Digestion in Teleost Fishes (INTRODUCTION)

Literature about digestive functions in teleost fishes is extensive in some areas, almost nil in others. The material to be presented here is not a comprehensive review of that literature because there are two recent reviews (Harder, 1975; Kapoor et al., 1975), which have extensive bibliographies on both the anatomy and physiology of teleost digestive systems. Readers desiring additional information should consult both reviews because they tend to be complementary, with Harder emphasizing anatomy of European fishes while Kapoor and co-authors emphasize digestion in North American and Asian fishes.
The general organization of this chapter begins with the anatomy of the gut, proceeding from anterior to posterior. Then the route is retraced to discuss the organ physiology of the digestive tract. A third pass through the tract discusses details of the enzymes. Then the typical methods used for studying digestion are described as a basis for the reader to make detailed comparisons among different methodologies and specific results or to perform his own experiments. Finally, some anatomical and functional comparisons are made for four species of fish with distinctly different feeding habits: carp (plant-oriented omnivore), catfish (animal-oriented omnivore), milkfish (specialized microplanktivore), and rainbow trout (carnivore). These comparisons are best made when accompanied by dissections of specimens of each species, although drawings are provided for readers having no access to the fish