Effect of Source of Calcium and Phosphorus on Antibiotic Potentiation and Egg Production of Caged Layers

Utilization of Calcium from Calcium Sulfate by Chicks and Laying Hens

“…The greater deposition of phosphorus in bones of chicks fed calcium sulfate (Table 4) seems analogous to the improved tetracycline absorption when limestone is replaced by calcium sulfate (Eoff et al, 1962). It was previously shown that absorption of both tetracycline and phosphorus is depressed with high dietary levels of calcium (Price et al, 1959;de-Lange, 1961), probably by forming complexes of low absorbability.…”

Potentiation of Chlortetracycline in Laying Chickens

“…They also observed that feeding rations containing 1.7% or less of calcium resulted in a lowered rate of egg production. Eoff et al (1962b) were unable to show a consistent potentiating effect from the substitution of calcium sulphate for oyster shell flour in rations containing different sources of phosphorus. While TPA has been used in laying rations (Eoff et al, 1962a;Slinger et al, 1962) without any apparent adverse effects, no data are available to indicate whether the use of the compound resulted in higher levels of antibiotic in the blood serum of the birds.…”