Document Type : Research Paper
Authors
1 Department of Animal Science, Razi University, Kermanshah, Iran
2 Department of Animal Science, Faculty of Agriculture and Natural Resources, Razi University, Kermanshah, Iran
3 Massey University, New Zealand
4 Department of Animal Science, Ilam University, Ilam, Iran
Abstract
This experiment was conducted to evaluate the effects of calcium (Ca) source and organic acid on performance, egg quality, digestibility coefficient of Ca in limestone, oyster shell and their combination in commercial laying hens. A total of 288 Lohmann (LSL-Lite) laying hens were assigned to 6 treatments, 8 replicates, and 6 hens per each from 50 to 62 wk of age in a completely randomized trial according to a 3×2 factorial arrangement with 3 sources of Ca: limestone (Lim), oyster shell (OS) and their 50:50 combination (LiOS) with or without organic acid (Tegacid®, 2 g/kg). The TIDCa for Lim, OS and LiOS were 69.9, 65.4, and 62.2%, respectively while by organic acid addition was obtained as 74.4, 74, and 75.3%, respectively. Inclusion of organic acid significantly improved ileal digestibility of Ca in diets containing OS or LiOS (P < 0.01). The interaction between Ca source and organic acid were significant (P > 0.05) for the performance parameters at the end of the experiment. The greatest percent of egg production was observed in the birds fed oyster shell + organic acid, which had a significant difference with other experimental treatments (P < 0.01). Overall, there was no considerable difference in Ca apparent digestibility coefficients in three sources of Lim, OS and 50:50 combination of OS + Lim in laying hens, but the addition of organic acid improved calcium digestibility and shell quality of the hens fed oyster shell alone or in combination with limestone.
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