Zinc Requirement Studies with Practical Rations

STUDIES on the zinc requirement of chicks by Young, Edwards and Gillis (1958) using a purified diet has shown that not more than 55 ppm. zinc was required for maximum rate of growth. Mehring, Brumbaugh and Titus (1956) studied the effect of supplementing a practical corn-soybean meal type diet with zinc. Their basal diet contained 36 ppm. zinc, and the drinking water supplied additional zinc to give a total zinc intake of 42–45 ppm. for chicks fed the basal diet. Further increases to approximately 820 ppm. failed to stimulate or depress growth. Since simple practical type corn-soybean meal diets contain approximately 40 ppm. of zinc it seemed possible that under certain conditions zinc supplementation may be necessary for maximum rate of growth. Therefore the following studies were carried out to obtain more information on the need for zinc supplementation in practical diets. EXPERIMENTAL Day old White Rock chicks were used …