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 bifido acteria 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.

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Two encapsulation techniques were applied to Bifidobacterium longum RO23 with the aim of increasing the stability of dried cultures during storage. Commercial freeze-dried cultures of B. longum RO23 were spray-coated with gelatin, xanthan gum or milk fat. The resulting products had water contents which varied from 4.3% (milk fat) to 7.1% water (xanthan gum). Viable counts and acidifying activities of the milk fat-coated cultures were slightly higher than the untreated control after 9 months of storage at 20 °C. The other spray-coated products had lower stability to storage than the untreated control. This might be related to the water contents of the cultures, rather than the coatings themselves, since a correlation was found between water content and storage stability. The addition of oxygen absorbers to 30 ml vials containing 3 g of powder was detrimental to the stability of the cultures. This was potentially due to a 3-4% increase in the water content of the powders under these experimental conditions. Further evaluation of the effect of oxygen absorbers must be made in conditions where water levels remain constant. Cultures of B. longum RO23 were also encapsulated by cocrystallization in lactose. Cocrystallization did not enable a substantial concentration of the culture during formation of the lactose precipitate. Great mortality occurred during the 19 hr crystallization incubation as a 5 log reduction in population was recorded. The survival rate to freeze-drying of the bifidobacteria-containing lactose crystals was estimated at 20%.

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Intact cell suspension and/or growing cells of Micrococcus sp. produced a large amount of D-xylonic acid from D-xylose. Utilization of D-xylonic acid by intestinal microorganisms was studied. All 5 species of the genera Bifidobacterium, B. adolescentis M101-4, B. bifidum A234-4, B. breve 153-8, B. infantis I-10-5 and B. longum M101-2, showed good growth on basal medium containing D-xylonic acid. Escherichia coli utilized well Dxylonic acid but not fructooligosaccharides.

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The gingival tissues from SUS rats with naturally occurring gingivitis were examined histopathologically. The observations indicated that the inflammation at the early stage was severe neutrophilic infiltration with edema and that the lesion progressed to subacute-chronic inflammation rich in plasma cellular infiltration. Electron microscopic observation indicated that rod-shaped bacteria were present in the connective tissue of gingiva at both inflammation stages. RES rats (control) showed no gingival inflammation and bacterial invasion on the surface of the gingiva. These findings suggested that bacterial invasion can occur at all stages of naturally occurring gingivitis and that it directly affects the gingival tissues

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