Effects of an enzyme blend in diets of different nutrient density fed to nursery pigs

Two 35-d experiments were conducted with four or five pigs per pen and 12 pens per treatment to determine the effects of an enzyme blend, containing carbohydrases and protease, in late nursery pig diets. In Exp. 1, 355 pigs (DNA 241 × 600, initially 13.3 ± 0.23 kg) were used to determine the effects of an enzyme blend in diets of different nutrient density. Pigs were blocked by body weight and allotted to one of six treatments, including 2 corn-soybean meal-based (CS) diets with 0 or 0.01% enzyme blend and four diets containing corn, soybean meal, wheat middlings, and low-oil corn dried distillers grains with solubles (CSBP) with 0, 0.01, 0.02, or 0.03% added enzyme. The CSBP diets were formulated to achieve a 77 kcal/kg reduction in net energy (NE) and a 1% reduction in crude protein (CP) compared to the CS diets. On d 35, fecal samples were collected from 6 pigs per treatment to determine apparent total tract digestibility (ATTD) of dry matter (DM), CP, acid detergent fiber (ADF), and neutral detergent fiber (NDF). The same pigs were euthanized for determination of apparent ileal digestibility (AID) of AA and intestinal morphology. In Exp. 2, 356 pigs (DNA 241 × 600, initially 12.4 ± 0.22 kg) were used to determine the effect of an enzyme blend in diets with reduced nutrient density. The five treatments included a CS diet with no added enzyme blend and 4 CSBP diets with 0, 0.01, 0.02, or 0.03% enzyme. The CSBP diets were formulated to achieve a 159 kcal/kg reduction in NE and a 10% reduction in standardized ileal digestible (SID) Lys compared to the CS diet. On d 35, fecal samples were collected from 12 pigs per treatment to determine ATTD of DM, CP, and NDF. For both experiments, pigs fed CS diets had increased (P < 0.05) ADG, G: F, and ATTD of some nutrients compared to pigs fed CSBP diets, but enzyme blend had no effect on growth and did not improve digestibility. In Exp. 1, pigs fed CSBP diets had increased (P < 0.05) duodenal villus height (VH) compared to pigs fed CS diets, but enzyme blend decreased (P = 0.017) duodenal VH in CS diets and decreased (linear, P < 0.05) duodenal VH and VH: CD in CSBP diets. Pigs fed CS diets had increased (P < 0.05) AID of some AA compared to pigs fed CSBP diets, but the enzyme blend did not improve digestibility. In summary, pigs fed CS diets had improved growth performance and ATTD of some nutrients compared to pigs fed CSBP diets. The enzyme blend did not improve ATTD and had no effect on overall growth performance.