College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, 450046, China; Key Laboratory of Livestock and Poultry Resources (Poultry) Evaluation and Utilization, Ministry of Agriculture and Rural Affairs, Zhengzhou, 450046, China.
College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, 450046, China; Key Laboratory of Livestock and Poultry Resources (Poultry) Evaluation and Utilization, Ministry of Agriculture and Rural Affairs, Zhengzhou, 450046, China; The Shennong Laboratory, Zhengzhou, 450002, China.
Poult Sci. 2023 Jul;102(7):102682. doi: 10.1016/j.psj.2023.102682. Epub 2023 Apr 5.
Valgus-varus deformity (VVD) is a common leg disease in commercial broilers, which seriously affects animal welfare and causes economic losses. Up to now, most of the studies on VVD have been on skeleton, whereas there are fewer studies on VVD muscle. In this study, carcass composition and meat quality of 35-day-old normal and VVD Cobb broilers assess the effect of VVD on broiler growth. Molecular biology, morphology, and RNA sequencing (RNA-seq) were used to study the difference between normal and VVD gastrocnemius muscle. In comparison with the normal broilers, the breast muscle and leg muscle of the VVD broilers had lower shear force, notably lower crude protein, lower water content, cooking loss, and deeper meat color (P < 0.05). The morphological results showed that the weight of skeletal muscle was significantly higher in the normal broilers than that in the VVD broilers (P < 0.01), the diameter and area of myofibrils in the affected VVD were smaller than in the normal broilers (P < 0.01). Quantitative real-time PCR (qPCR) of gastrocnemius muscle revealed that the expression of myasthenic marker genes, fast myofiber marker genes, and apoptosis-related factors were significantly higher in the VVD broilers than in the normal broilers (P < 0.01). In total, 736 differentially expressed genes (DEGs) were identified firstly in the normal and VVD leg muscle by RNA-seq. Gene ontology (GO) enrichment indicated that these DEGs were mainly involved in the multicellular organismal process and anatomical structure development. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that DEGs are significantly enriched in proteasome. Protein interaction analysis obtained that DEGs with high interaction were proteasome-related coding genes and ubiquitin-related genes, these DEGs were closely associated with muscle atrophy. These show that VVD has an adverse effect on growth characteristics, slaughter characteristics, and meat quality in broilers, which may cause leg muscle atrophy. This study provides some reference values and basis for studying the pathogenesis of VVD in broilers.
外翻-内翻畸形（VVD）是商品肉鸡的一种常见腿部疾病，严重影响动物福利并造成经济损失。到目前为止，大多数关于 VVD 的研究都集中在骨骼上，而关于 VVD 肌肉的研究较少。本研究评估了 VVD 对肉鸡生长的影响，对 35 日龄正常和 VVD Cobb 肉鸡的胴体组成和肉质进行了评估。采用分子生物学、形态学和 RNA 测序（RNA-seq）研究正常和 VVD 比目鱼肌之间的差异。与正常肉鸡相比，VVD 肉鸡的胸肌和腿肌的剪切力较低，粗蛋白、水分、蒸煮损失和肉色较深（P<0.05）。形态学结果表明，正常肉鸡的骨骼肌重量明显高于 VVD 肉鸡（P<0.01），受影响的 VVD 中的肌纤维直径和面积小于正常肉鸡（P<0.01）。比目鱼肌的定量实时 PCR（qPCR）显示，VVD 肉鸡的肌无力标记基因、快肌纤维标记基因和凋亡相关因子的表达明显高于正常肉鸡（P<0.01）。通过 RNA-seq 首次在正常和 VVD 腿部肌肉中鉴定出 736 个差异表达基因（DEGs）。GO 富集分析表明，这些 DEGs 主要参与多细胞生物过程和解剖结构发育。KEGG 分析表明，DEGs 显著富集于蛋白酶体。蛋白质相互作用分析表明，具有高相互作用的 DEGs 是与蛋白酶体相关的编码基因和泛素相关基因，这些 DEGs与肌肉萎缩密切相关。这些表明 VVD 对肉鸡的生长特性、屠宰特性和肉质有不良影响，可能导致腿部肌肉萎缩。本研究为研究肉鸡 VVD 的发病机制提供了一些参考值和依据。
