The effect of early feeding on growth and small intestinal development in the posthatch poult.

Poults with early access to feed in the hatchery or turkey house grew more than those reared under standard commercial practice. During 48 h posthatch, fed poults utilized yolk and exogenous feed to increase BW by 11 g. The small intestine increased from 3.8% of BW at hatch to 8.9% after 48 h. In contrast, BW in feed-deprived poults decreased by 10 g, whereas the small intestine increased slightly in weight and composed 4.5% of BW after 48 h. The number of cells per villus and the villus surface area increased dramatically posthatch in the duodenum but more slowly in the jejunum and ileum. Enterocyte width changed little, but length increased more than twofold in the duodenum and by approximately 50% in the jejunum and ileum by 6 d posthatch. Lack of access to feed depressed the rate of growth of villi and enterocyte length in all intestinal segments until 6 d posthatch. All intestinal epithelial cells were proliferating at hatch, which changed rapidly within 48 h posthatch, with proliferating cells becoming located mainly in the intestinal crypts where about half of the cells were proliferating. In feed-deprived poults, the decrease in the proportion of proliferating cells in the crypt was greater than that of fed poults; after refeeding, an increase in the rate of proliferation was observed in feed-deprived poults. Plasma concentrations of Na, glucose, triglycerides, and phospholipids were not affected by feed deprivation; however, nonesterified fatty acid concentrations were enhanced in feed-deprived poults, indicating a greater use of fatty acids for energy. Plasma triiodothyronine (T3) concentrations, which may mediate some of the intestinal effects of feed deprivation, were depressed in poults without access to feed.