The small intestinal lactase expression is reduced in the piglet with bowel inflammation

Abstract

The effects of dextran sodium sulfate (DSS) induced bowel inflammation on jejunal lactase activity and expression were examined in 12 Yorkshire piglets at 5 d of age with body weight (BW) of 3 kg were fitted with ig catheters and divided into control (CON) and treatment groups (DSS). Both groups of pigs were infused with an equal volume of either saline or 1.25 g DSS/kg BW.d in saline, respectively, for 10 d. Lactase protein abundance was carried out by Western blotting and the mRNA abundance was measured by quantitative real time RT‐PCR. â‐actin was used as the housekeeping gene. DSS treatment decreased (P<0.05) jejunal lactase maximal specific activity (Vmax, µmol/mg protein.min) in the tissue homogenate (CON, 87.66±0.14 vs. DSS, 24.05±0.30) by 73%, cytosol (CON, 45.83±0.68 vs. DSS, 12.58±1.15) by 73% and apical membrane (CON, 422.67±3.29 vs. DSS, 92.22±2.42) by 78%, respectively, with orresponding decreases (P<0.05) of 26, 48, and 32% in the jejunal lactase protein abundance. The relative abundance of the jejunal lactase mRNA was lower by 25% in the DSS piglets. Bowel inflammation reduced the lactase activity in the small intestine by lowering its expression at the transcriptional and translational levels. Supported by AFMNet, OMAFRA and NSERC of Canada.