Abstract: An experiment was conducted using a total of 336 day-old AA male broilers to investigate the effect of dietary manganese (Mn) source on carcass traits, meat quality, relative enzyme activities in abdominal fat and meat, and MnSOD mRNA level in meat. The broilers were randomly allotted to one of seven treatments in a completely randomized design involving a 3×3 factorial arrangement of treatments and fed the corn-soybean meal basal diets and the basal diet supplemented with 100 or 200 mg Mn/kg as Mn sulfate (MnSO4•H2O), Mn amino acid A (Mn AA A) or Mn amino acid B (Mn AA B) with moderate chelation strength, respectively, for a duration of 42 days. Birds fed diets supplemented with Mn had lower (P﹤0.10) percentages of abdominal fat, lipoprotein lipase (LPL) and malate dehydrogenase (MDH) activities in abdominal fat, and malondialdehyde (MDA) content in leg muscle than those fed the control diet. Birds fed diet supplemented with Mn from Mn AA A or Mn AA B had lower (P﹤0.05) LPL activities in abdominal fat than those fed diet supplemented with Mn sulfate. Birds fed diets supplemented with Mn had higher (P﹤0.02) hormone sensitive lipase (HSL) activities in abdominal fat, and Mn-containing superoxide dismutase (MnSOD) activities and mRNA level in breast and leg muscle mitochondria. Birds fed diets supplemented with Mn from Mn-AA A had higher (P﹤0.02) MnSOD mRNA level in leg muscle mitochondria than those fed diets supplemented with Mn from Mn sulfate. The results indicate that organic Mn with the moderate complex strength (Mn AA A) was more available than inorganic Mn source to decrease LPL activity in abdominal fat and increase MnSOD gene expression in mitochondria of leg muscle cells in broilers, leading to the improvement of carcass traits and meat quality.

Key words: Different manganese sources, Carcass traits, Meat quality, Modes of action, Broilers