A New Precision–Fed Chick Assay for Determining True Metabolizable Energy Values of some Poultry Feed Ingredients for Broiler Chickens

Two experiments were conducted to determine: first, the best time of excreta collection after force feeding of broilers to yield the maximal amount of excreta, and second, nitrogen-corrected true metabolizable energy contents of some poultry feedstuffs including yellow corn, soybean meal, corn gluten meal, canola meal and poultry by-product meal by a new precision-fed chick assay using 3-week-old broiler chicks. In experiment one, thirty-five 21-d-old male broiler chicks, with the same body weight were randomly assigned in to 7 experimental groups with 5 birds per each. Seven experimental treatments were designed with different excreta collection times. All chicks were precision-fed with 10 g of corn-soybean meal (60:40) mixture. Excreta were collected at 2, 4, 6, 8, 10, 12, and 14 h after precision feeding. In experiment two, thirty 21-d old male broiler chicks with 5 chicks per each feed ingredients were precision-fed by 10 g of experimental feedstuffs and 5 chicks fasted for determining endogenous energy losses. The maximum time of excreta collection for 3-week-old male broiler chicks was approximately 12 h after precision feeding. The average nitrogen-corrected true metabolizable energy values of yellow corn, soybean meal, corn gluten meal, canola meal and poultry by-product meal, were 3527.55, 2572.4, 4183.25, 1806.38 and 2678.06 kcal/kg, respectively. In conclusion, nitrogen-corrected true metabolizable energy values of feed-stuffs can be determined in 3-week-old broiler chicks by using a precision-fed assay. This research suggests using energy values obtained on young broiler chicks in formulating diets for the same birds.