616 RESEARCH NOTES EFFECT OF ANTIBIOTICS, SYNTHETIC VITAMINS, VITAMIN B AND AN APF SUPPLEMENT ON CHICK GROWTH1

Stokstad el al. (1949) reported that the animal protein factor was multiple in nature and evidence was presented show-ing that a whole fermented mash resulting from the growth of Streptomyces aureo-faciens in deep aerobic culture contained an unidentified chick growth factor(s). Since the fermentation product Stokstad et al. employed was a whole mash it oc-curred to us that this material may have contained significant quantities of the antibiotic aureomycin which conceivably could have influenced growth in a pro-found manner. The concept of antibiotics playing a role in the growth effect was brought to mind by the report of Moore el al. (1946) who showed that the feeding of streptomycin or sulfasuxidine to chicks on purified diets resulted in greatly ac-celerated growth. The present study therefore was undertaken to determine the effect of antibiotics on chick growth and to ascertain whether such activity might explain, in part at least, the growth pro-moting properties of the fermentation product used by Stokstad et al. Rhode Island Red chicks (from dam