The Assessment of the Antibiotic Growth Response in the Chick

Abstract COATES et al. (1951COATES et al. (1953) reported that chicks responded to antibiotics only when they were housed in old quarters. It has been our experience that under clean laboratory conditions the response of chicks to antibiotics was not consistent. Thus, we deliberately introduced contamination in the form of raw hen feces in the diet in order to obtain consistent antibiotic response in the chick. The purpose of these studies was to develop a method for the measurement of the antibiotic growth effect in the chick suitable for use in the laboratory and thereby to examine several compounds which possess structural or bactericidal similarity to certain antibiotics. EXPERIMENTAL Day-old crossbred Columbian X New Hampshire female chicks were employed. The chicks were housed in Petersime temperature-controlled batteries with raised wire floors. Feed and water were given ad libitum. Growth data were recorded at weekly intervals. The experiments were of four weeks’ duration. The …