Twenty-one castrated male pigs with a medium weight of 31.94 kg were used to simulate the phosphorus (P) flow between its anatomical or physiological compartments. The experiment was arranged in randomized blocks, with seven treatments and four replicates and one pig/box. Corn and soybean meal-based diets were fed and P was supplied from different phosphate sources: dicalcium (FBC), monodicalcium (MBC), triple superphosphate (ST), simple superphosphate (SS), catalão rock (ROCHA) and phosphoric acid (AcF) and diet control without supplemental P (CONT). At the end of the seventh day, 7.4MBq of 32P were injected in the animals. Samples of feces, urine and blood were collected during seven days. The amount of P excreted in the feces was greater in the ROCHA diet and smaller in the CONT and AcF diets. Urinary P was greater in the AcF, SS and ST diets and smaller in CONT. The diets did not influence the specific activity (SA) in the feces and in the bones. SA in the blood was smaller in the diet ROCHA. SA in the soft tissues was greater in the diet CONT and smaller in the ST and AcF diets. The flow of P in the digestive tract for the blood was smaller in the CONT diet. The diet containing ROCHA showed greater flow of P from the blood to the bone. Animals fed diets ROCHA and CONT reabsorbed more P from the bone. Soft tissue mobilization in the blood was greater in the ROCHA and CONT diets. It was concluded that CONT and ROCHA diet did not supply enough P to meet swine nutritional requirement, making the phosphorus flow from the soft tissues and bones more intense, in order to maintain a stable P in the blood. The use of tissues phosphoric acid and simple superphosphate levels in the diets overloaded the kidneys, in the elimination of surplus P though the urine.
kinetic; phosphate; metabolism; mineral absorption; nutrition; 32P
