Adeola, O., Sands, J.S. (2003) Does supplemental dietary microbial phytase improve amino acid utilization? A perspective that it does not. J Anim Sci. 81: 78-85.
Ahmadi, H., Rodehutscord, M. (2012) A meta-analysis of responses to dietary nonphytate phosphorus and phytase in laying hens. Poult Sci. 912: 2072–2078.
Bar, A., Razaphkovsky, V., Vax, E. (2002) Re-evaluation of calcium and phosphorus requirements in aged laying hens. Br Poult Sci. 43: 261–269
Boling, S.D., Douglas, M.W., Johnson, M.L., Wang, X., Parsons, C.M., Koelkebeck, K.W., Zimmerman, R.A. (2000) The effects of dietary available phosphorus levels and phytase on performance of young and older laying hens. Poult Sci. 79: 224-230.
Ceylan, N., Scheideler, S.E., Stilborn, H.L. (2003) High available phosphorus corn and phytase in layer diets. Poult Sci. 82: 789-795.
Cheryan, M. (1980) Phytic acid interactions in food systems. CRC Crit. Rev Food Sci Nutr. 13: 297–335.
Clark, W.D., Cox, W.R., Silversides, F.G. (2008) Bone fracture incidence in end-of-lay high-producing, noncommercial laying hens identified using radiographs. Poult Sci. 87: 1964-1970.
Das, S.N., Kumar, V., Chatterjee, S., Singh, J., Agrawala, S.K. (2004) Effect of MagaCal and commercial phytase supplementation on blood and bone mineral content of layer hens. Phytomedica. 5: 41-45.
Francesch, M., Broz, J., Brufau, J. (2005) Effects of an experimental phytase on performance, egg quality, tibia ash content and phosphorus bioavailability in laying hens fed on corn- or barley-based diets. Br Poult Sci. 46: 340-348.
Gordon, R., Bryant, M.M., Roland, D.A. (2009) Performance and profitability of second-cycle laying hens as influenced by body weight and body weight reduction during molt. J Appl Poult Res. 18: 223-231.
Hall, L.E., Shirley R.B., Bakalli R.I., Aggrey S.E., Pesti G.M., Edwards H.M.Jr. (2003) Power of two methods for the estimation of bone ash of broilers. Poult Sci. 82: 414-418.
Hartel, H. (1990) Evaluation of the dietary interaction of calcium and phosphorus in the high producing laying hen. Br Poult Sci. 31: 473-494.
Hassanien, H.H.M., Sanaa, H.M.E. (2011) Comparison difference levels of phytase enzyme supplementation on laying hen performance, egg quality and some blood parameters. Asian J Poult Sci. 5: 77-85.
Hughes, A.L., Dahiya, J.P., Wyatt, C.L., Classen, H.L. (2008) The efficacy of quantum phytase in a forty-week production trial using white leghorn laying hens fed corn-soybean meal-based diets. Poult Sci. 87: 1156-1161.
Hughes, A.L., Dahiya, J.P., Wyatt, C.L., Classen, H.L. (2009) Effect of Quantum phytase on nutrient digestibility and bone ash in White Leghorn laying hens fed maize-soybean meal-based diets. Poult Sci. 88: 1191-1198.
Jendral M.J., Korver D.R., Church J.S., Feddes J.J.R. (2008) Bone mineral density and breaking strength of white leghorns housed in conventional, modified, and commercially available colony battery cages . Poult Sci. 87: 828-837.
Jongbloed, A.W., Lenis, N.P. (1998) Environmental concerns about animal manure. J Anim Sci. 76: 2641-2648.
Junqueira, O.M., da Silva Filardi, R., Ligeiro, E.C., Casartelli, E.M., Sgavioli, S., Assuena, V., Duarte, K.F., de Laurentiz, A.C. (2010) Technical and economical evaluation of the nutritional matrix of phytase enzyme diets with sunflower meal for laying hens. Rev Bras Zootecn. 39: 2200-2206.
Keshavarz, K. (2000) Nonphytate phosphorus requirement of laying hens with and without phytase on a phase feeding program. Poult Sci. 79: 748–763.
Kies, A.K., Van Hemert, K.H.F. and Sauer, W. C. (2001) Effect of phytase on protein and amino acid digestibility and energy utilization. World Poult Sci J. 57: 109-125.
Kozlowski, K., Jeroch, H. (2011) Efficacy of different levels of Escherichia coli phytase in hens fed maize-soyabean meal based diets with a decreased non-phytate phosphorus content. J Anim Feed Sci. 20: 224-235.
Lei, Q.B., Shi, L.X., Zhang, K.Y., Ding, X.M., Bai, S.P., Liu, Y.G. (2011) Effect of reduced energy, protein and entire substitution of inorganic phosphorus by phytase on performance and bone mineralization of laying hens. Br Poult Sci. 52: 202-213.
Liebert, F., Htoo, J.K., Sünder, A. (2005) Performance and nutrient utilization of laying hens fed low-phosphorus corn-soybean and wheat-soybean diets supplemented with microbial phytase. Poult Sci. 84: 1576-1583.
Liu, N., Liu, G.H., Li, F.D., Sands, J.S., Zhang, S., Zheng, A.J., Ru, Y.J. (2007) Efficacy of phytases on egg production and nutrient digestibility in layers fed reduced phosphorus diets. Poult Sci. 86: 2337-2342.
Marounek, M., Skrivan, M., Dlouhá, G., Brenová, N. (2008) Availability of phytate phosphorus and endogenous phytase activity in the digestive tract of laying hens 20 and 47 weeks old. Anim Feed Sci Technol. 146: 353-359.
Marounek, M., Skrivan, M., Rosero, O., Rop, O. (2010) Intestinal and total tract phytate digestibility and phytase activity in the digestive tract of hens fed a wheat-maize-soyabean diet. J Anim Feed Sci. 19: 430-439.
Nys, Y., FrnPPin, D., Pointillart, A. (1999) Occurrence of phytase in plants, animals and microorganisms. in Phytase in Animal Nutrition and Waste Management: A BASF Reference. BASF Corp, Mount Olive, NJ, USA.
Panda, A.K., Rao, S.V.R., Raju, M.V.L.N., Bhanja, S.K. (2005) Effect of microbial phytase on production performance of White Leghorn layers fed on a diet low in non-phytate phosphorus. Br Poult Sci. 46: 464-469.
Pelicia, K., Garcia, E.A., Faitarone, A.B.G., Silva, A.P., Berto, D.A., Molino, A.B., Vercese, F. (2009) Calcium and available phosphorus levels for laying hens in second production cycle. Rev Bras Cienc Avic Braz J Poult Sci. 11: 39-49.
Scott, T.A., Kampen, R., Silvesides, F.G. (1999) The effect of phosphorus, phytase enzyme, and calcium on the performance of layers fed corn-based diets. Poult Sci. 78: 1742–1749.
Selle, P.H., Ravindran, V., Caldwell, R.V., Bryden, W.L. (2000) Phytate and phytase: Consequences for protein utilization. Nutr Res Rev. 13: 255-278.
Silva, J.H.V., Araujo, J.A., Goulart, C.C., Costa, F.G.P., Sakomura, N.K., Martins, T.D.D. (2008) Calcium:available phosphorus ratio and phytase levels for semi heavy laying hens in the first and second posture cycle. Rev Bras Zootecn. 37: 2166-2172.
Silversides, F.G., Hruby, M. (2009) Feed formulation using phytase in laying hen diets. J App Poult Res. 18: 15-22.
Singh, P.K. (2008) Significance of phytic acid and supplemental phytase in chicken nutrition: A review. World’s Poult Sci J. 64: 553-580.
Sohail, S.S., Roland, D.A. (2002) Influence of dietary phosphorus on performance of Hy-Line W36 hens. Poult Sci. 81: 75-83.
Summers, J.D. (1995) Reduced dietary phosphorus levels for layers. Poult Sci. 74: 1977–1983.
van der Klis, J.D., Versteegh, H.A.J., Simons P.C.M., Keis, A.K. (1997) The efficacy of phytase in corn-soybean meal-based diets for laying hens. Poult Sci. 76: 1535–1542.
Wu. G., Liu, Z., M. Bryant, M., Roland, Sr. D.A. (2006) Comparison of natuphos and phyzyme as phytase sources for commercial layers fed corn-soy diet. Poult Sci. 85: 64–69.
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