The experiment was designed to simulate the mathematical models that relate to the phophorus (P) flow, considering the hypotheses that the endogenous phosphorus from digestive tract was absorbed in the same proportion of the dietary phosphorus and that the input and output flow of this mineral in the compartments was constant. The variables absorption, retention. endogenous P that returns to the gastrointestinal tract (GIT), dietary absorbed P, accretion, reabsorption and balance of P in bone and in soft tissues and P from bone and soft tissue and from the total absorbed that returns to GIT, in g-rowing pigs fed diets containing P from different phosphate sources were evaluate. The model was deterministic and compartmental, in which the GTI (C1). bones (C2) and soft tissues, liver heart, kidney and muscle, (C3) represented the compartments. The information on metabolism and kinetics of the P in tissues obtained by isotopic dilution technique was used. It was concluded that: the hypotheses established in the model were coherent and the obtained values were adjusted to the P flow in pigs; the variables P intake, endogenous P that return to the GIT, P retention, dietary absorbed P, accretion, reabsorption and balance of P from bone and soft tissues and P from total absorbed that returned to the GIT were not influenced by the P from the phosphates sources the dietary phosphorus Could interfere on P distribution in the tissues after the process of absorption of that mineral; the P front total absorbed that return to the GIT was proportional to P intake.
