Argenzio R A, Southworth M
Am J Physiol. 1975 Feb;228(2):454-60. doi: 10.1152/ajplegacy.1975.228.2.454.
The relationship between diet, pH, and microbial digestion of carbohydrate was examined in 24 pigs fed either a conventional or a low-protein, high-cellulose experimental diet and sacrificed 2, 4, 8, or 12 h after a meal. In animals fed the control diet contents of the cranial half of the stomach demonstrated marked, cyclic fluctuations in pH and high concentrations of organic acids. Contents of the caudal (glandular) half were lower in both pH and organic acid concentration. Despite concentrations of volatile fatty acids (VFAs) as high as 250 meq/liter in the large intestine, the pH remained relatively neutral. The VFA levels remained relatively constant throughout the length of the colon. The VFA transport across isolated gastric and large intestinal mucosa also was examined. All four types of gastric mucosa absorbed and transported VFA at substantial rates. Mucosa of pig cecum and colon transported VFA at much greater rates than gastric mucosa and greater rates than previously determined in equine large intestinal mucosa or even bovine rumen epithelium. Comparison with results of earlier studies in the pony suggested that the higher concentration of VFA in the large intestinal contents of pigs was due to the more rapid rate of digesta passage rather than to less efficient absorption of fatty acids.
对24头猪进行研究，观察饮食、pH值与碳水化合物微生物消化之间的关系。这些猪分别喂食传统饲料或低蛋白、高纤维素的实验饲料，并在进食后2、4、8或12小时宰杀。喂食对照饲料的动物，胃颅侧半部内容物的pH值呈现明显的周期性波动，且含有高浓度的有机酸。胃尾侧（腺）半部的pH值和有机酸浓度则较低。尽管大肠中挥发性脂肪酸（VFA）的浓度高达250毫当量/升，但pH值仍保持相对中性。整个结肠长度内VFA水平相对恒定。还研究了VFA跨分离的胃和大肠黏膜的转运情况。所有四种类型的胃黏膜都以相当的速率吸收和转运VFA。猪盲肠和结肠的黏膜转运VFA的速率比胃黏膜快得多，也比先前在马大肠黏膜甚至牛瘤胃上皮中测定的速率快。与之前对小马的研究结果相比，猪大肠内容物中较高的VFA浓度是由于食糜通过速度更快，而非脂肪酸吸收效率较低。
