LAUSR

Three experiments were conducted to determine the metabolizable energy (ME) and nitrogen-corrected ME (MEn) contents of hydrolyzed feather meal (HFM) and flash-dried poultry protein (FDPP) for broiler chickens and to determine their digestible energy (DE) and ME for pigs. The energy-yielding ingredients in a reference diet (RD) were replaced at 0, 75, or 150 g/kg by HFM in experiment (Exp.) 1; at 0, 75, or 150 g/kg by FDPP in Exp. 2; and at 0, 150 g/kg HFM, or 150 g/kg FDPP in Exp. 3. Birds were fed a standard broiler starter diet from hatch to d 18 and 17 for respective Exp. 1 and 2, following which 144 birds (8 replicate cages of 6 birds per cage) were assigned to the 3 experimental diets in a randomized complete block design with body weight as the blocking factor. Experimental diets were fed for 5 d, and excreta were collected during the last 3 d. Twenty-four 20-kg barrows, individually housed in metabolic crates equipped with a feeder and drinker, were used in Exp. 3. The barrows were assigned to the 3 experimental diets in a randomized complete block design with body weight as a blocking factor. Following a 5-d adaptation period, feces and urine were collected for 5 d in a total collection method. Data were used to determine the regression-derived ME and MEn of HFM and FDPP for broiler chickens in Exp. 1 and 2, respectively. The DE and ME of HFM and FDPP for pigs in Exp. 3 were determined using the difference procedure. In Exp. 1, the inclusion of HFM linearly increased (P < 0.05) ME from 3,231 to 3,368 kcal/kg DM for 0 to 150 g/kg replacement of RD. The total tract retention of DM and metabolizability of energy linearly increased (P < 0.05) as replacement of RD with FDPP increased from 0 to 150 g/kg in Exp. 2. Inclusion of FDPP linearly increased (P < 0.01) ME from 3,425 to 3,591 kcal/kg DM. In Exp. 3, the diets containing 150 g/kg HFM or FDPP induced greater (P < 0.05) fecal DM and energy losses than the RD, however, the digestibility of energy across the 3 experimental diets was not different. The respective regression-derived ME and MEn of hydrolyzed feather meal for broiler chickens in the current study were 4,250 and 3,745 kcal/kg DM with corresponding values of 4,710 and 4,081 kcal/kg DM for flash-dried poultry protein. In pigs, 4,783 and 4,405 kcal/kg DM were the respective DE and ME of hydrolyzed feather meal, and 4,553 and 4,320 kcal/kg DM were the corresponding estimates for flash-dried poultry protein.