amylopectin and Fatty-Liver

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.

Topics: Amylopectin; Animals; Base Sequence; Cholesterol; Diet; DNA Primers; Fatty Liver; Insulin; Real-Time Polymerase Chain Reaction; Swine

Starch is one of the major dietary energy sources for mammals. However, the nutritional value of starch largely depends on its amylose and amylopectin ratio. In this study, the overall metabolic and transcriptomic responses of weaned pigs fed with different dietary starches were assessed. Sixteen weaned pigs were randomly allotted to two experimental diets containing either of pure cassava starch (CS) or maize starch (MS) as the sole energy source (the amylose-amylopectin ratio were 0.25 and 0.43, respectively). Results indicated that the body weight gain was not affected by different dietary starches. However, a moderate fatty liver was observed in CS-fed group. Long-term ingestion of CS not only increased the total liver fat content, but significantly elevated the liver triglyceride and cholesterol content (P<0.05). In addition, the serum insulin and cholesterol concentrations were both elevated in CS-fed group (P<0.05). Microarray analysis led to the identification of 648 genes differentially expressed in liver (P<0.05), and a lot of them were involved in lipid and carbohydrate metabolism. Additionally, pathway analysis indicated that both the insulin and PPAR signaling pathways were acutely affected by dietary amylose-amylopectin ratio. Long-term ingestion of CS activated the transcription of lipogenic genes such as hmgr and fasn, but decreased the expression of lipolytic genes such as aox1, ppara and fbp. The microarray results correlated well with the measurements of several key enzymes involved in hepatic lipid metabolism. Our results suggested that both the metabolic and transcriptomic responses of weaned pigs were tightly regulated by dietary starch composition, and a high amylose ratio starch (i.e MS) may be more healthful for mammals as the long-term energy source by down-regulation of hepatic lipogenesis and steroidogenesis.

Topics: Amylopectin; Amylose; Animals; Cholesterol; Dietary Carbohydrates; Energy Metabolism; Fatty Liver; Gene Expression Profiling; Insulin; Liver; Manihot; Oligonucleotide Array Sequence Analysis; Peroxisome Proliferator-Activated Receptors; Random Allocation; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Swine; Triglycerides; Weaning; Zea mays