Gross K L, Harmon D L, Avery T B
Kansas State University, Manhattan 66506.
J Anim Sci. 1990 Jan;68(1):214-21. doi: 10.2527/1990.681214x.
An experiment was performed using lambs fitted with chronic indwelling catheters in appropriate blood vessels for portal-drained visceral (PDV) flux measurements. The objective of the experiment was to evaluate PDV nutrient flux in alfalfa-fed and intragastrically infused lambs and to evaluate the effects of amount of energy and N infused on PDV nutrient metabolism. Lambs were fed alfalfa or infused with 1.64 and 10.9; 1.82 and 12.3; or 2.37 and 15.0 Mcal GE and g N/d, respectively. Arterial concentrations and PDV fluxes of glucose, L-lactate, acetate and portal blood flow were not different (P greater than .10) between alfalfa-fed and infused lambs. Net flux of alpha-amino N, ammonia N and branched-chain VFA were lower (P less than .05) and net flux of propionate, butyrate and total VFA were higher for intragastric infusion vs alfalfa. No consistent differences in PDV fluxes were noted among the three levels of energy and N infused, although the energy and N levels tested were near maintenance requirements. Nitrogen retention increased as level of energy and N infusion increased. Approximately 47, 70 and 22% of ruminally infused acetate, propionate and butyrate, respectively, were found on a net basis in portal blood as VFA. Measurements of net nutrient utilization by the PDV that eliminate the influence of ruminal fermentation are possible. How the changes in PDV tissues due to intragastric infusion influence these estimates is unknown.
使用在适当血管中植入慢性留置导管的羔羊进行实验，以测量门静脉引流内脏（PDV）通量。实验目的是评估苜蓿喂养和胃内输注羔羊的PDV营养通量，并评估能量和氮输注量对PDV营养代谢的影响。羔羊分别饲喂苜蓿或分别输注1.64和10.9；1.82和12.3；或2.37和15.0兆卡代谢能和克氮/天。苜蓿喂养和输注羔羊之间的葡萄糖、L-乳酸、乙酸盐的动脉浓度和PDV通量以及门静脉血流量没有差异（P大于0.10）。与苜蓿相比，胃内输注时α-氨基氮、氨氮和支链挥发性脂肪酸的净通量较低（P小于0.05），而丙酸盐、丁酸盐和总挥发性脂肪酸的净通量较高。尽管测试的能量和氮水平接近维持需要量，但在三个能量和氮输注水平之间未观察到PDV通量的一致差异。氮保留量随着能量和氮输注水平的增加而增加。在门静脉血中，分别约有47%、70%和22%的瘤胃输注乙酸盐、丙酸盐和丁酸盐以挥发性脂肪酸的形式净存在。可以测量消除瘤胃发酵影响的PDV净营养利用率。胃内输注引起的PDV组织变化如何影响这些估计尚不清楚。
