Abstract: 【Objective】 The objective of this trial was to investigate the protective effect of quercetin on the intestinal tract of Porcine epidemic diarrhea virus(PEDV)-infected piglets by studying the effect of quercetin on the intestinal morphology, intestinal antioxidant function and relative expression of genes related to jejunal lipid metabolism in pigs infected with PEDV.【Method】 Eighteen healthy 7-day-old weaned piglets were randomly divided into 3 groups:, control group, PEDV group, and quercetin+PEDV group, with 6 replicates per group and one pig per replicate.The trial lasted for 8 days.On the 0-7th days of the trial, the piglets in the quercetin+PEDV group were orally administered with quercetin at the dosage of 10 mg/kg BW, the rest of the groups were orally administered with equal volume of artificial milk.On the 5th day of the trial, piglets in the PEDV group and PEDV+quercetin group were administered with PEDV (10^4.5TCID₅₀), and piglets in control group were given the same volume of PBS solution.On 8th day of the trail, all piglets were sacrificed, duodenum, jejunum, ileum and colon samples were taken for testing and small intestinal tissue was sliced.【Result】 Compared with the control group, in the PEDV group, the villous height and the ratio of villi height to crypt depth of the jejun and ileum were reduced (P<0.01), the activities of glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) were decreased in jejunum, ileum, and colon (P<0.05), the viabilities of catalase (CAT) was decreased in duodenum, jejunum, ileum and colon (P<0.05), and the contents of malondialdehyde (MDA) was increased in ileum and colon (P<0.05), the relative expression of apolipoprotein A1(APOA1), apolipoprotein B(APOB), apolipoprotein C2 (APOC2), fatty acid binding protein 2 (FABP2), acyl-coenzyme A synthase long-chain family member 3 (ACSL-3) and fatty acid synthase (FASN) genes were downregulated in jejunum (P<0.01).Compared with the PEDV group, in the PEDV+quercetin group, the villus height and villus height to crypt depth ratio were increased in the jejunum and ileum of piglets (P<0.01), the activities of GSH-Px and T-SOD were increased in the jejunum, ileum and colon (P<0.05), the viabilities of CAT was increased in duodenum, jejunum and colon (P<0.05), the contents of MDA was decreased in the ileum and colon (P<0.05), the relative expression of APOB, FABP2, and FASN genes were upregulated in the jejunum(P<0.01).【Conclusion】 Dietary quercetin supplementation could alleviates the intestinal injury of piglets caused by PEDV infection, the intestinal antioxidant capacity and jejunal lipid metabolism of piglets were improved.

Key words: quercetin; piglets; Porcine epidemic diarrhea virus(PEDV); intestinal morphology; antioxidant function; lipid metabolism