Posthatch development of small intestinal function in the poult

The size, morphology, and mucosal enzyme activity of small intestines in poults were determined from hatch to 12 d of age. Mass and length of the small intestines increased at different rates in the duodenum, jejunum, and ileum and mass increased more than length. Intestinal weight increased more rapidly then other body organs, reaching a peak at about Day 6, and then decreased. Examination of the morphology of the small intestine showed that villus height and area increased several fold in the jejunum and duodenum and less in the ileum over the period examined. Enterocyte size increased slightly in the initial posthatch period. Activities of mucosal enzymes also increased at different rates in the different intestinal segments and sucrase, maltase, and y-glutamyltransferase activities per gram of intestine peaked at 2 to 5 d posthatch before decreasing. Regional mucosal intestine activities exhibited a steady increase, which was highly correlated with BW and thus mucosal hydrolysis may be a determining step in digestion. Poult villus size and area were smaller and mucosal enzyme activity was lower than that found in broilers and this may explain the initial slower growth rate in poults.