Factors Affecting the Metabolizable Energy Content of Poultry Feeds

THERE is evidence that the form in which a ration is fed may have a considerable influence upon its nutritional value. Heywang and Morgan (1944) observed that the efficiency of utilization of a chick ration was improved by pelleting. Robertson (1950) noted that crumbles allowed greater weight gains and better feed efficiencies than mash. The degree of improvement associated with pelleting or crumbling appeared to depend partly upon the fiber (Slinger et al., 1949; Bearse et al., 1952; Dymsza et al., 1955) and fat (Pepper et al., 1956; Combs, 1959) content of the rations. Several explanations have been offered for the responses attributed to pelleting. Lanson and Smyth (1955) stated that the increased density of the feed in pellet form allowed the birds to more readily fulfill their nutritional requirements. However, Hinds and Scott (1958) concluded that the response to pelleting was due largely to an improvement in the nutritional …