Effect of Vitamin Restriction on Cecal Microflora and Fermentation in Mice

Experiments were conducted to examine the effect of different vitamin mixture contents in a diet on the cecal microflora and short-chain fatty acid concentrations in male ICR mice. Mice fed a vitamin-free diet showed a profound increase in the numbers of enterobacteriaceae and enterococci and a significant increase in bacteroidaceae in the cecum, while they showed no remarkable changes in the numbers of lactobacilli, bifidobacteria and anaerobic gram-positive cocci. Short-chain fatty acid (SCFA) concentrations were profoundly reduced by the vitamin-free regimen. Mice on a 0.3% vitamin diet showed significant decreases in enterobacteriaceae and enterococci and a significant increase in bifidobacteria as compared to animals on a 1% vitamin diet (basal) although their body wcight gain was approximately 60% of the animals fed the basal or 2% vitamin diet. SCFAs showed decreased concentrations; in particular butyrate and valerate were significantly reduced in the 0.3% vitamin group compared to the basal group. The 2% vitamin mixture group showed no significant differences from the 1% vitamin group in cecal microflora composition and SCFA concentrations.