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ARS Home » Midwest Area » Lexington, Kentucky » Forage-animal Production Research » Research » Publications at this Location » Publication #257179

Title: The Small Intestinal Epithelia of Beef Steers Differentially Express Sugar Transporter Messenger Ribonucleic Acid in Response to Abomasal Versus Ruminal Infusion of Starch Hydrolysate

Author
item LIAO, S - University Of Kentucky
item HARMON, D - University Of Kentucky
item VANZANT, K - University Of Kentucky
item MCLEOD, K - University Of Kentucky
item BOLING, J - University Of Kentucky
item MATTHEWS, J - University Of Kentucky

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/27/2009
Publication Date: 1/1/2010
Citation: Liao, S.F., Harmon, D.L., Vanzant, K.R., Mcleod, K.R., Boling, J.A., Matthews, J.C. 2010. The Small Intestinal Epithelia of Beef Steers Differentially Express Sugar Transporter Messenger Ribonucleic Acid in Response to Abomasal Versus Ruminal Infusion of Starch Hydrolysate. Journal of Animal Science. 88:306-314. DOI.10.2527jas.2009-1992.

Interpretive Summary: In mammals, the absorption of mono¬saccharides from small intestinal lumen involves at least 3 sugar transporters (SugT): sodium-dependent glucose transporter 1 (SGLT1; gene SLC5A1) transports glucose and galactose, whereas glucose transporter (GLUT) 5 (GLUT5; gene SLC2A5) transports fructose, across the apical membrane of enterocytes. In contrast, GLUT2 (gene SLC2A2) transports all of these sugars across basolateral and apical membranes. To compare the dis¬tribution patterns and sensitivity with nutritional regu¬lation of these 3 SugT mRNA in beef cattle small intes¬tinal tissue, 18 ruminally and abomasally catheterized Angus steers (BW 260 kg) were assigned to water (control), ruminal cornstarch (partially hydrolyzed by a-amylase; SH), or abomasal SH infusion treatments (n = 6) and fed an alfalfa-cube-based diet at 1.3 x NE. requirement. The SH infusions amounted to 20% of ME intake. After 14- or 16-d of infusion, steers were killed; duodenal, jejunal, and ileal epithelia harvested; and total RNA extracted. The relative amount of SugT mRNA in epithelia was determined using real-time re¬verse transcription-FOR quantification methods. Basal expression of GLUT2 and SGLT1 mRNA was greater (P < 0.09) by jejunal than by duodenal or ileal epi¬thelia, whereas basal content of GLUT5 mRNA was greater (P < 0.02) by jejunal and duodenal than by ileal epithelia. The content of GLUT5 mRNA in small intestinal epithelia was not affected (P > 0.16) by ei¬ther SH infusion treatment. In contrast, GLUT2 and SGLT1 mRNA content in the ileal epithelium was in¬creased (P < 0.05) by 6.5- and 1.3-fold, respectively, after abomasal SH infusion. Duodenal SGLT1 mRNA content also was increased (P = 0.07) by 64% after ruminal SH infusion. These results demonstrate that the ileum of beef cattle small intestine adapts to an in¬creased luminal supply of glucose by increasing SGLT1 and GLUT2 mRNA content, whereas increased ruminal SH supply results in duodenal upregulation of SGLT1 mRNA content. These adaptive responses of GLUT2 and SGLT1 mRNA to abomasal or ruminal SH infusion suggest that beef cattle can adapt to increase their car¬bohydrate assimilation through small intestinal epithe¬lia, assuming that altered SugT mRNA contents reflect the altered transport functional capacities.

Technical Abstract: In mammals, the absorption of mono¬saccharides from small intestinal lumen involves at least 3 sugar transporters (SugT): sodium-dependent glucose transporter 1 (SGLT1; gene SLC5A1) transports glucose and galactose, whereas glucose transporter (GLUT) 5 (GLUT5; gene SLC2A5) transports fructose, across the apical membrane of enterocytes. In contrast, GLUT2 (gene SLC2A2) transports all of these sugars across basolateral and apical membranes. To compare the dis¬tribution patterns and sensitivity with nutritional regu¬lation of these 3 SugT mRNA in beef cattle small intes¬tinal tissue, 18 ruminally and abomasally catheterized Angus steers (BW 260 kg) were assigned to water (control), ruminal cornstarch (partially hydrolyzed by a-amylase; SH), or abomasal SH infusion treatments (n = 6) and fed an alfalfa-cube-based diet at 1.3 x NE. requirement. The SH infusions amounted to 20% of ME intake. After 14- or 16-d of infusion, steers were killed; duodenal, jejunal, and ileal epithelia harvested; and total RNA extracted. The relative amount of SugT mRNA in epithelia was determined using real-time re¬verse transcription-FOR quantification methods. Basal expression of GLUT2 and SGLT1 mRNA was greater (P < 0.09) by jejunal than by duodenal or ileal epi¬thelia, whereas basal content of GLUT5 mRNA was greater (P < 0.02) by jejunal and duodenal than by ileal epithelia. The content of GLUT5 mRNA in small intestinal epithelia was not affected (P > 0.16) by ei¬ther SH infusion treatment. In contrast, GLUT2 and SGLT1 mRNA content in the ileal epithelium was in¬creased (P < 0.05) by 6.5- and 1.3-fold, respectively, after abomasal SH infusion. Duodenal SGLT1 mRNA content also was increased (P = 0.07) by 64% after ruminal SH infusion. These results demonstrate that the ileum of beef cattle small intestine adapts to an in¬creased luminal supply of glucose by increasing SGLT1 and GLUT2 mRNA content, whereas increased ruminal SH supply results in duodenal upregulation of SGLT1 mRNA content. These adaptive responses of GLUT2 and SGLT1 mRNA to abomasal or ruminal SH infusion suggest that beef cattle can adapt to increase their car¬bohydrate assimilation through small intestinal epithe¬lia, assuming that altered SugT mRNA contents reflect the altered transport functional capacities.