Vitamin D had an anti-infection effect and benefited to the intestinal health. 
Autophagy signaling pathway was regulated by vitamin D3 to inhibit the infection 
of human immunodeficiency virus type-1. Rotavirus (RV) was a major cause of the 
severe diarrheal disease in young children and young animals. Although evidence 
suggested that vitamin D3 attenuates the negative effects of RV infection via 
the retinoic acid-inducible gene I signaling pathway, little is known of its 
antiviral effect whether through the regulation of autophagy. The present study 
was performed to investigate whether vitamin D3 alleviates RV infection in pig 
and porcine small intestinal epithelial cell line (IPEC-J2) models via 
regulating the autophagy signaling pathway. RV administration increased the 
Beclin 1 mRNA abundance in porcine jejunum and ileum. 5000 IU/kg dietary vitamin 
D3 supplementation greatly up-regulated LC3-II/LC3-I ratios and PR-39 mRNA 
expression under the condition of RV challenged. The viability of IPEC-J2 was 
significantly inhibited by RV infection. Incubation with 25-hydroxyvitamin D3 
significantly decreased the concentrations of RV antigen and non-structural 
protein 4 (NSP4), and up-regulated the mRNA expression of Beclin 1 and PR-39 in 
the RV-infected IPEC-J2 cells. And then, based on the 25-hydroxyvitamin D3 
treatment and RV infection, LC3-II mRNA expression in cells was inhibited by an 
autophagy inhibitor 3-methyladenine (3-MA). Bafilomycin A1 (Baf A1, a class of 
inhibitors of membrane ATPases, inhibits maturation of autophagic vacuoles) 
treatment numerically enhanced the LC3-II mRNA abundance, but had no effect on 
NSP4 concentration. Furthermore, 25-hydroxyvitamin D3 decreased the p62 mRNA 
expression and increased porcine cathelicidins (PMAP23, PG1-5 and PR-39) mRNA 
expression in the RV-infected cells. Taken together, these results indicated 
that vitamin D3 attenuates RV infection through regulating autophagic maturation 
and porcine cathelicidin genes expression.