Effect of intestinal blood flow on absorptive site blood flow and lysine absorption as examined in situ in Holstein calves.
Total blood flow from an intestinal segment (TBF) was altered to determine effects on blood flow at the absorptive site (ASBF) and lysine absorption. Venous blood flow was restricted using a peristaltic pump to 20, 35, 50, 65, and 80% of the initial unrestricted rate. Lysine absorption and ASBF were determined from recovery of 14C and 3H in blood from intestinally perfused [14C]L-lysine and 3H2O, respectively. Fluid flux in the intestinal lumen was estimated from the difference in polyethylene glycol concentrations in luminal infusate and effluent. Restriction of TBF proportionally reduced ASBF, which composed 3 to 6% of TBF. Lysine absorption was reduced linearly during reduction of TBF. Fluid absorption varied among calves but was independent of TBF. Differences between loss of radioactive marker from perfusate and recovery in blood suggested a loss of 3H2O from the intestinal segment that was independent of TBF. Changes in blood flow to the small intestine may affect nutrient absorption in ruminants.
Kohn
R A
RA
Department of Animal and Nutritional Sciences, University of New Hampshire, Durham 03824.
Schwab
C G
CG
Bozak
C K
CK
Hylton
W E
WE
D000818:Animals; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D005260:Female; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000098:blood supply*; D007421:Intestine, Small / Q000098:blood supply*; D008239:Lysine / Q000493:pharmacokinetics*; D008297:Male; D012039:Regional Blood Flow; D014680:Veins / Q000502:physiology
D008239:Lysine