Histopathological evaluation and morphometric analysis. (A) Representative micrographs (magnification, × 40) demonstrating variable degrees of villous atrophy at duodenum, jejunum and ileum from piglets inoculated with different recombinant viruses or post-inoculation (PI)-medium. Tissues were collected at 3 d post-inoculation and processed routinely for slide preparation for hematoxylin and eosin staining. (B–D) Villous height to crypt depth (VH:CD) ratios in the duodenum (B), jejunum (C), and ileum (D) for piglets at 3 DPI after inoculation with different recombinant viruses or PI-medium. Ten villi of each intestinal segment were examined in each piglet and each symbol represented the mean value of VH:CD ratio in an individual piglet. Statistical differences (p < 0.05) among virus-treated groups were compared using the Kruskal–Wallis test. Different letters indicate statistical significance (p < 0.05). Mock: PI-medium; iP5: iPEDVPT-P5; 96S: iPEDVPT-P5-96S; 5S, iPEDVPT-P96-5S; iP96, iPEDVPT-P96.