Determining the Phosphorus Release Curve for Smizyme TS G5 2,500 Phytase from 500 to 2,500 FTU/kg in Nursery Pig Diets

A total of 320 pigs (DNA 241 × 600; initially 26.2 ± 0.48 lb BW) were used in a 21-d growth study to determine the available P (aP) release curve for Smizyme TS G5 2,500 (Barentz, Woodbury, MN). At approximately 19 d age, weaned, randomly allotted pens, and fed common starter diets. Pigs blocked by average pen body weight (BW) 1 8 dietary treatments on 18 post-weaning, considered 0 study. Dietary derived from single basal diet ingredients including phytase, monocalcium P, limestone, sand added create treatment Treatments included 3 diets containing increasing (0.11, 0.19, 0.27%) inorganic or 5 with phytase (500, 1,000, 1,500, 2,000, FTU/kg) 0.11% aP. All corn-soybean meal-canola meal-based formulated contain 1.24% SID Lys an analyzed Ca:P ratio 1.10:1. Prior beginning study, all aP 2-d period (d 16 post-weaning). conclusion pig, closest mean each pen, was euthanized right fibula, rib, metacarpal collected bone ash, density, P. For overall experimental period, had improved (quadratic, ≤ 0.053) ADG, ADFI, F/G, final BW. 0.004) BW increased (linear, = 0.019) ADFI. characteristics, levels < 0.001) ash weight, percentage, Additionally, (P 0.05) either linear quadratic manner depending upon bone. The generated percentage is: (0.219 FTU) ÷ (993.238 + FTU).