title: Net portal nutrient flux in steers fed diets containing wheat and sorghum grain alone or in combination.
abstract: Three Holstein steers (280 to 353 kg during the experiment) fitted with hepatic portal, mesenteric venous and arterial catheters were fed 90% concentrate diets containing wheat, dry-rolled sorghum grain or a 50:50 mixture of the two to determine the effect of dietary grain source on net portal nutrient flux. Steers were allotted to a six-period crossover design with treatments lasting 2 wk. Diets were fed in 12 portions daily to equal intakes across treatments. Simultaneous arterial and portal blood samples were taken four times per day for the final 3 d of the treatment period. Portal blood flow was determined by continuous infusion of p-aminohippuric acid, and net portal nutrient absorption was calculated by venous-arterial difference X blood flow. Dry matter intakes averaged 6.2, 6.1 and 6.0 kg/d for wheat, 50:50 mixture and sorghum grain, respectively. Net fluxes of glucose, lactate, NH3, urea-N or alpha-amino-N were not affected by diet. Net fluxes increased for propionate and decreased for 2-methylbutyrate as the level of wheat increased (P less than .10). Overall, acetate and propionate net fluxes contributed 57% to 66% of the absorbed energy on these diets, with glucose contributing a maximum of 4% on the sorghum grain diet.
authors: Dept. of Anim. Sci. and Ind., Kansas State University, Manhattan 66506.
authors: K L
authors: KL
authors: Gross
authors: D L
authors: DL
authors: Harmon
authors: T B
authors: TB
authors: Avery
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004063:Digestion; D002523:Edible Grain; D008297:Male; D011168:Portal System / Q000502:physiology*; D012039:Regional Blood Flow; D014908:Triticum