Abstract
Feed enzymes may ameliorate reduced nutrient and energy digestibility in nursery pigs. The objective was to test effects of super-dosing phytase and fiber-degrading enzymes on digestibility of DM, GE, CP, AA, and Ca. We tested supplementing a super dose (added 1,500 FYT/kg) of phytase (Ronozyme Hi-Phos) with or without carbohydrase cocktail that contained 85 FXU β-xylanase/kg, 587 U/g endo-1,4-β-glucanase, 513 U/g endo-1,3(4)-β-glucanase, 15,000 U/g hemicellulases, and 3,000 U/g pectinases in corn-soybean meal diets in a 2 × 2 factorial arrangement. Diets included 68% corn, 17% SBM, and a basal level of 500 FTU/kg of phytase, and were formulated to contain 2.50 Mcal/kg NE and 5.10 gSID Lys/Mcal NE. Eight ileal-cannulated nursery pigs (initial BW 10 kg) were fed 4 diets at 3.0 × maintenance DE (110 kcal per kg of BW0.75) for four 9-day periods in a double 4 × 4 Latin square. Apparent hindgut fermentation (AHF) was calculated as apparent total tract digestibility (ATTD) minus apparent ileal digestibility (AID). Interactions between super-dosing phytase and carbohydrase cocktail were observed. Supplementing either carbohydrase cocktail or super dose phytase, but not their combination, increased (P < 0.05) diet AID of DM, GE, CP, and most AA by 4–5%-units. Supplementing super dose phytase increased (P < 0.05) AID of P by 16%-units and ATTD of P by 10%-units. Supplementing super dose phytase or carbohydrase cocktail did not affect AID of Ca and ATTD of GE, CP, and Ca, and diet DE value. Supplementing carbohydrase cocktail without super dose phytase decreased (P < 0.05) diet AHF of DM, GE, and CP. In conclusion, dietary inclusion of super dose phytase or carbohydrase cocktail increased ileal digestibility of nutrients in nursery pigs, and thereby reduced protein entering the large intestine. Additive or synergistic effects of carbohydrase cocktail and super dose phytase were not detected.
