Use of Neutron Activation Analysis in the Determination of Digestibility with Cerium as an Inert Marker

Abstract

Along-Standing problem in ruminant nutrition has been to find a suitable marker for determination of ration digestibility. Chromic oxide, plant chromagens and lignin have been used as inert indicators with varying degrees of success (Reid et al., 1950; Elam et al., 1962). The rare earth elements have the characteristics of ideal inert indicators. Gamer, Jones and Ekman (1960) showed that 144Ce is absorbed to a very small extent in the gut of the ruminant and suggested its use as a marker in digestibility trials. Huston and Ellis (1968) studied the affinity of radioactive cerium for feedstuffs and digesta particles in in vitro experiments and found that cerium was rapidly adsorbed onto and remained tenaciously bound to digesta particles. Padgitt, Martz and Graham (1966) used 144Ce for determining the digestibility of feedstuffs in growing rabbits, and Ellis and Huston (1968) tested radioactive cerium as a particulate flow marker in sheep with favorable results.