Toxicity of melamine and cyanuric acid in broilers and residues in tissues.

The purpose of this study was to characterize the toxicity potential of melamine (MEL), cyanuric acid (CYA), and a combination of MEL and CYA in broilers. A total of 720 commercial 1-day-old COBB 500 male broilers were randomly allotted into 6 groups with 6 replicates each and 20 broilers in each replicate. The dietary treatments were as follows: group I was the control group, group II included 10 mg/kg MEL and 3.3 mg/kg CYA, group III included 30 mg/kg MEL and 10 mg/kg CYA, group IV included 100 mg/kg MEL and 33.3 mg/kg CYA, group V included 100 mg/kg MEL, and group VI included 33.3 mg/kg CYA. The trial lasted for 42 days. CYA alone and the combination of MEL and CYA had adverse effects on the performance, but MEL alone had no effects on the performance. On day 21, the uric acid (UA) content of group IV was increased in serum (p < 0.05); on day 42, the serum aspartate aminotransferase (AST) activity and the level of tumor necrosis factor (TNF)-α and interleukin (IL)-8 increased in group IV (p < 0.05); 100 mg/kg MEL alone increased the level of TNF-α and the rate of renal apoptosis (p < 0.05); and 33.3 mg/kg CYA alone increased the level of IL-8 and the rate of renal apoptosis (p < 0.05). The livers contained MEL concentrations of 17-125 μg/kg wet weight and CYA concentrations of 28-73 μg/kg, and the muscle contained MEL concentrations of 14-105 μg/kg wet weight. It was indicated that MEL alone, CYA alone, and a combination of MEL and CYA inhibit the growth and damage the kidney and liver.