Department of Nutrition and Clinical Nutrition, Benha University, Toukh, Egypt.
Arch Anim Nutr. 2011 Jun;65(3):175-85. doi: 10.1080/1745039x.2011.556328.
The present study evaluated two previously developed methods for amplification of bovine mtDNA segments of 109 and 271 base pairs (bp) by real-time polymerase chain reaction (PCR). Beef samples were sterilised experimentally at different temperatures (126 degrees C, 129 degrees C, 132 degrees C and 135 degrees C). These experimentally sterilised beef samples and nine commercial meat and bone meals (MBM) were mixed to a reference plant concentrate in strengths of 50%, 10%, 5%, and 1%. The results of the following PCR showed that the Bos-109 real-time PCR assay was able to detect all the experimental beef samples with exception of the mixtures of beef heated experimentally to 135 degrees C. In mixtures of industrial MBM bovine DNA were always found. Comparatively, the beef sterilised at 135 degrees C and 132 degrees C (and their respective mixtures) and the mixture containing 1% of beef sterilised at 129 degrees C were not detectable with the PCR assay amplifying a target of 271 bp. Using this PCR mixtures of industrial MBM were only weakly detected. The low concentrated mixtures of the extremely processed MBM-1 and MBM-2 even reported negative. These results indicate that the detectability of bovine DNA is strongly influenced by the degree of the thermal treatment. Only the PCR assay amplifying relatively short fragments of a multi-copy mitochondrial target was reliable for the detection of correctly heated MBM in mixed feed.
本研究评估了两种先前开发的实时聚合酶链反应（PCR）扩增牛线粒体 DNA 109 和 271 个碱基对（bp）片段的方法。将牛肉样本在不同温度（126°C、129°C、132°C 和 135°C）下进行实验性灭菌。这些经实验性灭菌的牛肉样本和 9 种商业肉骨粉（MBM）与参考植物浓缩物按 50%、10%、5%和 1%的比例混合。以下 PCR 的结果表明，Bos-109 实时 PCR 检测法能够检测到除了经 135°C 加热的牛肉混合物之外的所有实验牛肉样本。在工业 MBM 的混合物中总是发现牛 DNA。相比之下，用扩增 271bp 靶标的 PCR 检测法无法检测到经 135°C 和 132°C （及其各自的混合物）灭菌的牛肉和经 129°C 灭菌的牛肉混合物中所含的牛 DNA。使用这种 PCR 检测法，工业 MBM 的混合物仅被微弱检测到。低浓度的超加工 MBM-1 和 MBM-2 混合物甚至报告为阴性。这些结果表明，牛 DNA 的可检测性受热处理程度的强烈影响。只有扩增多拷贝线粒体靶标相对较短片段的 PCR 检测法才能可靠地检测混合饲料中经过正确加热的 MBM。
