Cobb broilers (COBB) have been heavily selected for their production performance in the past several decades, while the Athens Canadian Random Bred (ACRB) chickens, a meat-type breed, have been kept as a non-selected control strain. The purpose of this study was to compare these two lines of chickens at late embryonic development and identify the molecular markers and fatty acid profiles underlining their differences in growth performance due to selection. Fertilized eggs of the ACRB (n = 6) and COBB (n = 6) were used at 14 and 18 embryonic days. Genes involved in lipogenesis and myogenesis were measured using quantitative real-time reverse transcroption-polymerase chain reaction (RT-PCR), and fatty acid (FA) compositions of egg yolk, muscle, and liver were measured using gas chromatography. COBB had higher egg weight, embryo weight, and breast and fat ratio. The gene expression in the liver showed an interaction between age and breed on FASN expression, with the highest level in COBB at E18. ACRB had higher ApoB and MTTP expression, but lower SREBP-1 expression compared to COBB. No difference was found in myogenesis gene expression in the muscle between two breeds. For the FA composition, muscle was largely affected by both breed and age. Yolk and liver were affected mainly by breed and age, respectively. Constant interaction effects in docosahexaenoic acid (DHA), indicating the highest level in all the tested tissues of ACRB at E14 and the constant main effects with higher myristic, palmitic, and gondoic, but lower linolenic acid in the liver and yolk of COBB compared to the levels in those of ACRB. Finally, fat accumulation in the liver had no obvious difference between the breeds but was higher when embryo was older. In conclusion, broiler breed affects egg, embryo, and tissue weight, as well as FA composition in initial egg yolk and throughout the embryonic development. The highest docosahexaenoic percentage was observed in ACRB, indicating that genetic selection may result in fatty acid profile changes such as lower DHA content in chicken tissues and eggs.

在过去的几十年中，考伯（Cobb）肉鸡（COBB）因其生产性能而受到广泛选择，而肉类品种雅典加拿大随机繁殖（ACRB）鸡一直作为非选择对照品系饲养。这项研究的目的是比较这两种鸡的胚胎发育后期，并鉴定出分子标记和脂肪酸谱，这些分子标记和脂肪酸谱强调了它们由于选择而导致的生长性能差异。ACRB的受精卵ñ = 6）和COBB（ñ= 6）在第14和18个胚胎天使用。使用定量实时逆转录聚合酶链反应（RT-PCR）测量涉及脂肪形成和肌发生的基因，并使用气相色谱法测量蛋黄，肌肉和肝脏的脂肪酸（FA）组成。COBB的蛋重，胚重，乳脂比更高。肝脏中的基因表达显示了年龄和品种之间的相互作用。财务会计准则表达，在E18中COBB的水平最高。ACRB较高载脂蛋白B 和 MTTP 表达，但较低 SREBP-1表达与COBB相比。在两个品种之间，肌肉中的肌生成基因表达没有发现差异。对于FA组成，肌肉在很大程度上受品种和年龄的影响。卵黄和肝脏分别受品种和年龄的影响。二十二碳六烯酸（DHA）中的相互作用持续不断，表明在E14的所有ACRB测试组织中的最高水平，并且与COBB相比，其较高的肉豆蔻酸，棕榈酸和甘地酸具有恒定的主要作用，而亚麻酸在COBB的肝脏和蛋黄中却较低ACRB中的水平。最后，不同品种之间肝脏中的脂肪积累没有明显差异，但是随着胚胎年龄的增长，脂肪积累更高。总之，肉鸡的品种会影响鸡蛋，胚胎和组织的重量，以及初始蛋黄和整个胚胎发育过程中的FA组成。