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Recovery over Time of Production Performance and Biological Functions of Laying Hens after Withdrawal Toxic Levels of Dietary Roxarsone |
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Chean-Ping Wu, Shiow-Min Tsay, Peter Wen-Shyg Chiou, Kuo-Lung Chen |
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| Abstract |
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Roxarsone (3-nitro-4-hydroxyphenylarsonic acid) has been used as feed additives in poultry industries to improve production and control coccidiosis. The effect of high dietary levels of Roxarsone (ROX) on the performance and function of internal organs and the kinetics of recovery as well as its after-effects were examined in laying hens. The inclusion rates of ROX were 0, 100, 200, 300, and 400 mg per kg feed. Inclusion up to 200 mg did not show any adverse effects (p>0.05), whereas in the 300 and 400 mg groups, significant effects, particularly in the latter, were observed for three weeks after ROX addition (p<0.05). Recovery of the physical appearance occurred soon after ROX addition was withdrawn. Recovery of performance and internal organs, however, appeared to be dependent on the amount of residual ROX in the body; as the amount of ROX decreased, the toxic effect of ROX also decreased. In the third week after the withdrawal of ROX, complete recovery was observed in the lower dosage groups (100 or 200 mg groups) (p>0.05), whereas in the higher dosage groups (300 or 400 mg groups), recovery took at least five weeks; when complete recovery was observed in egg production and in liver weight (p>0.05). On the other hand, ROX might have damaged the liver and other tissues. The recovery of liver weight was probably due to accumulation of fatty particles rather than repair. It appeared, therefore, there were little after-effects of ROX on the hen`s physical appearance, but some internal organs were probably damaged. |
| Keywords:
Roxarsone; Laying Hen; Egg Production; Liver Function; Lipid Metabolism |
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