Amino acid digestibility of corn, pearl millet, and sorghum for white Pekin ducks, Anas platyrinchos domesticus

The objective of the present experiment was to determine the digestibility of amino acids and nitrogencorrected apparent (AMEn) and true (TMEn) metabolizable energy contents of corn, pearl millet, and sorghum for White Pekin ducks. Fasting losses of nitrogen, amino acids, and energy were obtained from six drakes; and six drakes were assigned to each of corn, pearl millet, and sorghum. Each experiment lasted 102 h with an initial 48-h period and a 54-h excreta collection period. During the first 48-h period, all birds were tube-fed dextrose (30 g/100 mL of water) at 8 and 32 h after feed was withdrawn. Each feedstuff was tube-fed (30 g/100 mL of water; or 30 g dextrose for birds from which fasting losses were obtained) at 48 and 54h after feed withdrawal. Excreta were collected during the last 54 h into bags screwed onto lids sutured around the vent of each bird. Fasting nitrogen and energy losses per bird were 668 mg and 38kcal, respectively. Fasting losses of amino acids ranged from 22 mg for leucine to 128 mg for glutamate. The TMEn values for corn, pearl millet, and sorghum were 3.75 1, 3.777, and 3.620 kcal/g, respectively. Because of the differences in nitrogen retention between ducks fed pearl millet and corn. TMEn contents of pearl millet were greater (P0.05) than those of sorghum. Of the amino acids considered, only leucine showed ingredient-related differences in true digestibility with corn (92.4%) and pearl millet (%66%) being greater (P0.05) than sorghum (89.97%). The true digestibility of lysine (79.75, 78.85, or 79.5%), methionine (89.01, 88.42, or 89.15%), and tryptophan (97.46, 96.4, or 94.9%) were not different among corn, pearl millet, or sorghum, respectively. The data provide new information on amino acid digestibility values as well as AMEn and TMEn contents of corn, pearl millet, and sorghum for ducks.