Effect of combination of glycerol monolaurate, fructooligosaccharides, and lactic acid bacteria on fecal microflora in ICR mouse model

다국어 초록 (Multilingual Abstract)

Because the intestinal flora is important in the maintaining the health of the host, it has gained much attention recently. Glycerol monolaurate (GML) is known to inhibit various harmful bacteria without inhibiting the growth of lactic acid bacteria (LAB) such as Bifidobacterium and Lactobacillus at the 100 ppm level while fructooligosaccharides (FOS) are prebiotic food materials which can selectively promote the growth of LAB. The objective of this study was to observe the effect of combination diets containing GML, FOS, and LAB on the composition of the fecal microflora. The experimental diets contained GML 1 mg, FOS 5 mg, and LAB (B. bifidum BGN4, B. longum BORI, L. acidophilus AD031 at a ratio of 3:3:4) 4 x 108 CFU each and their combinations per 1 g of feed. Mice (n=56) were fed the experimental diets for 2 weeks, and fecal samples were collected once a week. Total bacteria, Bifidobacterium spp., Lactobacillus spp., Bacteroides spp., Clostridium butyricum and Enterobacter spp. & Escherichia spp. were analyzed with real-time PCR. After 1 week, the number of Lactobacillus spp. was significantly increased in the LAB, FOS, GML, LAB+FOS and LAB+GML groups (p < 0.01). The number of Bifidobacterium spp. was significantly increased in the LAB+FOS group (p < 0.05). The numbers of Enterobacter spp. & Escherichia spp. were significantly decreased in the FOS and LAB+FOS+GML groups. After 2 weeks, the number of Bacteroides spp. was significantly reduced in the LAB, FOS, FOS+GML and LAB+FOS groups. The GML alone group did not change the number of Bacteroides spp. and Enterobacter spp. & Escherichia spp. Noticeably, a significant increase in the number of Bifidobacterium spp. was observed in mice with a combination of LAB and FOS (LAB+FOS), whereas the increase was not significant in the LAB alone and FOS alone groups. Taken together, the combination of LAB and FOS, but not with GML, could be more effective than LAB or FOS alone in improving beneficial intestinal microflora.

목차 (Table of Contents)

• 1. Introduction 1
• 2. Materials and Methods 4
• 2.1. Microorganisms 4
• 2.2. Preparation of diets and animals 5
• 2.3. DNA extraction from bacterial cell and feces 6
• 2.4. Optimization of real-time PCR conditions for primers for fecal microflora analysis 6
• 2.5. Standard curves for calculation of the number of target bacteria 9
• 2.6. Fecal microflora analysis using real-time PCR 10
• 2.7. Statistical analysis 10
• 3. Results 12
• 3.1. Optimization of real-time PCR conditions for primers 12
• 3.2. Alteration of fecal microflora in ICR mice 12
• 3.2.1. Alteration of the number of Lactobacillus spp. 15
• 3.2.2. Alteration of the number of Bifidobacterium spp. 18
• 3.2.3. Alteration of the number of Bacteroides spp. 21
• 3.2.4. Alteration of the number of Enterobacter spp. & Escherichia spp. 24
• 4. Discussion 27
• 5. Conclusion 30
• References 31
• Abstract in Korean 40