Journal of Animal Science, Vol 78, Issue 3 675-681, Copyright © 2000 by American Society of Animal Science

JOURNAL ARTICLE

Phosphorus bioavailability and digestibility of normal and genetically modified low-phytate corn for pigs

J. D. Spencer, G. L. Allee and T. E. Sauber
Department of Animal Sciences, University of Missouri, Columbia 65211, USA.

We conducted two studies to determine the bioavailability and apparent digestibility of P in a low-phytate corn hybrid (.28% total P, .10% phytate P) genetically modified to be homozygous for the 1pa1-1 allele and a nearly isogenic corn hybrid (normal) (.25% total P, .20% phytate P). Additionally, we conducted an in vitro assay involving a peptic and pancreatin digestion to estimate P availability. The first study used 50 individually penned pigs (initial body weight 9 kg) and 10 treatments in a randomized complete block design. A cornstarch-soybean meal basal diet (.6% Ca, .2% P) was used. Treatments consisted of the basal diet and the basal diet plus .05, .10, or .15% P from monosodium phosphate (MSP), low-phytate corn, or normal corn. After a 35-d feeding period, pigs were killed to collect the fourth metacarpal for measurements of ash and breaking load. Breaking load was regressed on added P intake, and the bioavailability of P was determined by the slope ratio method. The bioavailabilities of P (relative to MSP) for low-phytate and normal corn were 62 and 9%, respectively. These were similar to the determined in vitro values of 57 and 11% for low-phytate and normal corn, respectively. In the second study, 20 pigs (initial BW 20 kg) were used in a randomized complete block design with a 2 x 2 factorial arrangement of treatments. Two corn lines (low-phytate and normal) and two levels of supplemental P (0 and .2%) from dicalcium phosphate were used. Diets with no added P were formulated to contain .9% lysine, .6% Ca, and .34% P. Apparent nutrient digestibilities were calculated from total collection of urine and feces for 5 d. There were no differences among treatments for energy and nitrogen digestibility. Pigs fed low-phytate corn with no added P had increased digestibility and retention of P and reduced total P excretion (P < .05). We conclude that low-phytate corn contains at least five times as much available P as normal corn. The use oflow-phytate corn greatly reduced the amount of P excreted by the pig and increased the N:P ratio in the manure.

This article has been cited by other articles:

				J. S. Paschold, B. J. Wienhold, R. B. Ferguson, and D. L. McCallister Soil Nitrogen and Phosphorus Availability for Field-Applied Slurry from Swine Fed Traditional and Low-Phytate Corn Soil Sci. Soc. Am. J., June 18, 2008; 72(4): 1096 - 1101. [Abstract] [Full Text] [PDF]

				J. S. Paschold, B. J. Wienhold, D. L. McCallister, and R. B. Ferguson Crop Nitrogen and Phosphorus Utilization following Application of Slurry from Swine Fed Traditional or Low Phytate Corn Diets Agron. J., June 16, 2008; 100(4): 997 - 1004. [Abstract] [Full Text] [PDF]

				M. Schulin-Zeuthen, E. Kebreab, W. J. J. Gerrits, S. Lopez, M. Z. Fan, R. S. Dias, and J. France Meta-analysis of phosphorus balance data from growing pigs J Anim Sci, August 1, 2007; 85(8): 1953 - 1961. [Abstract] [Full Text] [PDF]

				T. L. Veum, D. R. Ledoux, and V. Raboy Low-phytate barley cultivars improve the utilization of phosphorus, calcium, nitrogen, energy, and dry matter in diets fed to young swine J Anim Sci, April 1, 2007; 85(4): 961 - 971. [Abstract] [Full Text] [PDF]

				J. K. Htoo, W. C. Sauer, Y. Zhang, M. Cervantes, S. F. Liao, B. A. Araiza, A. Morales, and N. Torrentera The effect of feeding low-phytate barley-soybean meal diets differing in protein content to growing pigs on the excretion of phosphorus and nitrogen J Anim Sci, March 1, 2007; 85(3): 700 - 705. [Abstract] [Full Text] [PDF]

				G. F. Yi, A. M. Gaines, B. W. Ratliff, P. Srichana, G. L. Allee, K. R. Perryman, and C. D. Knight Estimation of the true ileal digestible lysine and sulfur amino acid requirement and comparison of the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine in eleven- to twenty-six-kilogram nursery pigs J Anim Sci, July 1, 2006; 84(7): 1709 - 1721. [Abstract] [Full Text] [PDF]

				W. J. Powers, E. R. Fritz, W. Fehr, and R. Angel Total and water-soluble phosphorus excretion from swine fed low-phytate soybeans J Anim Sci, July 1, 2006; 84(7): 1907 - 1915. [Abstract] [Full Text] [PDF]

				T. Kim, E. J. Mullaney, J. M. Porres, K. R. Roneker, S. Crowe, S. Rice, T. Ko, A. H. J. Ullah, C. B. Daly, R. Welch, et al. Shifting the pH Profile of Aspergillus niger PhyA Phytase To Match the Stomach pH Enhances Its Effectiveness as an Animal Feed Additive. Appl. Envir. Microbiol., June 1, 2006; 72(6): 4397 - 4403. [Abstract] [Full Text] [PDF]

				R. A. Bohlke, R. C. Thaler, and H. H. Stein Calcium, phosphorus, and amino acid digestibility in low-phytate corn, normal corn, and soybean meal by growing pigs J Anim Sci, October 1, 2005; 83(10): 2396 - 2403. [Abstract] [Full Text] [PDF]

				G. M. Pierzynski and K. A. Gehl Plant Nutrient Issues for Sustainable Land Application J. Environ. Qual., January 1, 2005; 34(1): 18 - 28. [Abstract] [Full Text] [PDF]

				A. B. Leytem, B. L. Turner, and P. A. Thacker Phosphorus Composition of Manure from Swine Fed Low-Phytate Grains: Evidence for Hydrolysis in the Animal J. Environ. Qual., November 1, 2004; 33(6): 2380 - 2383. [Abstract] [Full Text] [PDF]

				F. O. Omogbenigun, C. M. Nyachoti, and B. A. Slominski Dietary supplementation with multienzyme preparations improves nutrient utilization and growth performance in weaned pigs J Anim Sci, April 1, 2004; 82(4): 1053 - 1061. [Abstract] [Full Text] [PDF]

				B. J. Wienhold and P. S. Miller Phosphorus Fractionation in Manure from Swine Fed Traditional and Low-Phytate Corn Diets J. Environ. Qual., January 1, 2004; 33(1): 389 - 393. [Abstract] [Full Text] [PDF]

				J. M. Gentile, K. R. Roneker, S. E. Crowe, W. G. Pond, and X. G. Lei Effectiveness of an experimental consensus phytase in improving dietary phytate-phosphorus utilization by weanling pigs J Anim Sci, November 1, 2003; 81(11): 2751 - 2757. [Abstract] [Full Text] [PDF]

				C. A. Baxter, B. C. Joern, D. Ragland, J. S. Sands, and O. Adeola Phytase, High-Available-Phosphorus Corn, and Storage Effects on Phosphorus Levels in Pig Excreta J. Environ. Qual., July 1, 2003; 32(4): 1481 - 1489. [Abstract] [Full Text] [PDF]

				F. O. Omogbenigun, C. M. Nyachoti, and B. A. Slominski The effect of supplementing microbial phytase and organic acids to a corn-soybean based diet fed to early-weaned pigs J Anim Sci, July 1, 2003; 81(7): 1806 - 1813. [Abstract] [Full Text] [PDF]

				N. R. Augspurger, D. M. Webel, X. G. Lei, and D. H. Baker Efficacy of an E. coli phytase expressed in yeast for releasing phytate-bound phosphorus in young chicks and pigs J Anim Sci, February 1, 2003; 81(2): 474 - 483. [Abstract] [Full Text] [PDF]

				T. L. Veum, D. R. Ledoux, D. W. Bollinger, V. Raboy, and A. Cook Low-phytic acid barley improves calcium and phosphorus utilization and growth performance in growing pigs J Anim Sci, October 1, 2002; 80(10): 2663 - 2670. [Abstract] [Full Text] [PDF]