Stable C and N isotope ratio analysis for regional geographical traceability of cattle in China

The aim of this study was to examine the variation in carbon and nitrogen stable isotope ratios in cattle tissues from different provinces in China, and to investigate the correlations of δ13C and δ15N values between different cattle tissues. Furthermore, the success rate of classification using δ13C and δ15N values to distinguish the geographical origin of cattle was analyzed. Fifty nine cattle samples were collected from Jilin, Ningxia, Guizhou and Hebei provinces in China, and the δ13C and δ15N values of de-fatted beef, crude fat and tail hair were measured using isotope ratio mass spectrometry (IRMS). There were highly significant regional differences in the mean values of δ13C and δ15N values in the cattle tissues. A significant correlation was found in δ13C and δ15N between de-fatted beef, crude fat and tail hair, which indicated that all of these matrices could be used to trace cattle to their geographical origin. The results of discriminant analysis showed that δ13C was the better indicator for cattle origin traceability than δ15N. The classification success rate could be improved greatly by combining the two indicators. It was concluded that stable isotope analysis of C and N in cattle tissue can be used to trace cattle diet and origin in China.