Pesquisa Agropecuária Brasileira
On-line version ISSN 1678-3921
LOUVANDINI, Helder and VITTI, Dorinha Miriam Silber Schmidt. Phosphorus kinetics using mathematical models for adult sheep. Pesq. agropec. bras. [online]. 2007, vol.42, n.10, pp. 1467-1472. ISSN 1678-3921. http://dx.doi.org/10.1590/S0100-204X2007001000014.
An experiment was carried out to measure the phosphorus (P) flows in adult sheep by mathematical model. The work was conducted with 16 Suffolk sheep, live weight of 38.2±4.35 kg and 18-month aged, kept in individual cage to determine the effect of phosphorus (P) intake by adding bone meal (0, 1, 2 and 3 g P per animal per day) in the basal diet (225 g the concentrate and hay ad libitum). After 21 days, the lambs were injected with 7.4 MBq of 32P to trace the flows of P in the three compartments gastrointestinal tract, central (blood) and tissues (soft and bone). There was a positive relationship between P intake and P absorbed, P faeces, P urinary and P retained. Fecal endogenous loss of the P was exponentially related to P intake. The high levels of P on diet affected the exchanges between gastrointestinal and urinary tract. Results showed that 0.82 g of the P per day was enough for maintenance of the experimental animals.
Keywords : isotopic dilution; minerals; modeling.