Li S, Luo X, Liu B, Crenshaw T D, Kuang X, Shao G, Yu S
Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
J Anim Sci. 2004 Aug;82(8):2352-63. doi: 10.2527/2004.8282352x.
Twelve organic Mn sources and MnSO4 were evaluated by polarographic analysis and via solubility in buffers (pH 5 and 2) and deionized water. Fractions from solubility tests were evaluated by gel filtration chromatography for structural integrity. Organic Mn sources included five Mn methionine complexes (Mn Met A to Mn Met E), two Mn proteinates (Mn Pro A and Mn Pro B), and five Mn amino acids (Mn AA A to Mn AA E). Sources varied considerably in chemical characteristics. Chelation strength (Qf) ranged from weak (1.9 Qf-values) to strong complexes (115.4 Qf-values). No complexed Mn was found in filtrates at pH 2.0 or 5.0. A 42-d bioassay was used to estimate relative bioavailability of Mn sources for chicks fed diets supplemented with 60, 120, or 180 mg Mn/kg. Bone Mn, heart Mn, heart manganese-superoxide dismutase activity (MnSOD), and heart MnSOD mRNA increased (P < 0.001) as dietary Mn increased. Only heart MnSOD mRNA tended (P < 0.10) to differ among dietary Mn sources. For bioassays of Mn, the MnSOD mRNA level in heart was more sensitive than the MnSOD activity in heart or other indices. Relative to MnSO4 (assigned 100%), slope ratios of MnSOD mRNA levels in heart gave bioavailabilities of 99, 132, and 113% for Mn Met E, Mn AA B, and Mn AA C sources with weak, moderate, and strong chelation strength, respectively. The bioavailability of Mn was more closely related to chelation strength as measured by polarography than to chemical traits assessed by solubility or structural integrity.
通过极谱分析以及在缓冲液（pH 5和2）和去离子水中的溶解度对12种有机锰源和硫酸锰进行了评估。通过凝胶过滤色谱法对溶解度测试的级分进行结构完整性评估。有机锰源包括5种蛋氨酸锰络合物（蛋氨酸锰A至蛋氨酸锰E）、2种蛋白盐锰（蛋白盐锰A和蛋白盐锰B）以及5种氨基酸锰（氨基酸锰A至氨基酸锰E）。这些来源在化学特性上差异很大。螯合强度（Qf）范围从弱（1.9 Qf值）到强络合物（115.4 Qf值）。在pH 2.0或5.0的滤液中未发现络合锰。采用42天生物测定法来估计在添加了60、120或180 mg锰/千克的日粮中，锰源对雏鸡的相对生物利用率。随着日粮锰含量增加，骨骼锰、心脏锰、心脏锰超氧化物歧化酶活性（MnSOD）和心脏MnSOD mRNA水平升高（P < 0.001）。仅心脏MnSOD mRNA在不同日粮锰源之间有差异趋势（P < 0.10）。对于锰的生物测定，心脏中的MnSOD mRNA水平比心脏中的MnSOD活性或其他指标更敏感。相对于硫酸锰（设定为100%），心脏中MnSOD mRNA水平的斜率比分别给出了螯合强度弱、中和强的蛋氨酸锰E、氨基酸锰B和氨基酸锰C来源的生物利用率为99%、132%和113%。通过极谱法测定，锰的生物利用率与螯合强度的关系比与通过溶解度或结构完整性评估的化学特性的关系更为密切。
