Seegraber F J, Morrill J L
J Dairy Sci. 1982 Oct;65(10):1962-70. doi: 10.3168/jds.S0022-0302(82)82445-4.
Neonatal calves were fed whole milk (control) or one of three milk replacers with one-third of the total protein supplied by casein, Promocaf (a commercial soy protein concentrate), or an experimental soy flour. Xylose absorption was studied at 3 and 8 wk after a 12-h fast. Urine was collected for 5 h, and jugular blood was sampled at 0, 2.5, and 5 h after administration of xylose. Urinary excretions of xylose at 8 wk were 3.4, 5.3, 7.8, and 21.3% of xylose administered, respectively, for calves fed Promocaf, soy flour, casein, and milk. Increases in plasma xylose 2.5 h after administration were 7.7, 21.3, 31.8, and 46.5 mg/dl. Calves were sacrificed at 12 or 14 wk and duodenal tissues sampled for scanning electron microscopy. Micrographs revealed normal intestinal morphology with long, round, tapering villi when milk was fed. Casein feeding produced shorter, broader villi than did feeding whole milk. Abnormalities included absence of villi and short, blunted, convoluted villi on mucosal surfaces of calves fed soy proteins. Reduced surface area for intestinal absorption probably resulted from villous atrophy in calves with abnormal mucosae. Impairment of absorptive ability appears to be associated with morphological changes in intestinal structure.
新生小牛分别喂食全脂牛奶（对照组）或三种代乳品之一，三种代乳品中酪蛋白、Promocaf（一种商业大豆浓缩蛋白）或一种实验性大豆粉提供的蛋白质占总蛋白的三分之一。在禁食12小时后，于3周和8周时研究木糖吸收情况。收集5小时的尿液，并在给予木糖后的0、2.5和5小时采集颈静脉血样。对于喂食Promocaf、大豆粉、酪蛋白和牛奶的小牛，8周时木糖的尿排泄量分别为给予木糖量的3.4%、5.3%、7.8%和21.3%。给予木糖2.5小时后血浆木糖的增加量分别为7.7、21.3、31.8和46.5毫克/分升。在12周或14周时宰杀小牛，并采集十二指肠组织进行扫描电子显微镜检查。显微照片显示，喂食牛奶时肠道形态正常，绒毛长、呈圆形且逐渐变细。与喂食全脂牛奶相比，喂食酪蛋白时产生的绒毛更短、更宽。异常情况包括喂食大豆蛋白的小牛黏膜表面无绒毛以及绒毛短、钝且卷曲。肠道吸收表面积的减少可能是由于黏膜异常的小牛出现绒毛萎缩所致。吸收能力的损害似乎与肠道结构的形态变化有关。
