碳、氮同位素在牛肉产地溯源中的应用研究

【目的】探索稳定性同位素对中国牛肉产地溯源的可行性，了解牛不同组织中δ13C和δ15N指标在其中的作用。【方法】利用同位素比率质谱仪测定了来自吉林、贵州、宁夏、河北4个地域牛肉、牛尾毛、饲料中的δ13C和δ15N值，比较了不同地域牛组织中稳定性碳、氮同位素组成的差异，分析了各组织中同位素组成的相关关系，并结合牛的喂养方式，研究了δ13C和δ15N值的变化规律。【结果】不同地域牛组织中稳定性碳同位素组成有极显著差异，排序依次为吉林>贵州>宁夏>河北。吉林、宁夏两地样品与贵州、河北两地样品之间的δ15N值有极显著差异，且后者高于前者。不同地域喂养牛的主饲料成分有其明显的地域特征。脱脂牛肉粉、粗脂肪、牛尾毛中碳、氮同位素之间呈极显著相关性。【结论】牛组织中δ13C值可预测其膳食中C4植物所占的比例，δ15N值可区分牧区与农区喂养的牛；δ13C指标对牛肉产地来源的正确判别率高于δ15N指标，两项指标相互补充可显著提高产地来源的正确判别率；脱脂牛肉粉、粗脂肪、牛尾毛中δ13C、δ15N值均可作为牛肉产地溯源的指标，它们对牛肉产地来源的判别规律一致。

Application of Carbon and Nitrogen Isotope in Beef Origin Traceability

【Objective】To probed into the feasibility of isotopic traceability in beef geographical traceability in China, and found out the function of δ13C and δ15N values in it. 【Method】The δ13C and δ15N values of beef, cattle hair and feeds coming from four regions of Jilin, Guizhou, Ningxia, Hebei were determined using isotope ratio spectrometer, the difference of carbon and nitrogen composition of beef samples from different regions were compared, the correlations of isotope composition between cattle tissues were analyzed, and the changing laws of δ13C and δ15N values of beef were researched combining feeding mode. 【Results】The δ13C values of cattle tissues from different regions had much significant difference, the order was Jilin>Guizhou>Ninxia>Hebei. The δ15N values of cattle tissues also had obvious significant difference between the region of Jilin, Ningxia and the region of Guizhou and Hebei, and the latter two was higher than the former two. The staple feeds from different regions had their own character. In addition, the correlations of δ13C and δ15N values between defatted muscle, crude fat and cattle hair were very significant. 【Conclusion】The δ13C values of cattle tissues could predict the proportion of C4 feeds in their diets, and the δ15N values could discriminate the cattle which feeding with grass and cereal. The identification rates for the cattle geographical traceability using δ13C values were higher than using δ15N values, and the identification rates were improved using both δ13C and δ15N. The δ13C and δ15N values of defatted muscle, crude fat, cattle hair could be used for beef geographical origin assessment, and they provided the consistent information to geographical traceability.