Technological Study Of Isotope For Cattle Geographical Origin Traceability In Guanzhong

The technology of stable C, N isotope ratio is an effective method for geographical origin traceability of beef. In order to solve the problems in collecting samples and the problem of high cost, the relevant test of theδ13C andδ15N value in skim beef, crude fat and beef tail hair was carried out. The R2 values ofδ13C are 0.9635, 0.9540, 0.9823 and the R2 value ofδ15N is 0.8929, which shows that the carbon and nitrogen isotope in the three tissues has significant relevance. It's concluded that the beef tail hair can be used as the test specimen to replace beef tissues.Studies for the effects of feeds on theδ13C andδ15N value of the cattle tail hair were made in the article according to the factors of isotopic composition in animal tissues. The results show that feed has much greater impact on the grossδ13C,δ15N value of the cattle tail hair than individualities and species of beef. The main ingredients of feed are particularly closely related to theδ13C andδ15N value; its impact on theδ13C value is greater than that ofδ15N value.The effect of discriminating different beef-producing areas in small geographic scope using beef tail hair as test specimen is studied. Guanzhong area of Shanxi Province is chosen as the sampled area. The results got from variance analysis and cluster analysis show that cattle samples from Yangling district and Mei county are classified into one area; samples from Qishan county,Qian county and Yongshou county are clustered into same classification; samples from Linyou county are separated from others; but cattle samples from Fufeng county and Fengxiang county can not be obviously classified which can be divided into the previous three areas. The results showed that it's feasible to discriminate different beef-producing areas in small geographic scope with this method.Variance analysis ofδ13C andδ15N values was carried out in four main fattening cattle feed (wheat bran, corn, wheat straw and fodder) of the beef-producing area, the results showed that theδ13C Value of bran, corn, wheat straw and theδ15N value of corn, fodder had no differences on the level (P <0.05), which proved that cattle feed had no significant differences in different sampling counties. It can be concluded that the reason of differentδ13C andδ15N value in beef tail hair lies in the difference of kinds and ingredients of cattle feed in different counties. Finally, according to the map of Shanxi Guanzhong area, different beef-producing areas can be discriminated with the smallest scope of 20-30 km. Since there are far more factors that can affect discrimination of different beef-producing areas, it can not be easily used in smaller scopes of beef origin in other beef-producing areas.