Energy and nutrient utilization responses of ducks to enzyme supplementation of soybean meal and wheat

Abstract

The potential benefits of exogenous dietary enzymes in duck nutrition have been studied to a limited extent. Thus, the effects of protease and a cocktail of xylanase, amylase, and protease (Avizyme) on dry matter (DM), energy and nitrogen (N) utilization from soybean meal (SBM) and wheat, respectively, were investigated in White Pekin ducks in two 102-h studies. In exp. 1, three dietary treatments consisting of SBM supplemented with 0, 7500, or 15 000 units of protease acitivity kg-1 of soybean meal were each tube-fed to 12 ducks (4.41 ± 0.302 kg). In exp. 2, three dietary treatments consisting of wheat supplemented with 0, 450 units of xylanase, 600 units of amylase, and 6000 units of protease activity kg-1 or 600 units of xylanase, 800 units of amylase, and 12 000 units of protease activity kg-1 of wheat were each tube-fed to eight ducks (4.07 ± 0.363 kg). All birds were tube fed 30 g of dextrose at 24 and 30 h after feed withdrawal. Thirty grams of each diet were tube-fed at 48 and 54 h after feed withdrawal. Excreta were quantitatively collected during the 54 h after the first feeding. Endogenous energy and N per bird in the 54 h collection period in exp. 1 were 50.7 kcal ± 27.51 kcal and 1.595 ± 0.635 g, respectively. Corresponding values for exp. 2 were 27.5 ± 16.7 kcal and 0.96 ± 0.619 g, respectively. Protease supplementation to SBM improved energy (P < 0.05) utilization and tended to improve DM and N (P < 0.10) compared with the control. The AME, AMEn, TME, and TMEn values were higher (P < 0.05) in protease-supplemented SBM than in control. Avizyme addition to wheat did not affect DM or N utilization (P > 0.10). The only response criteria improved (P < 0.05) by Avizyme supplementation of wheat were AMEn and TMEn. It is concluded that energy and nutrient utilization in White Pekin ducks can be improved with exogenous dietary enzyme supplementation. Key words: Exogenous enzymes, energy and nitrogen metabolism, wheat, soybean meal,