FEEDING AND EXCRETA COLLECTION TECHNIQUES IN METABOLIZABLE ENERGY ASSAYS FOR DUCKS

Feeding and excreta collection techniques, lasting 102 h, for the dete rmination of ME in feed ingredients for ducks are described. Eight and 32 h after feed withdrawal, all ducks received 30 g of dextrose in 10 0 g of water by orogastric administration. By orogastric administratio n, ducks received 30 g of test ingredients or dextrose (for ducks used in estimation of endogenous losses of energy and nitrogen) in 100 g o f water at 48 and 54 h after feed withdrawal. The collection of excret a involved suturing a threaded plastic retainer ring to the vent and s crewing a Whirl-Pak(TM) plastic bag, mounted on the top portion of a P laytex(TM) baby nurser set plastic bottle cut off 3 cm below the threa ds, to the retainer ring. Excreta were collected by replacing the Whir l-Pak(TM) bags at 54, 60, 72, 84, 96, and 102 h after feed withdrawal. In each of two experiments, ducks with an average weight of 3.7 kg we re assigned to treatments. In Experiment 1, four ducks were assigned t o each of three test ingredients (corn, dehulled oats, and wheat) and four ducks were assigned to be deprived of feed for estimation of endo genous losses of nitrogen and energy. In Experiment 2, six ducks were assigned to each of two test ingredients (corn and sorghum) and six du cks were assigned to be deprived of feed. Ducks lost an average of 537 g (Experiment 1) and 462 g (Experiment 2) during the 102-h experiment al period and all the lost weight was regained within 7 d of return to full feed. Losses of nitrogen (milligrams per duck per 54 h) were 292 (Experiment 1) and 461 (Experiment 2) and energy (kilocalories per du ck per 54 h) were 12.12 and 22.26 in feed-deprived group. The determin ed AME(n) and TMEn for corn were 3.245 and 3.407, and 3.210 and 3.517 kcal/g for Experiments 1 and 2, respectively. For dehulled oats, wheat , and sorghum, the determined AME(n) and TMEn were 3.464 and 3.625, 3. 150 and 3.312, and 3.363 and 3.670 kcal/g, respectively.