Effect of administration of enteral feedings on the intestinal microflora of Macaca fascicularis

Changes in the intestinal microflora of Macaca fascicularis fed with two different enteral feedings were studied. Enteral feedings used are S-185 and ED-AC, which differ from each other in composition, especially in the source of nitrogen, carbohydrate and fat. Eight monkeys with an average age of five were divided into two groups and fed with each feedings at each four weeks (crossover method). From statistical analysis of microbial counts, both feedings appeared to have affected the constitution of three microbial groups, namely Streptococcus, Bifidobacterium and Peptococcaceae, present in the feces. The counts of Bifidobacterium were higher (ca. 1010/g-feces) in the monkeys fed with S-185 than in those fed with ED-AC (106-108/g-feces). In contrast, Streptococcus and Peptococcaceae became slightly higher (107-108/g-feces, 109/g-feces, respectively) when the monkeys were fed with ED-AD, compared to the group fed with S-185 (105-108/g-feces, 108-109/g-feces, respectively). Competition was found between Bifidobacterium and Bacteroidaceae in both groups, so that Bifidobacterium was higher than Bacteroidaceae in the monkeys fed with S-185. This phenomenon was reversed in the monkeys fed with ED-AC. Changes in the constitution of microflora may have resulted from the difference in the composition of two enteral nutritions, especially in the difference of nitrogen and carbohydrate sources. The predominancy of Bifidobacterium in the monkeys fed with S-185 may be supported by the fact that lactose and oligosaccharides contained in S-185 can be transported to the lower digestive tract, where Bifidobacterium exists, without being absorbed from small intestine. S-185 is considered better than ED-AC regarding the increase of Bifidobacterium in the digestive tract. These results might be apply to the adult human.