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 s
mall intestine increased from 3.8% of BW at hatch to 8.9% after 48 h. In co
ntrast, BW in feed-deprived poults decreased by 10 g, whereas the small int
estine 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 dramatica
lly posthatch in the duodenum but more slowly in the jejunum and ileum. Ent
erocyte width changed little, but length increased more than twofold in the
duodenum and by approximately 50% in the jejunum and ileum by 6 d posthatc
h. Lack of access to feed depressed the rate of growth of villi and enteroc
yte 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 ma
inly in the intestinal crypts where about half of the cells were proliferat
ing. In feed-deprived poults, the decrease in the proportion of proliferati
ng 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 pou
lts.
Plasma concentrations of Na, glucose, triglycerides, and phospholipids were
not affected by feed deprivation; however, nonesterified fatty acid concen
trations 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 depre
ssed in poults without access to feed.