Department of Animal Sciences, The Ohio State University, Columbus 43210.
Department of Animal Sciences, The Ohio State University, Columbus 43210
Poult Sci. 2014 Jul;93(7):1809-17. doi: 10.3382/ps.2013-03816. Epub 2014 May 7.
The United States is a world leader in poultry production, which is the reason why achieving better performance and muscle growth each year is a necessity. Reducing accretion of adipose tissue is another important factor for poultry producers because this allows more nutrients to be directed toward muscle growth, but the effect of embryonic adipose growth on posthatch development has not been fully understood. The purpose of this study was to investigate the total DNA mass, morphological characteristics, differentiation markers, and triglyceride breakdown factors of embryonic adipose tissue, and their relation to hyperplastic and hypertrophic growth within layers (Leghorn) and meat-type chickens (broilers). After embryonic day (E) 12, broiler weight was significantly higher than Leghorn, and this trend continued throughout the rest of incubation and posthatch (P < 0.05). Neck and leg fat pad weights between the 2 breeds did not differ at most of the time points. A remarkable increase in total DNA mass was observed between E12 and E14 in both Leghorn and broilers (P < 0.05), indicating a high potential for hyperplastic growth during this time. Histological analysis revealed clusters of preadipocytes at E12; however, the majority of these cells differentiated by E14 and continued to grow until the time of hatch. The adipocyte sizes between both breeds did not generally differ, even though broilers are known to have larger adipocytes posthatch. Fatty acid-binding protein 4 expression levels in Leghorn and broilers continued to rise with each time point, which paralleled the expansion of mature adipocytes. Adipose triglyceride lipase was highly expressed at E20 and d 1 posthatch to mobilize triglyceride degradation for energy during hatching. Thus, embryonic chicken adipose tissue was found to develop by hyperplastic mechanisms followed by hypertrophy. At embryonic stages and early posthatch, layer- and meat-type chicken adipose growth does not differ, which suggests breed differences occur posthatch.
美国是家禽生产的世界领导者，这就是为什么每年都要提高生产性能和肌肉生长速度。减少脂肪组织的积累是家禽生产者的另一个重要因素，因为这可以使更多的营养物质用于肌肉生长，但胚胎脂肪生长对孵化后发育的影响尚未完全了解。本研究旨在研究胚胎脂肪组织的总 DNA 质量、形态特征、分化标志物和甘油三酯分解因子，及其与层鸡（来亨鸡）和肉用型鸡（肉鸡）的增生和肥大生长的关系。在胚胎第 12 天（E）之后，肉鸡的体重明显高于来亨鸡，并且这种趋势在整个孵化和孵化后（P < 0.05）持续。在大多数时间点，两种鸡种的颈部和腿部脂肪垫重量没有差异。在来亨鸡和肉鸡中，从 E12 到 E14 之间观察到总 DNA 质量的显著增加（P < 0.05），表明在此期间具有很高的增生生长潜力。组织学分析显示，在 E12 时存在前体脂肪细胞的簇，但大多数细胞在 E14 时分化，并继续生长直至孵化时。尽管肉鸡在孵化后具有更大的脂肪细胞，但两种鸡种的脂肪细胞大小通常没有差异。脂肪酸结合蛋白 4 在来亨鸡和肉鸡中的表达水平随着每个时间点的增加而继续上升，这与成熟脂肪细胞的扩张相平行。脂肪甘油三酯脂肪酶在 E20 和孵化后第 1 天高度表达，以动员甘油三酯降解以提供孵化期间的能量。因此，发现鸡胚胎脂肪组织通过增生机制发育，然后通过肥大生长。在胚胎阶段和孵化后早期，层鸡和肉用鸡的脂肪生长没有差异，这表明孵化后出现了品种差异。
