Comparison of low dietary calcium and sodium sulfate for the potentiation of tetracycline antibiotics in broiler diets.

Three experiments were conducted to compare different methods of short-term potentiation of tetracycline antibiotics for broiler chicks. Reduction of dietary calcium and addition to sodium sulfate were compared in different combinations with various levels of chlortetracycline (CTC) and oxytetracycline (OTC). Reducing dietary calcium from 0.8 to 0.4% significantly increased serum levels of CTC and OTC. Adding sodium sulfate (1.25%) also increased serum levels; the majority of the response occurred at the higher calcium level. There was no benefit from adding sodium sulfate to the low-calcium diet. Neither body weight gain nor feed utilization were adversely affected during the 5-day test period.