Department of Animal Science, College of Agriculture, Shiraz University, Shiraz, Iran.
J Anim Sci. 2012 Jun;90(6):1807-15. doi: 10.2527/jas.2011-4791. Epub 2011 Dec 6.
This study was conducted to investigate relationships between mitochondrial respiratory chain complex activities, feed efficiency, and carcass traits in sheep. A group of Ghezel male lambs sired by a single ram were randomly allotted to individual pens. The lambs were fed ad libitum with a fattening diet containing 30% roughage (corn silage and alfalfa hay) and 70% concentrate for 70 d to individually phenotype each lamb for feed conversion ratio (FCR), adjusted FCR (aFCR), and residual feed intake (RFI). The lambs were then humanely killed and the liver, abdominal fat, pelvic fat, cardiac fat, warm carcass weight, and cold carcass weight, as well as the cross-sectional area of the LM and the fat depth over the 12th rib, were determined. A portion of LM was obtained to determine mitochondrial protein and respiratory chain complex activities (complexes I to V). Statistical analysis was carried out based on lambs exhibiting high and low RFI (n = 8), FCR (n = 8), or aFCR (n = 8) phenotypes. The lambs exhibiting the high-RFI phenotype consumed 110 g more feed daily (P < 0.05) than did the phenotype exhibiting low RFI, with no difference in ADG. Conversely, there was no difference in feed intake between the low- or high-FCR groups, but sheep exhibiting the low-FCR phenotype gained 70 g more (P < 0.05) per day compared with those exhibiting the high-FCR phenotype. It was determined that all 5 respiratory chain complex activities were greater (P < 0.05) in sheep exhibiting the low-RFI phenotype compared with those exhibiting the high-RFI phenotype, with significant (P < 0.001) negative correlation coefficients between RFI and respiratory chain complex activity. When efficiency was assessed using FCR, only activities of respiratory chain complexes III, IV, and V were less (P < 0.05) in the low-FCR phenotype compared with the high-FCR phenotype, and there were no differences (P > 0.1) in respiratory chain complex activities between groups when FCR was adjusted for metabolic BW (aFCR). There were no differences (P > 0.1) in carcass traits among any of the feed efficiency phenotypes. The results suggest that the inclusion of respiratory chain complex activities in breeding programs may be helpful in selecting for sheep exhibiting the low-RFI phenotype.
本研究旨在探讨绵羊线粒体呼吸链复合物活性、饲料效率和胴体性状之间的关系。一组由一只公羊配种的盖泽尔雄性羔羊被随机分配到单独的围栏中。羔羊自由采食含有 30%粗饲料（玉米青贮和紫花苜蓿干草）和 70%浓缩饲料的育肥日粮 70 天，以个体表型测定每只羔羊的饲料转化率（FCR）、调整 FCR（aFCR）和剩余饲料摄入量（RFI）。然后将羔羊人道处死，测定肝脏、腹部脂肪、骨盆脂肪、心脏脂肪、温热胴体重和冷胴体重，以及 LM 的横截面积和第 12 肋上方的脂肪深度。取一部分 LM 测定线粒体蛋白和呼吸链复合物活性（复合物 I 至 V）。根据表现出高 RFI（n = 8）、FCR（n = 8）或 aFCR（n = 8）表型的羔羊进行统计分析。表现出高 RFI 表型的羔羊每天多消耗 110 克饲料（P < 0.05），而表现出低 RFI 表型的羔羊没有差异。相反，低 FCR 或高 FCR 组之间的饲料摄入量没有差异，但表现出低 FCR 表型的羔羊每天多增重 70 克（P < 0.05）。与表现出高 RFI 表型的羔羊相比，表现出低 RFI 表型的羔羊所有 5 种呼吸链复合物活性均较高（P < 0.05），RFI 与呼吸链复合物活性之间呈显著（P < 0.001）负相关系数。当使用 FCR 评估效率时，仅表现出低 FCR 表型的羔羊的呼吸链复合物 III、IV 和 V 的活性较低（P < 0.05），而在调整代谢 BW（aFCR）后，两组之间的呼吸链复合物活性没有差异（P > 0.1）。在任何饲料效率表型中，胴体性状均无差异（P > 0.1）。结果表明，在选择表现出低 RFI 表型的绵羊时，将呼吸链复合物活性纳入育种计划可能会有所帮助。
