The influence of oral copper-methionine on matrix metalloproteinase-2 gene expression and activation in right-sided heart failure induced by cold temperature: A broiler chicken perspective

This study was designed to investigate the expression, activation and activity of matrix metalloproteinase-2 (MMP-2) in the heart of broiler chickens reared in cold conditions and fed with copper-methionine supplement at different levels. The chickens (n = 480) were randomly allotted to six treatments and four replicates. Treatments included two rearing temperatures (i.e. normal and cold temperatures) each combined with three levels of supplemental copper-methionine (i.e. 0, 100 and 200 mg/kg). On d 38 and 45 of age, four broilers from each treatment were sacrificed and their hearts were stored at −80 °C. Right-sided heart failure, as evident from abdominal and pericardial fluid accumulation, was observed in broilers under cold stress and not receiving supplemental copper. This clinical observation was confirmed at molecular level through increased MMP-2 expression, activation and activity in this group. Birds reared under normal temperature, however, were not involved in right-sided heart failure nor benefitted from copper-methionine supplementation. In contrast, gelatin zymography and real-time PCR demonstrated that dietary supplementation with copper-methionine decreased pro-MMP-2 and MMP-2 in the heart of chickens reared in cold conditions. However, gelatin reverse zymography did not show any difference between treatments in tissue inhibitor of metalloproteinase-2. Level of supplementation showed similar effects on parameters determined. It is concluded that dietary supplementation with copper-methionine reduced right-sided heart failure at clinical and molecular levels in cold-stressed chickens.