Effects of different feed enzyme combinations on apparent total tract digestibility of DM, N, phytate, DE, and ME in corn-soybean meal-DDGS based diets fed to pigs

Abstract Text: This study was to determine apparent total tract digestibility (ATTD) of DM, N, phytate, DE, and ME in a diet (54% corn, 21% soybean meal, 20%  DDGS, and 2% poultry fat, 3% others) fed to 16 barrows (27.5 ± 4.7 kg). Diets were mixed with 3 enzymes individually or in combinations. Enzymes were phytase (Ronozyme HiPhos, DSM, Parsippany, NJ), xylanase (Ronozyme WX), and protease (Ronozyme ProAct). Treatments were CON (no enzyme), Phy (phytase, 1,000 FYT/kg), Xyl (xylanase, 200 FXU/kg), Pro (protease, 15,000 PRO/kg), Phy+Xyl, Phy+Pro, Pro+Xyl, and Phy+Pro+Xyl. Pigs were individually housed in metabolic cages and assigned to treatment diets based on repeated 4 x 4 Latin square designs with 4 treatment diets and 4 periods. Each period consisted of 4 d adaptation and 3 d collection. Chromium oxide was used to indicate the beginning and the end of collection. Daily feed allowance was 0.09 x BW^0.75 kg divided to 2 equal amounts of meals fed at 0700 and 1700 h. Gross energy in diet, feed, and urine was measured using a bomb calorimeter (IKA, Wilmington, NC) and protein by a combustion method (LECO, St Joseph, MI) to calculate ME and ATTD of N. Use of enzymes did not affect ME and ATTD of DM. The DE tended to be greater for Pro+Xyl (P = 0.074; 3,552 Mcal/kg) and Phy+Pro+Xyl (P = 0.083; 3,566 Mcal/kg) compared with CON (3,512 kcal/kg). The ND of Phy+Pro+Xyl was greater (P < 0.05, 86.4%) than CON (83.7%). The PD of Phy (2,835 ug/g), Xyl (2,827 ug/g), Phy+Xyl (2,830 ug/g), Phy+Pro (2,832 ug/g), and Pro+Xyl (2,821 ug/g) were greater (P < 0.05) than CON (2,814 ug/g). Overall, a combinational use of enzymes (Phy+Pro+Xyl) improved DE and ATTD of N in corn-soybean meal-DDGS based diets. Phy, Xyl, and their combinations increased phytate degradation.

Keywords: phytase, pigs, protease, xylanase