Effect of dietary chitosan oligosaccharide levels and molecular weight with deacetylation degree characteristics on peptide transporter 1 gene expression in weaning pig’s small intestine

The present study aimed to assess the expression response of peptide transporter1 (PepT1) mRNA (SLC15A1) in weaning pig’s small intestine to the effect of dietary chitosan oligosaccharide (COS) supplement level, molecular weight (MW) and deacetylation degree (DD) characteristics. On days 28 and 56 of the experiments, small intestine samples obtained from our previous two experiments on weaned pigs were used to study the PepT1 mRNA expression. In experiment 1, pigs received either a basal diet or a basal diet supplemented with 75, 150, or 225 mg/kg COS. In experiment 2, pigs received either a basal diet or a basal diet supplemented with 150 mg/kg of one of the following COS differing in MW and DD: 8kDa~90%DD, 65kDa~80%DD, or 65kDa~90%DD. Relative expression of porcine PepT1 mRNA in duodenal, jejunal, and ileal mucosa was determined by real-time quantitative PCR. On day 56 of the experiment, pigs supplemented with not only COS levels but COS characteristics as well altered PepT1 gene expression in weaning pigs’ small intestine, which increased and decreased the expression of PepT1 mRNA in the jejunum and the duodenum (P < 0.05, respectively) when compared to the control pigs. Supplementing different levels and characteristics with a 28-day trial term of COS did not show any effect on the PepT1 mRNA expression. These data suggest that the regulation of PepT1 mRNA expression at the jejunum and the duodenum of weaning pigs depends on COS’ level, characteristics, and long-term diet supplementation.