Influence of starch and casein administered postruminally on small intestinal sodium-glucose cotransport activity and expression

Abstract

Twenty-four Holstein steer calves (88 ± 3kg) with abomasal catheters were randomly assigned within blocks to one of four treatments. The treatments consisted of four abomasal infusions: water (control), 4 g/kg BW.d-1 of partially hydrolyzed starch (SH), 0.6 g/kg BW.d-1 of casein, and a mix of SH + casein. The small intestine was collected and five equidistan, 1m sites were identified (duodenum, jejunum 1, jejunum 2 jejunum 3 and ileum). Maltase specific activity in mucosal homogenate and brush border membrane vesicles, SGLT1 protein abundance, and sodium-dependent glucose uptake in brush border membrane vesicles did not differ between the calves receiving different abomasal infusion treatments. However, maltase specific activity in homogenates and brush border membrane vesicles increased four-fold from the duodenum to the first jejunal site before declining steadily towards the ileum (p=0.0145 p=0.0020, respectively). The SGLT1 abundance differed by intestinal sampling site (p=0.0162). These data indicated that cattle might not have the ability to alter the capacity for glucose uptake when challenged with different substrates and that the regulation of SGLT1 expression could differ between bovine and other species

The small intestinal epithelia of beef steers differentially express sugar transporter messenger ribonucleic acid in response to abomasal versus ruminal infusion of starch hydrolysate1,2

“…A primary objective of the present study was to determine the relative tissue expression of GLUT5, GLUT2, and SGLT1 mRNA among small intestinal epithelia of growing, forage-fed beef steers. Our findings that the duodenal, jejuna, and ileal epithelia of growing Angus steers express all 3 of these mRNA using real-time RT-PCR analysis is consistent with previous observations that the bovine small intestinal epithelium expresses these mRNA, as previously observed for Holstein cows (GLUT5, GLUT2, and SGLT1; Zhao et al, 1993Zhao et al, , 1998 and steer calves (SGLT1; Guimaraes et al, 2007) using Northern blot analysis. In addition, our findings extend the previous observations by revealing a differential pattern of expression for GLUT5, GLUT2, and SGLT1 mRNA among duodenal, jejunal, and ileal epithelia of Angus steers.…”

Total nutrient digestibility and small intestine starch digestion in Nellore and Angus young bulls fed a whole shelled corn diet

“…Rodriguez et al () and Guimaraes et al () observed greater maltase activity in the jejunum compared to duodenum and ileum, which agrees with results found in this study, where maltase activity was greater in the jejunum than in the duodenum, regardless of breed or diet. In addition, Kreikemeier, Harmon, Brandt, Nagaraja, and Cochran () commented that diet has little or no effect on maltase and isomaltase activity in the small intestine.…”

“…Swanson, Matthews, Woods, and Harmon () evaluated the effect of abomasal infusion of partially hydrolysed starch and reported that starch tended to decrease expression of the gene that encodes pancreatic α‐amylase and also decreased the enzyme activity. In addition, differences in maltase activity may also be a factor that influences starch utilization (Bauer, Harmon, Bohnert, Branco, & Huntington, ; Guimaraes et al, ; Liao et al, ; Rodriguez et al, ).…”

“…Swanson, Matthews, Woods, and Harmon (2002) evaluated the effect of abomasal infusion of partially hydrolysed starch and reported that starch tended to decrease expression of the gene that encodes pancreatic α-amylase and also decreased the enzyme activity. In addition, differences in maltase activity may also be a factor that influences starch utilization (Bauer, Harmon, Bohnert, Branco, & Huntington, 2001;Guimaraes et al, 2007;Liao et al, 2010;Rodriguez et al, 2004). Therefore, since diet is an important factor influencing small intestinal starch digestion, it is necessary to evaluate how the use of whole shelled corn (WSC) without forage affects starch digestion in finishing cattle.…”

Carbohydrate quantitative digestion and absorption in ruminants: from feed starch and fibre to nutrients available for tissues

“…The two main routes for transfer of glucose from the lumen to the bloodstream are active transport and paracellular diffusion with absorption of water Noziè re, Ortigues-Marty, Loncke and Sauvant (Huntington, 1997). Glucose transporters have been characterized in the small intestine of ruminants (Shirazi-Beechey et al, 1995;Zhao et al, 1998;Guimaraes et al, 2007). SGLT1 consists of Na 1 -dependent glucose transporter located in the brush border membrane of enterocytes, and driven by an electrochemical gradient maintained by Na…”