Effect of delayed access to feed on villus height, crypt depth, and the villus height/crypt depth ratio. Villus height (VH) and crypt depth (CD) were measured and VH/CD was calculated for formalin-fixed, paraffin embedded tissue sections stained by in situ hybridization for olfactomedin 4 (Olfm4) mRNA and counterstained with hematoxylin. Ten to 15 random villi and crypts were measured for each of the 6 replicate samples. Groups included control with no feed delay (ND), 24 h feed delay (DAF24), and 36 h feed delay (DAF36). A t-test was used to analyze ND and DAF24 at 24 h. Significant differences (P < 0.05) are indicated by an asterisk. A 2-way ANOVA and Tukey's HSD test were used for analysis of ND, DAF24, and DAF36 from 36 h to 168 h. Significant differences (P < 0.05) are indicated by different letters.