Studies On Molecular Biology In The Availabilities Of Different Manganese Sources For Broilers

There were some experiments conducted to investigate the availabilities of different dietary manganese sources, but got different results, which might be related to the chemical characteristics of Mn, especially the complex strengths. Twelve organic Mn sources were collected from China and abroad, and characterized together with reagent grade MnSO4·H2O. At first, the paper analysis the characteristic of 13 kinds of Mn sources of mineral concentrations, amino acid contents, infrared spectral characteristics, solubilities in five solution and complex strengths. And then three kinds of Mn sources with different complex strengths were chosen for this study. The experiments were conducted to investigate the effects of different dietary Mn source and level on growth performance, heart Mn content, MnSOD activity in heart mitochondria, its gene expression and protein level, so as to evaluate their relative availabilities for broilers and find the most sensitive and effective indices in detecting organic Mn sources at transcriptive and translative level.The experiment was conducted with a total of 500 Arbor Acres (AA) commercial male broilers at the age of one day old. Birds were fed Mn-unsupplemented corn-soybean meal basal diets to enhance the sensitivity to manganese at 1~7 d. At eighth day 432 birds were randomly allotted by bodyweight to one of nine treatments (six pen replicates of eight chicks each) in a completely randomized design involving a 4×3 factorial arrangement of treatments, and fed Mn-unsupplemented corn-soybean meal basal diets (Control, 16.13mg/kg Mn) or basal diets supplemented with 100 or 200 mg/kg Mn as Mn sulfate, Availa Mn, MnAAB or Bioplex Mn for a duration of 14 days. The results showed that: 1) No differences (P>0.16) in ADG or ADFI were found duo to either Mn source and level or their interaction; 2) Dietary Mn level had effects (P<0.01) on heart Mn content, MnSOD activity in heart mitochondria and its gene expression level evidently, which indicated that dietary Mn might can both significantly affected heart MnSOD gene expression pre-translationally and after-translationally. 3) Dietary Mn source had effects on heart Mn content (P<0.09), MnSOD activity in heart mitochondria (P<0.02) and its gene expression (P<0.01), however, no differences (P>0.69) in protein level were found among organic Mn sources or between organic sources and inorganic Mn sulfate. The results indicate that heart MnSOD mRNA level as a criterion for relative availability assays of Mn sources was more sensitive than heart MnSOD activity or other indices. 4) In the instance that birds were fed Mn-unsupplemented corn-soybean meal basal diets to enhance the sensitivity to manganese at 1~7d, heart Mn content and MnSOD activity in heart mitochondria could evaluate the relative availability of Mn sources as MnSOD mRNA level do likewise.In conclusion, dietary Mn level had effects not only on heart Mn content, but MnSOD activity in heart mitochondria, its mRNA level; Dietary Mn source had effects on heart Mn content, MnSOD activity in heart mitochondria and its gene expression, but no differences (P>0.69) in protein level were found among different Mn sources. The results indicate that heart MnSOD mRNA level can evaluate the relative availability assays of Mn sources sensitively; In the instance that birds were fed Mn-unsupplemented corn-soybean meal basal diets at 1~7d to enhance the sensitivity to manganese, heart Mn content and MnSOD activity in heart mitochondria could evaluate the relative availability of Mn sources as MnSOD mRNA level do likewise. These findings have not been reported in literature before.