Effects of 1α-OH-D3 on Broiler Chickens, Performance

An experiment was conducted to evaluate the effects of 1α-OH-D3 either with or without Cholecalciferol، microbial phytase as well as different levels of dietary calcium، and phosphorus on broiler chickens، performance. A number of 576 male broiler chickens (Ross 308) were made use of in a completely randomized design of a factorial arrangement (3×2×2×3)، comprised of 36 treatments، 4 replicates of 4 chicks in each battery cage. Factors included three levels of 1α-OH-D3 (0، 5 and 10 μg/kg)، two levels of Cholecalciferol (0 and 5000 ICU/kg)، two levels of microbial phytase (0 and 500 FTU/kg)، as well as three levels of Ca and phosphorus (100، 75 and 50% of Ross broiler nutrition recommendation values). Dietary treatments were implemented within an age interval of from 1 to 42 days. Supplementation of diets of 5 and 10 μg/kg of 1α-OH-D3 reduced body weight and feed intake at 7، 35 and 42d (P<0. 01; P<0. 05). Supplementation of 500 FTU/kg of Phytase enzyme in the diet increased body weight at 7 and 14 days (P<0. 05). Interaction between 1α-OH-D3 and phytase on feed conversion ratio was significant (P<0. 01)، in a way that addition of 500 FTU/kg of Phytase to diet containing 5 μg/kg of 1α-OH-D3 improved feed conversion ratio at 28d (P≤0. 01). 1α-OH-D3 supplementation increased tibia breaking force، linearly (P<0. 01). Results indicated that addition of 1α-OH-D3 to broiler chickens، diets alleviates the risk of tibial dyschondroplasia incidence. Yet، the appropriate recommended dosage needs to be further investigated.