واکنش مرغهای تخمگذار به تغییرات کلسیم و مکمل ویتامین D3

An 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 supplementation (2000, 2200 and 2400 IU/kg diet) on the performance 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 W 36, 26 weeks old, were divided into 60 replicates, four hens per replicate. The experimental period lasted 90 days, until the hens reached 38 weeks of age. The results indicated that calcium levels did not have any significant effects on the percentage of egg production, feed consumption, feed conversion ratio and egg mass. Egg weight significantly (P < 0.05) increased at 3.4% Ca level. Vitamin D3 had no significant (P < 0.05) effects on egg weight, feed consumption and egg mass, but feed conversion ratio significantly (P < 0.05) decreased and percentage of egg production raised significantly (P < 0.05) due to added vitamin D3. Interaction between vitamin D3and calcium on egg weight and egg production was significant (P < 0.05). The regression equations indicated that performance traits can be estimated from calcium and vitamin D3levels in diet.