Krehbiel C R, Ferrell C L, Freetly H C
Roman L. Hruska U.S. Meat Animal Research Center, ARS, USDA, Clay Center, NE 68933, USA.
J Anim Sci. 1998 Sep;76(9):2464-73. doi: 10.2527/1998.7692464x.
Our objective was to determine the effects of frequency of soybean meal (SBM) supplementation on forage intake and net portal-drained viscera (PDV) and hepatic flux of nutrients in ewes that consume low-quality forage. Six Polled Dorset ewes (BW+/-SD = 82+/-9 kg) fitted with hepatic venous, hepatic portal, abdominal aortic, and mesenteric venous catheters were used in a replicated 3 x 3 Latin square design. Ewes consumed bromegrass hay (7.5% CP; DM basis). Treatments were no supplement (control), SBM fed once every 24 h, or SBM fed once every 72 h. In the SBM treatments, SBM was fed to provide 80 g/d of CP. Blood flow and net flux measurements were made on the 3rd d of each period so that ewes supplemented every 72 h were sampled the day of, the day after, and 2 d after supplementation. Arterial concentrations of alpha-amino N (AAN) and ammonia N were lower (P < .01) when SBM was fed, whereas arterial concentrations of urea N and oxygen were higher (P < .01). Feeding SBM increased net PDV release of AAN and ammonia N, net PDV removal of urea N, and oxygen consumption. A SBM x sampling day interaction (P < .05) occurred and resulted in greater net PDV absorption of AAN and ammonia N on the day after SBM supplementation when ewes were fed SBM on a 72-h interval. Net hepatic removal of AAN, ammonia N, and oxygen, and net hepatic release of urea N were greater (P < .01) with feeding SBM. The results indicate that the interval of SBM supplementation may affect the pattern of absorption without affecting the net absorption of nutrients.
我们的目标是确定补充豆粕（SBM）的频率对采食低质量牧草的母羊采食量、门静脉引流内脏（PDV）以及肝脏养分通量的影响。选用6只无角陶赛特母羊（体重±标准差=82±9千克），安装肝静脉、肝门静脉、腹主动脉和肠系膜静脉导管，采用重复的3×3拉丁方设计。母羊采食溴草干草（粗蛋白含量7.5%；干物质基础）。处理方式为不补充（对照）、每24小时喂一次SBM或每72小时喂一次SBM。在SBM处理组中，饲喂SBM以提供80克/天的粗蛋白。在每个时期的第3天进行血流和净通量测量，以便每72小时补充一次SBM的母羊在补充当天、补充后一天和补充后2天进行采样。饲喂SBM时，动脉血中α-氨基氮（AAN）和氨氮浓度较低（P<.01），而动脉血中尿素氮和氧浓度较高（P<.01）。饲喂SBM增加了PDV对AAN和氨氮的净释放、PDV对尿素氮的净清除以及氧消耗。出现了SBM×采样日交互作用（P<.05），导致每72小时饲喂一次SBM的母羊在补充SBM后一天PDV对AAN和氨氮的净吸收量更大。饲喂SBM时，肝脏对AAN、氨氮和氧的净清除以及肝脏对尿素氮的净释放量更大（P<.01）。结果表明，SBM补充间隔可能会影响吸收模式，但不影响养分的净吸收。
