有机锌源的理化特性及其体外瘤胃发酵的稳定性研究

Physical and Chemical Characteristics of Supplemental Organic Zinc Sources and Their Stabilities in vitro Fermentation Rumen

进行2个试验，研究有机锌源的理化特性及其体外瘤胃发酵的稳定性。在试验1中，分析了7种有机锌源产品的理化特性。结果表明：有机锌源产品的含锌量和氨基酸组成存在较大差异；所测2种有机锌源产品（ZnPro B和ZnAA B）均具有锌络合物的结构特征；所有有机锌源产品在盐酸、柠檬酸、中性柠檬酸铵缓冲液中的溶解度均在90％以上，在pH2缓冲液中的溶解度为53．92％～98．54％，在水和pH5缓冲液中的溶解度变化范围为6．04％～98．54％；未检测到有机锌源在pH2、0．2mol／LHCl-KCl或pH5、0．1mol／LKH2PO4-K2HPO4缓冲液及去离子水中的可溶部分有络合锌的存在；有4种有机锌源产品属于弱络合强度有机锌源，有1种有机锌源产品属于中等络合强度有机锌源，有2种有机锌源产品属于强络合强度有机锌源。在试验2中，采用6×4析因安排的完全随机设计，用体外瘤胃发酵法评价了不同络合强度有机锌源的瘤胃稳定性。结果表明：不同络合强度有机锌在模拟瘤胃环境下是稳定的，过瘤胃率分别在92％以上，其中又以强络合强度有机锌为最好（99．55％），弱络合强度有机锌（94．85％）次之，中络合强度有机锌（92．16％）相对最低。

Two experiments were conducted to test physical and chemical characteristics of organic Zn sources and their stabilities in vitro fermentation rumen. In experiment 1, physical and chemical characteristics of seven organic Zn sources were analyzed. The results showed that： Zn concentrations and amino acid composition of organic Zn sources varied greatly; Two organic Zn sources （ZnPro B and ZnAA B） had characteristic peaks of complexed Zn. The solubility of all Zn products was more than 90% in the buffer of HCl, citric acid and meutral ammonium citrate, and the solubility of Zn sources in pH2 buffer was ranged from 53.92% to 98.54%, and the solubility in water and pH5 buffer was changed from 6.04% to 98.54%; No complexed Zn was found for these organic Zn sources filtrates from pH2, 0.2 mol/L HCl KCl, pHS, 0.1 mol/L KH2PO4- K2HPO4 buffer, or deionized water; Four organic Zn sources showed weak complex strength,and one organic Zn source showed moderate complex strength, and two organic Zn sources showed strong complex strength. In experiment 2, a completely randomized design involving a 6 ×4 factorial arrangement of treatments was used to evaluate the stability of organic Zn sources with different complex strength in rumen by in vitro rumen fermentation method. The results showed that： The organic Zn sources with different complex strength were stable in the rumen in vitro, and the rumen by-pass ratio of them were more than 92 %. The rumen by-pass ratio of organic Zn source with strong complex strength was the highest （99.55%）, and that of organic Zn source with weak complex strength was in the middle （94.85%）, and that of organic Zn source with moderate complex strength was the lowest （92.16%）.