Table 5.

Morphologic and immunohistochemistry (IHC) evaluation of the small intestine from pigs that were challenged with porcine epidemic diarrhea virus (PEDV)–inoculated feed processed at increasing temperatures, Exp. 2¹

	Morphology2
Item	Villus height, μm	Crypt depth, μm	Villus height-to- crypt depth ratio	IHC3
Processed feed
Negative	365.1 ± 34.9ab	190.7 ± 17.3ab	1.9 ± 0.2abc	0
37.8°C	299.9 ± 20.1b	192.4 ± 10.0ab	1.6 ± 0.1ac	0.7
46.1°C	394.2 ± 20.1a	230. ± 10.0a	1.7 ± 0.1bc	0.6
54.4°C	393.9 ± 20.1a	200.0 ± 10.0ab	2.0 ± 0.1ab	0
62.8°C	405.1 ± 20.1a	206.8 ± 10.0ab	2.0 ± 0.1ab	0
71.1°C	420.9 ± 20.1a	184.1 ± 10.0b	2.3 ± 0.1a	0

^a–cMeans within a column with different superscripts differ (P < 0.05).

¹500 mL of tissue culture containing 4.5 · 10⁶ tissue culture infectious dose [TCID]₅₀ (the concentration used to see cytopathic effect in 50% of the cells)/mL of PEDV was inoculated into a 4.5 kg batch of feed and then added to 45 kg of PEDV-negative feed to form the positive treatment. One feed sample per temperature per replicate · 3 replicates was collected, divided into 3 aliquots, and diluted in PBS to form supernatants. Therefore, each feed supernatant value per treatment represents the mean of 3 replicates · 3 repetitions.

²Intestinal cross-sections were fixed in formalin and stained with hematoxylin and eosin for evaluation.

³Three sections of ileum were evaluated and averaged into 1 categorical value per pig. Categorical values were assigned for each pig (0 = no signal, 1 = mild, 2 = moderate, 3 = abundant, and 4 = diffuse) and reported as the mean from 3 pigs per treatment and, thus, the mean of 9 values.