JWSS - Journal of Water and Soil Science

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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.

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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<0.05) at 3.06% Ca level. Calcium levels had no effect on ash shell percentage. Vitamin D3 did not have a significant (P<0.05) effect on ash shell percentage and calcium shell, but shell strength, shell thickness and shell percentage significantly (P<0.05) increased at 2400 IU/kg diet vitamin D3. Only plasma calcium raised significantly (P<0.05) due to the added vitamin D3. Interaction between vitamin D3 and calcium on shell strength, shell thickness, shell percentage and plasma calcium were significant (P<0.05). Correlation between egg shell quality parameters and blood parameters with calcium and vitamin D3 was significant (P<0.05).