2. Material and methods
2.1. Strains
The probiotic preparation used in the current study was manufactured in our laboratory and contained 5.50 109 cfu/g live bacteria of L. brevis ZLB004. L. brevis ZLB004 was isolated from the gastrointestinal mucosa of healthy weaned piglets in our laboratory and identified by the China Center of Industrial Culture Collection (Beijing, China). Previous study has shown that the strain