THE ROLE PLAYED BY PHYTASE AND METABOLISM IN THE ACCUMULATION OF URANIUM IN THE POULTRY BONES J.D.T. Arruda-Neto 1,2 , A.C. Cestari 2 , G.P. Nogueira 3 , L.E.C. Fonseca 3 , C.B. Zamboni 4 , M. Saiki 4 , M.V. Manso Guevara 1 , V.R. Vanin 1 , A. Deppman 1 , V.P. Likhachev 1 , J. Mesa 1 , O.A.M. Helene 1 , S.A.C. Jorge 2,7 , M. N. Martins 1 , A.N.Gouveia 1,5 , O.Rodriguez 6 , F. Guzmán 6 and F.Garcia 8 1 Physics Institute, University of São Paulo - IFUSP/SP Rua do Matão, Travessa R, 187 05508-970 Butantã, São Paulo, SP, Brasil 2 University of Santo Amaro - UNISA/ SP Rua Prof. Enéas de Siqueira Neto, 340 04829-300 Jardim das Embuias, São Paulo, SP, Brasil 3 Faculty of Veterinary Medicine - UNESP/SP Rua Dr. José Bonifácio, 1193 16015-050 Vila Mendonça, Araçatuba, SP, Brasil 4 Institute for Energetic and Nuclear Research - IPEN-CNEN/SP Av. Lineu Prestes , 2.242 05508-900 Butantã, São Paulo, SP, Brasil 5 Institute of Biomedical Sciences, University of São Paulo - ICBUSP/SP Av. Lineu Prestes, 1.374 05508-900 Butantã, São Paulo, SP, Brasil 6 High Institute of Nuclear Science and Technologies - ISCTN Ave. Salvador Allende, esquina a Luaces, Quinta de Los Molinos, Plaza, Ciudad Habana,Cuba - 6163 7 Laboratory of Viral Immunology, Butantã Institute/SP Av. Vital Brasil, 1.500 05503-900 Butantã, São Paulo, SP, Brasil 8 Santa Cruz State University-UESC/BA Rodovia Ilhéus/Itabuna, km 16 45650-000 Ilhéus, Bahia, Brasil ABSTRACT Groups of seven days old Cobb broilers were fed with feed doped with uranyl nitrate at a fixed concentration of 20 ppm-U, and two concentrations of phytase (120 and 180 ppm). Two animals per group were sacrificed weekly up to their adultness. The uranium content in tibia was measured by neutron activation analysis. It was observed that the biokinetics of U does not change by administration of phytase, but the U concentration in the bones increased by up to a factor of 2, and in a nonexpected periodically time oscillating fashion. Quite surprising too, the concentration of uranium (μg-U/g-bone) is decreasing all along the animal life spanning period of 14-42 days, meaning that the skeleton mass is growing faster than the corresponding accumulation of uranium is. This last finding is interpreted as a possible interplay between two metabolic peculiarities, associated both with U transfer to (uptake), and U removed from (clearence) the bones, repectively. Keywords: uranium, biokinetics, fowl, metabolism