1Key Laboratory for Agro-Ecological Processes in Subtropical Region,and National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production,and South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture,Institute of Subtropical Agriculture,The Chinese Academy of Sciences,Changsha,Hunan 410125,P.R. China.
2Lethbridge Research Centre,Agriculture and Agri-Food Canada,Lethbridge,Alberta T1J 4B1,Canada.
Animal. 2019 Mar;13(3):509-517. doi: 10.1017/S1751731118001581. Epub 2018 Jul 10.
The gastrointestinal tract (GIT) of animals is capable of sensing various kinds of nutrients via G-protein coupled receptor-mediated signaling transduction pathways, and the process is known as 'gut nutrient chemosensing'. GPR40, GPR41, GPR43 and GPR119 are chemoreceptors for free fatty acids (FFAs) and lipid derivatives, but they are not well studied in small ruminants. The objective of this study is to determine the expression of GPR40, GPR41, GPR43 and GPR119 along the GIT of kid goats under supplemental feeding (S) v. grazing (G) during early development. In total, 44 kid goats (initial weight 1.35±0.12 kg) were slaughtered for sampling (rumen, abomasum, duodenum, jejunum, ileum, cecum, colon and rectum) between days 0 and 70. The expression of GPR41 and GPR43 were measured at both mRNA and protein levels, whereas GPR40 and GPR119 were assayed at protein level only. The effects of age and feeding system on their expression were variable depending upon GIT segments, chemoreceptors and expression level (mRNA or protein), and sometimes feeding system × age interactions (P0.05) on GPR43 expression; and there were no feeding system×age interactions (P>0.05) on GPR41 and GPR43 protein expression. The expression of GPR41 and GPR43 in rumen and abomasum linearly (P<0.01) increased with increasing age (from days 0 to 70). Meanwhile, age was the main factor affecting GPR40 expression throughout the GIT. These outcomes indicate that age and feeding system are the two factors affecting chemoreceptors for FFAs and lipid derivatives expression in the GIT of kids goats, and S enhanced the expression of chemoreceptors for FFAs, whereas G gave rise to greater expression of chemoreceptors for lipid derivatives. Our results suggest that enhanced expression of chemoreceptors for FFAs might be one of the benefits of early supplemental feeding offered to young ruminants during early development.
动物的胃肠道（GIT）能够通过 G 蛋白偶联受体介导的信号转导途径感知各种营养素，这个过程被称为“肠道营养化学感应”。GPR40、GPR41、GPR43 和 GPR119 是游离脂肪酸（FFAs）和脂质衍生物的化学感受器，但它们在小反刍动物中的研究还不够充分。本研究的目的是确定在早期发育过程中，补充喂养（S）与放牧（G）条件下，羔羊胃肠道（GIT）中 GPR40、GPR41、GPR43 和 GPR119 的表达情况。总共 44 只羔羊（初始体重 1.35±0.12kg）在 0 至 70 天之间被屠宰取样（瘤胃、皱胃、十二指肠、空肠、回肠、盲肠、结肠和直肠）。GPR41 和 GPR43 的表达在 mRNA 和蛋白水平上都进行了测量，而 GPR40 和 GPR119 仅在蛋白水平上进行了检测。年龄和饲养方式对其表达的影响因胃肠道节段、化学感受器和表达水平（mRNA 或蛋白）而异，有时还与饲养方式×年龄的相互作用有关（P0.05）。GPR43 的表达不受饲养方式×年龄相互作用的影响（P>0.05），而 GPR41 和 GPR43 蛋白表达不受影响。GPR41 和 GPR43 在瘤胃和皱胃中的表达随年龄的线性增加（P<0.01）（从 0 天到 70 天）。同时，年龄是影响整个胃肠道 GPR40 表达的主要因素。这些结果表明，年龄和饲养方式是影响羔羊胃肠道中 FFAs 和脂质衍生物化学感受器表达的两个因素，补充喂养增强了 FFAs 化学感受器的表达，而放牧则导致脂质衍生物化学感受器的表达增加。我们的结果表明，FFAs 化学感受器表达增强可能是早期补充喂养对早期发育中小反刍动物的益处之一。
