羊组织中碳、氮同位素组成及地域来源分析

Analysis of Stable Carbon and Nitrogen Isotope Compositions and Geographical Origins of Sheep Tissues

【目的】探讨羊组织中C、N同位素组成特征及其在地域间的变化规律,为利用稳定性同位素技术进行羊肉产地溯源提供科学依据。【方法】利用稳定性同位素比率质谱仪(IRMS)测定来自内蒙古自治区锡林郭勒盟、阿拉善盟和呼伦贝尔市3个牧区,重庆市和山东省菏泽市2个农区羊肉、羊颈毛及饲料样品中的δ13C和δ15N值,比较不同地域羊组织中稳定性碳、氮同位素组成的差异,分析羊组织同位素组成的相关关系,结合羊的饲喂方式和地域环境,探讨C、N同位素组成的变化规律。【结果】不同地域羊组织的δ13C、δ15N值有显著性差异,其δ13C值与牧草δ13C值高度相关,主要受牧草种类的影响;δ15N值与饲料和地域环境有关。脱脂羊肉、粗脂肪及羊颈毛的δ13C、δ15N值均呈极显著性相关。【结论】稳定性C、N同位素可以作为追溯羊肉产地及其饲喂体系的参考指标。脱脂羊肉、羊颈毛、粗脂肪均可用于羊肉产地溯源研究。

[Objective] The carbon and nitrogen isotope compositions of sheep tissues were investigated, and their variations among the regions were discussed, the aim is to provide the scientific basis for using stable isotope analysis to trace the geographical origin of mutton; [Method] The δ^13C and δ^15N values of sheep muscle, hair and their feeds originating from three pastoral areas including Alxa League, Xilin Gol League and Hulunbuir City of Inner Mongolia, and two agricultural areas including Chongqing City and Heze City were determined by Isotope Ratio Mass Spectrometry（IRMS）. The differences of carbon and nitrogen compositions in sheep tissues from above regions were compared, and the correlations of isotope compositions between different tissues were analyzed. Moreover, the change of δ^13C and δ^15N values in sheep tissues under different feeding modes and environmental conditions were also investigated; [Result] C and N isotope ratios of sheep tissues from different regions showed significant differences; the δ^13C values of tissues were highly correlated with the δ^13C value of their feeds, mainly affected by the kinds of forage; the δ^15N values were related with feeds and geographical origin. In addition, the δ^13C and δ^15N values between defatted muscle, crude fat and sheep hair were both significantly correlated. [Conclusion] The stable carbon and nitrogen isotopes could be used as reference indexes for tracing geographical origin and feeding practice of sheep. The defatted muscle, crude fat, and sheep hair could be used in mutton geographical origin assessment.