Arsanilic acid as a growth promoter for chicken broilers when administered via either the feed or drinking water
Two thousand four hundred male broiler chicks were used in three experiments to evaluate the biological and economic effects of using arsanilic acid as a growth promoter. In two experiments four treatments were (A) control diets (CD); (B) CD plus 99 mg kg−1 arsanilic acid; (C) CD plus drinking water containing arsanilic acid calculated to achieve equivalent exposure to treatment B; and (D) same as treatment C except arsanilic acid concentration reduced by 50%. A third experiment evaluated the dietary addition of arsanilic acid at 0, 33, 66 and 99 mg kg−1. Arsanilic acid supplementation had no significant (P > 0.05) effect on mortality, feed conversion, final live body weights or monetary returns at slaughter age (42 d). Analysis of breast, thigh and liver tissues using method with a sensitivity of 0.02 mg kg−1 showed a significant increase in liver arsenic residues when supplemented diets were fed to slaughter age. Withdrawal of arsanilic acid from diets 7 d prior to slaughter returned the arsenic residues to normal background (control) levels. It is concluded that the use of arsanilic acid at dietary concentrations up to 99 mg kg−1 (the maximum permissible in Canada) was ineffective in improving either the biological or economic performance of broiler chickens. Key words: Arsanilic acid, growth promoter, broiler chickens