フラゾリドン添加飼料による鶏腸内細菌叢の変動に関する研究

抄録

Chickens were fed diets containing furazolidone and examined for changes in the intestinal flora. The results obtained are summarized as follows.
1) In the case of administration at the rate of 200 ppm for a week, total bacterial counts showed a decrease in the contents at various levels of the intestinal tract, except in those of the cecum.
2) In the bacterial flora, lactobacilli (facultative anaerobic) decreased and Streptococcus increased in percentage. Bifidobacterium (obligate anaerobic, Gram-positive, non-spore-forming rods), that was the most predominant organism in the cecum, underwent little change.
3) In the case of continual administration at the rate of 30 ppm, it was difficult to find any change in viable bacterial counts in the feces. Changes, however, occurred to the flora and type A_IIIof lactobacilli, classified by Ochi et al., grew to be predominant.
4) In the case of continual administration at the rate of 200 ppm, bacterial counts decreased after administration, Streptococcus increased in percentage coincidentally with an increase of the total bacterial flora. Type A_IIIof lactobacilli began to increase three weeks after administration, when the total bacterial count recovered nearly to the level seen before administration.
5) Lactobacillus was the most predominant organism in both control and administered groups. Judging from the results obtained from continual administration, a special type of lactobacilli may have increased to a marked extent, probably making the bacterial flora simple.