Efficacy of different commercial phytase enzymes and development of an available phosphorus release curve for Escherichia coli-derived phytases in nursery pigs1,2

In 2 experiments, a total of 184 pigs (PIC, initial BW of 10.3 and 9.7 kg for Exp. 1 and 2, respectively) were used to develop an available P (aP) release curve for commercially available Escherichia coli-derived phytases. In both experiments, pigs were fed a corn-soybean meal basal diet (0.06% aP)...

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Bibliographic Details
Published in:Journal of animal science 2010-11, Vol.88 (11), p.3631
Main Authors: Jones, C K, Tokach, M D, Dritz, S S, Ratliff, B W, Horn, N L, Goodband, R D, DeRouchey, J M, Sulabo, R C, Nelssen, J L
Format: Article
Language:English
Subjects:
Animal sciences
Enzymes
Hogs
Phosphorus
Physical growth
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Summary:In 2 experiments, a total of 184 pigs (PIC, initial BW of 10.3 and 9.7 kg for Exp. 1 and 2, respectively) were used to develop an available P (aP) release curve for commercially available Escherichia coli-derived phytases. In both experiments, pigs were fed a corn-soybean meal basal diet (0.06% aP) and 2 diets with added inorganic P (iP) from monocalcium phosphate (Exp. 1: 0.075 and 0.15% aP; Exp. 2: 0.07 and 0.14% aP) to develop a standard curve. In Exp. 1, levels of 100, 175, 250, or 500 phytase units (FTU)/kg of OptiPhos 2000 or 200, 350, 500, or 1,000 FTU/kg of Phyzyme XP were added to the basal diet. In Exp. 2, levels of 250, 500, 750, or 1,000 FTU/kg of OptiPhos 2000; 500, 1,000, or 1,500 FTU/kg of Phyzyme XP; or 1,850 or 3,700 FTU/kg of Ronozyme P were added to the basal diet. One FTU was defined as the amount of enzyme required to release 1 µmol of iP per minute from sodium phytate at 37°C. For all phytase products, the manufacturer-guaranteed phytase activities were used in diet formulation. All diets were analyzed for phytase activity using both the Phytex and AOAC methods. Pigs were blocked by sex and weight and allotted to individual pens with 8 pens per treatment. Pigs were euthanized on d 21, and fibulas were collected and analyzed for bone ash. In both experiments, increasing levels of iP improved (linear, P < 0.01) G:F and percentage bone ash. Pigs fed increasing levels of OptiPhos had improved (Exp. 1: linear, P < 0.001; Exp. 2: quadratic, P < 0.001) percentage bone ash, as did pigs fed increasing levels of Phyzyme XP (linear, P < 0.001). In Exp. 2, increasing levels of Ronozyme P improved (quadratic, P < 0.01) percentage bone ash. Using analyzed values from the AOAC method and percentage bone ash as the response variable, an aP release curve was developed for up to 1,000 FTU/kg of E. coli-derived phytases (OptiPhos 2000 and Phyzyme XP) in P-deficient diets. The prediction equation was: Y = -0.000000125X^sup 2^ + 0.000236X + 0.016, where Y = aP release (%) and X = analyzed phytase level (FTU/kg) in the diet. [PUBLICATION ABSTRACT]
ISSN:0021-8812
1525-3163