Makkink C A, Berntsen P J, op den Kamp B M, Kemp B, Verstegen M W
Department of Animal Nutrition, Agricultural University, Wageningen, The Netherlands.
J Anim Sci. 1994 Nov;72(11):2843-50. doi: 10.2527/1994.72112843x.
Seventy pigs were weaned at 25 d of age and fed diets based on either skim-milk powder (SMP) or soybean protein concentrate (SOY). At 0, 3, 6, and 10 d after weaning, pigs were anesthetized, their pancreases were removed, and digesta were collected from different sections of the digestive tract. The ratio between trichloroacetic acid (TCA)-precipitable protein and total (crude) protein (pp:cp) in gastric digesta was higher with SOY feed than with SMP feed. In the jejunum, no difference was found; hence, the degree of protein breakdown in jejunal chyme did not differ between protein sources. Trypsin activities in jejunal chyme and in pancreatic tissue increased (P < .01) after weaning. Chymotrypsin activity in pancreatic tissue tended to decrease after weaning and did not reach "weaning levels" for at least 10 d. Pancreatic trypsin developed more rapidly than chymotrypsin after weaning. Chymotrypsin activities in jejunal digesta were higher (P < .05) for the pigs fed SMP than for those fed SOY. Protease activities in the jejunum at d 6 after weaning were clearly affected (P < .05) by feed intake after weaning. The ratio between trypsin and chymotrypsin activity in jejunal chyme was higher (P < .05) for SOY-fed pigs than for SMP-fed pigs. It was concluded that the stomach plays an important role in the digestion of milk protein and that the development of pancreatic proteases after weaning (synthesis, secretion, breakdown) depends on feed intake and on dietary protein source.
70头仔猪于25日龄断奶，分别饲喂以脱脂奶粉（SMP）或大豆浓缩蛋白（SOY）为基础的日粮。在断奶后0、3、6和10天，将仔猪麻醉，取出胰腺，并从消化道不同部位收集消化物。与SMP日粮相比，SOY日粮组胃消化物中三氯乙酸（TCA）可沉淀蛋白与总（粗）蛋白之比（pp:cp）更高。在空肠中未发现差异；因此，不同蛋白质来源的空肠食糜中蛋白质分解程度无差异。断奶后，空肠食糜和胰腺组织中的胰蛋白酶活性增加（P < 0.01）。胰腺组织中的糜蛋白酶活性在断奶后呈下降趋势，至少10天未达到“断奶水平”。断奶后胰腺胰蛋白酶的发育比糜蛋白酶更快。饲喂SMP的仔猪空肠消化物中的糜蛋白酶活性高于饲喂SOY的仔猪（P < 0.05）。断奶后第6天，空肠中的蛋白酶活性明显受断奶后采食量的影响（P < 0.05）。饲喂SOY的仔猪空肠食糜中胰蛋白酶与糜蛋白酶活性之比高于饲喂SMP的仔猪（P < 0.05）。研究得出结论，胃在乳蛋白消化中起重要作用，断奶后胰腺蛋白酶的发育（合成、分泌、分解）取决于采食量和日粮蛋白质来源。
