2002 Volume 39 Issue 4 Pages 229-242
The nutritional value of diets fed to chickens has traditionally been evaluated by growth performance and nutrient digestibility. In addition to nutritional physiological studies, research on intestinal structure is also important, as the intestine is the digestive and absorptive organ. In macroscopic anatomy, the guts of poultry differ relative to body weight (Thomas, 1984). Fowls produced for the meat purpose, such as broiler (BR) chickens and Peking ducks, have intestines of greater length, weight and area than those of egg-laying fowl, such as the White Leghorn (WL) chickens and wild ducks (Yamauchi et al., 1990b). Poultry innards are affected by diet (Moss, 1974; Miller, 1975; Langhout et al., 1999; Yasar and Forbes, 1999). Feeding habits rather than individual body weight difference account for gross anatomical differences in the intestine (Yamauchi and Zhou, 1988). These reports suggest that the nutritional value of diets may produce microscopic alterations in the intestinal mucosa. Although the general histological features of the intestine are well known, the relationship between the structure and function of the intestine has not been established. The reason that no information on the histological alterations related with intestinal function has been reported is related to the fact that studies on the interaction between them are limited to morphological observations, which is due to lack of an immunocytochemical procedure using antibodies. Confirmation that intestinal histological alterations are indeed induced by intestinal functions is currently impossible and can be established only by comparison of morphological characteristics with intestinal functions.
Consequently, over the past decade, there has been much interest in establishing how intestinal histological alterations are related to intestinal function. The intent of this interest is to assess the enteral nutrient absorption of feed ingredients histologically. This review highlights recent studies on histological alterations related to intestinal function, and adds new information to the assessment of the nutritional values of various kinds of chicken feed.