The effect of dietary penicillin on the growth of gnotobiotic chickens monoassociated with streptococcus faecium

1. When Streptococcus faecium strain SY1 was established in the intestine of gnotobiotic chickens it depressed their growth. 2. Dietary penicillin relieved the growth depression and caused a significant reduction in the count of S. faecium in the intestinal contents and in the number of bacteria attached to the duodenum wall.