Swanson K C, Benson J A, Matthews J C, Harmon D L
Department of Animal Sciences, University of Kentucky, Lexington 40546-0215, USA.
J Anim Sci. 2004 Jun;82(6):1781-7. doi: 10.2527/2004.8261781x.
Eight Angus steers (290 +/- 8 kg), surgically prepared with pancreatic pouch-duodenal reentrant cannulas and abomasal infusion catheters were used in a replicated 4 x 4 Latin square experiment to investigate the effects of abomasal infusion of starch hydrolyzate (SH) and/or casein on pancreatic exocrine secretion and plasma concentration of hormones. Steers were fed a basal diet of alfalfa (1.2 x NEm) in 12 equal portions daily. Abomasal infusion treatments (6-L total volume infused per day) were water (control), SH [2.7 g/(kg BW x d)], casein [0.6 g/(kg BW x d)], and SH + casein. Periods were 3 d for adaptation and 8 d of full infusion. Pancreatic juice and jugular blood samples were collected over 30-min intervals for 6 h on d 11. Weight and pH of pancreatic samples were measured, and a 10% subsample was composited and frozen until analysis of total protein and pancreatic enzyme activities. The remaining sample was returned to the duodenum. Plasma was harvested and frozen until analyzed. Pancreatic juice (67 mL/h) and protein (1.8 g/h) secretion rates were not affected by nutrient infusion. There were SH x casein interactions for all pancreatic enzyme secretions (U/h; alpha-amylase, P < 0.03; trypsin, P < 0.08; and chymotrypsin, P < 0.03) and plasma insulin concentration (P < 0.10). Secretion of pancreatic enzymes was increased by SH (trypsin) and casein (alpha-amylase, trypsin, and chymotrypsin) but not when SH + casein were infused together. Glucose (P < 0.10) and cholecystokinin octapeptide concentrations (CCK-8; P < 0.05) were increased by SH, but glucagon was decreased (P < 0.10). Casein decreased (P < 0.10) plasma CCK-8 concentrations. These data indicate that positive effects of postruminal casein on enzyme secretion were inhibited by SH, emphasizing the complexity of the regulatory mechanisms involved in dietary adaptation of pancreatic exocrine secretion. Changes in hormone concentration may not relate directly to changes in enzyme secretion.
选用8头安格斯阉牛（体重290±8千克），通过手术安装胰腺袋-十二指肠折返插管和皱胃灌注导管，用于一项重复4×4拉丁方实验，以研究皱胃灌注淀粉水解产物（SH）和/或酪蛋白对胰腺外分泌及血浆激素浓度的影响。阉牛每日分12等份饲喂苜蓿基础日粮（1.2×维持能量需要量）。皱胃灌注处理（每天总灌注量6升）分别为水（对照）、SH [2.7克/（千克体重×天）]、酪蛋白[0.6克/（千克体重×天）]以及SH +酪蛋白。适应期为3天，全量灌注期为8天。在第11天，每隔30分钟采集一次胰液和颈静脉血样，共采集6小时。测定胰液样本的重量和pH值，取10%的子样本混合并冷冻，直至分析总蛋白和胰酶活性。其余样本返回十二指肠。采集血浆并冷冻，直至进行分析。胰液分泌率（67毫升/小时）和蛋白质分泌率（1.8克/小时）不受营养物质灌注的影响。所有胰酶分泌（单位/小时；α-淀粉酶，P<0.03；胰蛋白酶，P<0.08；糜蛋白酶，P<0.03）和血浆胰岛素浓度（P<0.10）存在SH×酪蛋白互作。SH（胰蛋白酶）和酪蛋白（α-淀粉酶、胰蛋白酶和糜蛋白酶）可增加胰酶分泌，但SH +酪蛋白一起灌注时则不然。SH可增加葡萄糖浓度（P<0.10）和胆囊收缩素八肽浓度（CCK-8；P<0.05），但降低胰高血糖素浓度（P<0.10）。酪蛋白可降低血浆CCK-8浓度（P<0.10）。这些数据表明，瘤胃后酪蛋白对酶分泌的积极作用受到SH的抑制，强调了胰腺外分泌饮食适应中涉及的调节机制的复杂性。激素浓度的变化可能与酶分泌的变化没有直接关系。
