稳定同位素质谱技术追溯鸡蛋中的色素来源

研究了用同位素质谱仪测定鸡蛋中的δ13C、δ15N值，追溯鸡蛋中色素来源的方法。320只产蛋鸡随机分为4个玉米含量不同组和4个色素添加量不同组，在试验前期第28 d和后期第56 d测定蛋黄的RCF、δ13C、δ15N值。结果表明：玉米组中，随着玉米含量的增加，各组的RCF值和δ13C值也随之增加，并且各组之间差异极显著 (P<0.01)；后期10% 玉米组与70%玉米组互换饲料后，其蛋黄的RCF值和δ13C值与各自前期相比，差异极显著(P<0.01)，其他未改变饲料的两组与前期比较，差异不显著(P>0.05)。色素组中，前期随着色素添加量的增加，蛋黄RCF值显著升高(P<0.05)，撤除色素后，各处理间的RCF值差异不显著(P > 0.05)；蛋黄的δ13C值在撤除色素前后差异均不显著(P > 0.05)。玉米组中，蛋黄色度与其δ13C值呈显著正相关(P<0.01)，色素组中不存在相关性，当两组的RCF值相同时，δ13C值有显著差异。通过测定蛋黄的δ13C值可以追溯鸡蛋中的色素来源。
Abstract: The δ13C and δ15N values of eggs was measured using an isotope ratio mass spectrometer to trace the origin of pigments in eggs. A total of 320 layer chickens were randomly divided into four groups that were fed diets containing different corn content and an additional four groups that were fed diets containing different amounts of added artificial pigment. The values of Roche color fan (RCF), δ13C, and δ15N of yolks were measured on Day 28 (early stage) and Day 56 (late stage). The results indicated that the RCF and δ13C values of egg yolk in each group increased with an increasing corn content, and significant differences were observed between groups fed diets with different corn content (P < 0.01). In the late stage, when the feeds of the 10% corn and 70% corn groups were swapped, the RCF values and δ13C values of egg yolk in both groups were significantly different compared with their previous results (P < 0.01), while no significant differences were found in these values for the two groups without feed swapping (P > 0.05). For the varying pigment groups, the RCF values increased significantly with an increase in amount of added artificial pigment (P < 0.05) in the early stage, whereas after the removal of pigment, the RCF values showed no significant differences (P > 0.05). Additionally, no significant differences were found in δ13C values before and after pigment removal (P > 0.05). In the varying corn content groups, a strong positive correlation (P < 0.01) was found between RCF and δ13C values, but no correlation was found in the varying pigment groups. When the RCF values were the same in two groups, δ13C values showed significant differences. Thus, analysis of carbon stable isotope ratio (δ13C) in egg yolk can be used to trace the origin of pigment in eggs.