Infusion of short chain fatty acids in the ileum improves the carcass traits, meat quality and lipid metabolism of growing pigs.

Short chain fatty acids (SCFA) are the main products of indigestible carbohydrates undergoing bacterial fermentation in the hindgut, which are related to some physiological functions. This study was designed to investigate the effects of SCFA infusion by ileum on the carcass traits, meat quality and lipid metabolism of growing pigs. In a 28-day study, 24 growing barrows fitted with a T-cannula in distal ileum were divided into 4 treatments: 1) Control, 2) antibiotics (AB), 3) AB + 300 mL of SCFA1 solution (ABS1), 4) AB + 300 mL of SCFA2 solution (ABS2). The concentrations of acetate, propionate and butyrate in SCFA1 solution were respectively 61.84, 18.62 and 12.55 mmol/L, and in SCFA2 were respectively 40.08, 15.41 and 9.78 mmol/L. The results showed that the SCFA infusion increased the average daily feed intake and average daily gain of pigs (P < 0.05). Meanwhile, the SCFA treatments increased longissimus dorsi area (P < 0.05) and carcass weight (P = 0.058), decreased the drip loss of longissimus dorsi (P = 0.059), and reduced serum concentrations of triglyceride, total cholesterol and urea nitrogen (P < 0.05). Besides, the SCFA administration inhibited the mRNA expressions of fatty acid synthase (FAS) and acetyl-CoA carboxylase in longissimus dorsi (P < 0.05), the mRNA expression of FAS in the liver (P < 0.05), and the mRNA expression of hormone-sensitive lipase in abdominal fat (P < 0.05). Short chain fatty acid infusion also enhanced the mRNA expression of carnitine palmitoyltransferase-1α in the liver (P < 0.05), the mRNA expressions of peroxisome proliferator activated receptor gamma and lipoprotein lipase in abdominal fat (P < 0.05), and the mRNA expressions of free fatty acid receptor 2, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon (P < 0.05). These results suggested that SCFA administration in the ileum could improve the carcass traits and meat quality of growing pigs, which was possibly due to the fact that SCFA modulated lipid metabolism.

Sodium acetate, propionate, and butyrate reduce fat accumulation in mice via modulating appetite and relevant genes.

OBJECTIVES: Acetate, propionate, and butyrate, three of the most common short-chain fatty acids (SCFAs), can be produced when some non-digestible carbohydrates enter the large intestine and undergo bacterial fermentation. The aim of this study was to investigate the effects of these three SCFAs on appetite regulation and lipid metabolism and to determine the extent that appetite contributes to the beneficial influences of SCFAs. METHODS: In a 35-d study, 48 C57BL/6J male mice were randomly allocated to six groups: control; 5% sodium acetate; 5% sodium propionate; 5% sodium butyrate; pair fed 1; and pair fed 2. RESULTS: The study showed that dietary supplementation of sodium acetate reduced serum triacylglycerol, free fatty acids, glucose, and interleukin (IL)-6 levels (P < 0.05), increased serum glucagon-like peptide 1, and leptin levels (P < 0.05), downregulated the mRNA expressions of fatty acid synthase, peroxisome proliferator-activated receptor, and lipoprotein lipase (P < 0.05), and upregulated the mRNA expressions of fasting-induced adipose factor, nuclear respiratory factor 1, mitochondrial transcription factor A, tumor necrosis factor receptor superfamily member 9, cytochrome-C oxidase IV and free fatty acid receptor 2 (P < 0.05). Sodium propionate also reduced serum IL-1ß level (P < 0.05), increased serum peptide YY level (P < 0.05), downregulated the mRNA expressions of acetyl-coenzyme A carboxylase and sterol regulatory element-binding protein 1c (P < 0.05), and upregulated the mRNA expression of transmembrane protein 26 (P < 0.05). Additionally, sodium butyrate decreased average daily feed intake (P < 0.05) downregulated the mRNA expression of myosin heavy-chain (MyHc) Ⅱb (P < 0.05), and upregulated the mRNA expressions of lipase hormone-sensitive, MyHC Ⅱa and carnitine palmitoyltransferase-1α (P < 0.05). Moreover, the metabolic benefits of SCFAs were partly attributed to the reduction of feed intake. CONCLUSION: Taken together, SCFAs could reduce appetite and fat accumulation via modulating relevant genes and hormones, which might further illustrate the potential mechanisms that underlay the effects of SCFAs on lipid homeostasis and control of body weight.

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.