Short chain fatty acids could prevent fat deposition in pigs via regulating related hormones and genes

Short chain fatty acids (SCFAs) are produced when indigestible carbohydrates, such as fiber and resistant starch, undergo fermentation by specific microbiota in the hindgut. This study was designed to investigate the effects of different SCFAs on the glucolipid metabolism and appetite regulation of pigs. In a 28-day experiment, 30 barrows were divided into five groups: (1) control, (2) 0.1% sodium acetate, (3) 0.1% sodium propionate, (4) 0.1% sodium butyrate, and (5) 0.1% mixed sodium SCFAs (in the ratio of 3 : 1 : 1, respectively). Acetate administration reduced the average daily feed intake and average daily body weight gain of pigs (P < 0.05), decreased serum triglyceride (TG), total cholesterol (TC) and low density lipoprotein-cholesterol (LDL-c) concentrations (P < 0.05), increased serum glucagon-like peptide 1 (GLP-1), peptide YY (PYY) and leptin concentrations (P < 0.05), down-regulated fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC) and sterol regulatory element binding protein 1c (SREBP-1c) mRNA expressions in the liver (P < 0.05), enhanced silent information regulator1 (SIRT1) mRNA expression in the longissimus dorsi (P < 0.05), and up-regulated free fatty acids receptor 2 (FFAR2) and PYY mRNA expressions in the colon (P < 0.05). Propionate administration also decreased serum TG, TC, and LDL-c concentrations (P < 0.05), increased serum GLP-1, PYY and leptin concentrations (P < 0.05), down-regulated glucose-6-phosphatase (G6PC) mRNA expression in the liver (P < 0.05), enhanced PPARγ coactivator-1α (PGC-1α) mRNA expression in the liver (P < 0.05), stimulated SIRT1 mRNA expression in the longissimus dorsi (P < 0.05), and up-regulated G6PC and glucagon mRNA expressions in the colon (P < 0.05). Butyrate administration down-regulated G6PC mRNA expression in the liver (P < 0.05), enhanced PGC-1α mRNA expression in the liver (P < 0.05), and increased lipase hormone-sensitive (LIPE) and carnitine palmitoyltransferase-1α (CPT-1α) mRNA expressions in the longissimus dorsi (P < 0.05). Overall, these results suggested that SCFAs could reduce lipogenesis, and enhance lipolysis in different tissues of pigs via regulating related hormones and genes, which would further illustrate the mechanisms underlying the beneficial effects of SCFAs on appetite and body weight control.