Instituto de Neuroetología, Universidad Veracruzana, Av. Dr. Luis Castelazo s/n Col. Industrial Animas, Xalapa, Veracruz, C.P. 91160, Mexico.
J Comp Physiol B. 2013 Dec;183(8):1089-100. doi: 10.1007/s00360-013-0769-9. Epub 2013 Jun 7.
Mantled howler monkeys (Alouatta palliata) occupy a wide variety of tropical habitats and are the most folivorous of New World primates. However, their diet may include fruits, buds, petioles, and flowers, as well as leaves, suggesting they must cope with variations in the nutrient composition of their food. We studied the physiological basis of the dietary flexibility of these monkeys by comparing food choice, digestive performance and patterns of digesta flow in six adults, fed diets of either leaves or a mixture of fruit and leaves. Although monkeys ate similar amounts of the two diets, they ingested more digestible protein when offered the leaf diet, on which they lost body mass, but they ingested much more soluble sugars when offered fruit and leaves on which they gained mass. Digestibilities of dry matter, fat, energy and fibre did not differ between diets, but those of crude protein, soluble sugars and minerals were higher on the fruit-leaf diet. Mean retention times in the gut of solute (Co-EDTA) and particulate markers (Cr-mordanted cell walls) did not differ between diets, but on both diets the monkeys retained the particulate marker (mean retention time ca 55 h) for longer than they did the solute marker (MRT ca 50 h). A lack of selective retention of solutes and small particles in the gastro-intestinal tract of howler monkeys probably restricts them to mixed diets but their digestive strategy is sufficiently flexible to allow them to feed on a diet of leaves when fruit is unavailable.
丛冠吼猴（Alouatta palliata）栖息于多种热带生境，是新世界灵长类动物中最食叶的物种。然而，它们的食物可能包括水果、花蕾、叶柄和花，以及叶子，这表明它们必须应对食物中营养成分的变化。我们通过比较 6 只成年猴子在食用叶子或水果和叶子混合物这两种不同饮食时的食物选择、消化性能和食糜流动模式，研究了这些猴子饮食灵活性的生理基础。尽管猴子食用这两种饮食的量相似，但当提供叶子饮食时，它们摄入了更多可消化的蛋白质，导致体重下降，但当提供水果和叶子时，它们摄入了更多的可溶性糖，导致体重增加。干物质、脂肪、能量和纤维的消化率在两种饮食之间没有差异，但粗蛋白、可溶性糖和矿物质的消化率在水果-叶子饮食中更高。溶质（Co-EDTA）和颗粒标记物（Cr-鞣合细胞壁）在肠道中的平均保留时间在两种饮食之间没有差异，但在两种饮食中，猴子保留颗粒标记物（平均保留时间约 55 小时）的时间长于保留溶质标记物（MRT 约 50 小时）。吼猴胃肠道中溶质和小颗粒的缺乏选择性保留可能限制它们食用混合饮食，但它们的消化策略足够灵活，可以在没有水果时食用叶子饮食。
