Ontogenetic development of intestinal digestive functions in White Pekin ducks

The ontogenetic development of intestinal digestive functions for avian spe cies other than the domesticated chicken are not well documented. Therefore , this study was conducted to resolve the developmental patterns of some in testinal digestive functions in White Pekin ducks. The ducks were killed an d their intestines harvested when they were 1, 3, 5 and 7 wk old. Several s mall intestinal tissue characteristics, sucrase and alkaline phosphatase (A LP) activities of homogenates from the small intestine mucosa were measured , and the small intestinal L-threonine uptake capacities were estimated wit h brush border membrane vesicles prepared from the corresponding age groups . Between 1 wk (0.37 +/- 0.04 kg) and 7 wk (3.79 +/- 0.06), posthatch ducks exhibited relative body growth rates of 352, 77 and 28% from 1 to 3, 3 to 5 and 5 to 7 wk, respectively. Allometric changes in small intestine weight indicated that the small intestine grew in direct proportion to the duck's metabolic body weight. Total homogenate sucrase activity per unit body wei ght did not differ (P > 0.05) among the age groups studied. Total homogenat e ALP activity per body weight was lower at 3 wk than at 1 wk (P > 0.05) bu t did not differ (P > 0.05) among 3, 5 and 7 wk-old ducks. The development pattern of L-threonine uptake capacities normalized to body weights paralle led the course of relative body growth rates.