Influences of the artificial variation of pancreatic juice returned to the duodenum on nutrient digestion in the small intestine of ruminant

研究反刍动物胰腺外分泌与小肠营养物质消化的关系。将导管植入胆总管和胆管，并安装十二指肠、皱胃和回肠套管。在实验1中，向饲喂饲料的绵羊输注收集体积的0至300%的胰液。类似地，在实验2中，对于淀粉（100 g/d）和酪蛋白（50 g/d）的真胃输注物，人工改变返回率。结果如下。1.胰液分泌量随返流率的增加而减少，但蛋白质日分泌量无明显变化。2.果汁回流率的增加使消化酶的浓度呈二次曲线上升，尽管酶的每日分泌几乎是恒定的。3.脂肪酶和核酸酶的人工变异不影响脂质和RNA的消化。4.蛋白质消化在25%的返回率时达到平台。5.回归率（X%）与淀粉消化率（Y g/d）的关系可用Y = 0.61X + 59.1（R^2=0.96，P<0.001）表示。6.当绵羊摄入1.8倍维持水平的豆类干草时，α -淀粉酶的日分泌量比绵羊摄入维持水平的干草时增加2.5倍。总之，尽管分泌量随饲料而变化，但分泌的α -淀粉酶可能会限制小肠消化超过5.8 g/d/代谢体型的淀粉。

The main objective was to elucidate the relationships between the pancreatic exocrine secretion and the nutrient digestion in the small intestine of ruminant. Seep were implanted the catheters to the common and bile ducts, and fitted with the duodenum, abomasal, and ileal cannulas. In experiment 1, the sheep fed a diet were infused the pancreatic juice of 0 to 300% of the collected volume. Similarly, in the experiment 2 for abomasal infusates of starch (100 g/d) and casein (50 g/d), the return rate was artificially varied. The results were as follows. 1. The volume of secreted pancreatic juice decreased with increasing the return rate, but the daily protein secretion did not change. 2. The increased return rate of the juice quadratically raised the concentration of digestive enzymes, although the daily secretion of the enzymes was nearly constant. 3. The artificial variation of lipase and nuclease did not affect the digestion of lipids and RNA. 4. Protein digestion reached a plateau at 25% of the return rate. 5. The relationships between the return rate (X%) and starch digestion (Y g/d) could be expressed as Y = 0.61X + 59.1 (R^2=0.96, P<0.001). 6. The daily secretion of α -amylase when sheep ingested legume hay at 1.8 x the maintenance was increased by 2.5 fold than when sheep ingested grass hay at the maintenance level. In conclusion, the small intestinal digestion of starch over 5.8 g/d per metabolic body size may be limited by the secreted α -amylases in spite of the secretion variable with feed.