The Effect Of Galactooligosaccharides On Intestinal Flora In Mice

Functional oligosaccharides refer to the bioactive substances that can not be digested by human digestive enzymes, directly reach to the large intestine. They play important roles in promoting the proliferation of bifidobacteria and other probiotics, improving immunity, anti-virus and anti-tumor. The scientists have paid great attention to some Functional Oligosaccharide, such as oligofructose, and xylose oligomer, Isomaltooligosaccharidev, however investigations on galactooligosaccharide(GOS) are few.Objectives:To explore the impact of GOS on intestinal flora, and their metabolites (mainly short chain fatty acids and lactate). To study the effect of GOS in prebiotics and provide evidence for further study on the GOS prebiotic mechanism.Methods:Total of40BALB/c male mice about20g weight were ramdomly divided into control, and low, middle, high dose groups, The gavage dosage of GOS were0.25g,0.50g and1.50g per kilograms of body weight for low, middle, and high dose groups respectively. The GOS gavage was given for consecutive14days, while the control group mice were given same volume of saline instead of GOS. The fresh feces of mice were colleced on the day before (the0th day), the7th and14th day of gavage. The feces were homogenized and diluted, then inoculated to have the bacteria growed and indentified. The number of intestinal flora, such as bifidobacteria, lactobacillus, enterobacter, enterococcus, and clostridiumperfringens in each fecal sample was quantified. The prebiotics index (PI) was calculated based on the flora quantity to evaluate the effect of GOS on the inestinal flora. The content of lactate and short chain fatty acid was measured by gas chromatography to study the effect of GOS on flora metabolites. The experimental data were processed and analyzed using SPSS12.0. Repeated measurement AN OVA was used to compare group mean. Dunnett t test was used to compare the group means between the control group and others. The significant level was a=0.05. Results:Seven days after the gavage of GOS, the numbers of intestinal bifidobacteria and lactobacillus were significantly higher in middle and high dose groups than the control group (P<0.01). The control mice showed significant larger number of intestinal Escherichia coli, enterococcus, and clostridiumperfringens than the all dose groups, high dose group, and middle and high dose groups respectively (P<0.01). The effect of GOS on intestinal flora was dose dependent.The number of intestinal bifidobacteria and lactobacillus were significantly higher on7th and14th days of GOS gavage in three doseage groups than day0(P<0.01). The numbers of intestinal Escherichia coli, enterococcus, and clostridium perfringens in low dose group on day14, in middle and high dose group on day7and14were significantly lower than that on day0(P<0.01).In all GOS gavage groups, the PI values were significantly higher than the control group on both day7and14, and the values were larger on day14than day7(P<0.01).The quantities of inteatinal acetic acid and ethacetic acid were significantly higher than that of the control group and day0(P<0.01) on7th and14th days of GOS gavage.GOS gavage for7days, the quantities of inteatinal lactate in middle and high dose groups were significantly higher than that in control group and before gavage (P<0.01). GOS gavage for14days, the intestinal lactate content was significantly higher in all dose groups than the control group and before gavage (P<0.01).Conclution:GOS can promote the proliferation of Bifidobacterium and Lactobacillus, inhibit the growth and reproduction of the Enterobacteriaceae, enterococci and Clostridium perfringens Clostridiumb. GOS can regulate gut microflora prebiotic.GOS can effect intestinal short chain fatty acid and lactate.GOS plays prebiotic effect through regulating intestinal flora and the contents of short chain fatty acid and lactate.