INFLUENCE OF SPECIFIC BACTERIA AND A FILTERABLE AGENT ON THE GROWTH OF GNOTOBIOTIC CHICKS

Growth depression was induced in chicks and a collection of aerobic and anaerobic bacteria was isolated from the crop and caecum. The collection of bacteria was tested in gnotobiotic chickens for its ability to depress growth with and without a bacteria‐free faecal filtrate. None of the anaerobic bacteria depressed growth. Aerobic bacteria always depressed growth but only in the case of Streptococcus faecium was this statistically significant. The faecal filtrate also depressed growth. A statistically significant effect was obtained when faecal filtrate was combined with any of the following treatments: (a) the total collection of bacteria, (b) the aerobic group, (c) the anaerobic group, (d) Strep. faecalis var. liquefaciens, (e) Strep, faecium, (f) the unclassified streptococci, and (g) a group containing the lactobacilli and coliform organisms. The largest growth depression was obtained in chickens dosed with Strep, faecium and faecal filtrate. Copyright © 1979, Wiley Blackwell. All rights reserved