The Influence of EDTA on Blood Antibiotic Levels Following Oral Administration of Tetracycline Compounds

CONSIDERABLE effort has been devoted to increasing the concentration of tetracycline compounds in the blood when a given level of the antibiotic is administered orally. Techniques used to date have not proven entirely satisfactory and thus the search has continued for a practical means of potentiating broad spectrum antibiotics in poultry rations. Price et al. (1959) demonstrated that the calcium ion inhibited absorption of orally administered tetracycline compounds. Reduction of the dietary calcium level from 1.18 to 0.18% resulted in more than a two-fold increase in serum levels of oxytetracycline (OTC) or chlortetracycline (CTC). Harms and Waldroup (1961) reported maximum blood OTC levels when the diet contained a suboptimum level of calcium. Peterson (1958) reported that the addition of terephthalic acid to a poultry mash containing CTC resulted in a four-fold increase in serum antibiotic levels. A report by Eisner et al. (1953) indicated that oral administration of certain organic . . .