Study On The Tracing Technology Of Chicken By Stable Isotopes

In law on quality and safety of agricultural products enacted in October 2006, the traceabilitysystem of agro-product quality safety will be implemented. The unqualified agro-products will be tracedto orgins or the producers. The recall of thses unqualified agricultural products will be done based onthe traceability system. It will increase the confidences of consumers for the quality and safety ofagricultural products.At present, bar code systems are applied for tracing the origins of food. Besides it, other techniquesare applied for tracing agricultural products, such as stable isotope, PCR, near infrared spectroscopy.These techniques can validate authenticity of labeled products, identify the fraud products, discriminatethe products with different marks such as 'organic', 'green' and 'ecological', and they can be used as theparallel technology with the bar code system.Stable isotope technology was applied in the fields of geology, medical and environmentalscience in early time. In recent years, stable isotope analysis is applied in the traceability of animalproducts.In this study, carbon, nitrogen, oxygen, hydrogen, etc stable isotopes are considered as indicators totrace origin of pigments of chicken and places where the chicken fed. Thus, the origin of the chickenwas traced effectively. The two trials have been carded out for research on the tracing origin ofchickens.Experiment 1: 320 one-day-old broilers of AA were selected and assigned to 2 groups, each groupincluded 4 treatments with 4 replicates, then fed on basic diets added different concentration ofcarophyll red and basic diets with different contents of maize respectively. On the 21st and the 42nd dayof the feeding period, the RCF values of feet were determined and the samples were collected. After thehandling, theδ¹³C,δ¹⁵N values of chicken samples, theδ¹³C values of feed were determined. Theresults showed : the RCF values and the levels of carophyll red, the RCF values and the maize contentsof feed were positive correlated, theδ¹³C values in chicken and the maize contents of feed were alsopositive correlated, (r=0.96, r=0.98, r=0.99, p＜0.05) respectively. But theδ¹³C, theδ¹⁵N values inchicken and the levels of carophyll red were not correlated. So, if the chicken have the same RCF valuesbut differentδ¹³C values, the maize contents in feed could be estimated byδ¹³C values of the chicken.Thus, the origin of pigment can be traceed. Additionally, theδ¹³C values of chicken and theδ¹³Cvalues of feed in initial and final period were high correlated, (r=0.95, r=0.68, p＜0.01)respectively.Consequently, the main ingredient of feed can be inferred byδ¹³C values in chicken.Experiment 2: Species, feeding character and geological regions are considered as three mainfactors to determine the sample sites. The chicken samples, the feed samples and water samples werecollected from different regions with different latitude and climate conditions, then theδ¹³C,δ¹⁵N,δ²H values of chicken samples, theδ¹³C,δ¹⁵N values of feed andδ¹⁸O values of water were determined.The result showed that theδ¹³C values in chicken and theδ¹³C values in feed were high correlated (r=0.782, p＜0.01), theδ²H values in chicken and the water were also positively correlated (r=0.816,p＜0.01), which show the main ingredient in feed can be deduced byδ¹³C values in chicken, and theδ¹⁸O values can be figured out, and the geographic origin of the chicken can be traced.Theδ¹³C,δ¹⁵N,δ²H values of chicken, theδ¹⁵N values of feed andδ¹⁸O value of water weredetermined by stable isotope mass spectrometry technique, and the regression equations(Y=0.054X-20.84) betweenδ¹³C values of crude protein in chicken and the maize contents in feed,(Y=1.8626X-89.674) betweenδ²H values of crude protein in chicken andδ¹⁸O values in water wereestablished respectively, which confirmed the stable isotope mass spectrometry technique can be as aneffective tool in investigating the main component of feed and tracing the geographic origin of chicken.