Morphological and functional changes of the small intestine in growth-stunted broilers

The development of morphology and function of the small intestine was related to body weight changes in commercially bred broilers with free access to food. At days 16 and 36 of age the broilers were divided into four groups (12 broilers in each) with normal growth and with retarded growth and morphometric parameters (villous height and crypt depth) and the activity of brush-border-bound alkaline phosphatase (AP) in the duodenum and jejunum were determined. The results revealed significant villous atrophy and crypt hypertrophy (p < 0.001) as well as marked decrease of densitometrically determined AP activity(p < 0.001) in broilers with retarded growth as compared to normal growing control chickens during both periods under study. Our results indicate that these morphological and functional changes in the small intestine (despite free access to food) may result in impairing its absorptive capacity for normal body weight development. They may also be the underlying cause for the persistence of a decreased body weight in broilers in which the stunting syndrome had developed.