50 头21日龄断奶的胜利白猪随机分为5组，Ⅰ组（对照组）为基础日粮组；Ⅱ、Ⅲ、Ⅳ组分别为基础日粮+1%、2%、3%小肽营养素；Ⅴ组为基础日粮+2%SDPP。试验期28天。与对照组相比，断奶日粮中添加3%小肽营养素后，仔猪断奶至7周龄平均日增重提高33.91%（P<0.05），料重比下降8.4%（P<0.05），与添加2%SDPP的效果类似。添加小肽营养素后，仔猪十二指肠、空肠、回肠的绒毛长度增加、隐窝深度减小，这种趋势随着小肽营养素添加量的增加而提高。小肽营养素能刺激仔猪断奶后十二指肠食糜乳糖酶、淀粉酶、脂肪酶和胰蛋白酶的活性，以添加3%小肽营养素和2%SDPP效果较好。此外，小肽营养素可促进断奶仔猪免疫系统发育，增加血液中IgG浓度（P<0.05），降低腹泻率（P<0.05）。结果表明，小肽营养素可促进断奶仔猪生产性能及小肠发育，其作用随添加量的增大而提高，添加量以3%最好，并可代替2%SDPP。

The pancreas consists of two histologically distinct and functionally independent components, i.e., endocrine islets and exocrine acini. Cells in the endocrine islets produce hormones and regulate body metabolism via the blood circulation, while cells in the exocrine acini secrete digestive enzymes through the duct system into the duodenal lumen. The structure of the pancreas and its postnatal developmental changes in humans and laboratory rodents have been intensively reviewed in more recent publications (1-3). A similar review is lacking for the domestic animal species. This chapter focuses on morphological structure of the pancreas in pigs and its growth and structural changes during the postnatal period. Wherever possible, information derived directly from studies of pigs is used, or otherwise species origin of the data is defined. Comparisons with other domestic animal species are made when information is available.

To determine if milk-borne insulin-like growth factor I (IGFI) is absorbed in neonatal piglets, recombinant human IGF-I was iodinated and then administered via an oral-gastric tube to newborn and 3-day-old piglets together with fluorescent isothiocyanate dextran (FITC-D70s, a macromolecular marker for assessment of gut closure). Results showed that total radioactivity and trichloroacetic acid (TCA)-precipitable radioactivity rose significantly in the plasma of both newborn and 3-day-old piglets 1 hour after oral-gastric administration of 125I-IGF-I, although the magnitude of increase was greater in newborns than in 3-day-old piglets. In contrast, significant absorption of FITC-D70s was observed only in newborn piglets but not in 3-day-old piglets. Chromatographic analysis revealed that 125I-IGF-I represented up to 20% of total plasma radioactivity in the newborns and up to 10% in the 3-day-old piglets. The 125I-IGF-I found in the plasma was mostly bound to IGF-binding proteins. These results indicate that milkborne IGF-I can be absorbed in neonatal piglets and the absorption is independent of gut closure.

This study examined the effects of milk protein pre-hydrolyzation on the crypt cell proliferation and morphological alterations in the small intestine in neonatal piglets. The newborn unsuckled Erhualian piglets were bottle-fed for 3 days with cow milk formula or pre-hydrolyzed cow milk formula. When compared with newborn pigs, the height of the intestinal villi decreased by 30-45% in jejunal region inmilk-fed piglets, while no significant change was observed in the intestinal villus height in piglets fed pre-hydrolyzed milk. Microscopic examination showed an atrophy of the intestinal villi and accelerated proliferation of crypt cells in the milk-fed piglets, possibly due to a hypersensitive reaction of the intestine to dietary protein. The results indicate that the nature of dietary protein had a significant effect on the intestinal structure. This finding may have a significant implication in infant care and animal feeding.

本试验以离体犊牛小肠上皮细胞为试验对象，选择细胞增殖率和葡萄糖吸收率作为细胞生长发育与功能成熟的指标，研究了牛初乳的蛋白酶水解产物对细胞生长发育的影响。结果表明，初乳经胃蛋白酶水解处理90分钟后所产生的水解物对离体犊牛小肠上皮细胞有明显的促增殖作用（P<0.01），而初乳经胰蛋白酶处理则不表现促增殖活性。初乳酶解物对促进细胞吸收葡萄糖的作用随着酶解处理时间的延长逐渐增强，初乳经胰蛋白酶水解处理90分钟或经胃蛋白酶水解处理150分钟时的产物对细胞吸收葡萄糖的促进作用分别达到最强（P<0.01）。结果表明，初乳酶解物即小分子蛋白质（肽）具有刺激离体小肠上皮细胞增殖和功能发育的活性。