Abstract：
This study aimed to investigate the developmental change of body growth and gene expression related to fatty acid uptake and oxidation in the yolk sac membrane (YSM) and jejunum during embryogenesis in Muscovy ducks. The weights of embryos and yolk sac (YS) (5 embryos per replicate, n = 6) were recorded on embryonic days (E)16, E19, E22, E25, E28, E31, and the day of hatch (DOH). The fat and fatty acid contents in YSM, jejunal histology, and gene expression related to fatty acid metabolism in YSM and jejunum were determined in each sampling time. Among the nonlinear models, the maximum growth is estimated at 2.83 (E22.5), 2.67 (E22.1), and 2.60 (E21.3) g/d using logistic, Gompertz, and Von Bertalanffy models, respectively. The weight of YS, and ether extract-free YS as well as the amounts of fat and fatty acids in YS decreased (P < 0.05) linearly, whereas the villus height, crypt depth, villus height/crypt depth, and musculature thickness in jejunum increased (P < 0.05) linearly during embryogenesis. The mRNA expression of CD36, SLC27A4, and FABP1 related to fatty acid uptake as well as the mRNA and protein expressions of PPARα and CPT1 related to fatty acid oxidation increased in a quadratic manner (P < 0.05) in both YS and jejunum, and the maximum values were achieved during E25 to E28. In conclusion, the maximum growth rate of Muscovy duck embryos was estimated at 2.60 to 2.83 g/d on E21.3 to E23.5, while the accumulations of lipid and fatty acid in YS were decreased in association with the increased absorptive area of morphological structures in jejunum. The gene and protein expression involved in fatty acid metabolism displayed a similar enhancement pattern between YSM and jejunum during E25 to E28, suggesting that fatty acid utilization could be strengthened to meet the energy demand for embryonic development.
摘要：
本研究旨在研究番鸭胚胎发育过程中卵黄囊膜（YSM）和空肠内脂肪酸吸收和氧化相关基因表达的发育变化。胚胎和卵黄囊(YS)的重量(每个重复5个胚胎，n=6）记录在胚胎日（E）16，E19，E22，E25，E28，E31和孵化日（DOH）。YSM中的脂肪和脂肪酸含量，空肠组织学,在每个采样时间测定YSM和空肠中与脂肪酸代谢相关的基因表达。在非线性模型中，最大增长率估计为2.83(E22.5)，2.67(E22.1),和2.60（E21.3）g/d，使用逻辑，Gompertz,和VonBertalanffy模型,分别。YS的重量,无醚提取物YS以及YS中脂肪和脂肪酸的含量呈线性下降（P<0.05），而绒毛高度，地穴深度,绒毛高度/隐窝深度,在胚胎发生过程中，空肠肌肉组织厚度呈线性增加（P<0.05）。YS和空肠中与脂肪酸摄取相关的CD36，SLC27A4和FABP1的mRNA表达以及与脂肪酸氧化相关的PPARα和CPT1的mRNA和蛋白表达呈二次增加（P<0.05）。并且在E25至E28期间达到最大值。总之,在E21.3至E23.5上，番鸭胚胎的最大生长速率估计为2.60至2.83g/d，而YS中脂质和脂肪酸的积累随着空肠形态结构吸收面积的增加而减少。在E25至E28期间，参与脂肪酸代谢的基因和蛋白质表达在YSM和空肠之间显示出相似的增强模式，这表明可以加强脂肪酸的利用以满足胚胎发育的能量需求。
