“…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.…”