THE EFFECT OF THYROPROTEIN AND PROPYLTHIOURACIL FEED SUPPLEMENTATION ON CALCIUM LEVELS AND ALKALINE PHOSPHATASE ACTIVITY IN THE PLASMA AND UTERUS OF LAYING HENS

In both young and old laying hens the protein-bound calcium fraction in blood plasma decreased following feed supplementation of 0.05% thyroprotein, whereas the plasma alkaline phosphatase activity significantly increased. The enzyme response was found to be delayed in old as compared to young hens, significantly higher absolute levels being found in the latter. Propylthiouracil treatment caused a marked decrease in protein-bound calcium levels and alkaline phosphatase activity in both young and old hens. The uterine calcium levels and alkaline phosphatase activity in the thyroprotein treated birds did not show any significant differences as compared to the controls, except in the group of old hens receiving the highest dose, in which the calcium level was significantly decreased and the enzyme activity significantly increased. Both propylthiouracil treated groups showed a significant decrease in uterine calcium and alkaline phosphatase activity.