The concentration of total hydroxyproline and creatine in the urine, and the level of Ca, P, basic phosphatase, total protein, urea, creatine and cholesterol in blood was determined in 3 technological groups of pigs, i.e. in pregnant sows, sows and piglets. In the group of piglets there was found an increased excretion of hydroxyproline with urine, an increased concentration of P and cholesterol, and a higher activity of basic phosphatase with a simultaneous decrease of total protein and creatine in blood compared with these values in sows. The results indicate at the mineral disturbances and the process of demineralisation of bones in this group of animals.
The diagnostic value of the level of hydroxyproline in urine, compared with the set of mineral, protein and lipid metabolic indices, was assessed in case of experimental hypervitaminosis D in piglets. During two weeks of the experiment statistically significant changes in the expressed by the hydroxyproline/creatmine coefficient, were found after a single administration of 10 000 IU/kg vitamin D. At the same' time a transitory significant increase of the level of total calcium and a decrease of inorganic phosphorus and the activity of alkaline phosphatase. in the serum were observed. No differences were found in the concentration of total protein, urea, creatinine and cholesterol in the serum. Out of the parameters determining- the bone-mineral balance, the concentration of hydroxyproline in urine was of great importance; this index was sensitive and displayed smaller standard deviations and longer lasting possibilities to evaluate any changes due to hypervitaminosis D compared with the concentration of total calcium, inorganic phosphorus and the activity of alkaline phosphatase in the serum.