利用肉色相关候选基因对肉色性状进行预测

Utilization of meat color candidate genes in early postnatal prediction of pig meat color trait

1)选用肥育期苏太猪100头,屠宰后取背最长肌,采用相对定量RT-PCR法测定肉色候选基因肌红蛋白(MB)、肌细胞增强因子(MEF2)、钙调神经磷酸酶(Calcineurin)和活化T细胞核因子(NFATc1)mRNA水平;分别测定MB浓度和肌肉表观色度参数,并对肉色进行评分,再分析上述参数间的相关性。结果显示:MB mRNA与肉色评分(r=0.426**(**:P<0.01))、a*值(r=0.379**)、MB浓度(r=0.364**)均呈正相关;NFATc1 mRNA与肉色评分(r=0.407**)、a*值(r=0.406**)、MB浓度(r=0.345*(*:P<0.05))、MB mRNA(r=0.571**)也均存在正相关;且肉色候选基因表达之间均呈正相关。2)选用生长速度慢的肉脂兼用型二花脸猪与生长速度快的瘦肉型大白猪,分别于3、20、45、90、120和180日龄采集背最长肌样品,用相对定量RT-PCR法分析背最长肌中肉色相关候选基因表达的发育性变化,并进行品种和性别间比较。结果显示:MB、MEF2、Calcineurin mRNA发育性变化在品种间二花脸猪高于大白猪;NFATc1 mRNA则相反,大白猪高于二花脸猪。两品种MB、NFATc1、Calcineurin mRNA均在20日龄急剧升高,MEF2在两品种间差异最大,除3日龄外,二花脸公猪均显著高于大白公猪。性别间二花脸公、母猪MB mRNA和MEF2 mRNA仅在发育后期180日龄有显著差异,Calcineurin mRNA和NFATc1 mRNA在整个发育阶段均无显著差异。结论:推定最佳早期选育时间点为20日龄。

1 ） One hundred Sutai pigs of marketing body weight were slaughterd and longissimus dorsi （LD） muscles were sampled for measuring various parameters related to meat color. Semi-quantitative RT-PCR was applied to determine the mRNA level of MB （ Myoglobin）, myocyte enhancer factor 2 （ MEF2）, Calcineurin, and nuclear factor of activated T-cells （ NFATcl ） genes ; photometric method was used to measure MB concentration. Meat color was evaluated both by colorimeter and subjective color scoring. Correlation analysis was performed to investigate relationships between parameters. Results showed that MB mRNA positively corre- lated with subjective color scoring （ r = 0. 426^＊＊ （^＊＊ ： P〈0. 01 ） ）, a^＊ （ r = 0. 379^＊ ＊ ）, and MB concentration （ r = 0. 364^＊ ＊ ）. NFATcl mRNA positively correlated with subjective color scoring （ r = 0.407 ^＊＊ ） , a^＊ （ r = 0.406^＊ ＊ ）, MB concentralion （ r = 0. 345^＊ （ ^＊： P〈0. 05） ）, and MB mRNA （r=0. 571^＊ ＊ ）. 2） Large White boars, Erhualian boars and Erhualian gilts were employed to investigate the developmental patterns of expression level of four meat color candidate genes in LD muscle at day 3, 20, 45, 90, 120 and 180 respectively. Results indicated that the developmental pattern of Myoglobin, MEF2, and Calcineurin mRNA levels were similar, higher in Erhualian and lower in Large White except day 3. However, NFATcl was on the opposite, higher in Large White. MB, NFATc1 and Calcineurin mRNA levels all increased dramatically at day 20 and after no significant changes were abserved. As for gender difference, expressions of MB and MEF2 mRNA were similar, and significant changes happened only at day 180. The expression of Calcineurin and NFATcl mRNA showed no significant changes. So we suggest day 20 be the eligible time of early postnatal selection.