A feeding trial was conducted to evaluate the impact of dietary thermo - stable phytase and new analogue of vitamin D3 (1α-OH D3) supplementation on growth performance, blood parameters, and bone mineralization in broiler chicks. Four hundred and eighty, unsexed, 1-dold Ross 308 broilers were distributed in a randomized experimental design, with four groups,
3 replicates each and 120 birds per experimental unit. The whole experimental period was 33 days. The four dietary groups were : Group A served as positive control and fed diet containing an adequate level of Av. P (available phosphorus) and calcium, while, Group B fed on diet low in Av.P and calcium (negative control), However, Group C, fed on diet containing
the same level of Av.P and calcium as in the negative control one but supplemented with Thermo stable-phytase (500FTU/kg diet), while Group D was fed on diet containing the same level of Av.P and calcium as in the negative control but supplemented with 500FTU/kg phytase plus 5 ppb of 1α-OH D3. The combination of phytase and 1α-OH D3 were
significantly improved (P < 0.05) broiler chicken body weight, feed intake, feed conversion rate, bone ash, and serum Ca and P compared with those fed the negative and positive control groups.