Abstract

Down, mainly duck down and goose down, is one of the most important products in the poultry industry. To improve the accuracy of identification of duck and goose down by quantitative real-time PCR (qPCR), and the efficiency of extracted DNA from down was evaluated and optimized using the template preparation methods, including four pretreatment methods (shredding [PA], shredding + magnetic bead homogenization [PB], shredding + manually grinding in liquid nitrogen [PC], and shredding + grinding by 6875 Freezer [PD]) and three extraction methods (a magnetic bead adsorption method [MA], a membrane adsorption-elution method [MB], and a Chelex® 100 Resin method [MC]), and their combinations. The results showed that high-intensity grinding, and grinding in liquid nitrogen can help the improvement of DNA yield, therefore, PB, PC, and PD were superior to PA both in DNA concentration and purity. However, in the subsequent qPCR analysis, the DNA of the highest quantity and purity from PD indicated the lowest positive detection rate. According to the results of the current study, the extraction method had a greater impact on the quality of DNA than the pretreatment method. Although the concentrations and purities of the templates obtained by MA, MB, and MC were varied greatly, all the templates could meet the needs in the following qPCR assay. Furthermore, considering the simplicity of the methods, PA + MC was chosen as the most convenient and efficient combination to extract DNA from down. A quantitative calculation method for the identification of the authenticity of down products was established. Although quantification results could not estimate the target content accurately, they reflected the trend in the content. Nevertheless, the method may be useful as an alternative tool for qualitative and quantitative quality control of the down products.