宁夏不同区域安格斯育肥牛肉质特性及基因表达的比较研究

Comparative study on meat quality characteristics and gene expression of Angus fattening cattle in different regions of Ningxia

为了分析宁夏不同区域安格斯育肥牛肉质特性及相关差异表达基因,试验分别在宁夏银川市永宁县(Yongning组)和固原市原州区(Guyuan组)选择健康、体重相近的安格斯育肥公牛各3头,屠宰后采集背最长肌测定营养成分和肌纤维特性,同时采用全转录组测序技术测定背最长肌相关基因表达量,以|lb差异倍数(FC)|>1和校正后的P<0.05为条件筛选差异表达基因,进行主成分和聚类分析。通过GO和KEGG数据库对差异表达基因的功能和信号通路进行富集分析,并通过实时荧光定量PCR验证差异表达基因测序结果的准确性。结果表明:区域影响了育肥牛肉质特性,Guyuan组的肌内脂肪含量极显著高于Yongning组(P<0.01),肌纤维数量和肌纤维密度显著高于Yongning组(P<0.05)。区域影响了肉质调控基因的表达,测序共获得差异表达基因2389个,其中上调基因993个,下调基因1396个。GO一级分类中富集差异表达基因最多的功能分别是碳水化合物代谢过程(CMP)、胞外区(ER)和磷酸酯水解酶活性(PEHA)。共富集到12条差异显著的KEGG通路,参与的基因有281个,其中上调基因147个,下调基因134个。进一步结合PPAR和AMPK信号通路筛选出白细胞分化抗原36(CD36)、脂蛋白酯酶(LPL)和肌球蛋白重链(MyHC)3个与肌肉和脂质生长相关的差异表达基因。Yongning组的LPL和CD36基因相对表达量极显著高于Guyuan组(P<0.01),MyHC基因相对表达量显著高于Guyuan组(P<0.05),实时荧光定量PCR检测结果与转录组测序结果相似。说明不同区域育肥牛肉质特性及肉质调控基因表达存在差异,其中CD36、LPL和MyHC基因对肌肉生长和脂质沉积有促进作用。

To analyze the meat quality characteristics and differentially expressed genes(DEGs)of Angus fattening cattle in different regions of Ningxia,experiments were conducted in Yongning County,Yinchuan City(Yongning group),and Yuanzhou District,Guyuan City(Guyuan group).Three healthy Angus fattening bulls with similar weight were selected from each region.After slaughter,the longissimus dorsi muscles were collected to measure nutritional components and muscle fiber characteristics.RNA-seq technology was employed to determine the gene expression levels in the longissimus dorsi muscle.DEGs were screened with a fold change(FC)>1 and an adjusted P-value(Padj)<0.05,followed by principal component and clustering analyses.The functions and pathways of DEGs were enriched by using the GO and KEGG databases,and the accuracy of RNA-seq results was validated by real-time quantitative PCR(RT-qPCR).The results showed that the meat quality characteristics of fattening cattle were affected by the region.The intramuscular fat content in the Guyuan group was significantly higher than that in the Yongning group(P<0.01),and the number and density of muscle fibers were also significantly higher than those in the Guyuan group(P<0.05).Regional differences influenced the expression of meat quality regulation genes.A total of 2389 DEGs were identified,with 993 upregulated genes and 1396 downregulated genes.GO enrichment analysis revealed that the DEGs were predominantly involved in carbohydrate metabolic processes(CMP),extracellular region(ER),and phosphoric ester hydrolase activity(PEHA).KEGG pathway analysis identified 12 significantly different pathways,encompassing 281 DEGs,with 147 upregulated and 134 downregulated genes.Three DEGs—CD36(Cluster of Differentiation 36),LPL(Lipoprotein Lipase),and MyHC(Myosin Heavy Chain)—involved in muscle and lipid growth regulation were further screened by combining PPAR and AMPK signaling pathways.The relative expression levels of LPL and CD36 genes in the Yongning group were significantly higher than those in the Guyuan group(P<0.01),and the relative expression level of MyHC gene in the Yongning group was significantly higher than that in the Guyuan group(P<0.05).The results of real-time fluorescence quantitative PCR were similar to those of transcriptomic sequencing.The results indicated that there were differences in meat quality characteristics and expression of meat quality regulatory genes in different regions,among which CD36,LPL,and MyHC genes promoted muscle growth and lipid deposition.