Effect of the previous diet, body weight, and duration of starvation of the assay bird on the true metabolizable energy value of corn.

Two experiments were conducted with 36 adult White Leghorn roosters to determine the effect of previous intake of protein (Experiment 1) or purified cellulose (Experiment 2), body weight, and duration of starvation of the assay bird on the true metabolizable energy (TME) value of ground yellow corn. The mean TME value (+/- SE) of the corn was 4.06 +/- .03 and 4.06 +/- .04 kcal/g of dry matter in Experiment 1 and 2, respectively. Dietary levels of 10, 20, and 30% protein or 0, 7.5, and 15.0% supplementary cellulose, and body weight distribution had no significant (P greater than .05) effect on the TME value of the corn. Starvation for 12 hr before force feeding resulted in a significant (P less than .05) decrease of 4% in the TME value of the corn, whereas fasting periods of 24 or 48 hr had no significant effect. It is suggested that the assay birds be paired on the basis of body weight and starved for a minimum period of 24 hr prior to force feeding to reduce the variation associated with the estimate of TME.