Effects of different amylose to amylopectin ratios on serum indices related to glucose metabolism and glucose transporter expression in fattening lambs

Abstract

The objective of this study was to determine the effects of different amylose to amylopectin ratios on serum indices related to glucose metabolism and the mRNA expression of glucose transporters in the small intestinal mucosa of fattening lambs. A total of 36 male 7-day-old lambs of similar weight were randomly assigned to four treatments of iso-starch diets containing tapioca starch, maize starch, wheat starch, and pea starch, with the determined ratio for amylose to amylopectin of 0.12, 0.23, 0.24, and 0.48, respectively. Serum glucose, creatinine, insulin, and glucagon were reduced with the advancing age of lambs. The results indicated that feeding lambs with a pea starch diet (high amylose to amylopectin ratio) had increased serum cholesterol (P=0.047), lactate dehydrogenase (LDH) (P=0.010), and growth hormone (GH) (P=0.037). Pea starch did not influence the serum glucose (P=0.160), but significantly decreased the serum insulin (P=0.021). The pea starch diet significantly up-regulated the mRNA expression of glucose transporters, which may increase intestinal glucose uptake. By contrast, the consumption of tapioca starch resulted in the opposite effects, and significantly down-regulated the mRNA expression of glucose transporters. Collectively, these data suggest that starches with higher amylose to amylopectin ratios promote higher concentrations of plasma cholesterol, LDH and GH, and up regulate the gene expression profile of glucose transporters in fattening lambs.