Campus Units
Animal Science
Document Type
Article
Publication Version
Accepted Manuscript
Publication Date
1-2019
Journal or Book Title
Journal of Animal Science
Volume
97
Issue
1
First Page
327
Last Page
337
DOI
10.1093/jas/sky402
Abstract
Microbial phytase is widely used to enhance digestibility of phytate-P. By tradition, diets with P content well below requirement are used to quantify phytate-P release by phytase, but P-adequate diets may be more physiologically relevant. The objective of this study was to investigate the effects of phytase on P digestion and metabolism and develop a P release curve for phytase in Padequate diets (above requirement according to NRC, 2012), and to compare these effects in a Pdeficient diet. Three replicates of 24 barrows each (BW = 23.0 ± 1.8 kg) were randomly assigned to 1 of 8 dietary treatments, housed in individual pens for 21 d, then moved to metabolism crates for 5 d urine and fecal collections. A basal corn-soybean meal diet (P-adequate, A) was formulated at 0.36% standardized total tract digestible (STTD) P and total Ca:STTD P of 1.83. Phytase was added to A at 200 (A200), 400 (A400), 600 (A600), and 800 (A800) phytase units (FTU)/kg. A positive control diet (PC) was formulated using monocalcium phosphate (MCP) to increase STTD P by 0.16% to 0.52%, the expected STTD P release of 800 FTU/kg. A P-deficient diet (D) was formulated by reducing MCP to achieve 0.21% STTD P, and 200 FTU phytase/kg was added to D for D200. Pig was the experimental unit, and replicate and dietary treatment were fixed effects. Orthogonal polynomial contrasts were used to test linear and quadratic effects of phytase within A, A200, A400, A600, and A800. Phytase increased percent apparent total tract digestibility (ATTD) and STTD of P (quadratic P < 0.001), and quantity of absorbed P (linear P < 0.001; quadratic P = 0.069). Urinary P increased linearly with phytase (P < 0.001) and retained P also increased (linear P = 0.001, quadratic P = 0.094). Phytate-P release was estimated to be 0.049, 0.080, 0.093, and 0.09% STTD P for 200, 400, 600, and 800 FTU/kg, respectively. It appears that the effect of phytase may be lower in P-adequate diets as compared to P-deficient diets, given that there was a 12% improvement for A200 vs A, and a 28% improvement in STTD P for D200 vs D. In conclusion, phytase improved P digestibility and retention in P-adequate diets, and P digestibility was used to estimate the quantity of P released by phytase. Further research investigating P release by phytase in P-adequate diets, rather than Pdeficient diets, may be preferable.
Copyright Owner
The Author(s)
Copyright Date
2018
Language
en
File Format
application/pdf
Recommended Citation
Olsen, Kristin M.; Gould, Stacie A.; Walk, Carrie L.; Serão, Nick V. L.; Hansen, Stephanie L.; and Patience, John F., "Evaluating phosphorus release by phytase in diets fed to growing pigs that are not deficient in phosphorus" (2019). Animal Science Publications. 811.
https://lib.dr.iastate.edu/ans_pubs/811
Included in
Agriculture Commons, Animal Experimentation and Research Commons, Animal Sciences Commons
Comments
This is a manuscript of an article published as Olsen, Kristin M., Stacie A. Gould, Carrie L. Walk, Nick VL Serão, Stephanie L. Hansen, and John F. Patience. "Evaluating phosphorus release by phytase in diets fed to growing pigs that are not deficient in phosphorus." Journal of animal science 97, no. 1 (2019): 327-337. doi:10.1093/jas/sky402. Posted with permission.