Energy and phosphorus evaluation of poultry meal fed to broiler chickens using a regression method

Abstract

Two experiments were conducted to determine energy (Exp. 1) and P (Exp. 2) utilization in poultry meal (PM) for broiler chickens. A total of 192 birds were allotted to 3 experimental diets in a randomized complete block design with BW as a blocking factor on d 15 and 16 post hatching in Exp. 1 and 2, respectively. Each diet was fed to 8 replicate cages with 8 birds per cage in both experiments. Initial BW of birds in Exp. 1 and 2 were 438 ± 76.9 g and 543 ± 50.2 g, respectively. Three corn-soybean meal-based diets were prepared to contain 0, 80, or 160 g/kg in Exp. 1 and 0, 50, or 100 g/kg in Exp. 2. In Exp. 1, the addition of PM to the reference diet linearly decreased (P < 0.01) the apparent ileal digestibility of DM and gross energy (GE), as well as the apparent total tract utilization (ATTU) of DM, GE, and N in diets; but did not affect the ileal digestible energy, ME, and MEn of diets. The ileal digestible energy, ME, and MEn of PM estimated by the regression method were 4,002, 3,756, and 3,430 kcal/kg DM, respectively, representing 58 to 68% of the GE in PM. In Exp. 2, graded concentration of PM in the reference diet linearly decreased (P < 0.05) ATTU of DM but linearly increased (P < 0.01) ATTU of P and quadratically increased ATTU of Ca in diets. The true ileal digestibility and true total tract utilization of P in PM estimated by the regression method were 77.5 and 79.0%, respectively. In conclusion, these results showed that inclusion of poultry meal in the diets of broiler chickens reduced the digestibility of GE but increased the utilization of P. The regression-estimated energy values and P digestibility of PM in the current studies may be used in diet formulation.

Keywords: broiler; energy; phosphorus; poultry meal; regression.