Oral absorption of chlortetracycline in turkeys: influence of citric acid and Pasteurella multocida infection.

Plasma and tissue concentrations, following the oral administration of the antibiotic chlortetracycline (CTC) alone or with citric acid, were determined in healthy and infected (Pasteurella multocida) turkeys. The principal results were: 1) The dose (of CTC) versus plasma level relationship was nearly linear. 2) Addition of citric acid to an oral preparation produced significantly higher plasma levels when divalent cations Ca2+ (.3 g/liter) and Mg2+ (.1 g/liter) were present in the drinking water and dosage solution than when citric acid was omitted. 3) The concentration of CTC was considerably higher in the liver and kidney than in the muscle and brain. 4) Birds infected with P. multocida had significantly higher plasma levels than healthy birds. 5) Oral administration of CTC increased the survival rate of the birds infected with P. multocida.