TY - JOUR T1 - Effect of Different Levels of Calcium and Vitamin D3 on Eggshell Quality Traits TT - بررسی تاثیر سطوح مختلف کلسیم و ویتامین D3 بر صفات کیفی پوسته تخم مرغ JF - JCPP JO - JCPP VL - 5 IS - 2 UR - http://jcpp.iut.ac.ir/article-1-194-en.html Y1 - 2001 SP - 147 EP - 156 KW - Calcium KW - Vitamin D3 KW - Eggshell quality. N2 - This experiment was carried out to study the effect of different levels (3.06, 3.23, 3.4, 3.57 and 3.74%) of calcium and vitamin D3 (2000, 2200 and 2400 IU/kg diet) on eggshell quality of laying hens. In a completely randomized design and in a 5×3 (15 treatments) factorial arrangement, two hundred and forty (240) white leghorn laying hens, strain Hy-Line W36 and 26 weeks old, were divided into 60 replicates, four hens per replicate. The experimental period lasted 90 days until the hens were 38 weeks of age. The results indicated that shell strength, shell thickness and shell percentage increased significantly (P M3 ER -