Effect of Feeding Escherichia coli to Turkey Poults and Chicks in the Presence of Certain Antibiotics

Abstract

DURING the past few years, great importance has been ascribed to shifts in bacterial population of the gut as a major factor in explaining the growth-stimulating action of antibiotics. Supporting this theory is the fact that zinc bacitracin, a complex polypeptide molecule, is not absorbed into the blood stream, so any improvement in growth must result from its action in the digestive tract. Tetracycline-type antibiotics, on the other hand, are absorbed into the blood stream to some extent and so could act systemically as well as enterically. Furthermore, “broad-spectrum” antibiotics, such as the tetracycline-type inhibit both gram-positive and gram-negative organisms; whereas, “narrow-spectrum” antibiotics, such as penicillin and bacitracin, act more specifically against the common, disease-producing, gram-positive forms.The bacteriological approach has appealed to many workers since it was demonstrated early (Coates et al., 1951, 1952; Bird et al., 1952; Hill et al., 1953; Jacobs et al., 1953; and Waibel et …