Biological Assay of Inorganic Manganese for Chicks

MANY inorganic forms of manganese are available for use as supplements in poultry feeds. A suitable assay for biological availability of the element, however, is not available, and little is known of the relative utilization of the various supplemental sources by the chick. Early reports by Schaible et al. (1938) and Gallup and Norris (1939) stated that practically all the chemical forms were of equal value to the chick except for a few carbonate and silicate ores. In these studies, the only criterion of availability was the ability of the manganese supplement to prevent the occurrence of perosis. More recently, Hennig et al. (1967) reported that radioactive manganese as 54 MnCl2 was incorporated into the body of a chick to a significantly greater extent than manganese as 54 MnSO4 or 54 MnO2. Only a few of the products which are currently available for use as manganese supplements were tested, and the levels of…