Short chain fatty acids (SFCA) are synthesized by the colonic microflora primarily from non-absorbed carbohydrate; there is also some limited production from non-absorbed protein. In contrast, SFCA are not normally present in the diet. During the past 15 years SFCA have attracted considerable interest in human nutrition, physiology and pathophysiology as a result of the realization that SFCA represent an important mechanism for carbohydrate and calorie conservation and may play a role in various types of colitides and possibly in colonic neoplasia. In addition, SFCA, produced in large amounts by ruminants and other herbivores, have long been the province of veterinary physiologists. This book is based upon the presentations at the 73rd Falk Symposium held in Strasbourg, France, September 8--10, 1993, which brought together researchers and clinicians from five continents. It provides an excellent statement of the present state-of-the-art knowledge of SFCA.

Studies on the colon not only serve medical interest or clinical purposes, but are also a highly interesting subject of comparative physiology, from which we can learn much about the basic principles in physiology. Presented here are examples of research on colonic ion transport of each vertebrate group, including the classical models of epithelia, rat and rabbit, and also on the special and unique features in fish, amphibians, reptiles, birds, and selected mammals such as the guinea pig. Physiology and pathophysiology of ion transport in the human large intestine are as well covered as the use of colonic cell cultures as model systems for crypt cell properties.