Resumen

GODOY, Susmira  y  CHICCO, Claudio F. Absorción del fósforo y cinética de fósforo y calcio de ovinos alimentados con diferentes fosfatos . INCI [online]. 2005, vol.30, n.7, pp.414-418. ISSN 0378-1844.

In order to measure true absorption of P, and P and Ca kinetics, four sheep per phosphorus source, with different tissue "pool sizes" of fluorine, were fed during a 15 month period sedimentary phosphates of Riecito (RIO) and Monte Fresco (MONTE), and triple superphosphate fertilizer (TSP) to constitute the high F tissue pool group. In addition, four animals with low F tissue pool were fed during the last 30 days of the experiment with dicalcium phosphate (DICAL) plus 500 ppm F (D+F). A reference group was fed DICAL alone. Sheep were kept in metabolic crates. The diets (1kg/animal/day) had similar protein, caloric, P and Ca contents. P and Ca kinetics, and endogenous faecal P fraction were determined by isotopic dilution technique with ³²P and ⁴⁵Ca (200µCi/animal). True absorption of P showed higher values (P<0.05) for DICAL, D+F and TSP, and lower ones for RIO and MONTE. The half-life of fast ³²P blood clearance was lower for TSP, DICAL and D+F, in relation to RIO and MONTE. The t^½ for ⁴⁵Ca entry to plasma was lower for DICAL, intermediate for TSP and D+F, and higher for RIO and MONTE. The t^½ for ⁴⁵Ca clearance was significantly lower (P<0.05) for DICAL, followed by RIO, DICAL+F, MONTE and TSP. Capture of ³²P and ⁴⁵Ca in bone tissue was higher in less mineralized bone. The results indicate that P bioavailability is lower in sedimentary phosphates; that P kinetics is related to the bioavailability of the element; and that high levels of F, independent of tissue pool, have a negative effect on Ca absorption, with no apparent effect on P utilization.

Palabras clave : / Calcio ; Absorción / ; Cinética; Fosfatos; Fósforo; Rumiante.