This study aimed to investigate the effects of different levels of copper-methionine on ascites incidence and matrix metalloproteinase-2 ( MMP-2) changes in brain, heart, lung and liver. A total of 480 one-day-old broiler chicks were used in a completely randomized design in a 2×3 factorial arrangement of treatments including two ambient temperatures and three copper levels (0, 100, and 200 mg/kg as copper-methionine) with 4 replicates. Broilers were kept in an environmentally-controlled room from 1 to 28 days; then, half of them exposed to cold temperature from 28 to 45 days of age. The birds were sacrificed at days 38 and 45 of age. The lungs, heart, liver and brain from each chicken were stored at ?80 ?C for biological analyses including gelatin zymography, gelatin reverse zymography to detect matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2, respectively. Blood samples were collected in tubes with heparin. Formalin 10% were used for histopatological analysis. Then different tissues were stained with Hematoxylin and Eosin (H E). Ascitic broilers were observed in group subjected to cold temperature and control diet (without supplemental copper) at d 45 of age. Matrix metalloproteinase-2 increased in ascitic broilers. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and hematological parameters such as hematocrit, hemoglobin concentration, red blood cell count in ascitic broilers were significantly increased (P 0.05). Treatments did not affect tissue inhibitor of metalloproteinase-2 (TIMP-2) at 38 and 45 days of age. Hystopatological changes were detected in different tissues in control compare to other treatments. Although, feeding copper-methionine in normal temperature did not change any parameters but in cold condition decreased the negative effect of stress. Feeding 200 mg/ kg copper–methionine was better than 100 mg/ kg copper–methionine. In conclusion, copper–methionine can decrease probability of ascites incidence in broilers, especially under cold condition decreased matrix metalloproteinase-2 in different tissues. Keywords: Copper-methionine, Matrix metalloproteinase-2, Tissue inhibitor of metalloproteinase-2, Ascites, Cold temperature.
