The effects of a loin muscling quantitative trait locus (LoinMAX™) on carcass and VIA-based traits in crossbred lambs.
The effects of a loin muscling quantitative trait locus (LoinMAX™) on carcass and VIA-based traits in crossbred lambs.
复制标题
腰肌数量性状基因座 (LoinMAX™) 对杂交羔羊胴体和基于 VIA 的性状的影响。
作者：
A. Masri;N. Lambe;J. Macfarlane;S. Brotherstone;W. Haresign;E. Rius;L. Bünger
LoinMAX （LM）是在澳大利亚波尔多塞特羊中分离到的一个数量性状位点（QTL），定位于羊18号染色体远端。据报道，LM-QTL使背最长肌面积和重量分别增加11%和8%。本研究的目的是全面评估LM-QTL在英国绵羊产业分层结构典型遗传背景中的直接影响，然后再推荐在英国使用。杂交羔羊，无论是不携带或携带LM-QTL的单一副本，是由苏格兰骡子母羊（蓝脸莱斯特×苏格兰黑脸）与两只波尔多塞特公羊的精子人工受精产生的，这两只公羊是LM-QTL的杂合。出乎意料的是，其中一只公羊的QTL也是杂合的，该QTL影响整个胴体肌肉（MyoMAX™）。这是通过在统计分析中嵌套MyoMAX™状态（携带者或非携带者）来解释的。羔羊在平均113日龄时称重并使用x射线计算机断层扫描（CT）进行扫描。超声扫描测量，以及羔羊体重，在平均140天的时候进行，然后屠宰羔羊。根据美国肉类和畜牧业委员会（MLC）胴体分类方案对胴体称重并进行脂肪覆盖和构象评分，然后使用视频图像分析（VIA）系统进行扫描。CT扫描结果显示，LM-QTL杂合子羔羊的腰最长肌宽度大于非携带者（P < 0.05）。LM-QTL携带羔羊的MLL也显著加深，超声测量的第三腰椎肌深（+3.7%,P < 0.05）和CT扫描的第五腰椎肌深（+3.4%,P < 0.01）。因此，通过CT扫描测量，携带单拷贝LM-QTL的羔羊的MLL面积显著高于非携带者（+4.5%;P < 0.01）。通过CT测量的其他性状，如腿部肌肉尺寸、平均肌肉密度和组织比例，没有受到LM-QTL的显著影响。LM-QTL对胴体总瘦重、脂肪重、MLC构象和脂肪评分分类无显著影响。使用先前导出的算法，VIA可以检测到LM-QTL对腰肉原切肉产量的预测重量有显著影响（+2.2%;P < 0.05），但对其他原切肉或整个胴体没有影响。
LoinMAX (LM) is a quantitative trait locus (QTL), which was found to be segregated in Australian Poll Dorset sheep, and maps to the distal end of sheep chromosome 18. LM-QTL was reported to increase Musculus longissimus dorsi area and weight by 11% and 8%, respectively. The aim of this study was to comprehensively evaluate the direct effects of LM-QTL in a genetic background typical of the stratified structure of the UK sheep industry, before it can be recommended for use in the United Kingdom. Crossbred lambs, either non-carriers or carrying a single copy of LM-QTL, were produced out of Scottish Mule ewes (Bluefaced Leicester × Scottish Blackface) artificially inseminated with semen from two Poll Dorset rams that were heterozygous for LM-QTL. Unexpectedly, one of these rams was also heterozygous for a QTL that affects the overall carcass muscling (MyoMAX™). This was accounted for by nesting MyoMAX™ status (carrier or non-carrier) within sire in the statistical analysis. Lambs were weighed and scanned by using X-ray computed tomography (CT) at an average age of 113 days. Ultrasound scan measurements, along with lamb weights, were taken at an average age of 140 days and lambs were then slaughtered. Carcasses were weighed and classified for fat cover and conformation scores, based on the Meat and Livestock Commission (MLC) carcass classification scheme, and then scanned by using a video image analysis (VIA) system. M. longissimus lumborum (MLL) width, as measured by CT scanning, was greater (P < 0.05) in lambs heterozygous for LM-QTL compared with non-carriers. MLL in LM-QTL carrier lambs was also significantly deeper, as measured by both ultrasound muscle depth at the third lumbar vertebrae (+3.7%; P < 0.05) and CT scanning at the fifth lumbar vertebrae (+3.4%; P < 0.01). Consequently, MLL area, was measured by using CT scanning, was significantly higher (+4.5%; P < 0.01) in lambs carrying a single copy of LM-QTL compared with non-carriers. Additional traits measured by CT, such as leg muscle dimensions, average muscle density and tissue proportions, were not significantly affected by LM-QTL. LM-QTL did not significantly affect total carcass lean or fat weights or MLC conformation and fat score classifications. Using previously derived algorithms, VIA could detect a significant effect of the LM-QTL on the predicted weight of saleable meat yield in the loin primal cut (+2.2%; P < 0.05), but not in the other primal cuts, or the total carcass.
影响因子：
7
作者：
Freking, BA;Murphy, SK;Smith, TPL
通讯作者：
Smith, TPL
特克塞尔肌肉数量性状基因座对杂交羔羊胴体性状的影响。
DOI：
10.1017/s175173110800356x
发表时间：
2009
期刊：
an international journal of animal bioscience
影响因子：
--
作者：
Macfarlane JM
通讯作者：
Macfarlane JM