. 2017 Mar;95(3):1170–1178. doi: 10.2527/jas.2016.0961

Table 3.

Effects of porcine epidemic diarrhea virus (PEDV) dose, pelleting temperature, and conditioning retention time on morphologic and immunohistochemistry (IHC) evaluation of the small intestine from pigs, Exp. 1¹

		Morphology²
Item		Villus height, μm	Crypt depth, μm	Villus height-to-crypt depth ratio	IHC³
Unprocessed virus-free feed		463.4^abcd	112.5	4.2^abcde	0^b
Low-dose inoculated feed⁴		414.3^de	91.0	4.6^abcd	0.3^b
68.3°C⁵	45 s⁶	481.6^abcd	101.3	4.8^abc	0^b
	90 s	489.3^abcd	108.1	4.6^abcd	0^b
	180 s	504.4^abc	115.6	4.4^abcd	0^b
79.4°C	45 s	508.6^ab	108.9	4.7^abcd	0^b
	90 s	476.4^abdc	103.6	4.6^abcd	0^b
	180 s	460.6^abcde	93.1	4.9^ab	0^b
90.6°C	45 s	443.2^abcde	97.8	4.6^abcd	0^b
	90 s	514.5^a	103.3	5.0^a	0^b
	180 s	441.8^abcde	103.6	4.3^abcde	0^b
High-dose inoculated feed⁷		309.3^f	112.6	3.1^f	1.7^a
68.3°C	45 s	423.1^cde	105.3	4.0^abcdef	0^b
	90 s	429.4^bcde	118.3	3.7^def	0^b
	180 s	389.2^ef	100.0	4.0^bcdef	0^b
79.4°C	45 s	432.8^abcde	117.3	3.7^cdef	0^b
	90 s	390.6^ef	102.5	3.7^cdef	0^b
	180 s	448.7^abcde	104.5	4.3^abcd	0^b
90.6°C	45 s	383.1^ef	119.5	3.2^ef	0^b
	90 s	446.4^abcde	102.8	4.4^abcd	0^b
	180 s	408.9^de	105.7	3.9^bcdef	0^b
	SEM	29	10.2	0.4	0.2

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

¹An initial tissue culture containing a low dose or high dose of PEDV was used to inoculate batches of feed. Three feed samples per batch were collected and diluted in PBS. The supernatant from each sample was then collected for pig bioassay. The supernatant was administered 1 time via oral gavage on d 0 to each of 3 pigs per treatment (10 mL per pig). Therefore, each value represents the mean of 3 pigs per treatment necropsied at 7 d after infection. Pigs were initially 10 d old and 73.6 kg BW.

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.

⁴For low-dose feed, PEDV (1 · 10³ tissue culture infectious dose [TCID]₅₀ (the concentration used to see cytopathic effect in 50% of the cells)/mL) was diluted into feed to provide a dose of 1 · 10² TCID₅₀/g of feed.

⁵Temperature of feed exiting the conditioner.

⁶Retention time: the time feed was inside the conditioner.

⁷For high-dose feed, PEDV (1 · 10⁵ TCID₅₀/mL) was diluted into feed to provide a dose of 1 · 10⁴ TCID₅₀/g of feed.