ESTIMATION OF THE DAILY MILK INTAKE OF THE SUCKLING RAT USING THE TURNOVER RATE OF POTASSIUM

Kinetic parameters of potassium metabolism were utilized for the estimation of the daily milk intake of the suckling rat. These parameters included the turnover rate of potassium as determined from the whole-body retention curve of 42K, the total potassium content as measured by means of atomic absorption spectrometry, and the potassium content of milk samples from the lactating dams. The daily intake of potassium was calculated using the whole-body potassium content, the turnover rate constant, and the assumption that the body is a single instantaneously mixing compartment for potassium. The daily milk intake of suckling rat was calculated from the daily potassium intake and the concentration of potassium in rat milk. The results showed that the daily milk intake varies from 1.6g of milk for a newborn rat to 6g for a 14 day-old suckling rat.