A high-amylopectin diet caused hepatic steatosis associated with more lipogenic enzymes and increased serum insulin concentration.

Starch is the major energy source for monogastric mammals and humans. The present study was conducted to evaluate the liver metabolic responses of weaned pigs fed with different dietary starches. A total of sixteen weaned pigs were fed with two experimental diets containing either cassava starch (CS, 80 % amylopectin and 20 % amylose) or maize starch (70 % amylopectin and 30 % amylose). The present results showed that the growth performance was not affected by different dietary starches (P>0·05). However, ingestion of CS not only increased the lipid content in liver tissues, but also elevated the concentrations of serum cholesterol and insulin (P < 0·05). The metabolic responses induced by CS were associated with more lipogenic enzymes such as fatty acid synthase and 3-hydroxy-3-methyl-glutaryl-CoA reductase in liver (P < 0·05). Real-time PCR quantification for lipid metabolic genes indicated that ingestion of CS not only up-regulated the expression of these lipogenic genes, but also decreased the expression of lipolytic genes. These results suggested that the metabolic responses of weaned pigs fed with different dietary starches may vary widely depending on their composition, and ingestion of starches that are high in amylopectin may produce a stronger insulinaemic response and lead to an up-regulation of lipogenesis in the liver.