Goetsch A L, Ferrell C L, Freetly H C
Department of Animal Sciences, University of Arkansas, Fayetteville 72701.
Br J Nutr. 1994 Nov;72(5):701-12. doi: 10.1079/bjn19940072.
Fifteen sheep (53 kg), with catheters in a hepatic vein, the portal vein and a mesenteric vein and artery, were offered a bromegrass (Bromus inermis) hay (104 g crude protein (CP), 700 g neutral-detergent fibre and 65 g acid-detergent lignin/kg dry matter (DM) ad lib. with different supplements to determine the effects on net flux of oxygen and nutrients across the portal-drained viscera (PDV) and liver. The sheep were unsupplemented (Control) or received 5 g DM/kg body weight (BW) of ground maize (M), 7 g DM/kg BW of soya-bean hulls (H) or 0.73 g DM/kg BW of a mix of feedstuffs high in rumenundegradable protein (P). Apparent digestible energy (DE) intakes were 5.3, 10.4, 10.6 and 6.7 (SE 0.74) MJ/d and apparent digestible CP intakes were 37, 50, 79 and 68 (SE 4.3) g/d for Control, M, H and P treatments respectively. Splanchnic tissue oxygen consumption rates were 0.23, 0.32, 0.30 and 0.27 (SE 0.054) mol/h, and oxidative metabolism accounted for 0.46, 0.31, 0.33 and 0.47 (SE 0.051) of DE intakes for Control, M, H and P treatments respectively. Supplements increased (P < 0.05) release of alpha-amino nitrogen (AAN) by the PDV (4.2, 17.5, 19.6 and 18.1 mmol/h for Control, M, H and P treatments respectively). Splanchnic net flux of AAN was not affected by supplement treatments. Hepatic release of urea-N was increased (P < 0.05) by supplement treatments (27, 40, 46 and 44 mmol/h for Control, M, H and P respectively); the P treatment increased (P < 0.05) and the H treatment tended (P = 0.10) to increase splanchnic release of urea-N (7, 10, 20 and 27 mmol/h for Control, M, H and P treatments respectively). Net flux of glucose across the PDV was -4.6, 1.4, -5.6 and -7.2 (SE 1.65) mmol/h for Control, M, H and P treatments respectively. Hepatic glucose released averaged 23 (SE 2.0) mmol/h and was not affected by treatment. Treatments M and H increased (P < 0.05) PDV release of propionate compared with the Control treatment (4.5, 15.5, 16.8 and 7.7 mmol/h for Control, M, H and P treatments respectively). Release of acetate by the PDV was 43, 97, 118 and 67 (SE 23.9) mmol/h for Control, M, H and P treatments respectively. In summary, different supplements of low-quality grass did not increase the efficiency of N metabolism by splanchnic tissues. Treatment P had little effect on net flux across splanchnic tissues of glucose, L-lactate, beta-hydroxybutyrate and volatile fatty acids (VFA).(ABSTRACT TRUNCATED AT 400 WORDS)
选取15只体重53千克的绵羊，其肝静脉、门静脉以及肠系膜静脉和动脉均已插入导管。给这些绵羊随意喂食无芒雀麦干草（每千克干物质含104克粗蛋白（CP）、700克中性洗涤纤维和65克酸性洗涤木质素），并添加不同的补充剂，以确定其对氧和营养物质通过门静脉引流内脏（PDV）和肝脏的净通量的影响。绵羊分为不补充组（对照组），或分别按每千克体重（BW）补充5克干物质的玉米粉（M组）、每千克BW补充7克干物质的大豆皮（H组）、每千克BW补充0.73克干物质的瘤胃不可降解蛋白含量高的混合饲料（P组）。对照组、M组、H组和P组的表观可消化能量（DE）摄入量分别为5.3、10.4、10.6和6.7（标准误0.74）兆焦/天，表观可消化CP摄入量分别为37、50、79和68（标准误4.3）克/天。内脏组织氧消耗率分别为0.23、0.32、0.30和0.27（标准误0.054）摩尔/小时，氧化代谢分别占对照组、M组、H组和P组DE摄入量的0.46、0.31、0.33和0.47（标准误0.051）。补充剂使PDV释放的α-氨基氮（AAN）增加（P<0.05）（对照组、M组、H组和P组分别为4.2、17.5、19.6和18.1毫摩尔/小时）。补充剂处理对AAN的内脏净通量无影响。补充剂处理使肝脏尿素氮的释放增加（P<0.05）（对照组、M组、H组和P组分别为27、40、46和44毫摩尔/小时）；P组使内脏尿素氮的释放增加（P<0.05），H组有增加趋势（P = 0.10）（对照组、M组、H组和P组分别为7、10、20和27毫摩尔/小时）。对照组、M组、H组和P组通过PDV的葡萄糖净通量分别为-4.6、1.4、-5.6和-7.2（标准误1.65）毫摩尔/小时。肝脏释放的葡萄糖平均为23（标准误2.0）毫摩尔/小时，不受处理影响。与对照组相比，M组和H组使PDV的丙酸释放增加（P<0.05）（对照组、M组、H组和P组分别为4.5、15.5、16.8和7.7毫摩尔/小时）。对照组、M组、H组和P组PDV的乙酸释放分别为43、97、118和67（标准误23.9）毫摩尔/小时。总之，低质量牧草的不同补充剂并未提高内脏组织氮代谢的效率。P组对葡萄糖、L-乳酸、β-羟基丁酸和挥发性脂肪酸（VFA）通过内脏组织的净通量影响较小。（摘要截选至400字）
