有机锰源化学特性研究

Studies of Characteristics for Organic Manganese Sources

测定了5种蛋氨酸锰(Mn-MetA～E)、2种锰蛋白盐(Mn-ProA和Mn-ProB)和5种复合氨基酸锰(Mn-AAA～E)的元素含量、氨基酸组成、溶解度、红外光谱特征、在pH2、0 2mol/LHCl-KCl或pH5、0 1mol/LKH2PO4-K2HPO4缓冲液中的稳定性及络合强度。结果表明,12种有机锰源产品的含锰量为6 48%～17 44%,也含有不同数量的常量元素和微量元素,总氨基酸与锰的摩尔比为0 04∶1～1 83∶1。除Mn-AAD在0 4%盐酸溶液中的溶解度为90 3%、Mn-ProB和Mn-AAD在pH2、0 2mol/LHCl-KCl缓冲溶液中的溶解度分别为74 1%和85 3%外,所测有机锰源产品在0 4%盐酸、2%柠檬酸、中性柠檬酸铵及pH2、0 2mol/LHCl-KCl缓冲液中的溶解度均在95%以上,在水和pH5、0 1mol/LKH2PO4-K2HPO4缓冲液中的溶解度受载体性质影响,变化范围为5 8%～99 8%。所测4种有机锰源产品均具有金属元素络合物的结构特征。未检测到有机锰源产品在pH2、0 2mol/LHCl-KCl或pH5、0 1mol/LKH2PO4-K2HPO4缓冲液中的可溶部分经凝胶过滤后有以络合锰形式存在的锰。有7种有机锰源产品的络合强度低于10,属于弱络合强度络合物;有4种有机锰源产品的络合强度介于10～100之间,属于中等络合强度络合物;有1种有机锰源产品的络合强度介于100～1000之间,属于强络合强度络合物。本研究结果提示。

Twelve organic Mn sources were collected from China and abroad,and characterized together with reagent grade MnSO4·2H2O.The organic Mn sources were five Mnmethionine products(Mn-Met A～E),two Mn-proteinate products(Mn-Pro A～B),and five Mn-amino acid products(Mn-AA A～E),respectively.Mineral concentrations and amino acid contents in Mn sources were determined by ICAP-9000 emission spectrophotometry and HPLC.Structural characteristics were determined by infrared spectroscopy.Solubilities of Mn sources were measured in 04%HCl,2% citric acid,neutral ammonium citrate,water,02 mol/L HCl-KCl buffer(pH2),and 01 mol/L KH2PO4-K2HPO4 buffer(pH5).Complexed Mn percentages in soluble fractions of Mn sources were measured in 02 mol/L HCl-KCl beffer(pH2)and 01 mol/L KH2PO4-K2HPO4 buffer(pH5)by gel filtration chromatography.A polarography experiment was carried out with a hanging mercury drop electrode to determine complex quotients(Qf)of Mn sources.The results showed that:(1)Mn concentrations ranged from 618% to 1744% in organic Mn sources,however,some sources also contained some macroor microelements,molar ratios of total amino acid content to Mn in 10 organic Mn sources tested changed from 004∶1～183∶1;(2)Organic Mn sources had characteristic peaks of complexed Mn;(3)Except that the solubility of MnAA D in 04%HCl was 903%,and Mn-Pro B and Mn-AA D in pH2,02 mol/L HCl-KCl buffer was 741% and 853%,respectively,other organic Mn sources were highly soluble in 04%HCl,2% citric acid,neutral ammonium citrate,and pH2,02 mol/L HCl-KCl buffer with more than 95% solubility.Solubility of Mn sources varied from 58% to 998% in water and pH5,01 mol/L KH2PO4-K2HPO4 buffer;(4)Under this experimental condition,no complexed Mn was found for these organic Mn sources filtrates from pH2,02 mol/L HCl-KCl and pH5,01 mol/L KH2PO4-K2HPO4 buffer;(5)Organic Mn sources had different complex strengths.7 organic Mn sources had Qf values below 10,showing a weak complex strength,and 5 organic Mn sources had Qf values between 10 and 100,indicating a moderate complex strength,while 1 organic Mn source had a Qf value more than 100,showing a strong complex strength.The results indicate that these organic Mn sources vary considerably in chemical characteristics,and this study has set up a foundation for further investigations of the correlativity between complex strengths of organic Mn sources and their relative bioavailabilities for broilers in following experiments.