Oral copper-methionine decreases matrix metalloproteinase-2 activity in the liver and brain of broiler chickens subjected to cold stress for ascites incidence

Copper plays an antioxidant role in biological reactions. This study examined the impact of copper-methionine supplementation on the matrix metalloproteinase-2 (MMP-2) activity and gene expression in the liver and brain of broiler chickens subjected to cold temperature. A total of 480 broiler chickens were assigned to 6 groups and reared under either low (15-19 {o}C) or normal temperature (25-28{o}C) and fed a basal diet enriched with different concentrations of copper-methionine (Cu-Met) supplementation (0, 100 or 200 mg.kg-1). Ascites was exclusively observed in broiler chickens kept in low temperature and fed with basal diet without Cu-Met during the seventh week, identified by the presence of abdominal fluid accumulation. Broilers livers and brains were separated for MMP-2 and tissue inhibitor of metalloproteinase-2 (TIMP-2) analysis. Results of gelatin zymography on these samples demonstrated that incidence of ascites was associated with increased MMP-2 levels in liver and brain. MMP-2 activity assay confirmed the results obtained by zymography. RT-qPCR experiments revealed an upregulation in the mRNA expression of MMP-2. In contrast, the treatments did not induce significant alterations in TIMP-2 levels. Results suggest that oral copper-methionine can decrease the ascites occurrence and might be useful for prevention of ascites in broiler chickens.