Dose-dependent effects of a microbial phytase on phosphorus digestibility of common feedstuffs in pigs

  • Received : 2016.11.22
  • Accepted : 2017.01.06
  • Published : 2017.07.01


Objective: The objective of this study was to evaluate increasing doses of a novel microbial phytase (Cibenza Phytaverse, Novus International, St. Charles, MO, USA) on standardized total tract digestibility (STTD) of P in canola meal (CM), corn, corn-derived distiller's dried grains with solubles (DDGS), rice bran (RB), sorghum, soybean meal (SBM), sunflower meal (SFM), and wheat. Methods: Two cohorts of 36 pigs each (initial body weight = $78.5{\pm}3.7kg$) were randomly assigned to 2 rooms, each housing 36 pigs, and then allotted to 6 diets with 6 replicates per diet in a randomized complete block design. Test ingredient was the only dietary source of P and diets contained 6 concentrations of phytase (0, 125, 250, 500, 1,000, or 2,000 phytase units [FTU]/kg) with 0.4% of $TiO_2$ as a digestibility marker. Feeding schedule for each ingredient was 5 d acclimation, 5 d fecal collection, and 4 d washout. The STTD of P increased (linear or exponential $p{\leq}0.001$) with the inclusion of phytase for all ingredients. Results: Basal STTD of P was 37.6% for CM, 37.6% for corn, 68.6% for DDGS, 10.3% for RB, 41.2% for sorghum, 36.7% for SBM, 26.2% for SFM, and 55.1% for wheat. The efficiency of this novel phytase to hydrolyze phytate is best described with a broken-line model for corn, an exponential model for CM, RB, SBM, SFM, and wheat, and a linear model for DDGS and sorghum. Based on best-fit model the phytase dose (FTU/kg) needed for highest STTD of P (%), respectively, was 735 for 64.3% in CM, 550 for 69.4% in corn, 160 for 55.5% in SBM, 1,219 for 57.8% in SFM, and 881 for 64.0% in wheat, whereas a maximum response was not obtained for sorghum, DDGS and RB within the evaluated phytase range of 0 to 2,000 FTU/kg. These differences in the phytase concentration needed to maximize the STTD of P clearly indicate that the enzyme does not have the same hydrolysis efficiency among the evaluated ingredients. Conclusion: Variations in enzyme efficacy to release P from phytate in various feedstuffs need to be taken into consideration when determining the matrix value for phytase in a mixed diet, which likely depends on the type and inclusion concentration of ingredients used in mixed diets for pigs. The use of a fixed P matrix value across different diet types for a given phytase concentration is discouraged as it may result in inaccurate diet formulation.


  1. Raboy V. myo-Inositol-1,2,3,4,5,6-hexakisphosphate. Phytochemistry 2003;64:1033-43.
  2. Loewus FA, Murthy PPN. myo-Inositol metabolism in plants. Plant Sci 2000;150:1-19.
  3. NRC. Nutrient requirements of swine: Eleventh revised edition. 11 ed. Washington, DC: National Academies Press; 2012.
  4. Almeida FN, Stein HH. Performance and phosphorus balance of pigs fed diets formulated on the basis of values for standardized total tract digestibility of phosphorus. J Anim Sci 2010;88:2968-77.
  5. Dersjant-Li Y, Awati A, Schulze H, Partridge G. Phytase in nonruminant animal nutrition: a critical review on phytase activities in the gastrointestinal tract and influencing factors. J Sci Food Agric 2015;95:878-96.
  6. Akinmusire AS, Adeola O. True digestibility of phosphorus in canola and soybean meals for growing pigs: Influence of microbial phytase. J Anim Sci 2009;87:977-83.
  7. Rojas OJ, Stein HH. Digestibility of phosphorus by growing pigs of fermented and conventional soybean meal without and with microbial phytase. J Anim Sci 2012;90:1506-12.
  8. Augspurger NR, Webel DM, Lei XG, Baker DH. Efficacy of an E. coli phytase expressed in yeast for releasing phytate-bound phosphorus in young chicks and pigs. J Anim Sci 2003;81:474-83.
  9. Almeida FN, Sulabo RC, Stein HH. Effects of a novel bacterial phytase expressed in Aspergillus Oryzae on digestibility of calcium and phosphorus in diets fed to weanling or growing pigs. J Anim Sci Biotechnol 2013;4:8.
  10. FASS. Guide for the care and use of agricultural animals in research and teaching. 3 ed. Champaign, IL: Federation of Animal Science Societies; 2010.
  11. Almeida FN, Stein HH. Effects of graded levels of microbial phytase on the standardized total tract digestibility of phosphorus in corn and corn coproducts fed to pigs. J Anim Sci 2012;90:1262-9.
  12. Birkett S, de Lange K. Calibration of a nutrient flow model of energy utilization by growing pigs. Br J Nutr 2001;86:675-89.
  13. AOAC. Official methods of analysis. Gaithersburg, MD: Association of Official Analytical Chemists; 2007.
  14. International Organization for Standardization (ISO). Animal feeding stuffs: determination of phytase activity. International Organization for Standardization; 2009.
  15. Short FJ, Gorton P, Wiseman J, Boorman KN. Determination of titanium dioxide added as an inert marker in chicken digestibility studies. Anim Feed Sci Technol 1996;59:215-21.
  16. Stein HH, Seve B, Fuller MF, Moughan PJ, de Lange CFM. Invited review: Amino acid bioavailability and digestibility in pig feed ingredients: terminology and application. J Anim Sci 2007;85:172-80.
  17. Stein HH. Standardized total tract digestibility (STTD) of phosphorus. Indianapolis, IN: In: Midwest Swine Nutrition Conference; 2011. p. 47-52.
  18. Robbins KR, Saxton AM, Southern LL. Estimation of nutrient requirements using broken-line regression analysis. J Anim Sci 2006;84: E155-E65.
  19. Schwarz G. Estimating the dimension of a model. Ann Stat 1978;2: 461-4.
  20. Lei XG, Stahl CH. Biotechnological development of effective phytases for mineral nutrition and environmental protection. Appl Microbiol Biotechnol 2001;57:474-81.
  21. de Blas Beorlegui C, Mateos GG, Rebollar PG, Animal FEpeDdlN. FEDNA tables of composition and nutritional value of ingredients for feed manufacturing; 2003.
  22. Baker DH, Batal AB, Parr TM, Augspurger NR, Parsons CM. Ideal ratio (relative to lysine) of tryptophan, threonine, isoleucine, and valine for chicks during the second and third weeks posthatch. Poult Sci 2002;81:485-94.
  23. Parr TM, Kerr BJ, Baker DH. Isoleucine requirement of growing (25 to 45 kg) pigs1. J Anim Sci 2003;81:745-52.
  24. Mathai J. Effects of fiber on the optimum threonine:lysine ratio for 25 to 50 kg growing gilts [Thesis]. Champaign, IL: University of Illinois; 2015.
  25. Robbins KR, Norton HW, Baker DH. Estimation of nutrient requirements from growth data. J Nutr 1979;109:1710-4.
  26. Doherty C, Faubion JM, Rooney LW. Semiautomated determination of phytate in sorghum and sorghum products. Cereal Chem 1982;59: 373-7.
  27. O'Dell BL, De Boland AR, Koirtyohann SR. Distribution of phytate and nutritionally important elements among the morphological components of cereal grains. J Agr Food Chem 1972;20:718-23.
  28. Truong HH, Yu S, Peron A, et al. Phytase supplementation of maize-, sorghum- and wheat-based broiler diets with identified starch pasting properties influences phytate (IP6) and sodium jejunal and ileal digestibility. Anim Feed Sci Technol 2014;198:248-56.
  29. Leske K, Coon C. A bioassay to determine the effect of phytase on phytate phosphorus hydrolysis and total phosphorus retention of feed ingredients as determined with broilers and laying hens. Poult Sci 1999;78:1151-7.
  30. Adeola O, Sands JS. Does supplemental dietary microbial phytase improve amino acid utilization? A perspective that it does not. J Anim Sci 2003;81:E78-E85.