lactobacillus paracasei K56 on intestinal flora and laxative function in mice according to the technical specification for health food inspection and evaluation in China(2003 edition).Methods:The mice were administered by gavage with 0.000867,0.00867,0.0867,0.867,8.67 mg/kg Lactobacillus paracasei K56(The specification was 1.5×10¹¹ CFU/g)and the amounts of Bifidobacteria,Lactobacilli,Enterobacter,Enterococci,and Clostridium perfringens were detected before and after mice administered with Lactobacillus paracasei K56 for 14 d. After intervention the mice were sacrificed and movement rate of black ink in the small intestine,time of the first evacuation of black stool,and number and weight of black fecal pellets were measured. Results:The control group and all intervention groups had higher abundance in Bifidobacteria,Lactobacilli,and C. perfringens in the feces after 14 d(P<0.05)and no significant differences for Enterobacter and Enterococcus species(P>0.05). Compared to the normal control group,the numbers of Bifidobacteria and Lactobacilli increased significantly after receiving 0.00867,0.0867,0.867 mg/kg. L. paracasei K56(P<0.05),although the number of C. perfringens significantly raised in the 0.000867,0.00867,0.867 mg/kg groups(P<0.05). Compared with model group,the movement rate of ink in the small intestine increased significantly in group receiving 0.00867,0.867,8.67 mg/kg. L. paracasei K56 per day(P<0.05),and the numbers and weight of black fecal pellets were more in groups of 0.0867,0.867 mg/kg(P<0.05).The time of the first evacuation of black stool in all groups were not significantly different. Conclusion:This study verified that the probiotic strain Lactobacillus paracasei K56 exerted beneficial effect on regulating intestinal flora and relaxing bowel,implying its use as a functional ingredient in food products. The most effective dose of K56 on regulating intestinal flora was 0.0867 mg/kg(Person dose was 1.0×10⁸ CFU/d)and the minimum effective dose for the laxative function was 0.867 mg/kg(Person dose was 10⁹ CFU/g).