Intestinal calcium binding protein levels in the one month old turkey poult

Intestinal calcium binding protein CaBP) was studied in one month old poults which had been fed a vitamin D3-deficient diet unsupplemented or with 399, 600, 900 or 1200 I.U. vitamin D3 added per kg. diet. CaBP levels increased with vitamin D3 supplementation up to 600 I.U. but showed no further increase with higher dietary vitamin D3. Poults supplemented with 600 to 1200 I.U. vitamin D3/kg. diet had an average of 1.03 mg. CaBP/g. of duodenal mucosa cells collected. The calcium binding activity of these samples was approximately 0.9% per mg. protein and was highly correlated with CaBP concentration (r=0.94).