[Comparative study of the assimilation of phosphorus from monosodium and dicalcium phosphate in piglets]

Experiments were carried out with 6 pigs to study the assimilation of phosphorus of monosodium (NaH2PO4) and dicalcium (CaHPO4) 32P-labelled phosphate. A group of 3 pigs was given monosodium phosphate, and another goup of 3 pigs--dicalcium phosphate. Each pig was given 32P orally, once, at the rate of 20 microCi per kg body weight. A pig of each group was killed on the 3rd, 6th, and 9th day following the administration of 32P. It was found that 32P of NaH2PO4 and CaHPO4 was eliminated mainly with the feces and mostly during the first 48-72 hours after treatment. The total amount of 32P retained in the body of those of the animals that were given CaHPO4 was comparatively higher (89.45-66.80 per cent) than that n the pigs given NaH2PO4 (87.31-52.56 per cent). The percent of 32P retained in the femoral bones and the investigated organs proved higher in the animals that were given monosodium phosphate (10.37-3.08; 24.63-7.15) than in those that were treated with dicalcium phosphate (8.88-3.63; 20.37-5.91). The higher percent of 32P retention in the pigs treated with monosodium phosphate concerned chiefly the gastrointestinal tract. Highest percent of retention in the investigated organs in both groups of animals was established in the small intestine (9.24-4.35 and 6.70-2.90), the liver (6.55-3.33 and 6.00-2.22), and the large intestine (4.50-1.25 and 2.06-0.70). The level of radioactivity of the blood was highest in the first 24 hours. It is concluded that P of monosodium and dicalcium phosphate is almost equally retained and assimilated in the body of pigs.