The effect of dietary amylose/amylopectin ratio on serum and hepatic lipid content and its molecular mechanisms in growing-finishing pigs.
This study was conducted to investigate the effects of dietary amylose/amylopectin ratio (DAR) on serum and hepatic lipid content, luminal short-chain fatty acid (SCFA) concentrations, and the expression of host genes involved in fat and glucose metabolism in liver and mucosa in growing-finishing pigs. Forty-eight Duroc × Landrace × Large White pigs (49.8 ± 2.8 kg) were randomly allocated to low amylose/amylopectin ratio (LR) and high amylose/amylopectin ratio (HR) groups, each group consisting of six replicates (pen) with four pigs per pen. The DAR was 12/88 for LR and 30/70 for HR. Experiment lasted for 67 days. Results showed that, compared with HR group, ingestion of LR significantly increased the liver total lipid and cholesterol concentration (p < .05) and decreased the serum LDL-C concentration (p < .05). The concentration of propionate, butyrate and total SCFAs in caecum digesta was significantly lower in LR group than in HR group (p < .05). We observed a significant increase in glucose transporter 2 (GLUT2), sodium-dependent glucose transporter 1 (SGLT1) gene expression in LR-fed pigs in the jejunum mucosa (p < .01). A decrease in Na+-coupled monocarboxylate transporter (SMCT1) and free fatty acid receptor 3 (FFAR3) expression was found in the ileum mucosa with LR group (p < .05). Ingestion of LR diet significantly decreased the hexokinase (p < .01) and tend to decrease the pyruvate kinase (p = .050) activities in the liver. Meanwhile, the present results indicated that ingestion of LR diet significantly increased the transcription of gluconeogenesis and lipogenic genes such as forkhead box O1 (FOXO1), fatty acid synthetase3 (FAS3) (p < .05). These findings demonstrated that high amylopectin has harmful effects on hepatic lipid deposit through the modulation of the liver Foxo1 signalling and should be avoided from one's diet.