Short-chain fatty acids (SCFA) can regulate appetite by stimulating the secretion of satiety hormones. However, the impact of short-chain fatty acid propionate on the release of gut satiety hormones and appetite regulation in pigs is not completely understood. In this study, 16 pigs were infused with saline or sodium propionate through a fistula in the caecum during a 28-day experimental period. We characterized the effects of propionate administration on peptide YY (PYY) and glucagon-like peptide 1 (GLP-1) secretion from colonic tissue, and investigated the role of propionate infusion on the expression of appetite-related genes in the colon and hypothalamus. Further, the direct impact of propionate administration on the expression of orexigenic neuropeptide agouti-related protein (AgRP) in hypothalamic N38 cells was also examined. The results showed that intra-cecal infusion of propionate reduced the short-term feed intake (P < 0.05) but not the long-term feed intake in pigs (P > 0.05). Propionate administration stimulated PYY and GLP-1 release from colon tissue in vivo and ex vivo (P < 0.05). It also upregulated PYY expression in the colonic mucosa (P < 0.05). Meanwhile, the GLP-1 and PYY levels in the blood were increased after intra-cecal infusion of propionate at d 28 (P < 0.05). Additionally, intra-cecal infusion of propionate upregulated the mRNA and protein expression of free fatty acid receptor 2/3 (FFAR2/FFAR3) in the colonic mucosa (P < 0.05). Propionate infusion also downregulated the orexigenic AgRP mRNA expression (P < 0.05) and upregulated the anorexigenic cocaine-and amphetamine-regulated transcript (CART) mRNA expression (P = 0.09) in the hypothalamus. Moreover, propionate administration directly downregulated AgRP expression in hypothalamic N38 cells in a dose-dependent manner (P < 0.05). Collectively, these findings demonstrated that cecal propionate stimulated colonic secretion of satiety hormones and suppressed appetite to reduce the short-term feed intake in pigs. This study highlights that microbial-derived propionate exerts an important role in regulating the physical functions of the host.

短链脂肪酸（SCFA）可以通过刺激饱腹感激素的分泌来调节食欲。然而，短链脂肪酸丙酸盐对猪肠道饱腹感激素释放和食欲调节的影响尚不完全清楚。在这项研究中，在为期 28 天的实验期间，通过盲肠中的瘘管向 16 头猪输注盐水或丙酸钠。我们描述了丙酸盐给药对结肠组织中肽 YY (PYY) 和胰高血糖素样肽 1 (GLP-1) 分泌的影响，并研究了丙酸盐输注对结肠和下丘脑中食欲相关基因表达的作用。此外，丙酸盐给药对促食欲神经肽刺鼠相关蛋白（AgRP ）表达的直接影响) 在下丘脑 N38 细胞中也进行了检查。结果表明，盲肠内注射丙酸盐降低了猪的短期采食量（P < 0.05），但不降低猪的长期采食量（P > 0.05）。丙酸盐在体内和体外刺激结肠组织中 PYY 和 GLP-1 的释放（P < 0.05）。它还上调结肠黏膜中PYY的表达（P < 0.05）。同时，盲肠内输注丙酸盐后第28天血中GLP-1和PYY水平升高（P < 0.05）。此外，盲肠内输注丙酸盐可上调结肠黏膜游离脂肪酸受体 2/3（FFAR2/FFAR3）的 mRNA 和蛋白表达（P< 0.05)。丙酸盐输注还下调了下丘脑中的厌食性AgRP mRNA 表达 ( P < 0.05) 并上调了厌食性可卡因和安非他明调节的转录物 ( CART ) mRNA 表达 ( P = 0.09)。此外，丙酸盐给药以剂量依赖性方式直接下调下丘脑N38细胞中AgRP的表达（ P <0.05）。总的来说，这些研究结果表明，丙酸盲肠刺激结肠分泌饱腹感激素并抑制食欲，从而减少猪的短期采食量。这项研究强调了微生物来源的丙酸盐在调节宿主的身体机能方面发挥着重要作用。